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.

Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators:Outcome analysis using telemetry review

AIM:To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).METHODS:Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008.authors searched for unexplained electrocardiogram (ECG) findings,changes in CP andICD set parameters,any abnormality in transmitted capsule data,and adverse clinical events.RESULTS:There were no adverse events or hemodynamically significant arrhythmias reported.CP and ICD set parameters were preserved.The majority of ECG abnormalities were also found in pre-or post-SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate.Two patients seemed to have episodes of undersensing by the CP.However,similar findings were documented in ECGs taken outside the time frame of the SBCE.One patient was observed to have a low signal encountered from the capsule resulting in lack of localization,but no images were lost.CONCLUSION:Capsule-induced EMI remains a possibility but is unlikely to be clinically important.CPinduced interference of SBCE is also possible,but is infrequent and does not result in loss of images transmitted by the capsule.

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.

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.

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.

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.

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.

Determination of the optimal atrioventricular and interventricular delays in cardiac resynchronization therapy

Objective In order to provide the maximum benefit of cardiac resynchronization therapy(CRT),we tried to use an echocardiography method to optimize the atrioventricular and interventricular delay.Methods The study included 6 patients who underwent implantation of biventricular pacemakers for drug-resistant heart failure.Two-dimensional echocardiography and tissue Doppler imaging were carried out before and after the pacemaker implantation.The optimal AV delay was defined as the AV delay resulting in maximum timevelocity integral(TVI)of transmitral filling flow,the longest left ventricular filling time(LVFT)and the minimum mitral regurgitation(MR).The optimal VV delay was defined as the VV delay producing the maximum LV synchrony and the largest aortic TVI.Results CRT was successfully performed in all patients.After pacemaker implantation,an acute improvement in left ventricular ejection fraction(LVEF)was observed from 26.5%to 35%.Meanwhile,the QRS duration decreased from 170ms to 150ms.The optimal AV delay was programmed at 130,120,120,120,150 and 110ms respectively with heart rate corrected,LVFT significantly lengthened and TVI of MR decreased(non-optimal vs optimal AV delay:LVFT:469ms vs 523ms;TVI of MR:16.43cm vs 13.06cm,P<0.05).The optimal VV delay was programmed at 4,4,4,8,12 and 8ms with LV preactivation respectively.Programming the optimal VV delay increased the aortic TVI from 17.33cm up to 21.42cm(P<0.05).In the septal and lateral wall,peak systolic velocities improved from2.70cm/s to 3.02cm/s(P>0.05)and froml.31cm/s to 2.50cm/s(P<0.05)respectively.The septal-to-lateral delay in peak velocity improved from 56.4ms to 13.3ms after CRT(P<0.01).Conclusions Optimization of AV and VV delays may further enhance the efficacy of CRT.However,there was interindividual variability of optimal values,warranting individual patient examination.

Successful Treatment of Cardiac Failure Due to Cardiomyopathy in Propionic Acidemia by Cardiac Resynchronization Therapy and Hemodialysis in a Young Adult

Propionic acidemia is an autosomal recessive disorder that is due to deficiency in the enzyme propionyl-CoA carboxylase. Cardiomyopathy is a well-known phenomenon in propionic acidemia that it may rapidly progress to death. Here we describe a case of propionic acidemia in a 27-year-old man who developed adult-onset secondary dilated cardiomyopathy. In early infancy he was diagnosed with propionic acidemia and was later noted to have mild mental retardation, mild renal failure, and optic nerve atrophy. Although he was in good energy status with a low-protein diet and carnitine supplementation, he was admitted to our university hospital with decompensate heart failure, which resulted in low-output cardiac syndrome with massive mitral regurgitation and left ventricular dyssynchrony. Cardiac resynchronization therapy (CRT) and continuous hemodiafiltration followed by hemodialysis (HD) dramatically improved his clinical status.

Exercise Training Post Cardiac Resynchronization Therapy Improves Exercise Tolerance and Quality of Life

Background: Cardiac resynchronization therapy (CRT) results in improved morbidity, mortality, symptoms, quality of life (QOL) and exercise capacity, in appropriate chronic heart failure (CHF) patients. Moreover, combined exercise training (ET) and CRT maximize these improvements in these patients. The study evaluated the effect of ET on these patients in terms of QOL, functional class, exercise capacity and left ventricular ejection fraction (LVEF). Results: There were significant improvements in the QOL, functional class, exercise capacity, and LVEF compared with the Control Group. Comparison of both groups confirmed the cumulative effects of ET with CRT. The QOL improved by the end of training in the exercise group (p = 0.001), compared to the Control Group (p = 0.850). NYHA functional class improved significantly in the Exercise Group (p = 0.013). Percent-predicted peak oxygen consumption (VO2 peak) had significantly improved in the trained (p < 0.001) versus the untrained CRT Group (p= 0.596). There was a mean percent rise of the ejection fraction from 39.2 ± 12.86 to 44.40% ± 14.42% in the Exercise Group compared to a non-significant change in the Control Group. Conclusion: ET in resynchronized CHF patients is feasible and further enhances QOL and exercise tolerance in addition to the improvements seen after CRT. The study therefore recommends for the prescription of ET after implantation in order to maximize the expected benefit.

Successful treatment of systemic sclerosis complicated by ventricular tachycardia with a cardiac resynchronization therapydefibrillator:A case report

BACKGROUND Systemic sclerosis is a rare connective tissue disease characterized by localized or diffuse skin thickening and fibrosis,which usually accumulates in various organs throughout the body.Tachyarrhythmia is a common clinical manifestation of cardiovascular damage in systemic sclerosis patients.However,few studies have reported the use of catheter ablation and an implantable cardioverter defibrillator in patients with systemic sclerosis complicated by ventricular tachycardia.CASE SUMMARY A 39-year woman with an 11-year history of systemic sclerosis was referred to our hospital due to three syncopal episodes in the past 6 mo.The results of an electrocardiogram and a transthoracic echocardiogram revealed ventricular tachycardia and left ventricular systolic and ventricular septum segmental motion abnormalities,respectively.The results of an electrocardiogram showed a sinus rhythm with complete blockage of the left bundle branch.In light of the progressive nature of systemic sclerosis,the presence of a left bundle branch block,and the decreased ejection fraction,a cardiac resynchronization therapydefibrillator was implanted.The patient’s clinical conditions improved,and at the3-mo follow-up,the patient was free of ventricular tachycardia and all cardiac symptoms.CONCLUSION We report the first case of systemic sderosis complicated by ventricular tachycardia that was successfully treated with a cardiac resynchronization therapy-defibrillator.

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.

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.

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.

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 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.

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.

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.