Left bundle branch pacing set to outshine biventricular pacing for cardiac resynchronization therapy?

The deleterious effects of long-term right ventricular pacing necessitated the search for alternative pacing sites which could prevent or alleviate pacinginduced cardiomyopathy.Until recently,biventricular pacing(BiVP)was the only modality which could mitigate or prevent pacing induced dysfunction.Further,BiVP could resynchronize the baseline electromechanical dssynchrony in heart failure and improve outcomes.However,the high non-response rate of around 20%-30%remains a major limitation.This non-response has been largely attributable to the direct non-physiological stimulation of the left ventricular myocardium bypassing the conduction system.To overcome this limitation,the concept of conduction system pacing(CSP)came up.Despite initial success of the first CSP via His bundle pacing(HBP),certain drawbacks including lead instability and dislodgements,steep learning curve and rapid battery depletion on many occasions prevented its widespread use for cardiac resynchronization therapy(CRT).Subsequently,CSP via left bundle branch-area pacing(LBBP)was developed in 2018,which over the last few years has shown efficacy comparable to BiVP-CRT in small observational studies.Further,its safety has also been well established and is largely free of the pitfalls of the HBP-CRT.In the recent metanalysis by Yasmin et al,comprising of 6 studies with 389 participants,LBBPCRT was superior to BiVP-CRT in terms of QRS duration,left ventricular ejection fraction,cardiac chamber dimensions,lead thresholds,and functional status amongst heart failure patients with left bundle branch block.However,there are important limitations of the study including the small overall numbers,inclusion of only a single small randomized controlled trial(RCT)and a small follow-up duration.Further,the entire study population analyzed was from China which makes generalizability a concern.Despite the concerns,the meta-analysis adds to the growing body of evidence demonstrating the efficacy of LBBP-CRT.At this stage,one must acknowledge that the fact that still our opinions on this technique are largely based on observational data and there is a dire need for larger RCTs to ascertain the position of LBBPCRT in management of heart failure patients with left bundle branch block.

Cardiac Resynchronization Therapy in Heart Failure in Sub-Saharan Africa Environment: Experience of the Principal Hospital of Dakar (Senegal)

Background: Heart failure is a major public health challenge in sub-Saharan Africa. In patients with chronic Heart Failure and cardiac desynchrony, studies have suggested that cardiac resynchronization, can improve cardiac function and the quality of life of patients. However, in Sub-Saharan Africa, very few studies have been done on cardiac resynchronization which is in its infancy. The aim of this study is to report the local data from our hospital. Method: It was a transversal, descriptive and analytical study conducted from November 2019 to September 2022 at the Cardiology Department of the Principal Hospital of Dakar. Results: Twelve patients were implanted for Cardiac Resynchronization Therapy (CRT). The sex ratio was 8 males/4 females. The average age was 67 ± 11 years. Ten patients had non-ischemic heart disease and the two others had ischemic one. All of them had NYHA III or IV scores before CRT. The Quality of Life (QOL) was judged as poor by all of the patients. The average duration of QRS was 156 ± 9 ms. 27.9% ± 5% was the mean Left Ventricular ejection fraction (LVEF). Complications occur in 3/12 patients (25%). It was one CS vein dissection, one micro LV lead dislodgement and one phrenic nerve stimulation. Nine patients, who were considered as responders, had an improvement of QOL and NYHA, the LVEF increased and the end-diastolic dimension, and the duration of the QRS interval all decreased. Two patients do not respond and one (1) who had permanent atrial fibrillation, was a secondary responder after an atrioventricular junction ablation. Conclusion: Cardiac resynchronization is a therapy that improves the QOL of patients, the LVEF and reduces the duration of the QRS interval. However, this procedure is not without risk of complications. In sub-Saharan Africa, the major challenge is to improve the financial accessibility of this therapy for the population.

