An individual patient meta-analysis of five randomized trials assessing the effects of cardiac resynchronization therapy on morbidity and mortality in patients with symptomatic heart failure

Conduction System Pacing for CRT: A Physiological Alternative

There are many factors contributing to the failure of conventional CRT with biventricular pacing, including coronary anatomy and an inability to stimulate diseased tissue. In this paper, we review evolving conduction system pacing (CSP), a physiological alternative to conventional CRT. CSP allows correction of bundle branch block and provides new opportunities to address multiple limitations of conventional CRT. Further studies are required to determine how the techniques are best applied in specific clinical situations.

Optimizing Patient Selection for Cardiac Resynchronization Therapy With or Without Defibrillator in a Multicenter Study of Japanese Patients - Assessment of the MADIT-ICD Benefit Score

BACKGROUND

Although the MADIT-ICD benefit score (MBS) helps select suitable implantable cardioverter defibrillator (ICD) candidates, optimal indicators for cardiac resynchronization therapy (CRT) remain uncertain. Evaluating the applicability of the MBS in Japanese CRT patients is imperative.

METHODS AND RESULTS

This multicenter study assessed the cumulative incidence of ventricular tachycardia/fibrillation (VT/VF) and non-arrhythmic mortality (AM) in CRT patients grouped according to potential benefit (lowest, highest, and intermediate). Among 400 primary prevention patients (mean age 65 years, 76% male), VT/VF occurred in 4 (7%), 68 (24%), and 14 (23%) patients in the lowest-, intermediate-, and highest-benefit groups, respectively (P=0.027), over a median follow-up of 34 months. Non-arrhythmic death was observed in 15 (25%), 91 (33%), and 9 (15%) patients in the lowest-, intermediate-, and highest-benefit groups, respectively (P=0.025). Multivariate analysis identified VT/VF score ≥7 (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.09-4.19; P=0.027) as a significant VT/VF predictor. The presence of left bundle branch block (HR 0.51; 95% CI 0.29-0.92; P=0.025) was associated with a reduced risk of VT/VF events. Non-AM score ≥3 (HR 1.70; 95% CI 1.01-2.88; P=0.047), systolic blood pressure <100 mmHg (HR 1.84; 95% CI 1.25-2.70; P=0.002), and estimated glomerular filtration rate <30 mL/min/1.73 m2(HR 1.98; 95% CI 1.23-3.20; P=0.005) were significant predictors of non-arrhythmic death.

CONCLUSIONS

The MBS can identify suitable candidates for CRT-D among Japanese individuals.

Temporal trends in population characteristics and type of device among primary prevention implantable cardioverter defibrillator recipients: The DAI-PP programme

BACKGROUND

Patient characteristics, technology and clinical practice surrounding primary prevention implantable cardioverter defibrillators have evolved continuously over time.

AIM

To explore the temporal changes in patient characteristics, pharmacological therapy and device types among implantable cardioverter defibrillator recipients implanted for the primary prevention of sudden cardiac death over the last two decades in France.

METHODS

Characteristics of participants and type of device from the retrospective DAI-PP Pilot Study (2002-2012) were compared with those from the ongoing prospective DAI-PP Consortium (2018 onwards).

RESULTS

This study included 9588 participants overall (DAI-PP Pilot Study, n=5539; DAI-PP Consortium, n=4049). Compared with the DAI-PP Pilot Study, the DAI-PP Consortium subjects were older at implantation (62.5 vs 65.2 years; P=0.001) and had a higher proportion of women (15.1% vs 20.6%; P<0.001), a similar proportion of ischaemic heart disease (60.2% vs 60.2%; P=0.98), a higher left ventricular ejection fraction (27±7% vs 30±8%; P<0.001) and more patients with narrow QRS complexes (30.5% vs 46.0%; P<0.001). The proportion of patients treated with heart failure drugs increased significantly (70.1% vs 83.1%; P<0.001), whereas the use of amiodarone became much less frequent (22.7% vs 14.7%; P<0.001). Finally, the proportions of cardiac resynchronization therapy defibrillators (53.8% vs 46.4%; P<0.001) and dual-chamber defibrillators (23.3% vs 17.3%; P<0.001) decreased, whereas subcutaneous implantable cardioverter defibrillators now account for a sizeable proportion of implants (14.6%).

CONCLUSIONS

Over a 20-year period, the primary prevention implantable cardioverter defibrillator population has evolved significantly, with an older age and a higher proportion of women. The type of device has changed, with fewer cardiac resynchronization therapy defibrillators and more subcutaneous implantable cardioverter defibrillators.

The association between GRACE score at admission for myocardial infarction and the incidence of sudden cardiac arrests in long-term follow-up - the MADDEC study

Background. Sudden cardiac arrest (SCA), often also leading to sudden cardiac death (SCD), is a common complication in coronary artery disease. Despite the effort there is a lack of applicable prediction tools to identify those at high risk. We tested the association between the validated GRACE score and the incidence of SCA after myocardial infarction. Material and methods. A retrospective analysis of 1,985 patients treated for myocardial infarction (MI) between January 1st 2015 and December 31st 2018 and followed until the 31st of December of 2021. The main exposure variable was patients' GRACE score at the point of admission and main outcome variable was incident SCA after hospitalization. Their association was analyzed by subdistribution hazard (SDH) model analysis. The secondary endpoints included SCA in patients with no indication to implantable cardioverter-defibrillator (ICD) device and incident SCD. Results. A total of 1985 patients were treated for MI. Mean GRACE score at baseline was 118.7 (SD 32.0). During a median follow-up time of 5.3 years (IQR 3.8-6.1 years) 78 SCA events and 52 SCDs occurred. In unadjusted analyses one SD increase in GRACE score associated with over 50% higher risk of SCA (SDH 1.55, 95% CI 1.29-1.85, p < 0.0001) and over 40% higher risk for SCD (1.42, 1.12-1.79, p = 0.0033). The associations between SCA and GRACE remained statistically significant even with patients without indication for ICD device (1.57, 1.30-1.90, p < 0.0001) as well as when adjusting with patients LVEF and omitting the age from the GRACE score to better represent the severity of the cardiac event. The association of GRACE and SCD turned statistically insignificant when adjusting with LVEF. Conclusions. GRACE score measured at admission for MI associates with long-term risk for SCA.

[Left bundle branch pacing is superior to classic cardiac resynchronisation therapy : Pros and cons]

Cardiac resynchronisation therapy (CRT) is an effective method for increasing quality of life and life expectancy for many patients with heart failure. Due to the good results, this procedure is used frequently in Germany and has established itself as a class I indication in heart failure therapy. In addition to His bundle pacing, left bundle branch pacing has now also made a name for itself, as it shows a good success rate and can be used in a wider range of patients. Now the question arises as to whether left bundle branch pacing is superior to classic biventricular pacing and what the evidence situation is in this respect. This question shall be discussed in this article considering current studies and guideline recommendations.

Heart failure in Europe: Guideline-directed medical therapy use and decision making in chronic and acute, pre-existing and de novo, heart failure with reduced, mildly reduced, and preserved ejection fraction - the ESC EORP Heart Failure III Registry

AIMS

We analysed baseline characteristics and guideline-directed medical therapy (GDMT) use and decisions in the European Society of Cardiology (ESC) Heart Failure (HF) III Registry.

