Chronic functional mitral regurgitation(FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy(DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in...Chronic functional mitral regurgitation(FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy(DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle(LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy(CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.展开更多
The present study investigated the application of echocardiography to evaluation of cardiac dyssynchrony in patients with congestive heart failure（CHF）. A total of 348 consecutive CHF patients who were admitted for ...The present study investigated the application of echocardiography to evaluation of cardiac dyssynchrony in patients with congestive heart failure（CHF）. A total of 348 consecutive CHF patients who were admitted for cardiac resynchronization（CRT） and presented with low ejection fraction（EF） and wide QRS duration were enrolled in this study, along with 388 healthy individuals. Dyssynchrony was assessed based on filling time ratio（FT/RR）, left ventricular pre-ejection delay（PED）, interventricular mechanical delay（IVMD）, longitudinal opposing wall delay（LOWD） and radial septal to posterior wall delay（RSPWD）. Response to CRT was defined as a ≥15% increase in EF. The results showed that FT/RR was decreased while PED, IVMD, LOWD and RSPWD were increased in the CHF group compared with the control group（P〈0.01）. In the CHF group, FT/RR was negatively correlated with the QRS duration, LV end-diastolic diameter（LVESd）, LV end-diastolic volume（LVEDV） and LV end-systolic volume（LVESV）（P〈0.01）, but positively with the LVEF（P〈0.01）. Additionally, PED, IVMD, LOWD and RSPWD were positively correlated with the QRS duration, LVESd, LVEDV and LVESV（P〈0.01）, but negatively with the LVEF（P〈0.01）. The CHF group was divided into three subgroups according to the varying degrees of LVEF. FT/RR decreased successively from the LVEF-1 group to the LVEF-2 group to the LVEF-3 group, while the PED, IVMD, LOWD and RSPWD successively increased in the same order（P〈0.01）. The CHF group was divided into three subgroups according to the varying degrees of QRS duration, and FT/RR decreased successively in a sequence from the QRS-1 group to the QRS-2 group to the QRS-3 group, while the PED, IVMD, LOWD and RSPWD successively increased in the same order（P〈0.01）. Speckle tracking radial dyssynchrony ≥130 ms was predictive of an EF response in patients in QRS-1 group（78% sensitivity, 83% specificity）, those in QRS-2 group（83% sensitivity, 77% specificity） and in QRS-3 group（89% sensitivity, 79% specificity）. In conclusion, echocardiography is a convenient and sensitive method for evaluating cardiac dyssynchrony in patients with CHF.展开更多
Background Two-dimensional speckle tracking imaging （2D-STI） and real-time three-dimensional echocardiography （RT-3DE） have more advantages in evaluating left ventricular （LV） systolic dyssynchrony than traditio...Background Two-dimensional speckle tracking imaging （2D-STI） and real-time three-dimensional echocardiography （RT-3DE） have more advantages in evaluating left ventricular （LV） systolic dyssynchrony than traditional echocardiographic techniques. The study aimed to evaluate LV dyssynchrony parameters by both 2D-STI and RT-3DE, and the correlation between these two techniques. Methods A total of 43 chronic heart failure （CHF） patients and 27 healthy volunteers were enrolled. There were 23 dyssynchrony parameters selected to evaluate left ventricular systolic synchronization, involving 15 from 2D-STI and 8 from RT-3DE. Results Few of the dyssynchrony parametersshowednegative correlations with LV ejection fraction （LVEF） in the CHF group. The difference between time to peak-systolic radial strain of the anteroseptal and posterior segments at the level of papillary muscles [AS-P（RS）] from 2D-STI showed positive correlations with parts of the parameters from RT-3DE （P 〈 0.05）. Conclusions LV systolic dysfunction does not correlate with dyssynchrony. Moreover, there is a weak association between 2D-STI and RT-3DE in assessment of left ventricular dyssynchrony.展开更多
Objectives Left ventricular systolic dyssynchrony is the most important determinant of response to cardiac resynchronization therapy （CRT）, playing a vital role to predict improvement of systolic function or LV reve...Objectives Left ventricular systolic dyssynchrony is the most important determinant of response to cardiac resynchronization therapy （CRT）, playing a vital role to predict improvement of systolic function or LV reverse remodeling. CardioGRAF is a novel programmer based on the ECG gated single photon emission computed tomography （G-SPECT） imaging to detect LV systolic and diastolic dyssynchrony simultaneously. This study was to investigate the prevalence of systolic and diastolic left ventricular （LV） dyssynchrony in patients with heart failure. Methods We retrospectively studied 69 patients with heart disease, including 31 patients who had symptoms of heart failure （NYHA class Ⅱ-Ⅲ）, and 38 patients who had no symptoms of heart failure. （NYHA class Ⅰ）. G- SPECT data were analyzed by cardiaGRAF, and measurements included the time to end systole （TES）, the time to peak ejection （TPE）, the time to peak filling （TPF）, TES＋TPF and maximal difference （MD） of each parameters were obtained, using the 95th percentile of the control group as a cutoffof 150 ms for MD-TES, 139 ms for MD-TPE, 345 ms for MD-TPF and 315 ms for MD-TES＋TPF. Results The prevalence of LV systolic dyssynchrony was significantly higher in heart failure patients with reduced LV ejection fraction （LVEF）〈45% （72% for MD-TES; 64% for MD-TPE） compared with heart failure patients with preserved LVEF=45% （14% for both MD-TES and MD-TPE; P=0.002, P=0.005, respectively）; The prevalence of MD-TES〈150 ms was higher in NYHA class Ⅲ patients （64%） compared with NYHA class Ilpatients （27%, P=0.049）. However, the prevalence of the LV diastolic dyssynchrony were high but not difference between NYHA class III（47% for both MD-TPF and MD-TES＋TPF） and class Ⅲ（63% for MD-TPF; 69% for MD-TES＋TPF; P=NS） patients as well as between patients with preserved LVEF （43% for both MD-TPF and MD-TES＋TPF） and patients with reduced LVEF（64% for MD-TPF; 72% for MD-TES＋TPF; P=NS）. Conclusions The prevalence of LV systolic dyssynchrony was high in heart failure patients with reduced LVEF. Diastolic dyssynchrony was common in patients with heart failure. CardioGRAF maybe a useful method to detect LV dyssynchrony （J Gerlatr Cardio12009; 6：151-156）.展开更多
Background:Signifi cant left ventricular dysfunction may arise in right-sided accessory pathways with ventricular preexcitation in the absence of recurrent or incessant tachycardia.This has just been realized and not ...Background:Signifi cant left ventricular dysfunction may arise in right-sided accessory pathways with ventricular preexcitation in the absence of recurrent or incessant tachycardia.This has just been realized and not enough attention has been paid to it.Methods:In the last 7 years,we identifi ed 12 consecutive children with a diagnosis of ventricular preexcitation–induced dilated cardiomyopathy.This report describes the clinical and echocardiographic characteristics of the patients before and after ablation.Results:Dyssynchronous ventricular contraction was observed by M-mode echocardiography and two-dimensional strain analysis in all patients.The basal and middle segments of the interventricular septum became thin and moved similarly to an aneurysm,with typical bulging during the end of systole.The locations of the accessory pathways were the right-sided septum(n=5)and the free wall(n=7).Left ventricular synchrony was obtained shortly after ablation.The left ventricular function recovered to normal and the left ventricular end-diastolic diameter decreased gradually during follow-up.Conclusions:A causal relationship between ventricular preexcitation and the development of dilated cardiomyopathy is supported by the complete recovery of left ventricular function and reversed left ventricular remodeling after the loss of ventricular preexcitation.Preexcitation-related dyssynchrony was thought to be the crucial mechanism.Ventricular preexcitation–induced dilated cardiomyopathy is an indication for ablation with a good prognosis.展开更多