High sensitivity C-reactive protein and cardfiac resynchronization therapy in patients with advanced heart failure

Background The data on the prognostic values of high sensitivity C-reactive protein （hsCRP） levels in patients with advanced symp-tomatic heart failure （HF） receiving cardiac resynchronization therapy （CRT） are scarce. The aim of present study was to investigate the association of serum hsCRP levels with left ventricle reverse remodeling after six months of CRT as well as long-term outcome. Methods A total of 232 CRT patients were included. The assessment of hsCRP values, clinical status and echocardiographic data were performed at baseline and after six months of CRT. Long-term follow-up included all-cause mortality and hospitalizations for HF. Results During the mean follow-up periods of 31.3 ± 31.5 months, elevated hsCRP （〉3 mg/L） prior to CRT was associated with a significant 2.39-fold increase （P=0.006） in the risk of death or HF hospitalizations. At 6-month follow-up, patients who responded to CRT showed significant reductions or maintained low in hsCRP levels （–0.5 ± 4.1 mg/L reduction） compared with non-responders （1.7 ± 6.1 mg/L increase, P=0.018）. Com-pared with patients in whom 6-month hsCRP levels were reduced or remained low, patients in whom 6-month hsCRP levels were increased or maintained high experienced a significantly higher risk of subsequent death or HF hospitalizations （Log-rank P〈0.001）. The echocardio-graphic improvement was also better among patients in whom 6-month hsCRP levels were reduced or remained low compared to those in whom 6-month hsCRP levels were raised or maintained high. Conclusions Our findings demonstrated that measurement of baseline and follow-up hsCRP levels may be useful as prognostic markers for timely potential risk stratification and subsequent appropriate treatment strategies in patients with advanced HF undergoing CRT.

Predictors of non-response to cardiac resynchronization therapy implantation in patients with class Ⅰ indications: the markedly dilated left ventricular end-diastolic dimension and the presence of fragmented QRS

Background Cardiac resynchronization therapy(CRT)is a highly effective treatment in patients with a class I recommendation.However,a small proportion of the strictly selected patients still fail to respond.This study was designed to identify predictors of non-response in patients with class I indications for CRT and determine the non-response probability of the patients.Methods A total of 296 consecutive patients with a class I recommendation received CRT from January 2009 to January 2017 were retrospectively analyzed.Multivariate logistic regression analysis was performed to identify predictors for non-response(defined as cardiac death,heart transplantation,or HF hospitalization during 1-year follow-up).Results Among 296 patients,30(10.1%)met non-response.Multivariate analysis demonstrated that non-response to CRT was associated with a fragmented QRS(odd ratio(OR)=2.86,95%CI:1.14–7.12;P=0.025)and left ventricular end-diastolic dimension(LVEDD)≥77 mm(OR=3.02,95%CI:1.17–7.82;P=0.022).Patients with both of the predictors had a non-response probability of 46.2%(95%CI:19.1%–73.3%).Conclusion In patients with left bundle branch block and wider QRS duration,the proportion of non-response to CRT is not low in real world.The presence of the dilated LVEDD or fragmented QRS is a strong predictor of non-response to CRT.The probability of non-response in the patients with the two predictors was 46.2%.

Predictors of super-response to cardiac resynchronization therapy： the significance of heart failure medication, pre-implant left ventricular geometry and high percentage of biventricular pacing

Background Super-responders （SRs） are defined as patients who show crucial cardiac function improvement after cardiac resynchro- nization therapy （CRT）. The purpose of this study is to identify and validate predictors of SRs after CRT. Methods This study enrolled 201 patients who underwent CRT during the period from 2010 to 2014. Clinical and echocardiographic evaluations were conducted before CRT and 6 months after. Patients with a decrease in New York Heart Association （NYHA） fimctional class 〉 1, a decrease in left ventricular end-systolic volume （LVESV） ≥ 15%, and a final left ventricular ejection fraction （LVEF） ≥ 45% were classified as SRs. Results 29% of the 201 patients who underwent CRT were identified as SRs. At baseline, SRs had significantly smaller left atrial diameter （LAD）, LVESV, left ventricular end-diastolic volume （LVEDV） and higher LVEF than the non-super-responders （non-SRs）. The percentage of patients using angiotensin-converting enzyme inhibitors or angiotensin receptor blockers （ACEI/ARB） was higher in SRs than non-SRs. Most SRs had Biventricular （BiV） pacing percentage greater than 98% six months after CRT. In the multivariate logistic regression analysis, the independ- ent predictors of SRs were lower LVEDV [odd ratios （OR）： 0.93; confidence intervals （CI）： 0.90-0.97], use of ACEI/ARB （OR： 0.33; CI： 0.13~3.82） and BiV pacing percentage greater than 98% （OR： 0.29; CI： 0.16~.87）. Conclusion Patients with a better compliance of ACEI/ARB and a less ectatic ventricular geometry before CRT tends to have a greater probability of becoming SRs. Higher percentage of BiV pacing is essential for becoming SRs.