METHODS AND RESULTS

Between 1 November 2018 and 31 December 2020, 10 162 patients with acute HF (AHF, 39%, age 70 [62-79], 36% women) or outpatient visit for HF (61%, age 66 [58-75], 33% women), with HF with reduced (HFrEF, 57%), mildly reduced (HFmrEF, 17%) or preserved (HFpEF, 26%) ejection fraction were enrolled from 220 centres in 41 European or ESC-affiliated countries. With AHF, 97% were hospitalized, 2.2% received intravenous treatment in the emergency department, and 0.9% received intravenous treatment in an outpatient clinic. AHF was seen by most by a general cardiologist (51%) and outpatient HF most by a HF specialist (48%). A majority had been hospitalized for HF before, but 26% of AHF and 6.1% of outpatient HF had de novo HF. Baseline use, initiation and discontinuation of GDMT varied according to AHF versus outpatient HF, de novo versus pre-existing HF, and by ejection fraction. After the AHF event or outpatient HF visit, use of any renin-angiotensin system inhibitor, angiotensin receptor-neprilysin inhibitor, beta-blocker, mineralocorticoid receptor antagonist and loop diuretics was 89%, 29%, 92%, 78%, and 85% in HFrEF; 89%, 9.7%, 90%, 64%, and 81% in HFmrEF; and 77%, 3.1%, 80%, 48%, and 80% in HFpEF.

CONCLUSION

Use and initiation of GDMT was high in cardiology centres in Europe, compared to previous reports from cohorts and registries including more primary care and general medicine and regions more local or outside of Europe and ESC-affiliated countries.

Cardiac Resynchronization Therapy in Ischemic Versus Nonischemic Cardiomyopathy: Patient-Level Meta-Analysis of 7 Randomized Clinical Trials

BACKGROUND

Data on whether cardiac resynchronization therapy (CRT) results in better clinical and echocardiographic outcomes in patients with nonischemic cardiomyopathy (NICM) vs ischemic cardiomyopathy (ICM) are conflicting.

OBJECTIVES

The authors conducted this meta-analysis of 7 clinical trials of CRT to determine the association between etiology of cardiomyopathy and clinical and echocardiographic outcomes.

METHODS

The authors analyzed patient-level data using Bayesian Hierarchical Weibull survival regression modeling to determine the association between etiology of cardiomyopathy and time to all-cause death or heart failure hospitalization (HFH). Linear regression was used to assess the association between etiology of cardiomyopathy and echocardiographic measurements.

RESULTS

Of 6,252 patients included, 4,717 (75%) were men, median age was 66 years (IQR: 58-73 years), 3,704 (59%) had ICM, and 3,778 (60%) received CRT. CRT increased the time to HFH or all-cause death (HR: 0.67; 95% credible interval [CrI]: 0.56-0.82; P < 0.001) with no difference by etiology of cardiomyopathy (HR ratio: 1.06 [95% CrI: 0.87-1.29]; P = 0.57). Likewise, CRT increased the time to all-cause death (HR: 0.71 [95% CrI: 0.55-0.93]; P = 0.019) with no difference by etiology of cardiomyopathy (HR ratio: 1.06 [95% CrI: 0.80-1.43]; P = 0.70). Echocardiographic data that were available for 2,430 (39%) patients showed that CRT improvements in left ventricular ejection fraction, left ventricular end-diastolic diameter, and left ventricular end-systolic diameter were larger for patients with NICM.

CONCLUSIONS

Although CRT led to greater increases in left ventricular ejection fraction and reductions in ventricular dimensions for patients with NICM compared with those with ICM, CRT significantly increased the time to HFH or all-cause death independently of the etiology of cardiomyopathy. Further studies on improving patient selection for CRT are needed.

Lateral QRS amplitude is independently associated with outcome after cardiac resynchronization therapy: Advancing patient selection?

BACKGROUND

Cardiac resynchronization therapy (CRT) is a cornerstone in the treatment of selected heart failure patients. However, a relevant proportion of patients do not show beneficial response. Identification of simple, additive, and outcome-relevant selection criteria may improve selection of patients.

OBJECTIVE

We sought to determine whether baseline QRS amplitude is associated with outcome in CRT.

METHODS

Quantification of intrinsic, pre-CRT implantation QRS amplitude was performed in an observational multinational 2-center retrospective cohort analysis (derivation cohort Zurich, n = 178, 2000-2015; validation cohort Leuven, n = 183, 1999-2016) with a composite end point of all-cause mortality, ventricular assist device implantation, or heart transplantation at 5 years.

RESULTS

Higher baseline to peak amplitude in lateral leads (lead I and V6) was associated with a lower risk of reaching the composite end point (lead I: hazard ratio, 0.86 [95% confidence interval, 0.78-0.95] per millivolt, P = .002; lead V6: hazard ratio, 0.94 [95% confidence interval, 0.88-1.00] per millivolt, P = .043). Concordance index-based comparison of quartile, spline, and receiver operating characteristic curve analysis suggested cutoff values of 6 mV for lead I and 3 mV for V6 for optimal discrimination of outcome. External validation confirmed the cutoff of 3 mV in lead V6 as a highly significant discriminator of outcome (P < .001) associated with a risk reduction of 65%.

CONCLUSION

Low QRS amplitude in lateral electrocardiogram leads is associated with higher risk of poor outcome in CRT patients. A cutoff of 3 mV in lead V6 proved highly discriminative. Further studies need to confirm the additive value of QRS amplitude in selection of patients for CRT and to assess whether CRT may be made available to more patients.

Prognostic Evaluation of Chagasic and Non-Chagasic Patients Undergoing Pacemaker Implantation and Cardiac Resynchronization in a Tertiary Center

BACKGROUND

Chagas cardiomyopathy (ChCC) is one of the causes of the implantation of pacemakers (PM) in many patients and has been associated with an adverse prognosis.

OBJECTIVES

To compare the prognosis of the chagasic and non-chagasic populations undergoing PM and cardiac resynchronizer implantation.

METHODS

Observational, retrospective study, which analyzed a cohort of patients who underwent implantation of these devices, in a tertiary center, from October 2007 to December 2017, comparing the chagasic group with non-chagasic patients. The non-parametric Kaplan-Meier method was used to calculate patient survival. The significance level adopted in the statistical analysis was 5%. The primary outcome was mortality from any cause, while the secondary outcomes were the occurrence of hospitalization and the combination of hospitalization and death.

RESULTS

A total of 911 patients were included, of which 23.4% had ChCC. In a Cox analysis adjusted for sex and age, Chagas disease (ChD) was not associated with an increased risk of death (HR: 1.14, CI:95%, 0.86-1.51, p=0.365), hospitalization (HR: 0.79, CI:95%, 0.61-1.04, p=0.09) or combined outcome of death and hospitalization (HR: 0.90, CI:95%, 0.72-1 .12, p=0.49).

CONCLUSIONS

ChD was not associated with an increased risk of death, hospitalization, or combined outcome of death and hospitalization, even after adjustment for sex and age. These results contrast with those of previous studies and suggest changes in the quality of care of patients with cardiomyopathy.