Cardiac resynchronization therapy (CRT) is an established therapy for selected heart failure (HF) patients to improve symptoms, ventricular function, and survival. Although increasingly used, left ventricular (LV) dys...Cardiac resynchronization therapy (CRT) is an established therapy for selected heart failure (HF) patients to improve symptoms, ventricular function, and survival. Although increasingly used, left ventricular (LV) dyssynchrony assessment by echocardiography has failed to show enough predictive value to assess patient response to CRT and the current guidelines do not recommend its routine use. Furthermore, a variety of echocardiographic techniques used for the purpose, including tissue Doppler imaging (TDI), real time three-dimensional echocardiography, M-mode, and various Doppler parameters, showed limited value and poor agreement between the studies and methods, greatly influenced by interobserver variability. Speckle tracking echocardiography (STE) is a more recent approach that uses strain imaging to assess LV dyssynchrony. This article discusses the speckle tracking for LV dyssynchrony and its current clinical applications.展开更多
Objective: Long-term right ventricular pacing has been associated with an increased risk of heart failure and cardiomyopathy. The pathophysiology of cardiomyopathy associated with right ventricular pacing remains uncl...Objective: Long-term right ventricular pacing has been associated with an increased risk of heart failure and cardiomyopathy. The pathophysiology of cardiomyopathy associated with right ventricular pacing remains unclear. We aim to evaluate the burden and short-term outcomes of ventricular dyssynchrony after immediate permanent pacemaker implantation. Materials and Methods: This prospective cohort study examined consecutive patients who had permanent pacemaker implantation at Vajira Hospital in 2019. Left ventricular systolic function, specifically left ventricular ejection fraction (LVEF) and echocardiographic ventricular dyssynchrony parameters were assessed. The endpoints included the prevalence of ventricular dyssynchrony, new-onset cardiomyopathy, heart failure, and death. The correlation between QRS complex duration, the burden of ventricular pacing, and echocardiographic ventricular dyssynchrony was measured. Results: Thirty-six consecutive patients underwent pacemaker implantation. The prevalence of mechanical ventricular dyssynchrony was 22.2% using the interventricular conduction delay method, 41.7% using LV pre-ejection period method, and 11.1% using the septal posterior wall motion abnormality method. Electrical ventricular dyssynchrony was 86.1% and new-onset cardiomyopathy was 17.1% after 3 months of permanent pacemaker implantation. The right ventricular pacing of more than 20% was significantly associated with cardiomyopathy (p < 0.022) and heart failure (log-rank, p = 0.049) within 3 months. But heart failure was not associated with mechanical ventricular dyssynchrony parameters (log-rank, p = 0.610;hazard ratio [HR], 1.53;95% confidence interval [CI], 0.29 - 7.96;p = 0.613 for IVMD and log-rank, p = 0.398;HR, 0.04;95% CI, 0.01 - 3316.7 for SPWMD). Conclusion: Mechanical and electrical ventricular dyssynchrony are common findings in right ventricular pacing. High-burden right ventricular pacing after 3 months of permanent pacemaker implantation is often associated with cardiomyopathy and heart failure, but mechanical and electrical ventricular dyssynchrony does not predict a short-term decline in left ventricular systolic function and heart failure.展开更多
Objectives To assess the prevalence of systolic dyssynchrony of the left ventricular （LV） walls in patients of heart failure（HF） with a normal QRS duration by Doppler tissue imaging （DTI）. Methods 20 patients of...Objectives To assess the prevalence of systolic dyssynchrony of the left ventricular （LV） walls in patients of heart failure（HF） with a normal QRS duration by Doppler tissue imaging （DTI）. Methods 20 patients of HF with a normal QRS duration and 20 healthy individuals were investigated with DTI to quantitatively analyze their pulsed-wave Doppler spectrum of basal and middle segments in six walls of left ventricle. The time between the onset of the QRS complex of the surface ECG and the onset of the systolic wave of pulsed-wave Doppler spectrum was measured （TS）. LV systolic synchronization was assessed by the maximal difference （MD） in time of TS, the standard deviation （SD） and the coefficient of variation （CV） of TS in the all 12 LV segments. Results When a TS-MD of TS〉 53.08 ms, a TS-SD of TS 〉18.08 ms and a TS-CV of TS 〉 0.91 （＋1.65 SD of normal controls） was used to define significant systolic dyssynchrony, the prevalence of systolic dyssynchrony was 55.0 %, 55.0 % and 55.0 %, respectively, in the HF patients group, significantly higher than those in the normal control and the locations of delayed contraction of these patients were different. Conclusions LV systolic dyssynchrony could be commonly demonstrated by DTI in HF patients with a normal QRS duration. This finding will support the view about the possibility that more HF patients could benefit from cardiac resynchronization therapy.展开更多
Background: Altered myocardial sympathetic innervation activity (AMSI) is known to be present in systolic heart failure patients (SHF) and recently SPECT imaging using I-123 mIBG heart to mediastinum (H/M) ratio <1...Background: Altered myocardial sympathetic innervation activity (AMSI) is known to be present in systolic heart failure patients (SHF) and recently SPECT imaging using I-123 mIBG heart to mediastinum (H/M) ratio <1.6 has been shown to predict MACE in the ADMIRE-HF trial. Left ventricular mechanical dyssynchrony (LVMD) is known to be present in a substantial number of SHF patients and has been studied mainly to guide CRT therapy. Recently gated SPECT has shown promise to provide an accurate assessment of LVMD. It remains unclear how the combination of AMSI and LVMD collectively affect clinical outcomes and other cardiovascular parameters. Objectives: The objectives are to examine the clinical characteristics and incremental prognostic value for MACE of LVMD determined by SPECT in SHF patients with or without abnormal cardiac MIBG uptake (H/M ratio < 1.6). Methods: Out of 30 SHF patients who participated from our institution in the ADMIRE-HF trial studying MIBG based AMSI, we included 22 patients with abnormal MIBG H/M ratio of <1.6. We performed gated SPECT LVMD analysis on these patients using the Emory Cardiac Toolbox. The 2 SPECT variables for LVMD assessed were histogram bandwidth and phase standard deviation both of which assess the extent of dispersion of LV activation during contraction as a marker of LVMD. Patients were followed up for a mean period of 6 years. The primary end point was mortality from any cause and secondary end point was heart failure admission or myocardial infarction or ICD shock. Results: 2 Groups were defined: Group A: n = 17 with H/M MIBG ratio < 1.6 and +LVMD and Group B, n = 5 H/M MIBG ratio −LVMD. Baseline characteristics, cardiac risk factors and medications were comparable between both groups. LVEF was lower and RBBB was less common in Group A. There was no statistical difference in achievement of primary or secondary end points in the two groups including death heart failure readmissions, ICD shocks or MI. Conclusions: In our pilot study, we did not find definitive value of adding SPECT based LVMD to abnormal cardiac MIBG imaging in SHF patients with regards to predicting outcomes. Although our sample size is too small to make any definitive conclusions, it is possible that LVMD works independently through different pathways in the progression of SHF and hence may not necessarily add incremental value to AMSI determination using MIBG.展开更多