Left univentricular pacing for cardiac resynchronization therapy using rate-adaptive atrioventricular delay

Objective To evaluate left univentricular （LUV） pacing for cardiac resynchronization therapy （CRT） using a rate-adaptive atrioven- tricular delay （RAAVD） algorithm to track physiological atrioventricular delay （AVD）. Methods A total of 72 patients with congestive heart failure （CHF） were randomized to RAAVD LUV pacing versus standard biventricular （BiV） pacing in a 1 ： 1 ratio. Echocardiography was used to optimize AVD for both groups. The effects of sequential BiV pacing and LUV pacing with optimized A-V （right atrio-LV） delay using an RAAVD algorithm were compared. The standard deviation （SD） of the S/R ratio in lead VI at five heart rate （HR） segments （Rs/R-SD5）, defined as the ＂tracking index,＂ was used to evaluate the accuracy of the RAAVD algorithm for tracking physiological AVD. Results TheQRS complex duration （132 ± 9.8 vs. 138± 10ms, P 〈 0.05）, the time required for optimization （21 ±5 vs. 50±8min, P〈 0.001）, the mitral regurgitant area （1.9 ± 1.1 vs. 2.5 ± 1.3 em2, P 〈 0.05）, the interventricular mechanical delay time （60.7 ± 13.3 ms vs. 68.3 ± 14.2 ms, P 〈 0.05）, and the average annual cost （13,200 ± 1000 vs. 21,600 ± 2000 RMB, P 〈 0.001） in the RAAVD LUV pacing group were significantly less than those in the standard BiV pacing group. The aortic valve velocity-time integral in the RAAVD LUV pacing group was greater than that in the standard BiV pacing group （22.7 ± 2.2 vs. 21.4 ± 2.1 cm, P 〈 0.05）. The Rs/R-SD5 was 4.08 ± 1.91 in the RAAVD LUV pacing group, and was significantly negatively correlated with improved left ventricular ejection fraction （LVEF） （ALVEF, Pearson＇s r = -0.427, P = 0.009）, and positively correlated with New York Heart Association class （Spearman＇s r - 0.348, P 0.037）. Conclusions RAAVD LUV pacing is as effective as standard BiV pacing, can be more physiological than standard BiV pacing, and can de- crease the average annual cost of CRT.

Cardiac resynchronization therapy for heart failure induced by left bundle branch block after transcatheter closure of ventricular septal defect

A 54-year-old female patient with congenital heart disease had a persistent complete left bundle branch block three months after closure by an Amplatzer ventricular septal defect occluder. Nine months later, the patient suffered from chest distress, palpitation, and sweating at daily activities, and her 6-min walk distance decreased significantly （155 m）. Her echocardiography showed increased left ventricular end-diastolic diameter with left ventricular ejection fraction of 37%. Her symptoms reduced significantly one week after received cardiac resynchronization therapy. She had no symptoms at daily activities, and her echo showed left ventricular ejection fraction of 46%and 53%. Moreover, left ventricular end-diastolic diameter decreased 6 and 10 months after cardiac resynchronization therapy, and 6-min walk dis-tance remarkably increased. This case demonstrated that persistent complete left bundle branch block for nine months after transcatheter closure with ventricular septal defect Amplatzer occluder could lead to left ventricular enlargement and a significant decrease in left ventricular systolic function. Cardiac resynchronization therapy decreased left ventricular end-diastolic diameter and increased left ventricular ejection fraction, thereby improving the patient’s heart functions.

