Benefit Of Cardiac Resynchronization Therapy Research Articles

P531Cardiac resynchronization therapy in patients with permanent atrial fibrillation: insights from the HMEA database

Abstract Funding Acknowledgements This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Background/Introduction: The benefits of cardiac resynchronization therapy with defibrillator (CRT-D) in heart failure are well established. However, a gap of evidence is still present for patients with permanent atrial fibrillation (perm-AF) Purpose To investigate outcomes of CRT-D patients with perm-AF in terms of appropriate shock for ventricular arrhythmia and all-cause mortality in a long-term time horizon. Methods We used the Home Monitoring Expert Alliance (HMEA) database, a nationwide data repository of daily remote monitoring transmissions. The episodes with delivered shock were adjudicated by a board of 3 electrophysiologists. Results Among 1226 CRT-D patients (mean age 71.2 ± 10.0 years; 75.5% males), 276 (22.5%) had perm-AF at device implantation. These patients had more frequently rate responsive function (19.7% vs 64.1%) and higher basic rate (median value 60 bpm vs 70 bpm) as compared to all other patients (p < 0.001). The CRT pacing percentage calculated over the first 2 months was slightly lower for perm-AF patients (median value 96.0% vs 98.8%, p < 0.001). At 5-year appropriate shock incidence was 34.2% (95% confidence interval [CI], 25.1%-45.3%) for perm-AF and 19.9% (15.6%-25.1%) for all other patients. All-cause mortality was 27.7% (17.7%-41.8%) for perm-AF and 15.6% (12.2%-19.9%) for all other patients. The age- and sex-adjusted hazard ratio between perm-AF and all other patients was 1.81 (95% CI: 1.25-2.64, p = 0.002) for appropriate shock and 0.92 (95% CI: 0.57-1.50, p = 0.748) for all-cause mortality. Conclusion Although a higher incidence of appropriate shock, perm-AF at the time of CRT-D implantation was not associated with increased long-term mortality, Abstract Figure. Appropriate shock and mortality

P1169Cardiac resynchronization theraphy. Long term benefit

Abstract Introduction The benefit of cardiac resynchronization therapy (CRT) in patients (pts) with left ventricular dysfunction is mainly evaluated in multicenter studies with a follow up of 6, 12 or 24 months (m). Objectives To describe the response of pts implanted with a CRT-D/P, from a single center prospective registry, at 12, 24, 36 and 48 m. Methods Between june 2009 and june 2018, 381 pts implanted with CRT-D/P were followed at 12, 24, 36 and 48 m. Indications were performed according to international guidelines. Primary prevention: 335 pts (88%). The A-V and V-V delay were programmed according the results of Cardiac Doppler after implantation and when it was necesary. All pts had an out patient control and 10% remote monitoring control. The pts were considered Responders: decrease ≥ 1 FC NYHA or increase LVEF ≥ 5% (absolute), Super-Responders: increase LVEF ≥ 10% (absolute) and with LVEF normalization: LVEF ≥ 50%. Baseline characteristics: Age 64 ± 11 years, men 268 p (70%), ischemic cardiomyopathy 144 pts (38%), nonischemic cardiomyopathy 237 (62%), FC II-III NYHA 341 p (90%), LBBB 246 p (72%), mean QRSd 165 ± 27ms, mean LVDD 68 ± 10mm, mean LVSD 56 ± 12mm, and mean LVEF 24 ± 9%. Pts were on β-blockers (93%), ACEi/ARBs (90%), mineral receptor blockers (83%) and diuretics (73%). Results Responders: 227/276 pts (82%) at 12 m, 184/224 pts (82%) at 24 m, 141/180 p (78%) at 36 m and 112/137 (82%) at 48 m. Super-Responders: 92/186 pts (49%) at 12 m, 92/172 pts (53%) at 24 m, 71/128 (55%) at 36 m and 66/116 (57%) at 48 m. LVEF normalization: 22/186 pts (12%) at 12 m, 31/172 pts (18%) at 24 m, 24/128 pts (19%) at 36 m and 23/116 pts (20%) at 48 m. Conclusion In our study population, pts with CRT-D/P implanted according an appropriate indication, programming and follow up, with in-office and/or remote monitoring control, showed an elevated percentage of Responders, Super-Responders and LVEF normalization. The benefit was sustained or even incresed over time.

Evaluating multisite pacing strategies in cardiac resynchronization therapy in the preclinical setting.