Rhythm and rate control strategies in patients with long-standing persistent atrial fibrillation treated with cardiac resynchronization: the results of the randomized Pilot-CRAfT study

BACKGROUND

Atrial fibrillation (AF) is common in cardiac resynchronization therapy (CRT) recipients. It is a marker of impaired CRT response mainly mediated by the reduction of effectively captured biventricular paced beats (BiVp). There are no randomized trials comparing strategies to maintain high BiVp percentage.

OBJECTIVE

To compare the efficacy of rhythm vs rate control strategies in CRT recipients with long-standing persistent AF.

METHODS

We performed a randomized trial including CRT recipients with persistent AF resulting in low BiVp%. All patients received amiodarone, the rhythm control group received external electrical cardioversion (EC), and the rate control group received atrioventricular node ablation, if needed. The primary end-point was 12-month BiVp% (NCT).

RESULTS

43 patients were included in the analysis. The mean age was 68.4 (SD: ± 8.3) years and the mean BiVp% 82.4% ± 9.7%. AF lasted 25 ± 19 months. The mean baseline left ventricular ejection fraction (LVEF), left atrium area, and the maximal oxygen uptake (VO2max) were: 30 ± 8%, 33 ± 7 cm2, and 14 ± 5 mL/(kg*min), respectively. The EC success rate was 58%. 38% patients remained in sinus rhythm (SR) after 12 months. BiVp% increased similarly in both arms reaching 99% [95% CI 97.3-99.8] and 98% [94.0-99.0], P = 0.14 in rhythm and rate control groups, respectively. LVEF raised significantly only in the rhythm control group (ΔLVEF 4.1 (± 7.3), P = 0,018) which was driven by the patients who maintained SR. No differences in VO2max, QoL, clinical and safety end-points were observed.

CONCLUSION

Despite comparable BiVp% in both groups, only restoration of SR led to improved left ventricular ejection fraction in CRT patients with long-standing AF.

TRIAL REGISTRATION

NCT01850277 registered on 22/04/2013.

The Suboptimal QLV Ratio May Indicate the Need for a Left Bundle Branch Area Pacing-Optimized Cardiac Resynchronization Therapy Upgrade

Background: The QLV ratio (QLV/baseline QRS width) is an established intraoperative-measurable parameter during cardiac resynchronization therapy (CRT) device implantation, potentially predicting the efficacy of electrical resynchronization. Methods: Left bundle branch area pacing-optimized CRT (LOT-CRT) is a novel approach with the potential to improve both responder rate and responder level in the CRT candidate patient group, even when an optimal electro-anatomical left ventricular lead position is not achievable. In our observational study, 72 CRT-defibrillator candidate patients with a QRS duration of 160 ± 12 ms were consecutively implanted. Using a QLV-ratio-based implant strategy, 40 patients received a biventricular CRT device (Biv-CRT) with an optimal QLV ratio (≥70%). Twenty-eight patients with a suboptimal QLV ratio (<70%) were upgraded intraoperatively to a LOT-CRT system. Patients were followed for 12 months. Results: The postoperative results showed a significantly greater reduction in QRS width in the LOT-CRT patient group compared to the Biv-CRT patients (40.4 ± 14 ms vs. 32 ± 13 ms; p = 0.024). At 12 months, the LOT-CRT group also demonstrated a significantly greater improvement in left ventricular ejection fraction (14.9 ± 8% vs. 10.3 ± 7.4%; p = 0.001), and New York Heart Association functional class (1.2 ± 0.5 vs. 0.8 ± 0.4; p = 0.031), and a significant decrease in NT-pro-BNP levels (1863± 380 pg/mL vs. 1238 ± 412 pg/mL; p = 0.012). Notably, the LOT-CRT patients showed results comparable to Biv-CRT patients with a super-optimal QLV ratio (>80%) in terms of QRS width reduction and LVEF improvement. Conclusions: Our single-center study demonstrated the feasibility of a QLV-ratio-based implantation strategy during CRT implantation. Patients with a LOT-CRT system showed significant improvements, whereas Biv-CRT patients with a super-optimal QLV ratio may not be expected to benefit from an additional LOT-CRT upgrade.

Effects of dapagliflozin according to QRS duration across the spectrum of left ventricular ejection fraction: An analysis of DAPA-HF and DELIVER

AIMS

The primary aim was to evaluate the effect of dapagliflozin according to QRS duration across the spectrum of left ventricular ejection fraction (LVEF), given that prolongation of QRS duration is associated with less favourable ventricular remodelling with pharmacological therapy and worse outcomes.

METHODS AND RESULTS

A pooled analysis of the DAPA-HF and DELIVER trials, excluding patients with a paced rhythm and cardiac resynchronization therapy. Overall, 4008 patients had heart failure (HF) with reduced ejection fraction (HFrEF), and 5816 had HF with mildly reduced/preserved ejection fraction (HFmrEF/HFpEF). QRS duration was <120 ms in 7039 patients (71.7%), 120-149 ms in 1725 (17.6%), and ≥150 ms in 1060 patients (10.8%). The median follow-up time was 23 months. The rate of the primary composite outcome of cardiovascular death or worsening HF was 9.2 (95% confidence interval [CI] 8.7-9.7), 14.3 (13.0-15.7), and 15.9 (14.1-17.9) per 100 patient-years in the <120, 120-149, and ≥150 ms groups, respectively. This gradient in event rates was observed both in HFrEF and HFmrEF/HFpEF. Dapagliflozin, compared with placebo, reduced the risk of the primary outcome consistently across the QRS duration subgroups (hazard ratio [95% CI] 0.75 [0.67-0.85], 0.79 [0.65-0.96], and 0.89 [0.70-1.13] in the <120, 120-149, and ≥150 ms groups, respectively; p for interaction = 0.28). The effect of dapagliflozin on the primary outcome was consistent across the QRS duration regardless of HF phenotype that is, HFrEF or HFmrEF/HFpEF.

CONCLUSIONS

Prolongation of QRS duration is associated with worse outcomes irrespective of HF phenotype. Dapagliflozin reduced the risk of the primary outcome, regardless of QRS duration, in DAPA-HF and DELIVER.

Outcomes of Cardiac Resynchronization Therapy by New York Heart Association Class: A Patient-Level Meta-Analysis

BACKGROUND

Data on the benefits of cardiac resynchronization therapy (CRT) in patients with severe heart failure symptoms are limited. We investigated the relative effects of CRT in patients with ambulatory New York Heart Association (NYHA) IV versus III functional class at the time of device implantation.