Effect of serum γ-glutamyltranferase and albumin levels on the response to cardiac resynchronization therapy in the elderly

Background Several liver function tests have been identified as predictors of hospitalization for heart failure(HF) and death in patients with chronic HF. The relationship between serum γ-glutamyltranferase(GGT) and albumin(SA) levels with the response to cardiac resynchronization therapy(CRT) has not been reliably determined. The aim of the study was to evaluate the impact of liver function tests on the results of CRT in the elderly. Methods Baseline GGT and SA were assessed before CRT device implantation in the elderly(> 70-year-old) patients. The endpoints were:(1) CRT response defined as > 5% left ventricular ejection fraction improvement and no hospitalization for HF or cardiovascular death;(2) hospitalizations;and(3) mortality. Results Eighty of 138(58%) included patients were responders at nine months. Compared to responders, the SA levels were not significantly different(35.1 ± 5.4 vs. 33.6 ± 5.5 g/L, P = 0.103);but the GGT levels, higher(81.6 ± 69.3 vs. 54.7 ± 49.6 U/L, P = 0.013) in non-responders to CRT. GGT level was independently associated with non-response to CRT(P < 0.001, OR = 0.17;95% CI: 0.08–0.38, P < 0.001). GGT cut-off value ≥ 55 U/L was highly predictive of non-response [AUC = 0.65, 64% Sensitivity, 69% Specificity(95% CI: 0.56–0.74)]. GGT ≥ 55 U/L was also associated with higher risk of hospitalization for atrial fibrillation(AF)(95% vs. 83%, P = 0.024). Both SA and GGT had no impact on overall(P = 0.220, P = 0.723) mortality. Conclusions Higher level of GGT is an independent predictor of non-response to CRT in patients over age 70 years and is associated with higher risk of hospitalization for AF. Baseline serum levels of albumin and GGT and have no impact on mortality in elderly patients undergoing CRT.

Does ‘super-responder’ patients to cardiac resynchronization therapy still have indications for neuro-hormonal antagonists? Evidence from long-term follow-up in a single center

Background Whether cardiac resynchronization therapy super-responders (CRT-SRs) still have indications for neuro-hormonal antagonists or not remains uninvestigated.Methods We reviewed clinical data from 376 patients who underwent CRT implantation in Fuwai Hospital from 2009 to 2015 and followed up to 2017.CRT-SRs were defined by an improvement of the New York Heart Association functional class and left ventricular ejection fraction to ≥ 50% in absolute values at 6-month follow-up.All CRT-SRs were assigned into two groups on the basis of whether persistently receiving neuro-hormonal antagonists (NHA)(defined as angiotensin-converting enzyme inhibitors/ angiotensin receptor blockers and β-blockers) after 6-month follow-up and then we compared long-term outcome.Results A total of 60 patients met criteria for super-response.One of thirteen (7.7%) CRT-SRs without NHA had all-cause death,which also occurred in 2 of 47 (4.3%) in CRT-SRs with NHA (P = 0.526).However,3 of 13 (23.1%) CRT-SRs without NHA had heart failure (HF) hospitalization,1 of 47 (2.1%) CRT-SRs with NHA had this endpoint (P = 0.040).Besides,subgroup analysis indicated that,for ischemic etiology group,CRT-SRs receiving NHA had considerably lower incidence of HF hospitalization than those without NHA (0 vs.75%,P = 0.014),which was not observed in non-ischemic etiology group (2.6% vs.0,P = 1.000) during long-term follow-up.Conclusions Our study found that for ischemic etiology,compared with CRT-SRs with NHA,CRT-SRs without NHA were associated with a higher risk of HF hospitalization.However,for non-ischemic etiology,we found that CRT-SRs with NHA or without NHA at follow-up were associated with similar outcomes,which needed further investigation by prospective trials.

Transvenous versus open chest lead placement for resynchronization therapy in patients with heart failure： comparison of ventricular electromechanical synchronicity