BackgroundMultisite pacing strategies that improve response to cardiac resynchronization therapy (CRT) have been proposed. Current available options are pacing 2 electrodes in a multipolar lead in a single vein (multipoint pacing [MPP]) and pacing using 2 leads in separate veins (multizone pacing [MZP]).ObjectiveThe purpose of this study was to compare in a systematic manner the acute hemodynamic response (AHR) and electrophysiological effects of MPP and MZP and compare them with conventional biventricular pacing (BiVP).MethodsHemodynamic and electrophysiological effects were evaluated in a porcine model of acute left bundle branch block (LBBB) (n = 8). AHR was assessed as LVdP/dtmax. Activation times were measured using >100 electrodes around the epicardium, measuring total activation time (TAT) and left ventricular activation time (LVAT).ResultsCompared to LBBB, BiVP, MZP, and MPP reduced TAT by 26% ± 10%, 32% ± 13%, and 32% ± 14%, respectively (P = NS between modes) and LVAT by 4% ± 5%, 11% ± 5%, and 12% ± 5%, respectively (P <.05 BiVP vs MPP and MZP). On average, BiVP increased LVdP/dtmax by 8% ± 4%, and optimal BiVP increased LVdP/dtmax by 13% ± 4%. The additional improvement in LVdP/dtmax by MZP and MPP was significant only when its increase during BiVP and decrease in TAT were poor (lower 25% of all sites in 1 subject). The increase in LVdP/dtmax was larger when large interelectrode distances (>5 cm vs <2.2 cm) were used.ConclusionIn this animal model of acute LBBB, MPP and MZP create similar degrees of electrical resynchronization and hemodynamic effect, which are larger if interelectrode distance is large. MPP and MZP increase the benefit of CRT only if the left ventricular lead used for BiVP provides poor response.

Impact of Cardiac Resynchronization Therapy on Heart Transplant-Free Survival in Pediatric and Congenital Heart Disease Patients

Background - Cardiac resynchronization therapy (CRT) studies in pediatric and/or congenital heart disease (CHD) patients have shown an improvement in ejection fraction and heart failure symptoms. However, a survival benefit of CRT in this population has not been established. This study aimed to evaluate the impact of CRT upon heart transplant-free survival in pediatric and CHD patients, using a propensity score-matched analysis. Methods - This single-center study compared CRT patients (implant date 2004-2017) and controls, matched by 1:1 propensity-score matching (PSM) using 21 comprehensive baseline indices for risk stratification. CRT patients were <21 years or had CHD; had systemic ventricular ejection fraction <;45%; symptomatic heart failure; and had significant electrical dyssynchrony, all prior to CRT implant. Controls were screened from non-selective imaging and ECG databases. Controls were retrospectively enrolled when they achieved the same inclusion criteria at an outpatient clinical encounter, within the same time period. Results - Of 133 patients who received CRT during the study period, 84 met all study inclusion criteria. 133 controls met all criteria at an outpatient encounter. Following PSM, 63 matched CRT-control pairs were identified with no significant difference between groups across all baseline indices. Heart transplant or death occurred in 12 (19%) PSM-CRT subjects and 37 (59%) PSM-controls with a median follow-up of 2.7 years (quartiles 0.8-6.1 years). CRT was associated with markedly reduced risk of heart transplant or death (hazard ratio 0.24 [95% CI 0.12-0.46], p<0.001). There was no CRT procedural mortality and one system infection at 54 months post-implant. Conclusions - In pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplant-free survival.

Left bundle branch block increases left ventricular diastolic pressure during tachycardia due to incomplete relaxation.