Background:We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines.Methods:A total of eight dogs were includ...Background:We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines.Methods:A total of eight dogs were included in the experiment,four were tachypaced in right ventricle apex (RVAP) and 4 were paced in right atrium after the ablation of left bundle branch to achieve left bundle branch block (RAP+LBBB).Three weeks of follow-up were conducted to observe the changes in cardiac function and myocardial staining was performed at the end of the experiment.Results:Both experimental approaches successfully established heart failure with reduced ejection fraction models,with similar trends in declining cardiac function.The RAP+LBBB group exhibited a prolonged overall ventricular activation time, delayed left ventricular activation,and lesser impact on the right ventricle.The RVAP approach led to a reduction in overall right ventricular compliance and right ve ntricular enlargement.The RAP+LBBB group exhibited significant reductions in left heart compliance (LVGLS,%:RAP+LBBB-12.60±0.12 to-5.93±1.25;RVAP-13.28±0.62to-8.05±0.63, p=0.023;LASct,%:RAP+LBBB-15.75±6.85 to-1.50±1.00;RVAP-15.75±2.87 to-10.05±6.16,p=0.035).Histological examination revealed more pronounced fibrosis in the left ventricular wall and left atrium in the RAP+LBBBgroup while the RVAP group showed more prominent fibrosis in the right ventricular myocardium.Conclusion:Both approaches establish HFrEF models with comparable trends.The RVAP group shows impaired right ventricular function,while the RAP+LBBB group exhibits more severe decreased compliance and fibrosis in left ventricle.展开更多
Background Chronic heart failure （CHF） is life-threatening without timely or effective intervention. In this study, we investigated the association between QT dispersion corrected for heart rate （cQTd） and heart f...Background Chronic heart failure （CHF） is life-threatening without timely or effective intervention. In this study, we investigated the association between QT dispersion corrected for heart rate （cQTd） and heart function in patients with CHF. Methods From January 2013 to December 2015, we continuously enrolled 240 patients categorized as New York Heart Association functional class （NYHA） III-IV with a left ventricular ejection fraction （LVEF） 〈 40%. Based on the etiology, the patients were divided into a dilated cardiomyopathy （DCM） group （n = 120） and an ischemic cardiomyopathy （ICM） group （n = 120）. Then, based on the cQTd width, the ICM group was divided into two subgroups： a QS group （cQTd ≤60 ms, n = 70） and a QL group （cQTd 〉 60 ms, n = 50）. All patients were examined by echocardiography and 12-lead electrocardiography （ECG） at 1, 3, 6, and 12 months after enrollment. Results After one year of optimized medical treatment, patients in both groups showed significant improvement in LVEF and NYHA classification from baseline. However, the cQTd in the ICM group, especially the QL, was significantly shorter than that in the DCM group at each time point. In addition, the cQTd was negatively correlated with LVEF and 6-min walking test and positively correlated with NYHA class in the ICM group. Conclusions The present findings clearly demonstrate that cQTd is a meaningful parameter for assessing heart function in the follow-up of ICM patients.展开更多
More than 50% of people living with congestive heart failure have diastolic heart failure(DHF).Most of them are older than 70 years,and female.The prevalence of DHF has increased with time.DHF is caused by left ventri...More than 50% of people living with congestive heart failure have diastolic heart failure(DHF).Most of them are older than 70 years,and female.The prevalence of DHF has increased with time.DHF is caused by left ventricular(LV) diastolic dysfunction(DD) which is induced by diastolic dyssynchrony.Cardiac and extracardiac factors play important roles in the development of heart failure(HF) symptoms.The diagnosis of DHF is generally based on typical symptoms and signs of HF,preserved or normal LV ejection fraction,DD and no valvular abnormalities on examination,using noninvasive and invasive methodologies.The outcomes with pharmacological therapy in patients with DHF are frequently neutral in clinical trials,and prognosis still remains poor with a 5-year mortality of 42.3% after hospitalization for HF.Further trials are necessary.展开更多
Cardiac resynchronization therapy(CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class Ⅱ, Ⅲ and ambulatory Ⅳ, reduce...Cardiac resynchronization therapy(CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class Ⅱ, Ⅲ and ambulatory Ⅳ, reduced left ventricular(LV) function, and a widened QRS complex. CRT has been shown to improve symptoms, LV function, hospitalization rates, and survival. In order to maximize the benefit from CRT and reduce the number of non-responders, consideration should be given to target the optimal site for LV lead implantation away from myocardial scar and close to the latest LV site activation; and also to appropriately program the device paying particular attention to optimal atrioventricular and interventricular intervals. We herein review current data related to both optimal LV lead placement and device programming and their effects on CRT clinical outcomes.展开更多
Functional mitral regurgitation is a common finding among heart failure patients with ischemic and non-ischemic dilated cardiomyopathies.The presence of moderate or severe mitral regurgitation is associated with highe...Functional mitral regurgitation is a common finding among heart failure patients with ischemic and non-ischemic dilated cardiomyopathies.The presence of moderate or severe mitral regurgitation is associated with higher morbidity and mortality.Heart failure patients meeting electrocardiogram and left ventricle function criteria are good candidates for cardiac resynchronization therapy,which may reduce the degree of functional mitral regurgitation in the short and long term,specifically targeting myocardial dyssynchrony and inducing left ventricle reverse remodeling.In this article,we analyze data from the literature about predictors of mitral regurgitation improvement after cardiac resynchronization therapy implantation.展开更多