Background Transvenous lead placement is the standard approach for left ventricular （LV） pacing in cardiac resynchronization ther- apy （CRT）, while the open chest access epicardial lead placement is currently the most frequently used second choice. Our study aimed to compare the ventricular electromechanical synchronicity in patients with heart failure after CRT with these two different LV pacing tech- niques. Methods We enrolled 33 consecutive patients with refractory heart failure secondly to dilated cardiomyopathy who were eligible for CRT in this study. Nineteen patients received transvenous （TV group） while 14 received open chest （OP group） LV lead pacing. Intraand inter-ventricular electromechanical synchronicity was assessed by tissue Doppler imaging （TDI） before and one year after CRT procedure. Results Before CRT procedure, the mean QRS-duration, maximum time difference to systolic peak velocity among 12 left ventricle segments （LV Ts-12）, standard deviation of time difference to systolic peak velocity of 12 left ventricle segments （LV Ts-SD）, and inter-ventficular mechanical delay （IVMD） in OP and TV group were 166 ± 17 ms and 170 ± 21 ms, 391 ±42 ms and 397 ± 36 ms, 144 ± 30 ms and 148 ± 22 ms, 58 ± 25 ms and 60 ± 36 ms, respectively （all P 〉 0.05）. At one year after the CRT, the mean QRS-duration, LV Ts-12, LV Ts-SD, and IVMD in TV and OP group were 128 ± 14 ms and 141 ± 22 ms （P = 0.031）, 136 ± 37 ms and 294 ± 119 ms （P = 0.023）, 50± 22 ms and 96 ± 34 ms （P = 0.015）, 27 ± 11 ms and 27 ± 26 ms （P = 0.86）, respectively. The LV lead implantation procedure time was 53.4±16.3 rain for OP group and 136 ± 35.1 min for TV group （P = 0.016）. The mean LV pacing threshold increased significantly from 1.7 ± 0.6 V/0.5 ms to 2.3 ± 1.6 V/0.5 ms （P 〈 0.05） in TV group while it remained stable in the OP group. Conclusions Compared to conventional endovascular approach, open chest access of LV pacing for CRT leads to better improvement of the intraventricular synchronization.

The role of electrocardiography in the elaboration of a new paradigm in cardiac resynchronization therapy for patients with nonspecific intraventricular conduction disturbance

Cardiac resynchronization therapy （CRT） is associated with a favorable outcome only in patients with left bundle branch block （LBBB） pattern and in patients with a QRS duration 〉 150 ms, in patients with non-LBBB pattern with a QRS duration of 120-150 ms usually is not beneficial. After adjusting for QRS duration, QRS morphology was no longer a determinant of the clinical response to CRT. In contrast to the mainstream view, we hypothesized that the unfavorable CRT outcome in patients with non-LBBB and a QRS duration of 120-150 ms is not due to the QRS morphology itself, but to less dyssynchrony and unfavorable patient characteristics in this subgroup, such as more ischemic etiology and greater prevalence of male patients compared with patients with LBBB pattern. Further, the current CRT technique is devised to eliminate the dyssynchrony present in patients with LBBB pattern and inappropriate to eliminate the dyssynchrony in patients with non-LBBB pattern. We also hypothesized that electrocardiography may also provide information about the presence of interventricular and left intraventricular dyssynchrony and the approximate location of the latest activated left ventricular （LV） region. To this end, we devised new ECG criteria to estimate interventricular and LV intraventricular dyssynchrony and the approximate location of the latest activated LV region. Our preliminary data demonstrated that the latest activated LV region in patients with nonspecific intraventricular conduction disturbance （NICD） pattern might be at a remote site from that present in patients with LBBB pattern, which might necessitate the invention of a novel CRT technique for patients with NICD pattern. The application of the new interventricular and LV intraventricular dyssynchrony ECG criteria and a potential novel CRT technique might decrease the currently high nonresponder rate in patients with NICD pattern.

Left bundle branch pacing with optimization of cardiac resynchronization treatment:A case report

BACKGROUND Cardiac resynchronization therapy(CRT)is a well-established therapy for patients with cardiomyopathy.CASE SUMMARY The patient underwent left bundle branch area and left ventricular(reaching the left ventricular lateral vein through the coronary sinus)pacing.The optimal CRT was performed under the right bundle branch of the patient by adjusting the optimal a-v and v-v interphases to achieve the maximal benefit of the treatment.CONCLUSION The patient was diagnosed with left bundle branch block and heart failure.A left bundle branch area pacemaker assisted in correcting the complete left bundle branch block.However,the shorter QRS wave shape after pacemaker implantation through the left bundle branch area indicated a complete right bundle branch block pattern.Hence,the left bundle branch area pacemaker is not always considered as the optimal treatment.The left bundle branch pacing with the optimization of cardiac resynchronization treatment may serve as a new CRT strategy.