We investigated whether tachycardia in left bundle branch block (LBBB) decreases left ventricular (LV) diastolic distensibility and increases diastolic pressures due to incomplete relaxation, and if cardiac resynchronization therapy (CRT) modifies this response. Thirteen canines were studied at baseline heart rate (120 beats/min) and atrial paced tachycardia (180 beats/min) before and after induction of LBBB and during CRT. LV and left atrial pressures (LAP) were measured by micromanometers and dimensions by sonomicrometry. The time constant τ of exponential pressure decay and degree of incomplete relaxation at mitral valve opening (MVO) and end diastole (ED) based on extrapolation of the exponential decay were assessed. Changes in LV diastolic distensibility were investigated using the LV transmural pressure-volume (PV) relation. LBBB caused prolongation of τ (P < 0.03) and increased the degree of incomplete relaxation during tachycardia at MVO (P < 0.001) and ED (P = 0.08) compared with normal electrical activation. This was associated with decreased diastolic distensibility seen as upward shift of the PV relation at MVO by 18.4 ± 7.0 versus 12.0 ± 5.0 mmHg, at ED by 9.8 ± 2.3 versus 4.7 ± 2.3 mmHg, and increased mean LAP to 11.4 ± 2.7 versus 8.5 ± 2.6 mmHg, all P < 0.006. CRT shifted the LV diastolic PV relation downwards during tachycardia, reducing LAP and LV diastolic pressures (P < 0.03). Tachycardia in LBBB reduced LV diastolic distensibility and increased LV diastolic pressures due to incomplete relaxation, whereas CRT normalized these effects. Clinical studies are needed to determine whether a similar mechanism contributes to dyspnea and exercise intolerance in LBBB and if effects of CRT are heart rate dependent.NEW & NOTEWORTHY Compared with normal electrical conduction, tachycardia in left bundle branch block resulted in incomplete relaxation during filling, particularly of the late activated left ventricular lateral wall. This further resulted in reduced left ventricular diastolic distensibility and elevated diastolic pressures and thus amplified the benefits of cardiac resynchronization therapy in this setting.

Indications of Cardiac Resynchronization in Non-Left Bundle Branch Block: Clinical Review of Available Evidence.

Cardiac resynchronization therapy (CRT) benefits have been firmly established in patients with heart failure and reduced left ventricular ejection fraction (HFrEF), who remain in New York Heart Association (NYHA) functional classes II and III, despite optimal medical therapy, and have a wide QRS complex. An important and consistent finding in published systematic reviews and in subgroup analyses is that the benefits of CRT are maximum for patients with a broader QRS durations, typically described as QRS duration > 150 ms, and for patients with a typical left bundle branch block (LBBB) QRS morphology. It remains uncertain whether patients with non-LBBB QRS complex morphology clearly benefit from CRT or only modestly respond.

218 His Bundle Pacing for Cardiac Resynchronisation Following Coronary Sinus Left Ventricular Lead Failure

Cardiac Resynchronisation Therapy (CRT) has been well established to provide both symptomatic and prognostic benefit in patients with heart failure with reduced ejection fraction (HFREF) and ventricular dyssynchrony, however coronary sinus (CS) lead placement is unsuccessful in between 2 and 5% of patients due to unsuitable cardiac vein anatomy or phrenic nerve stimulation. His-bundle pacing (HBP) is a strategy which may be capable of providing the benefits of CRT in patients where CS lead placement is unsuccessful. We reviewed outcomes in patients from a single centre where HBP was employed as a salvage therapy following failed CS lead placement. 5 cases were identified where CS lead placement was unsuccessful. All patients had Class I indications for CRT as recommended by the 2013 ESC guidelines. In 3 patients cardiac branch vein anatomy was unsuitable and in 2 patients unacceptable phrenic nerve stimulation was present at threshold voltages. All 5 patients underwent successful HBP without procedural complications. Median threshold for selective His-bundle capture was 0.8 V (IQR 0.5–2.5V). Median QRS duration was significantly reduced from 160msec (IQR 137.5 – 183msec) to 120msec (IQR 105–142msec) with HBP (mean of differences -37.2msec, p=0.0004). Median LVEF significantly improved from 25% (IQR 24–32) to 37.5% (IQR 35–45%, mean of differences 12.25, p=0.004). All 5 patients reported subjective improvement in heart failure symptoms. This case series illustrates the utility of HBP as an alternative method of CRT in patients who have failed CS lead implantation, reinforcing HBP as an essential tool in the armamentarium of the modern electrophysiologist.

Contribution of cardiac resynchronization therapy in hypertrophic cardiomyopathy with systolic dysfunction: A case-control study