METHODS AND RESULTS

In this meta-analysis, we pooled patient-level data from the MIRACLE (Multicenter InSync Randomized Clinical Evaluation), MIRACLE-ICD (Multicenter InSync Implantable Cardioversion Defibrillation Randomized Clinical Evaluation), and COMPANION (Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure) trials. Outcomes evaluated were time to the composite end point of the first heart failure hospitalization or all-cause mortality, and time to all-cause mortality alone. The association between CRT and outcomes was evaluated using a Bayesian hierarchical Weibull survival regression model. We assessed if this association differed between NYHA III and IV groups by adding an interaction term between CRT and NYHA class as a random effect. A sensitivity analysis was performed by including data from RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure). Our pooled analysis included 2309 patients. Overall, CRT was associated with a longer time to heart failure hospitalization or all-cause mortality (adjusted hazard ratio [aHR], 0.79 [95% credible interval [CI], 0.64-0.99]; posterior probability or P=0.044), with a similar association with time to all-cause mortality (aHR, 0.78 [95% CI, 0.59-1.03]; P=0.083). Associations of CRT with outcomes were not significantly different for those in NYHA III and IV classes (ratio of aHR, 0.72 [95% CI, 0.30-1.27]; P=0.23 for heart failure hospitalization/mortality; ratio of aHR, 0.70 [95% CI, 0.35-1.34]; P=0.27 for all-cause mortality alone). The sensitivity analysis, including RAFT data, did not show a significant relative CRT benefit between NYHA III and IV classes.

CONCLUSIONS

Overall, there was no significant difference in the association of CRT with either outcome for patients in NYHA functional class III compared with functional class IV.

[New pacing strategies for heart failure]

In patients with a reduced left ventricular (LV) systolic function (ejection fraction < 35%) and a left bundle branch block with a QRS duration > 130 ms, cardiac resynchronization therapy (CRT) can contribute to an improvement in the quality of life and a reduction in mortality. The resynchronization is mostly achieved by pacing via an epicardial LV lead in the coronary sinus; however, this approach is often limited by the patient's venous anatomy and an increase in the stimulation threshold over time. In addition, up to 30% of patients do not respond to the intervention. New treatment approaches involve direct stimulation of the conduction system by pacing of the bundle of His or left bundle branch. This enables a more physiological propagation of the stimulus. Pacing of the left bundle branch is achieved by advancing the lead into the right ventricle and screwing it deep into the interventricular septum. Due to the relatively large target area of the left bundle branch the success rate is very high (currently > 90%). Observational studies have shown a greater reduction in the QRS duration, a more pronounced improvement in systolic function and a lower hospitalization rate for heart failure associated with conduction system pacing compared to CRT using a coronary sinus lead. These findings have been confirmed in small randomized trials. Therefore, the use of left bundle branch pacing should be considered not only as a bail out in the case of failed resynchronization using coronary sinus lead placement but increasingly also as an initial pacing strategy. The results of the first large randomized trials are expected to be released in late 2024.

Implication of geriatric nutritional risk index on treatment response and long-term prognosis in patients with cardiac resynchronization therapy

PURPOSE

Geriatric Nutritional Risk Index (GNRI) is a simple tool for assessing the nutritional status of the aging population. This study aims to explore the clinical implication of GNRI on treatment response and long-term clinical outcomes in heart failure (HF) patients receiving cardiac resynchronization therapy (CRT).

METHODS

Patients who underwent CRT implantation or upgrade at our hospital were retrospectively included. The association of GNRI and its tertiles with the echocardiographic response, all-cause mortality or heart transplantation, and the first hospitalization due to HF were investigated.

RESULTS

Totally, 647 patients were enrolled, with a median age of 60 [Interquartile Range (IQR): 52-67] years and mean score of GNRI at 107.9 ± 23.7. Super-response rates increased significantly among the GNRI T1, T2, and T3 groups (25.1%, 29.8% vs. 41.1%, P = 0.002). Patients with higher GNRI were more likely to have better LVEF improvement after multiple adjustments (OR = 1.13, 95% CI: 1.04-1.23, P = 0.010). Higher GNRI was independently associated with a lower risk of all-cause mortality or heart implantation (HR = 0.95, 95% CI: 0.93-0.96, P < 0.001) and HF hospitalization (HR = 0.96, 95% CI: 0.95-0.98, P < 0.001). The inclusion of GNRI enhanced the predictability of all-cause mortality based on traditional model, including sex, New York Heart Association functional class, left bundle branch block, QRS reduction, and N-terminal pro-B-type natriuretic peptide level (C statistics improved from 0.785 to 0.813, P = 0.007).

CONCLUSION

Higher GNRI was associated with better treatment response and long-term prognosis in HF patients with CRT. Evaluation of nutritional status among CRT population is necessary for individualized choice of potential responders.

[Advances in heart failure management]

Heart failure is a pathological condition characterized by substantial prevalence and mortality, particularly in the Western world. Over recent decades, both pharmacological and non-pharmacological interventions have emerged, significantly enhancing patient survival and overall quality of life. Moreover, advancements in diverse imaging modalities facilitate precise diagnosis and comprehensive investigation into the fundamental etiology, enabling the development of more precise therapeutic approaches. Nonetheless, discernible gaps persist in comprehending specific facets of this condition, albeit persistent research endeavors seek to elucidate these inquiries.

Sex-related similarities and differences in responses to heart failure therapies

Although sex-related differences in the epidemiology, risk factors, clinical characteristics and outcomes of heart failure are well known, investigations in the past decade have shed light on an often overlooked aspect of heart failure: the influence of sex on treatment response. Sex-related differences in anatomy, physiology, pharmacokinetics, pharmacodynamics and psychosocial factors might influence the response to pharmacological agents, device therapy and cardiac rehabilitation in patients with heart failure. In this Review, we discuss the similarities between men and women in their response to heart failure therapies, as well as the sex-related differences in treatment benefits, dose-response relationships, and tolerability and safety of guideline-directed medical therapy, device therapy and cardiac rehabilitation. We provide insights into the unique challenges faced by men and women with heart failure, highlight potential avenues for tailored therapeutic approaches and call for sex-specific evaluation of treatment efficacy and safety in future research.

Clinical utility of QRS duration normalized to left ventricular volume for predicting cardiac resynchronization therapy efficacy in patients with "mid-range" QRS duration

BACKGROUND

Cardiac resynchronization therapy (CRT) is effective for patients with heart failure with QRS duration (QRSd) ≥150 ms. However, its beneficial effect seems to be limited for those with "mid-range" QRSd (120-149 ms). Recent studies have demonstrated that modifying QRSd to left ventricular end-diastolic volume (LVEDV)-modified QRSd-improves the prediction of clinical outcomes of CRT.

OBJECTIVE

The purpose of this study was to investigate the clinical impact of the modified QRSd on the efficacy of CRT in patients with "mid-range" QRSd.

METHODS

We conducted a retrospective, multicenter, observational study, with heart failure hospitalization (HFH) after CRT as the primary endpoint. Modified QRSd is defined as QRSd divided by LVEDV, determined through the Teichholtz method of echocardiography.

RESULTS

Among the 506 consecutive patients considered, 119 (mean age 61 ± 15 years; 80% male, QRSd 135 ± 9 ms) with a "mid-range" QRSd who underwent de novo CRT device implantation were included for analysis. During median follow-up of 878 days [interquartile range 381-1663 days], HFH occurred in 45 patients (37%). Fine-Gray analysis revealed modified QRSd was an independent predictor of HFH (hazard ratio [HR] 0.97; 95% confidence interval [CI] 0.96-0.99; P <.01). Receiver operating characteristic curve analysis revealed a cutoff value of 0.65 ms/mL for the modified QRSd in predicting HFH. Patients above the threshold exhibited a significantly lower incidence of HFH than patients below the threshold (HR 0.46; 95% CI 0.25-0.86; P = .01).