The value of serum metabolomics analysis in predicting the response to cardiac resynchronization therapy

Objective To construct a prediction model based on metabolic profiling for predicting the response to cardiac resynchronization therapy(CRT).Methods Peripheral venous(PV)and coronary sinus(CS)blood samples were collected from 25 patients with heart failure(HF)at the time of CRT implantation,and PV blood samples were obtained from ten healthy controls.The serum samples were analyzed by liquid chromatography-mass spectrometry(LC-MS).As per the clinical and echocardiographic assessment at the 6-month follow-up,the HF patients were categorized as CRT responders and non-responders.Results HF patients had altered serum metabolomic profiles that were significantly different from those of the healthy controls.Differential metabolites were also observed between CRT responders and non-responders.A prediction model for CRT response(CRT-Re)was constructed using the concentration levels of the differential metabolites,L-arginine and taurine.The optimal cutoff value of the CRT-Re model was found to be 0.343 by ROC analysis(sensitivity,88.2%;specificity,87.5%;Area under curve(AUC)=0.897,P=0.002).The concentration levels of the differential metabolites,L-arginine and lysyl-gamma-glutamate,in PV serum were significantly correlated with that in CS serum(r=0.945 and 0.680,respectively,all P<0.001).Conclusions Our results suggest that serum-based metabolic profiling may be a potential complementary screening tool for predicting the outcome of CRT.

The Temporal Relation between Cardiomyopathy and LBBB and Response to Cardiac Resynchronization Therapy:Case Series and Literature Review

Background:Left bundle branch block(LBBB)-induced cardiomyopathy has been proposed,but the association between LBBB and cardiac resynchronization therapy(CRT)response remains unclear and practical criteria for selecting CRT candidates are needed.Methods:One hundred and seventeen consecutive heart failure patients were reviewed,24 of whom received CRT.Only two patients had a clear temporal relation between cardiomyopathy and LBBB.Results:Compared with the patient with“cardiomyopathy-induced LBBB,”the patient with“LBBB-induced cardiomyopathy”had higher left ventricular(LV)wall thickness,higher LV wall thickening rate,higher peak circumferential strain,and longer peak circumferential strain delay.The LV deformation patterns in the two patients were obviously distinct on cardiovascular magnetic resonance tissue tracking.During follow-up,the patient with LBBB-induced cardiomyopathy had a good response to CRT(LV ejection fraction 23 before CRT vs.30%at 6 months vs.29 at 12 months vs.32%at 18 months;LV end-diastolic diameter 77 mm before CRT vs.66 mm at 6 months vs.62 mm at 12 months vs.63 mm at 18 months),and the other patient had no response to CRT(LV ejection fraction 29 before CRT vs.29%at 6 months vs.26 at 12 months vs.22%at 24 months;LV end-diastolic diameter 85 mm before CRT vs.88 mm at 6 months vs.85 mm at 12 months vs.84 mm at 24 months).Conclusion:The temporal relation between cardiomyopathy and LBBB could be a determinant for CRT response.Cardiovascular magnetic resonance tissue tracking may be a useful tool to identify the chronological order and a principal consideration for selecting candidates for CRT.Larger prospective clinical trials are needed to study the prevalence of,time course of,and risk factors for LBBB-induced cardiomyopathy.

Clinical outcome of cardiac resynchronization therapy in dilated-phase hypertrophic cardiomyopathy

Backgrounds Clinical trials have demonstrated that cardiac resynchronization therapy （CRT） is effective in patients with ＂non-is- chemic cardiomyopathy＂. However, patients with dilated-phase hypertrophic cardiomyopathy （DHCM） have been generally excluded from such trials. We aimed to compare the clinical outcome of CRT in patients with DHCM, idiopathic dilated cardiomyopathy （IDCM）, or ischemic cardiomyopathy （ICM）. Methods A total of 312 consecutive patients （DHCM： n = 16; IDCM： n = 231; ICM： n = 65） undergoing CRT in Fuwai hospital were studied respectively. Response to CRT was defmed as reduction in left ventricular end-systolic volume （LVESV） _〉 15% at 6-month follow-up. Results Compared with DHCM, IDCM was associated with a lower total mortality （HR： 0.35, 95% CI： 0.13-0.90）, cardiac mortality （HR： 0.29; 95% CI： 0.11-0.77）, and total mortality or heart failure （HF） hospitalizations （HR： 0.34, 95% CI： 0.17-0.69）, independent of known confounders. Compared with DHCM, the total mortality, cardiac mortality and total mortality or HF hospitalizations favored ICM but were not statistically significant （HR： 0.59, 95% CI： 0.22-1.61; HR： 0.59, 95% CI： 0.21-1.63; HR： 0.54, 95% CI： 0.26-1.15; respectively）. Response rate to CRT was lower in the DHCM group than the other two groups although the differences didn＇t reach statistical significance. Conclusions Compared with IDCM, DHCM was associated with a worse outcome after CRT. The clinical outcome of DHCM patients receiving CRT was similar to or even worse than that of ICM patients. These indicate that DHCM behaves very differently after CRT.