Cardiac resynchronization therapy (CRT), known as an effective treatment for heart failure in dilated cardiomyopathy (DCM), remains uncertain in hypertrophic cardiomyopathy (HCM), with conflicting results reported from previous studies. We aimed to study the efficiency of CRT in patients with HCM, heart failure and left ventricle systolic dysfunction. From implantable cardioverter defibrillator (ICD) data-base of a single university center, patients with HCM, who received CRT, were identified and matched with resynchronized DCM in a 2:1 ratio on age at implantation (± 5 years), gender and left ventricular ejection fraction (LVEF) at implantation (± 5%). Clinical, electro-cardiographic and echocardiographic parameters were gathered at 1–6 months, 6–12 months and last follow-up after implantation. Between 2007 and 2018, we included 18 HCM patients (women 7(39%); at ICD implantation, age 59 ± 9 years, LVEF 38 ± 6%, NYHA class 2.8 ± 0.4) matched with 36 controls. At one year after implantation, the relative median change from baseline showed better improvement in HCM patients regarding: 1/NYHA class (−50% vs. − 20%, P < 0.001), 2/LVEF (+ 30% vs. + 6%, P < 0.01), 3/left ventricular end-systolic (LVES) volume (− 39% vs. − 21%, P < 0.01), 4/cardiac output (+ 18% vs. + 5%, P < 0.001) and 5/BNP (− 51% vs. − 24%, P = 0.02). HCM patients retained the benefit of CRT at last follow-up (41 ± 24 months) for NYHA (− 33% vs. − 12%, P < 0.01), LVEF (− 36% vs. − 11%, P < 0.01), LVES volume (− 42% vs. − 20%, P = 0.01) and cardiac output (+1 8% vs. − 2%, P < 0.001). The rate of bi-ventricular pacing (98% vs. 99%, P = 0.81) and the QRS duration (130ms vs. 130ms, P = 0.57) at one year after CRT were comparable in the both groups. Among HCM patients, 2 (11%) of them died and 2 (11%) had a heart transplant. CRT improved heart failure symptoms and carried out reverse remodeling of the left ventricle in HCM with better outcomes than in DCM in long-term follow-up.

Can machine learning improve patient selection for cardiac resynchronization therapy?

RationaleMultiple clinical trials support the effectiveness of cardiac resynchronization therapy (CRT); however, optimal patient selection remains challenging due to substantial treatment heterogeneity among patients who meet the clinical practice guidelines.ObjectiveTo apply machine learning to create an algorithm that predicts CRT outcome using electronic health record (EHR) data avaible before the procedure.Methods and resultsWe applied machine learning and natural language processing to the EHR of 990 patients who received CRT at two academic hospitals between 2004–2015. The primary outcome was reduced CRT benefit, defined as <0% improvement in left ventricular ejection fraction (LVEF) 6–18 months post-procedure or death by 18 months. Data regarding demographics, laboratory values, medications, clinical characteristics, and past health services utilization were extracted from the EHR available before the CRT procedure. Bigrams (i.e., two-word sequences) were also extracted from the clinical notes using natural language processing. Patients accrued on average 75 clinical notes (SD, 29) before the procedure including data not captured anywhere else in the EHR. A machine learning model was built using 80% of the patient sample (training and validation dataset), and tested on a held-out 20% patient sample (test dataset). Among 990 patients receiving CRT the mean age was 71.6 (SD, 11.8), 78.1% were male, 87.2% non-Hispanic white, and the mean baseline LVEF was 24.8% (SD, 7.69). Out of 990 patients, 403 (40.7%) were identified as having a reduced benefit from the CRT device (<0% LVEF improvement in 25.2%, death by 18 months in 15.6%). The final model identified 26% of these patients at a positive predictive value of 79% (model performance: Fβ (β = 0.1): 77%; recall 0.26; precision 0.79; accuracy 0.65).ConclusionsA machine learning model that leveraged readily available EHR data and clinical notes identified a subset of CRT patients who may not benefit from CRT before the procedure.

P5688Is renal dysfunction associated with the outcome of CRT patients?