Almost 50 years ago,we published detailed hemodynamic findings in a patient with heart failure and intermittent left bundle branch block.Delayed intraventricular conduction was consistently accompanied by an increased...Almost 50 years ago,we published detailed hemodynamic findings in a patient with heart failure and intermittent left bundle branch block.Delayed intraventricular conduction was consistently accompanied by an increased duration of left ventricular(LV)isometric contraction,a drop in systolic blood pressure,a rise in heart rate,and a drop in cardiac output.To our knowledge,this observation provided the first ever evidence that delayed mechanical LV contraction was associated with deterioration,and return to a normal pre-ejection phase with improvement in LV function.展开更多
Traditional right ventricular(RV) apical pacing has been associated with heart failure, atrial fibrillation and increased mortality. To avoid the negative consequences of RV apical pacing different strategies have bee...Traditional right ventricular(RV) apical pacing has been associated with heart failure, atrial fibrillation and increased mortality. To avoid the negative consequences of RV apical pacing different strategies have been developed, among these a series of pacing algorithms designed to minimize RV pacing. These functions are particularly useful when there is not the need for continuous RV pacing: intermittent atrioventricular blocks and, mainly, sinus node disease. However, in order to avoid RV pacing, the operationalfeatures of these algorithms may lead to adverse(often under-appreciated) consequences in some patients. We describe a case of a patient with sinus node disease, in whom right atrial only pacing involved long atrio-ventricular delay to allow intrinsic ventricular conduction, which led to symptomatic hypotension that could be overcome only by "forcing" also right ventricular apical pacing. We subsequently discuss this case in the context of current available literature.展开更多
Permanent pacemaker implant is a commonly performed cardiac procedure for treatment of bradycardia or conduction system abnormality.With conventional right ventricular(RV)pacing a lead is implanted at the RV apex or o...Permanent pacemaker implant is a commonly performed cardiac procedure for treatment of bradycardia or conduction system abnormality.With conventional right ventricular(RV)pacing a lead is implanted at the RV apex or on the RV septum.However,RV apical or RV septal pacing causes iatrogenic left bundle-branch block and ventricular dyssynchrony and can lead to adverse cardiac remodeling,a pacing-mediated cardiomyopathy,and congestive heart failure.Alternatively,permanent His-bundle pacing uses the intrinsic rapidly-conducting His-Purkinje system to activate the ventricle,thereby maintaining(or sometimes even restoring)ventricular synchrony.Many patients may derive benefit from permanent His-bundle pacing.展开更多
The routine and potential future applications of equilibrium radionuclide angiocardiography/multigated acquisition (MUGA) in clinical decision making are explored in this review. The non-invasive nature of the test, l...The routine and potential future applications of equilibrium radionuclide angiocardiography/multigated acquisition (MUGA) in clinical decision making are explored in this review. The non-invasive nature of the test, less operator dependence, lower radiation dose and ease of performing, even in ill patients, are important considerations in clinical cardiology practice. Two important routine uses of this modality in day-to-day clinical practice include the following: serial assessment of left ventricular ejection fraction (LVEF) in patients receiving cardiotoxic chemotherapy, and determination of accurate LVEF in patients with intractable heart failure. Other potential utilities of MUGA that could be translated into clinical practice include determination of regional LVEF, obtaining information about both right and left ventricle in suitable patients as a part of first pass angiocardiography, identification of diastolic dysfunction in patients with heart failure with preserved LVEF, and demonstration of dyssynchrony prior to cardiac resynchronisation, specifically by MUGA single photon emission tomography.The last two indications are particularly important and evolving at this point.展开更多
Objectives To assess the regional diastolic function in patients with hypertrophic cardiomyopathy （HCM） by using single-beat, real-time, three-dimensional echocardiography （RT-3DE）. Methods Sixty-five patients wit...Objectives To assess the regional diastolic function in patients with hypertrophic cardiomyopathy （HCM） by using single-beat, real-time, three-dimensional echocardiography （RT-3DE）. Methods Sixty-five patients with HCM in sinus rhythm together with fifty age- and gender-matched normal controls were studied by two dimensional echocardiography （2DE） and RT-3DE. The parameters analyzed by RT-3DE included： left ventrieular （LV） volumes, left ventricular ejection fraction （LVEF）, end diastolic sphericity index （EDSI）, diastolic dyssynchrony index （DDI）, dispersion end diastole （DISPED）, and normalized 17 segmental volume-time curves. Results Evaluated by RT-3DE, LVEF was slightly lower compared with 2DE （63.2 ± 6.8% vs. 59.1 ± 6.4%, P 〈 0.0001）. Normal subjects had relatively uniform volumetric curves for all LV segments. In HCM patients, the segmental volumetric curves were dyssynchronous. Increased DDI and DISPED in end diastole were observed in patients with HCM （9.95 ± 3.75, 41.76 ± 17.19, P 〈 0.0001）, and not all abnormal volumetric segments occurred in the hypertrophic regions. Conclusions Patients with HCM have presented regional diastolic dyssynchrony in the diastole phase, and this preclinical lesion can be recognized by single-beat RT-3DE.展开更多
Epicardial Cardiac pacing may lead to severe Mitral Regurgitation by one of the following mechanisms: 1) Inappropriate Atrioventricular interval. 2) Myocardial ischemia due to fast heart rate may cause transient papil...Epicardial Cardiac pacing may lead to severe Mitral Regurgitation by one of the following mechanisms: 1) Inappropriate Atrioventricular interval. 2) Myocardial ischemia due to fast heart rate may cause transient papillary muscle dysfunction. 3) Right Ventricular apical pacing may lead to Left Ventricular dyssynchrony in the presence of optimal Atrioventricular synchrony. Acute severe Mitral Regurgitation leading to acute severe hemodynamic deterioration is a reported complication of Permanent Pacemaker insertion. Our case demonstrated acute severe MR as a consequence of RV Pacing leading to acute hemodynamic deterioration, which was relieved on withdrawal of pacing. Left Ventricular dyssynchrony can be relieved by reducing the peacemaker rate or changing to biventricular pacing, this reduces the severity of Mitral Regurgitation and improves the hemodynamics due to simultaneous activation of left and right ventricles. This case illustrates the acute and potentially dramatic effects of intra-Left Ventricular dyssynchrony upon Mitral Valve function. Informed consent was obtained from the patient to report the case. Thus right ventricular pacing can cause left ventricular dyssynchrony leading to worsening of Mitral Regurgitation. It is important to pay attention to mode of pacing when evaluating Mitral Regurgitation in patients with Right Ventricular pacemaker and unstable hemodynamics after initiation of pacing.展开更多
文摘Chronic functional mitral regurgitation(FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy(DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle(LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy(CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.