CONCLUSION

Modified QRSd can effectively predict the efficacy of CRT in patients with a "mid-range" QRSd.

Pilot study to evaluate left-to-right ventricular offset in biventricular pacing-comparison of electrocardiographic imaging and ECG

INTRODUCTION

Biventricular pacing (BiVp) improves outcomes in systolic heart failure patients with electrical dyssynchrony. BiVp is delivered from epicardial left ventricular (LV) and endocardial right ventricular (RV) electrodes. Acute electrical activation changes with different LV-RV stimulation offsets can help guide individually optimized BiVp programming. We sought to study the BiVp ventricular activation with different LV-RV offsets and compare with 12-lead ECG.

METHODS

In five patients with BiVp (63 ± 17-year-old, 80% male, LV ejection fraction 27 ± 6%), we evaluated acute ventricular epicardial activation, varying LV-RV offsets in 20 ms increments from -40 to 80 ms, using electrocardiographic imaging (ECGI) to obtain absolute ventricular electrical uncoupling (VEUabs, absolute difference in average LV and average RV activation time) and total activation time (TAT). For each patient, we calculated the correlation between ECGI and corresponding ECG (3D-QRS-area and QRS duration) with different LV-RV offsets.

RESULTS

The LV-RV offset to attain minimum VEUabs in individual patients ranged 20-60 ms. In all patients, a larger LV-RV offset was required to achieve minimum VEUabs (36 ± 17 ms) or 3D-QRS-area (40 ± 14 ms) than that for minimum TAT (-4 ± 9 ms) or QRS duration (-8 ± 11 ms). In individual patients, 3D-QRS-area correlated with VEUabs (r 0.65 ± 0.24) and QRS duration correlated with TAT (r 0.95 ± 0.02). Minimum VEUabs and minimum 3D-QRS-area were obtained by LV-RV offset within 20 ms of each other in all five patients.

CONCLUSIONS

LV-RV electrical uncoupling, as assessed by ECGI, can be minimized by optimizing LV-RV stimulation offset. 3D-QRS-area is a surrogate to identify LV-RV offset that minimizes LV-RV uncoupling.

Efficacy of left bundle branch area pacing versus biventricular pacing in patients treated with cardiac resynchronization therapy: Select site - cohort study

BACKGROUND

Cardiac resynchronization therapy (CRT) is typically attempted with biventricular (BiV) pacing. One-third of patients are nonresponders. Left bundle branch area pacing (LBBAP) has been evaluated as an alternative means.

OBJECTIVE

The purpose of this study was to assess the feasibility and clinical response of permanent LBBAP as an alternative to BiV pacing.

METHODS

Of 479 consecutive patients referred with heart failure, 50 with BiV-CRT and 51 with LBBAP-CRT were included in this analysis after study exclusions. Quality-of-Life (QoL) assessments, echocardiographic measurements, and New York Heart Association (NYHA) class were obtained at baseline and at 6-monthly intervals.

RESULTS

There were no differences in baseline characteristics between groups (all P > .05). Clinical outcomes such as left ventricular ejection fraction, left ventricular end-systolic volume, QoL, and NYHA class were significantly improved for both pacing groups compared to baseline. The LBBAP-CRT group showed greater improvement in left ventricular ejection fraction at 6 months (P = .001) and 12 months (P = .021), accompanied by greater reduction in left ventricular end-systolic volume (P = .007). QRS duration < 120 ms (baseline 160.82 ± 21.35 ms vs 161.08 ± 24.48 ms) was achieved in 30% in the BiV-CRT group vs 71% in the LBBAP-CRT group (P ≤ .001). Improvement in NYHA class (P = .031) and QoL index was greater (P = .014). Reduced heart failure admissions (P = .003) and health care utilization (P < .05) and improved lead performance (P < .001) were observed in the LBBAP-CRT group.

CONCLUSION

LBBAP-CRT is feasible and effective CRT. It results into a meaningful improvement in QoL and reduction in health care utilization. This can be offered as an alternative to BiV-CRT or potentially as first-line therapy.

Left Bundle Branch Area Pacing versus Biventricular Pacing for Cardiac Resynchronization Therapy on Morbidity and Mortality

BACKGROUND

Left bundle branch area pacing (LBBAP) has emerged as an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We aimed to compare the morbidity and mortality associated with LBBAP versus BVP in patients undergoing CRT implantation.

METHODS

Consecutive patients who received CRT from two high-volume implantation centers were retrospectively recruited. The primary endpoint was a composite of all-cause death and heart failure hospitalization, and the secondary endpoint was all-cause death.

RESULTS

A total of 491 patients receiving CRT (154 via LBBAP and 337 via BVP) were included, with a median follow-up of 31 months. The primary endpoint was reached by 21 (13.6%) patients in the LBBAP group, as compared with 74 (22.0%) patients in the BVP group [hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.43-1.14, P = 0.15]. There were 10 (6.5%) deaths in the LBBAP group, as compared with 31 (9.2%) in the BVP group (HR 0.91, 95% CI 0.44-1.86, P = 0.79). No significant difference was observed in the risk of either the primary or secondary endpoint between LBBAP and BVP after multivariate Cox regression (HR 0.74, 95% CI 0.45-1.23, P = 0.24, and HR 0.77, 95% CI 0.36-1.67, P = 0.51, respectively) or propensity score matching (HR 0.72, 95% CI 0.41-1.29, P = 0.28, and HR 0.69, 95% CI 0.29-1.65, P = 0.40, respectively).

CONCLUSION

LBBAP was associated with a comparable effect on morbidity and mortality relative to BVP in patients with indications for CRT.

Implantable Cardiac Devices in Patients with Brady- and Tachy-Arrhythmias: An Update of the Literature

Implantable cardiac devices are a vital treatment option in the management of tachy/brady-arrhythmias and heart failure with conduction disease. In the recent years, these devices have become increasingly sophisticated, with high implantation success rates and longevity. However, these devices are not without risks and complications, which need to be carefully considered before implantation. In an era of rapidly evolving cardiac device therapies, this review article will provide an update on the literature and outline some of the emerging technologies that aim to maximise the efficiency of implantable devices and reduce complications. We discuss novel pacing techniques, including alternative pacing sites in anti-bradycardia and biventricular pacing, as well as the latest evidence surrounding leadless device technologies and patient selection for implantable device therapies.

Landmark Evolutions in Time and Indication for Cardiac Resynchronization Therapy: Results from a Multicenter Retrospective Registry

Background: Cardiac resynchronization therapy (CRT) has evolved into an established therapy for patients with chronic heart failure and a wide QRS complex. Data on long-term outcomes over time are scarce and the criteria for implantation remain a subject of investigation. Methods: An international, multicenter, retrospective registry includes 2275 patients who received CRT between 30 November 2000 and 31 December 2019, with a mean follow-up of 3.6 ± 2.7 years. Four time periods were defined, based on landmark trials and guidelines. The combined endpoint was a composite of all-cause mortality, heart transplantation, or left ventricular assist device implantation. Results: The composite endpoint occurred in 656 patients (29.2%). The mean annual implantation rate tripled from 31.5 ± 17.4/year in the first period to 107.4 ± 62.4/year in the last period. In the adjusted Cox regression analysis, the hazard ratio for the composite endpoint was not statistically different between time periods. When compared to sinus rhythm with left bundle branch block (LBBB), a non-LBBB conduction pattern (sinus rhythm: HR 1.51, 95% CI 1.12-2.03; atrial fibrillation: HR 2.08, 95% CI 1.30-3.33) and a QRS duration below 130 ms (HR 1.64, 95% CI 1.29-2.09) were associated with a higher hazard ratio. Conclusions: Despite innovations, an adjusted regression analysis revealed stable overall survival over time, which can at least partially be explained by a shift in patient characteristics.