Cardiac resynchronization therapy improved the clinical outcomes in pacemaker patients upgraded to biventricular device

The right ventricular pacing （RVP） is the standard treat- ment for patients with severe bradyarrhythmias; however, it may cause and exacerbate heart failure symptoms in a long run under some circumstances.{1] In fact, significant left ventricular （LV） systolic dysfimction and symptomatic heart failure （HF） is commonly found in patient population with pacemaker implantations.

Cardiac resynchronization therapy: Dire need for targeted left ventricular lead placement and optimal device programming

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.

Reversal of Wolff-Parkinson-White Syndrome induced dilated cardiomyopathy via resynchronization and subsequent accessory pathway ablation

Recurrent or incessant tachycardia is frequently found in symptomatic Wolff-Parkinson-White （WPW） syndrome, leading to ventricular dysfunction, dilated cardiomyopathy （DCM） and heart failure in infants and children.[1] Recently, Winter, et al.[2] report that WPW syndrome could provoke many kinds of cardiac dysfunction, leading to remodeling and progressive ventricular dilatation through pre-excita- tion-related dyssynchrony, even without arrhythmia.

Intermediate-term mortality and incidence of ICD therapy in octogenarians after cardiac resynchronization therapy

Background Clinical outcomes of cardiac resynchronization therapy （CRT） in patients over the age of 80 have not been well de-scribed.MethodsWe retrospectively identified 96 consecutive patients≥ 80 years old who underwent an initial implant or an upgrade to CRT, with or without defibrillator （CRT-Dvs. CRT-P）, at our institution between January 2003 and July 2008. The control cohort consisted of 177 randomly selected patients 〈 80 years old undergoing CRT implant during the same time period. The primary efficacy endpoint was all-cause mortality at 36 months, assessed by Kaplan-Meier time to first event curves.Results In the octogenarian cohort, mean age at CRT implant was 83.1 ± 2.9 yearsvs. 60.1 ± 8.8 years among controls （P 〈 0.001）. Across both groups, 70% were male, mean left ventricular ejection fraction （LVEF） was 24.8% ± 14.1% and QRS duration was 154 ± 24.8 ms, without significant differences between groups. Octo-genarians were more likely to have ischemic cardiomyopathy （74%vs. 37%,P 〈 0.001） and more likely to undergo upgrade to CRT instead of an initial implant （42%vs. 19%,P 〈 0.001）. The rate of appropriate defibrillator shocks was lower among octogenarians （14%vs. 27%,P = 0.02） whereas the rate of inappropriate shocks was similar （3%vs. 6%,P = 0.55）. At 36 months, there was no significant difference in the rate of all-cause mortality between octogenarians （11%） and controls （8%,P = 0.381）.ConclusionAppropriately selected octogenarians who are candidates for CRT have similar intermediate-term mortality compared to younger patients receiving CRT.

Cardiac resynchronization therapy in acute pulmonary edema: A case report

We are reporting a case of 71-year old lady with a dual chamber demand pacemaker,who developed acute pulmonary edema due to an acute left ventricular(LV)dysfunction and worsening in mitral valve regurgitation after atrioventricular nodal ablation for uncontrolled atrial fibrillation.This was attributed to right ventricular apical pacing leading to LV dyssynchronization.Patient dramatically improved within 12-24 h after upgrading her single chamber pacemaker to biventricular pacing.Our case demonstrates that biventricular pacing can be an effective modality of treatment of acute congestive heart failure.In particular,it can be used when it is secondary to LV dysfunction and severe mitral regurgitation attributed to significant dyssynchrony created by right ventricular pacing in patients with atrioventricular nodal ablation for chronic atrial fibrillation.