文摘The present study investigated the application of echocardiography to evaluation of cardiac dyssynchrony in patients with congestive heart failure（CHF）. A total of 348 consecutive CHF patients who were admitted for cardiac resynchronization（CRT） and presented with low ejection fraction（EF） and wide QRS duration were enrolled in this study, along with 388 healthy individuals. Dyssynchrony was assessed based on filling time ratio（FT/RR）, left ventricular pre-ejection delay（PED）, interventricular mechanical delay（IVMD）, longitudinal opposing wall delay（LOWD） and radial septal to posterior wall delay（RSPWD）. Response to CRT was defined as a ≥15% increase in EF. The results showed that FT/RR was decreased while PED, IVMD, LOWD and RSPWD were increased in the CHF group compared with the control group（P〈0.01）. In the CHF group, FT/RR was negatively correlated with the QRS duration, LV end-diastolic diameter（LVESd）, LV end-diastolic volume（LVEDV） and LV end-systolic volume（LVESV）（P〈0.01）, but positively with the LVEF（P〈0.01）. Additionally, PED, IVMD, LOWD and RSPWD were positively correlated with the QRS duration, LVESd, LVEDV and LVESV（P〈0.01）, but negatively with the LVEF（P〈0.01）. The CHF group was divided into three subgroups according to the varying degrees of LVEF. FT/RR decreased successively from the LVEF-1 group to the LVEF-2 group to the LVEF-3 group, while the PED, IVMD, LOWD and RSPWD successively increased in the same order（P〈0.01）. The CHF group was divided into three subgroups according to the varying degrees of QRS duration, and FT/RR decreased successively in a sequence from the QRS-1 group to the QRS-2 group to the QRS-3 group, while the PED, IVMD, LOWD and RSPWD successively increased in the same order（P〈0.01）. Speckle tracking radial dyssynchrony ≥130 ms was predictive of an EF response in patients in QRS-1 group（78% sensitivity, 83% specificity）, those in QRS-2 group（83% sensitivity, 77% specificity） and in QRS-3 group（89% sensitivity, 79% specificity）. In conclusion, echocardiography is a convenient and sensitive method for evaluating cardiac dyssynchrony in patients with CHF.
文摘Background Two-dimensional speckle tracking imaging （2D-STI） and real-time three-dimensional echocardiography （RT-3DE） have more advantages in evaluating left ventricular （LV） systolic dyssynchrony than traditional echocardiographic techniques. The study aimed to evaluate LV dyssynchrony parameters by both 2D-STI and RT-3DE, and the correlation between these two techniques. Methods A total of 43 chronic heart failure （CHF） patients and 27 healthy volunteers were enrolled. There were 23 dyssynchrony parameters selected to evaluate left ventricular systolic synchronization, involving 15 from 2D-STI and 8 from RT-3DE. Results Few of the dyssynchrony parametersshowednegative correlations with LV ejection fraction （LVEF） in the CHF group. The difference between time to peak-systolic radial strain of the anteroseptal and posterior segments at the level of papillary muscles [AS-P（RS）] from 2D-STI showed positive correlations with parts of the parameters from RT-3DE （P 〈 0.05）. Conclusions LV systolic dysfunction does not correlate with dyssynchrony. Moreover, there is a weak association between 2D-STI and RT-3DE in assessment of left ventricular dyssynchrony.
文摘Objectives Left ventricular systolic dyssynchrony is the most important determinant of response to cardiac resynchronization therapy （CRT）, playing a vital role to predict improvement of systolic function or LV reverse remodeling. CardioGRAF is a novel programmer based on the ECG gated single photon emission computed tomography （G-SPECT） imaging to detect LV systolic and diastolic dyssynchrony simultaneously. This study was to investigate the prevalence of systolic and diastolic left ventricular （LV） dyssynchrony in patients with heart failure. Methods We retrospectively studied 69 patients with heart disease, including 31 patients who had symptoms of heart failure （NYHA class Ⅱ-Ⅲ）, and 38 patients who had no symptoms of heart failure. （NYHA class Ⅰ）. G- SPECT data were analyzed by cardiaGRAF, and measurements included the time to end systole （TES）, the time to peak ejection （TPE）, the time to peak filling （TPF）, TES＋TPF and maximal difference （MD） of each parameters were obtained, using the 95th percentile of the control group as a cutoffof 150 ms for MD-TES, 139 ms for MD-TPE, 345 ms for MD-TPF and 315 ms for MD-TES＋TPF. Results The prevalence of LV systolic dyssynchrony was significantly higher in heart failure patients with reduced LV ejection fraction （LVEF）〈45% （72% for MD-TES; 64% for MD-TPE） compared with heart failure patients with preserved LVEF=45% （14% for both MD-TES and MD-TPE; P=0.002, P=0.005, respectively）; The prevalence of MD-TES〈150 ms was higher in NYHA class Ⅲ patients （64%） compared with NYHA class Ilpatients （27%, P=0.049）. However, the prevalence of the LV diastolic dyssynchrony were high but not difference between NYHA class III（47% for both MD-TPF and MD-TES＋TPF） and class Ⅲ（63% for MD-TPF; 69% for MD-TES＋TPF; P=NS） patients as well as between patients with preserved LVEF （43% for both MD-TPF and MD-TES＋TPF） and patients with reduced LVEF（64% for MD-TPF; 72% for MD-TES＋TPF; P=NS）. Conclusions The prevalence of LV systolic dyssynchrony was high in heart failure patients with reduced LVEF. Diastolic dyssynchrony was common in patients with heart failure. CardioGRAF maybe a useful method to detect LV dyssynchrony （J Gerlatr Cardio12009; 6：151-156）.