Clinical significance of regional constructive and wasted work in patients receiving cardiac resynchronization therapy

Background

Previous studies have shown that global constructive work (CW) and wasted work (WW) predict response to cardiac resynchronization therapy (CRT). This study evaluated the predictive value of regional CW and WW for reverse remodeling and clinical outcomes after CRT.

Methods

We performed a prospective study involving 134 CRT candidates with left bundle branch block and left ventricular ejection fraction ≤35%. Global and regional CW and WW were calculated using pressure-strain loop analysis. CRT response was defined by reverse remodeling as a reduction of ≥15% in left ventricular end-systolic volume after six months.

Results

At six-month follow-up, 92 (69%) patients responded to CRT. Of the regional CW and WW measures, lateral wall (LW) CW and septal WW were most strongly and significantly correlated with reverse remodeling. At multivariate analysis, LW CW and septal WW were both independent determinants of reverse remodeling. When LW CW and septal WW were included in the model, global CW and WW were not independently associated with reverse remodeling. LW CW and septal WW predicted reverse remodeling with an area under the curve (AUC) of 0.783 (95% CI: 0.700-0.866) and 0.737 (95% CI: 0.644-0.831), respectively. Using both variables increased the AUC to 0.832 (95% CI: 0.755-0.908). Both LW CW ≤878 mmHg% (HR 2.01; 95% CI: 1.07-3.79) and septal WW ≤181 mmHg% (HR 2.60; 95% CI: 1.38-4.90) were significant predictors of combined death and HF hospitalization at two-year follow-up.

Conclusion

LW CW and septal WW before CRT are important determinants of reverse remodeling and clinical outcomes.

Electrical therapies in heart failure: Evolving technologies and indications

Device therapy for heart failure has rapidly evolved over 2 decades. The knowledge of indications, assessment lead and device technology has expanded to include CRT, leadless pacing and conduction system pacing such as His bundle and left bundle branch area pacing. But there is still a lack of evidence for these new technologies as well as for common indications such as atrial fibrillation and upgrading from a previous device. The role of personalized medicine will become increasingly important when selecting candidates for CRT, primary preventive ICD ablation procedures and emerging new devices such as cardiac contractility modulation (CCM). Rapidity of therapy is associated with outcome which will be a challenge. If properly implemented devices and drugs will have a large positive affect of HF outcomes.

Assessing cardiac resynchronization therapy response in heart failure patients: a comparative analysis of efficacy and outcomes between transvenous and epicardial leads

Cardiac resynchronization therapy (CRT) is an effective treatment for selected heart failure (HF) patients. Although transvenous implantation is the standard method, it is not feasible in some patients, so the epicardial lead emerges as an alternative. We aim to compare CRT response, procedure-related complications, and the occurrence of clinical outcomes between patients with transvenous and epicardial leads. In a single-center retrospective study, we enrolled consecutive HF patients submitted to CRT implantation with a defibrillator between 2013 and 2022. Clinical response was defined as an improvement of at least one of the New York Heart Association classes with no occurrence of cardiovascular death or HF hospitalization in the first year of follow-up. Echocardiographic response was attained with an increase in left ventricular ejection fraction 10% or a reduction of left ventricular end-diastolic volume >15% at 6-12 months after CRT implantation. Major adverse cardiovascular events (MACE) (cardiovascular mortality and HF hospitalization) and all-cause mortality were evaluated. From a total of 149 patients, 38% (n=57) received an epicardial lead. Clinical (63% versus 60%, p=0.679) and echocardiographic (63% versus 60%, p=0.679) responses were similar between the transvenous and epicardial groups. Patients in the transvenous group had a shorter hospital stay (2 versus 7 days, p<0.001). Procedure-related complications were comparable between groups (24% versus 28%, p=0.572), but left ventricular lead-related complications were more frequent in the transvenous group (14% versus 2%). During a median follow-up of 4.7 years, the rate of MACE was 30% (n=44), with no differences in both groups (p=0.591), neither regarding HF hospitalization (p=0.917) nor cardiovascular mortality (p=0.060). Nevertheless, the epicardial group had a higher rate of all-cause mortality (35% versus 20%, p=0.005), the majority occurring during long-term follow-up (>12 months), with no deaths in the postoperative period. Considering the comparable rates of CRT response, procedure-related complications, and MACE between groups, we conclude that epicardial lead is a feasible alternative for CRT when transvenous lead implantation is not possible. The occurrence of a higher number of all-cause deaths in epicardial patients in the long-term follow-up was mainly due to infectious complications (unrelated to the lead) and the progression of oncological/chronic diseases.

Antiarrhythmic Treatment in Heart Failure

PURPOSE OF REVIEW

Arrhythmias are common in patients with heart failure (HF) and are associated with a significant risk of mortality and morbidity. Optimal antiarrhythmic treatment is therefore essential. Here, we review current approaches to antiarrhythmic treatment in patients with HF.

RECENT FINDINGS

In atrial fibrillation, rhythm control and ventricular rate control are accepted therapeutic strategies. In recent years, clinical trials have demonstrated a prognostic benefit of early rhythm control strategies and AF catheter ablation, especially in patients with HF with reduced ejection fraction. Prevention of sudden cardiac death with ICD therapy is essential, but optimal risk stratification is challenging. For ventricular tachycardias, recent data support early consideration of catheter ablation. Antiarrhythmic drug therapy is an adjunctive therapy in symptomatic patients but has no prognostic benefit and well-recognized (proarrhythmic) adverse effects. Antiarrhythmic therapy in HF requires a systematic, multimodal approach, starting with guideline-directed medical therapy for HF and integrating pharmacological, device, and interventional therapy.

Long-Term Outcomes of Resynchronization-Defibrillation for Heart Failure

BACKGROUND

The Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed a greater benefit with respect to mortality at 5 years among patients who received cardiac-resynchronization therapy (CRT) than among those who received implantable cardioverter-defibrillators (ICDs). However, the effect of CRT on long-term survival is not known.

METHODS

We randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more (or a paced QRS duration of 200 msec or more) to receive either an ICD alone or a CRT defibrillator (CRT-D). We assessed long-term outcomes among patients at the eight highest-enrolling participating sites. The primary outcome was death from any cause; the secondary outcome was a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device.