Abstract Background The benefit of cardiac resynchronization therapy (CRT) in patients (pts) with chronic kidney disease (CKD) remains controversial despite frequent use. Pts with impaired renal function have systematically been excluded from randomized clinical trials and therefore specific recommendations for the use of CRT in these pts are still lacking. Purpose Study objectives were to assess long-term outcomes and clinical/echocardiographic response in a large population of patients with moderate-to-severe impaired renal function implanted with a CRT device in accordance with the current standard of care. Methods We prospectively analyzed clinical, instrumental data and survival of pts with CKD who received a CRT device in the CRT-MORE registry from 2011 to 2014. Adverse events for the analysis of clinical outcome comprised death from any cause and nonfatal HF events requiring hospitalization after CRT implantation. LV reverse remodeling and Clinical Response (CR) were also evaluated at 12-month follow-up. Patients were stratified according to current definition of CKD stage: low-moderate CKD with a GFR = 45–59 mL/min (stage 3A); moderate CKD with a GFR = 30–44 mL/min (stage 3B) and severe CKD with a GFR = 15–29 mL/min (stage 4). Results Of the 922 consecutive patients enrolled in the registry, 416 (45%) pts had a moderate-to-severe impaired renal function (43% Stage 3A, 43% Stage 3B and 14% Stage 4). The mean follow-up was 935±506 days. By the end of the study, 85 pts had died and 47 pts had been hospitalized for HF. The combined end-point of death or HF hospitalization was reached by 121 (29%) pts. After 12 months the absolute LVEF improvement was greater than 10% in 37% of pts and 58% of pts displayed a positive clinical response. The percentage of pts who died was higher in the group of pts with severe CKD (32.8% vs 18.4%; p=0.012, compared to the group of pts with moderate CKD). On the contrary the percentage of pts who had at least one HF hospitalization was lower in the group with more severe CKD (2% vs 13%; p=0.011). According to CKD stage both LV remodeling (LVEF improvement ranging from 43.7% - 3A - to 30.8% - 4) and CR (positive response ranging from 63.9% - 3A - to 50% - 4) were higher in low-moderate stage and decreased with CKD severity. At multivariate Cox regression analysis adjusted for baseline confounders, CKD class at implantation [HR=1.5; 95% CI: 1.06–2.14; p=0.0219], chronic obstructive pulmonary disease [HR=1.89; 1.18–3.01; p=0.0077], persistent/permanent AF [HR=1.86; 1.15–3.01; p=0.0115] and male gender [HR=1.92; 1.07–3.46; p=0.0301] remained associated with death. Conclusions Among CKD patients in the CRT-MORE registry, severity of renal dysfunction at the time of CRT implantation was associated with worse prognosis, lower clinical response and LV reverse remodeling. Acknowledgement/Funding None

P5974Prognostic value of global tangential strain by three-dimensional echocardiography heart failure patients with intermediate ECG criteria for cardiac resynchronization therapy

Abstract Background In the current clinical guidelines, cardiac resynchronization therapy (CRT) is recommended in heart failure (HF) patients with left bundle branch block (LBBB) with QRS width ≥150ms as Class I indication. In terms of HF patients with intermediate ECG criteria, prediction for benefit of CRT is still controversial in routine echocardiography. Purpose The aim was to assess whether three-dimensional (3D) echocardiographic indexes of global LV function at baseline has a prognostic value following CRT implantation in patients who fulfilled with intermediate ECG criteria. Methods We studied 62 HF patients who fulfilled with the indication criteria of CRT implantation according to current the clinical guidelines. In addition to routine two-dimensional echo, 3D echo dataset was acquired for determination of 3D global tangential strain (GTS) and 3D global longitudinal strain (GLS). We tracked predefined unfavorable outcomes for 3 years after CRT implantation: death, hospitalization due to worsening HF. Results LBBB with QRS width ≥150ms was evident in 26 of 62 patients (aged 68±11 years with 160±26 ms of QRS duration and 29±7% of LV ejection fraction), and the other 36 patients only fulfilled intermediate ECG criteria (QRS width 120–149ms or non-LBBB). Unfavorable events occurred in 21 patients (34%). The median GTS was −15.4%. Although GLS was not predictive, GTS greater than −15.4% had high probability of unfavorable outcomes over 3 years (Log-rank, p&lt;0.05). There is no difference in the probability of unfavorable outcomes between LBBB and intermediate ECG criteria. Baseline GTS in patients with intermediate ECG criteria was associated with unfavorable outcomes: −12.6±2.6% vs. −17.3±3.8% (p&lt;0.05). Outcome was better in the intermediate ECG criteria patients with GTS ≤−15.4% than in those with LBBB and in those with intermediate ECG criteria patients with GTS &gt;−15.4% (Log-rank: p&lt;0.05, p&lt;0.0001, respectively). Conclusions Baseline GTS by 3D echocardiography is useful for predicting outcome over 3 years after CRT implantation regardless of the ECG criteria for CRT indication.