文摘Background:Signifi cant left ventricular dysfunction may arise in right-sided accessory pathways with ventricular preexcitation in the absence of recurrent or incessant tachycardia.This has just been realized and not enough attention has been paid to it.Methods:In the last 7 years,we identifi ed 12 consecutive children with a diagnosis of ventricular preexcitation–induced dilated cardiomyopathy.This report describes the clinical and echocardiographic characteristics of the patients before and after ablation.Results:Dyssynchronous ventricular contraction was observed by M-mode echocardiography and two-dimensional strain analysis in all patients.The basal and middle segments of the interventricular septum became thin and moved similarly to an aneurysm,with typical bulging during the end of systole.The locations of the accessory pathways were the right-sided septum(n=5)and the free wall(n=7).Left ventricular synchrony was obtained shortly after ablation.The left ventricular function recovered to normal and the left ventricular end-diastolic diameter decreased gradually during follow-up.Conclusions:A causal relationship between ventricular preexcitation and the development of dilated cardiomyopathy is supported by the complete recovery of left ventricular function and reversed left ventricular remodeling after the loss of ventricular preexcitation.Preexcitation-related dyssynchrony was thought to be the crucial mechanism.Ventricular preexcitation–induced dilated cardiomyopathy is an indication for ablation with a good prognosis.
文摘Cardiac resynchronization therapy (CRT) is an established therapy for selected heart failure (HF) patients to improve symptoms, ventricular function, and survival. Although increasingly used, left ventricular (LV) dyssynchrony assessment by echocardiography has failed to show enough predictive value to assess patient response to CRT and the current guidelines do not recommend its routine use. Furthermore, a variety of echocardiographic techniques used for the purpose, including tissue Doppler imaging (TDI), real time three-dimensional echocardiography, M-mode, and various Doppler parameters, showed limited value and poor agreement between the studies and methods, greatly influenced by interobserver variability. Speckle tracking echocardiography (STE) is a more recent approach that uses strain imaging to assess LV dyssynchrony. This article discusses the speckle tracking for LV dyssynchrony and its current clinical applications.
文摘Objective: Long-term right ventricular pacing has been associated with an increased risk of heart failure and cardiomyopathy. The pathophysiology of cardiomyopathy associated with right ventricular pacing remains unclear. We aim to evaluate the burden and short-term outcomes of ventricular dyssynchrony after immediate permanent pacemaker implantation. Materials and Methods: This prospective cohort study examined consecutive patients who had permanent pacemaker implantation at Vajira Hospital in 2019. Left ventricular systolic function, specifically left ventricular ejection fraction (LVEF) and echocardiographic ventricular dyssynchrony parameters were assessed. The endpoints included the prevalence of ventricular dyssynchrony, new-onset cardiomyopathy, heart failure, and death. The correlation between QRS complex duration, the burden of ventricular pacing, and echocardiographic ventricular dyssynchrony was measured. Results: Thirty-six consecutive patients underwent pacemaker implantation. The prevalence of mechanical ventricular dyssynchrony was 22.2% using the interventricular conduction delay method, 41.7% using LV pre-ejection period method, and 11.1% using the septal posterior wall motion abnormality method. Electrical ventricular dyssynchrony was 86.1% and new-onset cardiomyopathy was 17.1% after 3 months of permanent pacemaker implantation. The right ventricular pacing of more than 20% was significantly associated with cardiomyopathy (p < 0.022) and heart failure (log-rank, p = 0.049) within 3 months. But heart failure was not associated with mechanical ventricular dyssynchrony parameters (log-rank, p = 0.610;hazard ratio [HR], 1.53;95% confidence interval [CI], 0.29 - 7.96;p = 0.613 for IVMD and log-rank, p = 0.398;HR, 0.04;95% CI, 0.01 - 3316.7 for SPWMD). Conclusion: Mechanical and electrical ventricular dyssynchrony are common findings in right ventricular pacing. High-burden right ventricular pacing after 3 months of permanent pacemaker implantation is often associated with cardiomyopathy and heart failure, but mechanical and electrical ventricular dyssynchrony does not predict a short-term decline in left ventricular systolic function and heart failure.
文摘Objectives To assess the prevalence of systolic dyssynchrony of the left ventricular （LV） walls in patients of heart failure（HF） with a normal QRS duration by Doppler tissue imaging （DTI）. Methods 20 patients of HF with a normal QRS duration and 20 healthy individuals were investigated with DTI to quantitatively analyze their pulsed-wave Doppler spectrum of basal and middle segments in six walls of left ventricle. The time between the onset of the QRS complex of the surface ECG and the onset of the systolic wave of pulsed-wave Doppler spectrum was measured （TS）. LV systolic synchronization was assessed by the maximal difference （MD） in time of TS, the standard deviation （SD） and the coefficient of variation （CV） of TS in the all 12 LV segments. Results When a TS-MD of TS〉 53.08 ms, a TS-SD of TS 〉18.08 ms and a TS-CV of TS 〉 0.91 （＋1.65 SD of normal controls） was used to define significant systolic dyssynchrony, the prevalence of systolic dyssynchrony was 55.0 %, 55.0 % and 55.0 %, respectively, in the HF patients group, significantly higher than those in the normal control and the locations of delayed contraction of these patients were different. Conclusions LV systolic dyssynchrony could be commonly demonstrated by DTI in HF patients with a normal QRS duration. This finding will support the view about the possibility that more HF patients could benefit from cardiac resynchronization therapy.