RESULTS

The trial enrolled 1798 patients, of whom 1050 were included in the long-term survival trial; the median duration of follow-up for the 1050 patients was 7.7 years (interquartile range, 3.9 to 12.8), and the median duration of follow-up for those who survived was 13.9 years (interquartile range, 12.8 to 15.7). Death occurred in 405 of 530 patients (76.4%) assigned to the ICD group and in 370 of 520 patients (71.2%) assigned to the CRT-D group. The time until death appeared to be longer for those assigned to receive a CRT-D than for those assigned to receive an ICD (acceleration factor, 0.80; 95% confidence interval, 0.69 to 0.92; P = 0.002). A secondary-outcome event occurred in 412 patients (77.7%) in the ICD group and in 392 (75.4%) in the CRT-D group.

CONCLUSIONS

Among patients with a reduced ejection fraction, a widened QRS complex, and NYHA class II or III heart failure, the survival benefit associated with receipt of a CRT-D as compared with ICD appeared to be sustained during a median of nearly 14 years of follow-up. (RAFT ClinicalTrials.gov number, NCT00251251.).

Beyond biventricular pacing: Exploring the advantages of his-bundle pacing and left bundle branch pacing in heart failure-A systematic review and meta-analysis

BACKGROUND

This meta-analysis compares His-Purkinje system pacing (HPSP), a novel cardiac resynchronization therapy (CRT) technique that targets the intrinsic conduction system of the heart, with conventional biventricular pacing (BiVP) in heart failure (HF) patients with left ventricular (LV) dysfunction and dyssynchrony.

METHODS

We searched multiple databases up to May 2023 and identified 18 studies (five randomized controlled trials and 13 observational studies) involving 1291 patients. The outcome measures were QRS duration, left ventricular ejection fraction (LVEF) improvement, left ventricular end-diastolic diameter (LVEDD) change, HF hospitalization, and New York Heart Association (NYHA) functional class improvement. We used a random-effects model to calculate odds ratios (OR), and mean differences (MD) with 95% confidence intervals (CI). We also assessed the methodological quality of the studies.

RESULTS

The mean LVEF was 30.7% and the mean follow-up duration was 8.1 months. Among LBBP, HBP, and BiVP, HBP provided the shortest QRS duration [MD: -18.84 ms, 95% CI: -28.74 to -8.94; p = 0.0002], while LBBP showed the greatest improvement in LVEF [MD: 5.74, 95% CI: 2.74 to 7.46; p < 0.0001], LVEDD [MD: -5.55 mm, 95% CI: -7.51 to -3.59; p < 0.00001], and NYHA functional class [MD: -0.58, 95% CI: -0.80 to --0.35; p < 0.00001]. However, there was no significant difference in HF hospitalization between HPSP and BiVP.

CONCLUSION

LBBP as modality of HPSP demonstrated superior outcomes in achieving electrical ventricular synchrony and systolic function, as well as alleviating HF symptoms, compared to other pacing techniques.

Mechanocardiography detects improvement of systolic function caused by resynchronization pacing

Objective.Cardiac resynchronization therapy (CRT) is commonly used to manage heart failure with dyssynchronous ventricular contraction. CRT pacing resynchronizes the ventricular contraction, while AAI (single-chamber atrial) pacing does not affect the dyssynchronous function. This study compared waveform characteristics during CRT and AAI pacing at similar pacing rates using seismocardiogram (SCG) and gyrocardiogram (GCG), collectively known as mechanocardiogram (MCG).Approach.We included 10 patients with heart failure with reduced ejection fraction and previously implanted CRT pacemakers. ECG and MCG recordings were taken during AAI and CRT pacing at a heart rate of 80 bpm. Waveform characteristics, including energy, vertical range (amplitude) during systole and early diastole, electromechanical systole (QS2) and left ventricular ejection time (LVET), were derived by considering 6 MCG axes and 3 MCG vectors across frequency ranges of >1 Hz, 20-90 Hz, 6-90 Hz and 1-20 Hz.Main results.Significant differences were observed between CRT and AAI pacing. CRT pacing consistently exhibited higher energy and vertical range during systole compared to AAI pacing (p< 0.05). However, QS2, LVET and waveform characteristics around aortic valve closure did not differ between the pacing modes. Optimal differences were observed in SCG-Y, GCG-X, and GCG-Y axes within the frequency range of 6-90 Hz.Significance.The results demonstrate significant differences in MCG waveforms, reflecting improved mechanical cardiac function during CRT. This information has potential implications for predicting the clinical response to CRT. Further research is needed to explore the differences in signal characteristics between responders and non-responders to CRT.

The Micra Transcatheter Pacing System: past, present and the future

Leadless permanent pacemakers represent an important innovation in cardiac device developments. Although transvenous permanent pacemakers have become indispensable in managing bradyarrhythmia and saving numerous lives, the use of transvenous systems comes with notable risks tied to intravascular leads and subcutaneous pockets. This drawback has spurred the creation of leadless cardiac pacemakers. Within this analysis, we compile existing clinical literature and proceed to evaluate the efficacy and safety of the Micra Transcatheter Pacing System. We also delve into the protocols for addressing a malfunctioning or end-of-life Micra as well as device extraction. Lastly, we explore prospects in this domain, such as the emergence of entirely leadless cardiac resynchronization therapy-defibrillator devices.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Temporal trends in evidence supporting therapeutic interventions in heart failure and other European Society of Cardiology guidelines

AIMS

This study aimed to determine whether any change occurred over time in level of evidence (LoE) of therapeutic interventions supporting heart failure (HF) and other European Society of Cardiology guideline recommendations.

METHODS AND RESULTS

We selected topics with at least three documents released between 2008 and April 2022. Classes of recommendations (CoR) and supporting LoE related to therapeutic interventions within each document were collected and compared over time. A total of 1822 recommendations from 18 documents on 6 topics [median number per document = 112, 867 (48%) CoR I] were included in the analysis. There was a trend towards a reduction over time in the percentage of CoR I in HF (46-36-34%), non-ST elevation myocardial infarction (NSTEMI; 78-58-54%), and pulmonary embolism (PE; 65-50-39%) guidelines, with a decrease in the total number of recommendations for HF only. Percentage of CoR I was stable over time around 40% for valvular heart disease (VHD) and atrial fibrillation (AF), and around 60% for cardiovascular prevention (CVP), with an increase in the total number of recommendations for VHD and CVP and a decrease for AF. Among CoR I, 319 (37%) were supported by LoE A, with a decrease over time for HF (56-46-42%), an increase for NSTEMI (29-38-48%) and AF (28-31-36%), a bimodal distribution for PE and CVP, and a lack for VHD.

CONCLUSIONS

LoE supporting therapeutic recommendations in contemporary European guidelines is generally low. Physicians should be aware of these limitations, and scientific societies promote a greater understanding of their significance and drive future research directions.

Adaptive versus conventional cardiac resynchronisation therapy in patients with heart failure (AdaptResponse): a global, prospective, randomised controlled trial

BACKGROUND

Continuous automatic optimisation of cardiac resynchronisation therapy (CRT), stimulating only the left ventricle to fuse with intrinsic right bundle conduction (synchronised left ventricular stimulation), might offer better outcomes than conventional CRT in patients with heart failure, left bundle branch block, and normal atrioventricular conduction. This study aimed to compare clinical outcomes of adaptive CRT versus conventional CRT in patients with heart failure with intact atrioventricular conduction and left bundle branch block.