Atrial fibrillation incidence and impact of biventricular pacing on long-term outcome in patients with heart failure treated with cardiac resynchronization therapy

BackgroundIn patients with cardiac resynchronization therapy (CRT), atrial fibrillation (AF) is associated with an unfavorable outcome and may cause loss of biventricular pacing (BivP). An effective delivery of BivP of more than 98% of all ventricular beats has been shown to be a major determinant of CRT-success.MethodsAt a Swedish tertiary referral center, data was retrospectively obtained from patient registers, medical records and preoperative electrocardiograms. Data regarding AF and BivP during the first year of follow-up was assessed from CRT-device interrogations. No intra-cardiac electrograms were studied. Kaplan-Meier curves and Cox-regression analyses adjusted for age, etiology of heart failure, left ventricular ejection fraction, left bundle branch block and NYHA class were performed to assess the impact of AF and BivP on the risk of death or heart transplantation (HTx) at 10-years of follow-up.ResultsPreoperative AF-history was found in 54% of the 379 included patients and was associated with, but did not independently predict death or HTx. The one-year incidence of new device-detected AF was 22% but not associated with poorer prognosis. At one-year, AF-history and BivP≤98%, was associated with a higher risk of death or HTx compared to patients without AF (HR 1.9, 95%CI 1.2–3.0, p = 0.005) whereas AF and BivP> 98% was not (HR 1.4, 95%CI 0.9–2.3, p = 0.14).ConclusionsIn CRT-recipients, AF-history is common and associated with poor outcome. AF-history does not independently predict mortality and is probably only a marker of a more severe underlying disease. BivP≤98% during first-year of CRT-treatment independently predicts poor outcome thus further supporting the use of 98% threshold of BivP, which should be attained to maximize the benefits of CRT.

Implantable Cardioverter-Defibrillators and Cardiac Resynchronization Therapy in Older Adults With Heart Failure.

Implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) are cardiac implantable electronic devices that may improve morbidity and mortality in select patients with heart failure. Although the benefits of these devices have been well defined, competing mortality risks, comorbid conditions, and frailty pose difficulty in determining risk-benefit trade-offs when these options are considered for older adults. In this review, we focus on the benefit, risk, and use of ICD and CRT in older adults, particularly because the goals of care for many older adults include a shift away from life-prolonging interventions. Additionally, we discuss periprocedural risk, cost, and maintenance in older populations. Finally, we introduce a framework for helping clinicians and older adults make these challenging decisions collectively. J Am Geriatr Soc 67:2193-2199, 2019.

Cardiac Resynchronization Defibrillator Therapy for Nonspecific Intraventricular Conduction Delay Versus Right Bundle Branch Block

BackgroundThe benefits of cardiac resynchronization therapy (CRT) in patients with non-left bundle branch block (LBBB) conduction abnormality have not been fully explored. ObjectivesThis study sought to evaluate clinical outcomes among Medicare-aged patients with nonspecific intraventricular conduction delay (NICD) versus right bundle branch block (RBBB) in patients eligible for implantation with a CRT with defibrillator (CRT-D). MethodsUsing the National Cardiovascular Data Registry implantable cardioverter-defibrillator (ICD) registry data between 2010 and 2013, the authors compared outcomes in CRT-eligible patients implanted with CRT-D versus ICD-only therapy among patients with NICD and RBBB. Also, among all CRT-D–implanted patients, the authors compared outcomes in those with NICD versus RBBB. Survival curves and multivariable adjusted hazard ratios (HRs) were used to assess outcomes including hospitalization and death. ResultsIn 11,505 non-LBBB CRT-eligible patients, after multivariable adjustment, among patients with RBBB, CRT-D was not associated with better outcomes, compared with ICD alone, regardless of QRS duration. Among patients with NICD and a QRS ≥150 ms, CRT-D was associated with decreased mortality at 3 years compared with ICD alone (HR: 0.602; 95% confidence interval [CI]: 0.416 to 0.871; p = 0.0071). Among 5,954 CRT-D–implanted patients, after multivariable adjustment NICD compared with RBBB was associated with lower mortality at 3 years in those with a QRS duration of ≥150 ms (HR: 0.757; 95% CI: 0.625 to 0.917; p = 0.0044). ConclusionsAmong non-LBBB CRT-D–eligible patients, CRT-D implantation was associated with better outcomes compared with ICD alone specifically in NICD patients with a QRS duration of ≥150 ms. Careful patient selection should be considered for CRT-D implantation in patients with non-LBBB conduction.

The relationship between ECG predictors of cardiac resynchronization therapy benefit.