文摘Background: Altered myocardial sympathetic innervation activity (AMSI) is known to be present in systolic heart failure patients (SHF) and recently SPECT imaging using I-123 mIBG heart to mediastinum (H/M) ratio <1.6 has been shown to predict MACE in the ADMIRE-HF trial. Left ventricular mechanical dyssynchrony (LVMD) is known to be present in a substantial number of SHF patients and has been studied mainly to guide CRT therapy. Recently gated SPECT has shown promise to provide an accurate assessment of LVMD. It remains unclear how the combination of AMSI and LVMD collectively affect clinical outcomes and other cardiovascular parameters. Objectives: The objectives are to examine the clinical characteristics and incremental prognostic value for MACE of LVMD determined by SPECT in SHF patients with or without abnormal cardiac MIBG uptake (H/M ratio < 1.6). Methods: Out of 30 SHF patients who participated from our institution in the ADMIRE-HF trial studying MIBG based AMSI, we included 22 patients with abnormal MIBG H/M ratio of <1.6. We performed gated SPECT LVMD analysis on these patients using the Emory Cardiac Toolbox. The 2 SPECT variables for LVMD assessed were histogram bandwidth and phase standard deviation both of which assess the extent of dispersion of LV activation during contraction as a marker of LVMD. Patients were followed up for a mean period of 6 years. The primary end point was mortality from any cause and secondary end point was heart failure admission or myocardial infarction or ICD shock. Results: 2 Groups were defined: Group A: n = 17 with H/M MIBG ratio < 1.6 and +LVMD and Group B, n = 5 H/M MIBG ratio −LVMD. Baseline characteristics, cardiac risk factors and medications were comparable between both groups. LVEF was lower and RBBB was less common in Group A. There was no statistical difference in achievement of primary or secondary end points in the two groups including death heart failure readmissions, ICD shocks or MI. Conclusions: In our pilot study, we did not find definitive value of adding SPECT based LVMD to abnormal cardiac MIBG imaging in SHF patients with regards to predicting outcomes. Although our sample size is too small to make any definitive conclusions, it is possible that LVMD works independently through different pathways in the progression of SHF and hence may not necessarily add incremental value to AMSI determination using MIBG.
基金This work was financially supported by National Natural Science Foundation of China(Nos.82000325,82100325,82070349)Young Elite Scientists Sponsorship Program by Beijing Association for Science and Technology(No.BYESS2023392)+2 种基金The Beijing Gold-bridge project(No.ZZ21055)The Peking University First Hospital Seed Foundation(No.2020SF19)High-level hospital clinical research funding of Fuwai Hospital,Chinese Academy of Medical Sciences(No.2022-GSP-GG-11).
文摘Background:We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines.Methods:A total of eight dogs were included in the experiment,four were tachypaced in right ventricle apex (RVAP) and 4 were paced in right atrium after the ablation of left bundle branch to achieve left bundle branch block (RAP+LBBB).Three weeks of follow-up were conducted to observe the changes in cardiac function and myocardial staining was performed at the end of the experiment.Results:Both experimental approaches successfully established heart failure with reduced ejection fraction models,with similar trends in declining cardiac function.The RAP+LBBB group exhibited a prolonged overall ventricular activation time, delayed left ventricular activation,and lesser impact on the right ventricle.The RVAP approach led to a reduction in overall right ventricular compliance and right ve ntricular enlargement.The RAP+LBBB group exhibited significant reductions in left heart compliance (LVGLS,%:RAP+LBBB-12.60±0.12 to-5.93±1.25;RVAP-13.28±0.62to-8.05±0.63, p=0.023;LASct,%:RAP+LBBB-15.75±6.85 to-1.50±1.00;RVAP-15.75±2.87 to-10.05±6.16,p=0.035).Histological examination revealed more pronounced fibrosis in the left ventricular wall and left atrium in the RAP+LBBBgroup while the RVAP group showed more prominent fibrosis in the right ventricular myocardium.Conclusion:Both approaches establish HFrEF models with comparable trends.The RVAP group shows impaired right ventricular function,while the RAP+LBBB group exhibits more severe decreased compliance and fibrosis in left ventricle.
基金Acknowledgments This study was supported by the National Natural Science Foundation of China （No. 8130 1276） and the Heilongjiang Provincial Department of Education （No. 12541544）. The authors declare that there are no competing interests.
文摘Background Chronic heart failure （CHF） is life-threatening without timely or effective intervention. In this study, we investigated the association between QT dispersion corrected for heart rate （cQTd） and heart function in patients with CHF. Methods From January 2013 to December 2015, we continuously enrolled 240 patients categorized as New York Heart Association functional class （NYHA） III-IV with a left ventricular ejection fraction （LVEF） 〈 40%. Based on the etiology, the patients were divided into a dilated cardiomyopathy （DCM） group （n = 120） and an ischemic cardiomyopathy （ICM） group （n = 120）. Then, based on the cQTd width, the ICM group was divided into two subgroups： a QS group （cQTd ≤60 ms, n = 70） and a QL group （cQTd 〉 60 ms, n = 50）. All patients were examined by echocardiography and 12-lead electrocardiography （ECG） at 1, 3, 6, and 12 months after enrollment. Results After one year of optimized medical treatment, patients in both groups showed significant improvement in LVEF and NYHA classification from baseline. However, the cQTd in the ICM group, especially the QL, was significantly shorter than that in the DCM group at each time point. In addition, the cQTd was negatively correlated with LVEF and 6-min walking test and positively correlated with NYHA class in the ICM group. Conclusions The present findings clearly demonstrate that cQTd is a meaningful parameter for assessing heart function in the follow-up of ICM patients.
文摘More than 50% of people living with congestive heart failure have diastolic heart failure(DHF).Most of them are older than 70 years,and female.The prevalence of DHF has increased with time.DHF is caused by left ventricular(LV) diastolic dysfunction(DD) which is induced by diastolic dyssynchrony.Cardiac and extracardiac factors play important roles in the development of heart failure(HF) symptoms.The diagnosis of DHF is generally based on typical symptoms and signs of HF,preserved or normal LV ejection fraction,DD and no valvular abnormalities on examination,using noninvasive and invasive methodologies.The outcomes with pharmacological therapy in patients with DHF are frequently neutral in clinical trials,and prognosis still remains poor with a 5-year mortality of 42.3% after hospitalization for HF.Further trials are necessary.