METHODS

This global, prospective, randomised controlled trial was done in 227 hospitals in 27 countries across Asia, Australia, Europe, and North America. Eligible patients were aged 18 years or older with class 2-4 heart failure, an ejection fraction of 35% or less, left bundle branch block with QRS duration of 140 ms or more (male patients) or 130 ms or more (female patients), and a baseline PR interval 200 ms or less. Patients were randomly assigned (1:1) via block permutation to adaptive CRT (an algorithm providing synchronised left ventricular stimulation) or conventional biventricular CRT using a device programmer. All patients received device programming but were masked until procedures were completed. Site staff were not masked to group assignment. The primary outcome was a composite of all-cause death or intervention for heart failure decompensation and was assessed in the intention-to-treat population. Safety events were collected and reported in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02205359, and is closed to accrual.

FINDINGS

Between Aug 5, 2014, and Jan 31, 2019, of 3797 patients enrolled, 3617 (95·3%) were randomly assigned (1810 to adaptive CRT and 1807 to conventional CRT). The futility boundary was crossed at the third interim analysis on June 23, 2022, when the decision was made to stop the trial early. 1568 (43·4%) of 3617 patients were female and 2049 (56·6%) were male. Median follow-up was 59·0 months (IQR 45-72). A primary outcome event occurred in 430 of 1810 patients (Kaplan-Meier occurrence rate 23·5% [95% CI 21·3-25·5] at 60 months) in the adaptive CRT group and in 470 of 1807 patients (25·7% [23·5-27·8] at 60 months) in the conventional CRT group (hazard ratio 0·89, 95% CI 0·78-1·01; p=0·077). System-related adverse events were reported in 452 (25·0%) of 1810 patients in the adaptive CRT group and 440 (24·3%) of 1807 patients in the conventional CRT group.

INTERPRETATION

Compared with conventional CRT, adaptive CRT did not significantly reduce the incidence of all-cause death or intervention for heart failure decompensation in the included population of patients with heart failure, left bundle branch block, and intact AV conduction. Death and heart failure decompensation rates were low with both CRT therapies, suggesting a greater response to CRT occurred in this population than in patients in previous trials.

FUNDING

Medtronic.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

One-Year Mortality in Patients Undergoing an Implantable Cardioverter Defibrillator or Cardiac Resynchronization Therapy Pulse Generator Replacement: Identifying Patients at Risk

Implantable cardioverter defibrillators (ICDs) significantly contribute to the prevention of sudden cardiac death in selected patients. However, it is essential to identify those who are likely to not have benefit from an ICD and to defer a pulse generator exchange. Easily implementable guidelines for individual risk stratification and decision making are lacking. This study investigates the 1-year mortality of patients who underwent an ICD or cardiac resynchronization therapy with defibrillator function (CRT-D) pulse generator replacement in a contemporary real-world tertiary hospital setting. The cause of death and patient- and procedure-related factors are stratified, and predictive values for 1-year mortality are evaluated. Patients with a follow-up of ≥365 days (or prior mortality) after an ICD or CRT-D exchange at the Leiden University Medical Center from 1 January 2018 until 31 December 2021 were eligible. In total, 588 patients were included (77% male, 69 [60-76] years old, 59% primary prevention, 46% ischemic cardiomyopathy and 37% mildly reduced left ventricular ejection fraction (LVEF)). Patients undergoing a CRT-D replacement or upgrade had a significantly higher 1-year all-cause mortality (10.7% and 11.9%, respectively) compared to patients undergoing ICD (2.8%) exchange (p = 0.002). LVEF ≤ 30%, New York Heart Association class ≥ 3, estimated glomerular filtration rate ≤ 30 mL/min/m2 and haemoglobin ≤ 7 mmol/L were independently associated with mortality within 1 year after pulse generator replacement. There is a growing need for prospectively validated risk scores to weight individualized risk of mortality with the expected ICD therapy benefit and to support a well-informed, shared decision-making process.

Hemodynamic forces from 4D flow magnetic resonance imaging predict left ventricular remodeling following cardiac resynchronization therapy

BACKGROUND

Patients with heart failure and left bundle branch block (LBBB) may receive cardiac resynchronization therapy (CRT), but current selection criteria are imprecise, and many patients have limited treatment response. Hemodynamic forces (HDF) have been suggested as a marker for CRT response. The aim of this study was therefore to investigate left ventricular (LV) HDF as a predictive marker for LV remodeling after CRT.

METHODS

Patients with heart failure, EF < 35% and LBBB (n = 22) underwent CMR with 4D flow prior to CRT. LV HDF were computed in three directions using the Navier-Stokes equations, reported in median N [interquartile range], and the ratio of transverse/longitudinal HDF was calculated for systole and diastole. Transthoracic echocardiography was performed before and 6 months after CRT. Patients with end-systolic volume reduction ≥ 15% were defined as responders.

RESULTS

Non-responders had smaller HDF than responders in the inferior-anterior direction in systole (0.06 [0.03] vs. 0.07 [0.03], p = 0.04), and in the apex-base direction in diastole (0.09 [0.02] vs. 0.1 [0.05], p = 0.047). Non-responders had larger diastolic HDF ratio compared to responders (0.89 vs. 0.67, p = 0.004). ROC analysis of diastolic HDF ratio for identifying CRT non-responders had AUC of 0.88 (p = 0.005) with sensitivity 57% and specificity 100% for ratio > 0.87. Intragroup comparison found higher HDF ratio in systole compared to diastole for responders (p = 0.003), but not for non-responders (p = 0.8).

CONCLUSION

Hemodynamic force ratio is a potential marker for identifying patients with heart failure and LBBB who are unlikely to benefit from CRT. Larger-scale studies are required before implementation of HDF analysis into clinical practice.

Cardiac Resynchronisation with Conduction System Pacing

To date, biventricular pacing (BiVP) has been the standard pacing modality for cardiac resynchronisation therapy. However, it is non-physiological, with the activation spreading between the left ventricular epicardium and right ventricular endocardium. Up to one-third of patients with heart failure who are eligible for cardiac resynchronisation therapy do not derive benefit from BiVP. Conduction system pacing (CSP), which includes His bundle pacing and left bundle branch area pacing, has emerged as an alternative to BiVP for cardiac resynchronisation. There is mounting evidence supporting the benefits of CSP in achieving synchronous ventricular activation and repolarisation. The aim of this review is to summarise the current options and outcomes of CSP when used for cardiac resynchronisation in patients with heart failure.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

Beyond Conventional Cardiac Resynchronisation Therapy: A Review of Electrophysiological Options in the Management of Chronic Heart Failure

The incidence of heart failure (HF) continues to grow and burden our health care system. Electrophysiological aberrations are common amongst patients with heart failure and can contribute to worsening symptoms and prognosis. Targeting these abnormalities with cardiac and extra-cardiac device therapies and catheter ablation procedures augments cardiac function. Newer technologies aimed to improvement procedural outcomes, address known procedural limitations and target newer anatomical sites have been trialled recently. We review the role and evidence base for conventional cardiac resynchronisation therapy (CRT) and its optimisation, catheter ablation therapies for atrial arrhythmias, cardiac contractility and autonomic modulation therapies.