IntroductionCardiac resynchronization therapy (CRT) is an effective treatment that reduces mortality and improves cardiac function in patients with left bundle branch block (LBBB). However, about 30% of patients passing the current criteria do not benefit or benefit only a little from CRT. Three predictors of benefit based on different ECG properties were compared: 1) “strict” left bundle branch block classification (SLBBB); 2) QRS area; 3) ventricular electrical delay (VED) which defines the septal-lateral conduction delay. These predictors have never been analyzed concurrently. We analyzed the relationship between them on a subset of 602 records from the MADIT-CRT trial.Methods & resultsSLBBB classification was performed by two experts; QRS area and VED were computed fully automatically. High-frequency QRS (HFQRS) maps were used to inspect conduction abnormalities. The correlation between SLBBB and other predictors was R = 0.613, 0.523 and 0.390 for VED, QRS area in Z lead, and QRS duration, respectively. Scatter plots were used to pick up disagreement between the predictors. The majority of SLBBB subjects– 295 of 330 (89%)–are supposed to respond positively to CRT according to the VED and QRS area, though 93 of 272 (34%) non-SLBBB should also benefit from CRT according to the VED and QRS area.ConclusionSLBBB classification is limited by the proper setting of cut-off values. In addition, it is too “strict” and excludes patients that may benefit from CRT therapy. QRS area and VED are clearly defined parameters. They may be used to optimize biventricular stimulation. Detailed analysis of conduction irregularities with CRT optimization should be based on HFQRS maps.

Cardiac resynchronization therapy in patients with heart failure and moderately reduced ejection fraction: Could it trigger a super-response?

Background/AimDespite the well-established benefits of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with left ventricular ejection fraction (LVEF) ≤35%, many patients with less reduced EF remain refractory to optimized medical treatment and at high risk of morbidity and mortality. The objective of the study is to evaluate the effects of CRT in optimally treated patients with New York Heart Association (NYHA) classes II–IV, LVEF of 36–45%, and left bundle branch (LBBB), including clinical, structural and biochemical response. MethodsA selected group of HF patients have been implanted with CRT-P devices and were followed up for 6 months at 4, 12 and 24 weeks. Clinical assessment included NYHA class, quality of life and 6-min walk distance (6 MWD) test. Echocardiographic assessment included LV dimensions and function and left atrial volume. Serum N-terminal pro b-type natriuretic peptide (NT-ProBNP) was measured at the same intervals. ResultsThis prospective single center study included 23 patients. NYHA functional class significantly improved after CRT-P (p < 0.0001), associated with improvement in QOL (p < 0.0001) and 6 MWD, which increased, from 145.7 ± 20.1 m to 219.5 ± 42.2 m (p < 0.0001). Mean QRS duration showed significant shortening from 164.4 ± 13.2 ms to 126.4 ± 13.6 ms (p < 0.0001). CRT induced reverse remodeling with reduction in both left ventricular end diastolic diameter (LVEDD) from 68.95 ± 5.05 mm to 62.8 ± 4.47 mm, p = 0.0002 and left ventricular end systolic diameter (LVESD) from 54.1 ± 4.5 mm to 46.5 ± 4.1 mm, p < 0.0001, and significant increase in LVEF (from 40.3 ± 2.8 to 48.3 ± 4.2 mm, p < 0.0001). The biochemical response to CRT showed significant reduction in serum NT-ProBNP from 1025.6 ± 363.1 pg/ml to 594.9 ± 263.5 pg/ml (p < 0.0001). ConclusionsSymptomatic HF patients on maximal optimized medical treatment who have LBBB and baseline LVEF 35–45% appeared to derive significant clinical and structural benefit from CRT.

Clinical outcomes of cardiac resynchronization therapy with and without a defibrillator in elderly patients with heart failure.

BackgroundEvidence regarding the incremental benefit of cardiac resynchronization therapy (CRT) with a defibrillator (CRT‐D) versus without (CRT‐P) in elderly patients with heart failure is limited. We compared mortality and cardiac hospitalisation between CRT‐D and CRT‐P in the elderly.MethodsA retrospective chart review identified all consecutive patients with age ≥75 with CRT implantation over the last 10 years at a Canadian tertiary care cardiac centre. Kaplan‐Meier survival analyses and cumulative incidence curves were used to compare mortality and time to first cardiac hospitalisation, respectively, with CRT‐D versus CRT‐P over a 3 year period. Analyses were also repeated with propensity score matching based on age, sex, primary versus secondary prevention, date of implant, and Charlson Comorbidity Index.ResultsOne hundred and seventy CRT patients were identified. A total of 128 received CRT‐D while 42 received CRT‐P. Median age was 79 (IQR 77‐81), and the majority were male (83%). CRT‐P patients had a higher burden of comorbidities (Charlson score 7, IQR 6‐8) than CRT‐D patients (Charlson score 5, IQR 5‐7; P < 0.001). There was no significant difference in survival between the two groups in an unmatched comparison (P = 0.69) and with a propensity score‐matched cohort (P = 0.91). Secondary prevention CRT‐D patients had a higher risk of hospitalisation compared to primary prevention CRT‐D patients; however, there was no significant difference in hospitalisation between the CRT‐D and CRT‐P groups.ConclusionThis study suggests there is no significant difference in mortality or cardiac hospitalisation between CRT‐D and CRT‐P in elderly patients with heart failure.