文摘Cardiac resynchronization therapy(CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class Ⅱ, Ⅲ and ambulatory Ⅳ, reduced left ventricular(LV) function, and a widened QRS complex. CRT has been shown to improve symptoms, LV function, hospitalization rates, and survival. In order to maximize the benefit from CRT and reduce the number of non-responders, consideration should be given to target the optimal site for LV lead implantation away from myocardial scar and close to the latest LV site activation; and also to appropriately program the device paying particular attention to optimal atrioventricular and interventricular intervals. We herein review current data related to both optimal LV lead placement and device programming and their effects on CRT clinical outcomes.
文摘Functional mitral regurgitation is a common finding among heart failure patients with ischemic and non-ischemic dilated cardiomyopathies.The presence of moderate or severe mitral regurgitation is associated with higher morbidity and mortality.Heart failure patients meeting electrocardiogram and left ventricle function criteria are good candidates for cardiac resynchronization therapy,which may reduce the degree of functional mitral regurgitation in the short and long term,specifically targeting myocardial dyssynchrony and inducing left ventricle reverse remodeling.In this article,we analyze data from the literature about predictors of mitral regurgitation improvement after cardiac resynchronization therapy implantation.
文摘Almost 50 years ago,we published detailed hemodynamic findings in a patient with heart failure and intermittent left bundle branch block.Delayed intraventricular conduction was consistently accompanied by an increased duration of left ventricular(LV)isometric contraction,a drop in systolic blood pressure,a rise in heart rate,and a drop in cardiac output.To our knowledge,this observation provided the first ever evidence that delayed mechanical LV contraction was associated with deterioration,and return to a normal pre-ejection phase with improvement in LV function.
文摘Traditional right ventricular(RV) apical pacing has been associated with heart failure, atrial fibrillation and increased mortality. To avoid the negative consequences of RV apical pacing different strategies have been developed, among these a series of pacing algorithms designed to minimize RV pacing. These functions are particularly useful when there is not the need for continuous RV pacing: intermittent atrioventricular blocks and, mainly, sinus node disease. However, in order to avoid RV pacing, the operationalfeatures of these algorithms may lead to adverse(often under-appreciated) consequences in some patients. We describe a case of a patient with sinus node disease, in whom right atrial only pacing involved long atrio-ventricular delay to allow intrinsic ventricular conduction, which led to symptomatic hypotension that could be overcome only by "forcing" also right ventricular apical pacing. We subsequently discuss this case in the context of current available literature.
文摘Permanent pacemaker implant is a commonly performed cardiac procedure for treatment of bradycardia or conduction system abnormality.With conventional right ventricular(RV)pacing a lead is implanted at the RV apex or on the RV septum.However,RV apical or RV septal pacing causes iatrogenic left bundle-branch block and ventricular dyssynchrony and can lead to adverse cardiac remodeling,a pacing-mediated cardiomyopathy,and congestive heart failure.Alternatively,permanent His-bundle pacing uses the intrinsic rapidly-conducting His-Purkinje system to activate the ventricle,thereby maintaining(or sometimes even restoring)ventricular synchrony.Many patients may derive benefit from permanent His-bundle pacing.
文摘The routine and potential future applications of equilibrium radionuclide angiocardiography/multigated acquisition (MUGA) in clinical decision making are explored in this review. The non-invasive nature of the test, less operator dependence, lower radiation dose and ease of performing, even in ill patients, are important considerations in clinical cardiology practice. Two important routine uses of this modality in day-to-day clinical practice include the following: serial assessment of left ventricular ejection fraction (LVEF) in patients receiving cardiotoxic chemotherapy, and determination of accurate LVEF in patients with intractable heart failure. Other potential utilities of MUGA that could be translated into clinical practice include determination of regional LVEF, obtaining information about both right and left ventricle in suitable patients as a part of first pass angiocardiography, identification of diastolic dysfunction in patients with heart failure with preserved LVEF, and demonstration of dyssynchrony prior to cardiac resynchronisation, specifically by MUGA single photon emission tomography.The last two indications are particularly important and evolving at this point.
文摘Objectives To assess the regional diastolic function in patients with hypertrophic cardiomyopathy （HCM） by using single-beat, real-time, three-dimensional echocardiography （RT-3DE）. Methods Sixty-five patients with HCM in sinus rhythm together with fifty age- and gender-matched normal controls were studied by two dimensional echocardiography （2DE） and RT-3DE. The parameters analyzed by RT-3DE included： left ventrieular （LV） volumes, left ventricular ejection fraction （LVEF）, end diastolic sphericity index （EDSI）, diastolic dyssynchrony index （DDI）, dispersion end diastole （DISPED）, and normalized 17 segmental volume-time curves. Results Evaluated by RT-3DE, LVEF was slightly lower compared with 2DE （63.2 ± 6.8% vs. 59.1 ± 6.4%, P 〈 0.0001）. Normal subjects had relatively uniform volumetric curves for all LV segments. In HCM patients, the segmental volumetric curves were dyssynchronous. Increased DDI and DISPED in end diastole were observed in patients with HCM （9.95 ± 3.75, 41.76 ± 17.19, P 〈 0.0001）, and not all abnormal volumetric segments occurred in the hypertrophic regions. Conclusions Patients with HCM have presented regional diastolic dyssynchrony in the diastole phase, and this preclinical lesion can be recognized by single-beat RT-3DE.
文摘Epicardial Cardiac pacing may lead to severe Mitral Regurgitation by one of the following mechanisms: 1) Inappropriate Atrioventricular interval. 2) Myocardial ischemia due to fast heart rate may cause transient papillary muscle dysfunction. 3) Right Ventricular apical pacing may lead to Left Ventricular dyssynchrony in the presence of optimal Atrioventricular synchrony. Acute severe Mitral Regurgitation leading to acute severe hemodynamic deterioration is a reported complication of Permanent Pacemaker insertion. Our case demonstrated acute severe MR as a consequence of RV Pacing leading to acute hemodynamic deterioration, which was relieved on withdrawal of pacing. Left Ventricular dyssynchrony can be relieved by reducing the peacemaker rate or changing to biventricular pacing, this reduces the severity of Mitral Regurgitation and improves the hemodynamics due to simultaneous activation of left and right ventricles. This case illustrates the acute and potentially dramatic effects of intra-Left Ventricular dyssynchrony upon Mitral Valve function. Informed consent was obtained from the patient to report the case. Thus right ventricular pacing can cause left ventricular dyssynchrony leading to worsening of Mitral Regurgitation. It is important to pay attention to mode of pacing when evaluating Mitral Regurgitation in patients with Right Ventricular pacemaker and unstable hemodynamics after initiation of pacing.