Benefit of Cardiac Resynchronization Therapy in Patients with Heart Failure

Heart failure is a disease characterized by cardiac remodeling or progressive dilation of left ventricle and a consequent reduction in contraction. Ventricular remodeling has been shown to be a negative prognostic factor alone, and therefore the most beneficial drugs are those that prevent or reduce left ventricular dilation. The pharmacological therapy of heart failure, although maximal, has proven to be not fully effective. The aim of our research was to evaluate resynchronization therapy in a lot of patients, monitoring their cardiac performance before and after cardiac resynchronization therapy.

Usefulness of Cardiac Resynchronization Therapy in Patients With Continuous Flow Left Ventricular Assist Devices

The benefit of cardiac resynchronization therapy in patients supported by a left ventricular assist device (LVAD) is unknown. There are currently no guidelines regarding the continuation, discontinuation or pacemaker (PM) settings post-LVAD implant. The aim of the study was to assess the hemodynamic benefit of biventricular (BiV) pacing in LVAD patients. We studied 22 patients supported by LVADs (age 62 ± 9, 21 males) who had received a BiV PM before LVAD implant. A total of 123 complete sets of hemodynamics were obtained during BiV pacing (n = 54), right ventricular (RV) pacing (n = 54), and intrinsic rhythm (n = 15). There were no significant differences in right atrial (RA) pressure, mean pulmonary artery pressure (mPA), PCWP, cardiac output, PA saturation (PASat) and right ventricular stroke work index between BiV and RV pacing. Hemodynamics obtained during intrinsic rhythm in 15 non-PM-dependent patients were not significantly different compared with those obtained during BiV or RV pacing. Furthermore, hemodynamics were similar at different heart rates ranging 50 to 110 beats/min. Right ventricular stroke work index was significantly lower at the highest heart rate compared with baseline and lowest heart rates suggesting decreased RV performance at higher heart rate. In conclusion, BiV pacing does not have any acute hemodynamic benefit compared with RV pacing or intrinsic rhythm in LVAD patients. A lower heart rate may confer better RV performance.

COMPARING CLINICAL OUTCOMES OF CRT-P VS CRT-D IN ELDERLY PATIENTS WITH HEART FAILURE

There is limited evidence regarding the incremental benefit of cardiac resynchronization therapy (CRT) with a defibrillator (CRT-D) versus without (CRT-P) in elderly patients with heart failure receiving optimal medical therapy. This study compared mortality and cardiac hospital admissions between CRT-D and CRT-P in the elderly. A retrospective chart review identified all consecutive patients with age > 75 who underwent CRT implantation over the last 10 years at a Canadian tertiary care cardiac centre. Kaplan-Meier survival analyses and cumulative incidence curves were used to compare mortality and time to first cardiac hospitalization, respectively, in patients receiving CRT-D versus CRT-P over a three year time period. Analyses were also repeated with propensity score matching based on age, sex, primary versus secondary prevention, date of implant, and Charlson Comorbidity Index. 170 CRT patients were identified. 128 received CRT-D while 42 received CRT-P. Median age was 79(IQR 77 - 81), and the majority were male (83%). CRT-P patients had a higher burden of comorbidities (Charlson score 7, IQR 6 - 8) than CRT-D patients (Charlson score 5, IQR 5 - 7; p < 0.001). There was no significant difference in survival between the two groups in an unmatched comparison (P = 0.69) and with a propensity score-matched cohort (P = 0.91). Secondary prevention CRT-D patients had a higher risk of hospitalization compared to primary prevention CRT-D patients; however there was no significant difference in hospitalization between the CRT-D group when compared to CRT-P patients. There is no significant difference in mortality or hospitalizations for cardiac cause between CRT-D and CRT-P in patients over the age of 75 with heart failure receiving optimal medical therapy.