Merkely, Béla

Importance Clinical trials in cardiovascular medicine aim to deliver high-quality evidence with greater efficiency, including smaller sample sizes and shorter timelines. The selection of sensitive and reliable end points is central to this goal. Right ventricular (RV) structure and function play a critical role in many cardiovascular conditions; however, RV-specific parameters remain underused and inconsistently applied in interventional clinical trials. In this article, the current and emerging role of RV-focused imaging and hemodynamic parameters as end points in clinical trials are explored and a comprehensive framework for their development, validation, and broader implementation is proposed. Observations Across multiple disease domains, RV-focused parameters derived from echocardiography, cardiac magnetic resonance imaging, computed tomography, and right-sided heart catheterization demonstrate potential value in assessing the therapeutic effects of new medicines or devices across a wide range of conditions including heart failure, cardiomyopathies, valve diseases, pulmonary hypertension, and congenital heart conditions. However, their use is inconsistent, and feasibility challenges are common, particularly in multicenter clinical trial settings. Key limitations include variability in imaging acquisition, incomplete data capture, lack of standardized protocols, and insufficient validation linking short-term RV changes to long-term clinical outcomes. Emerging tools such as artificial intelligence may improve reproducibility and efficiency, while collaborative, multidisciplinary efforts are essential for advancing end-point development. Conclusions and Relevance RV-specific end points hold substantial promise for enhancing the sensitivity and mechanistic insight of clinical trials but remain inadequately integrated into current practice. Optimal end-point selection requires balancing clinical relevance, analytical validity, and operational feasibility, with consideration of disease-specific pathophysiology and trial design. Standardization of acquisition, validation of clinically meaningful changes, and centralized data analysis are important next steps. Broader adoption of robust RV metrics supported by technological innovation and cross-sector collaboration has the potential to improve trial efficiency, accelerate therapeutic development, and ultimately enhance patient outcomes.

Abstract Aims To evaluate clinical outcomes, echocardiographic features, and the efficacy and safety of sacubitril/valsartan compared to valsartan across age groups in the PARAGON-HF trial. Methods and results A total of 4796 participants ≥50 years of age with chronic heart failure (HF) and left ventricular ejection fraction (LVEF) ≥45% were divided into three age groups: <65 years (n = 825), 65–74 years (n = 1772), and ≥75 years (n = 2199). Echocardiograms of 1097 patients were analysed in a standardized fashion at a core imaging laboratory. The primary composite outcome was total HF hospitalizations and cardiovascular (CV) death. Older patients were more likely to experience primary composite outcomes (compared to patients <65 years, adjusted rate ratio [aRR] for ≥75 years: 1.39, 95% confidence interval [CI] 1.21–1.61), total HF hospitalization (aRR 1.27, 95% CI 1.09–1.49), and CV death (adjusted hazard ratio [aHR] 2.04, 95% CI 1.44–2.87). Age did not modify the effect of sacubitril/valsartan compared to valsartan on primary composite endpoint (pinteraction = 0.79) in the overall population or in those with LVEF ≤57%. Older adults randomized to sacubitril/valsartan were more likely to develop hypotension compared to those receiving valsartan (pinteraction = 0.026). Older patients had smaller left ventricular chamber sizes, higher LVEF, and were more likely to have abnormal measures of diastolic function. Conclusion Older patients with HF with preserved ejection fraction had higher event rates than younger patients, more adverse events overall, and more hypotension when treated with sacubitril/valsartan; however, the treatment benefits of sacubitril/valsartan were retained in older patients.

BACKGROUND: Substernal lead placement of the extravascular implantable cardioverter defibrillator (EV ICD) permits both defibrillation at thresholds similar to those seen with transvenous implantable cardioverter defibrillators and effective anti-tachycardia pacing (ATP) while avoiding the vasculature and associated complications. The global Pivotal study has shown the EV ICD system to be safe and effective through 6 months, but long-term experience has yet to be published. Our aim was to report the performance and safety of the EV ICD system throughout the study. METHODS: The EV ICD Pivotal study was a prospective, global, single-arm, premarket clinical study. Individuals with a Class I or IIa indication for a single-chamber implantable cardioverter defibrillator per guidelines were enrolled. Freedom from major system- or procedure-related complications and appropriate and inappropriate therapy rates were assessed through 3 years with the Kaplan-Meier method. ATP success was calculated from simple proportions. RESULTS: An implantation was attempted in 316 patients (25.3% female; 53.8±13.1 years of age; 81.6% primary prevention; left ventricular ejection fraction, 38.9±15.4%). Of 299 patients with a successful implantation, 24 experienced 82 spontaneous arrhythmic episodes that were appropriately treated with ATP only (38, 46.3%), shock only (34, 41.5%), or both (10, 12.2%) for a Kaplan-Meier–estimated rate of first any appropriate therapy of 9.2% at 3 years. ATP was successful in 77.1% (37/48) of episodes, and ATP use significantly increased from discharge to last follow-up visit ( P <0.0001). Shock therapy was successful in 100% (27/27) of discrete, spontaneous ventricular arrhythmias. The inappropriate shock rates at 1 and 3 years were 9.8% and 17.5%, respectively, with P-wave oversensing the predominant cause. No major intraprocedural complications were reported, and the estimated freedom from system- or procedure-related major complications was 91.9% at 1 year and 89.0% at 3 years. The most common major complications were lead dislodgement (10 events; n=9 patients, 2.8%), postoperative wound or device pocket infection (n=8, 2.5%), and device inappropriate shock delivery (n=4, 1.3%). Twenty-four system revisions were performed as a result of major complications related to the EV ICD system or procedure. CONCLUSIONS: From implantation to study completion, the EV ICD Pivotal study demonstrated that a single integrated system with an extravascular lead placed in the substernal space maintains high ATP success, effective defibrillation, and a consistent safety profile. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04060680.

Introduction: Exercise parameters such as peak heart rate (HR) are generally adjusted for age, whereas HR recovery is generally given as an absolute value: < 13 bpm at 1 minute post-peak exercise being abnormal. Hypothesis: We analyzed a large cohort of patients to determine the impact of age on HR recovery (HRRec) and if the prognostic performance of HRRec is improved by adjustment for age. Methods: Non-imaging exercise tests performed on patients aged 30-79 years from 1993 to 2010 were included. Patients with known cardiovascular diseases were excluded. Patients were assigned to 5 groups according to age: 30-39, 40-49, 50-59, 60-69, and 70-79. Mortality was reported according to HRRec during the first minute of active recovery using Cox regression analysis. Mortality was determined from Minnesota and National Death Indices. Results: 22,643 patients (64 % male) were included. The median HRRec in the age groups with IQR were as follows: 30-39: 20 [15-26]; 40-49: 19 [14-25]; 50-59: 18 [13-23]; 60-69: 15 [10-20]; and 70-79: 11 [6-16]. There were 1566 deaths (6.9%) over a mean follow-up of 11.8 ± 5.0 years. HRRec of 13 would fall at the 17 th percentile for patients 30-39 years old, but this increased to the 20 th , 27 th , 40 th , and 60 th percentiles with increasing age group. The mortality in age groups according to HRRec is shown in the Figure. For age groups 30-39 and 40-49, the hazard ratio for mortality at a HRRec of 11-12 bpm (i.e. just below the standard of 13) versus patients with a HRRec of ≥ 20 bpm was > 2.0. For age 50-59 and 60-69, however, a HRRec of < 11 bpm is necessary to obtain a doubling of risk, and for age 70-79 a HRRec of < 9 bpm is necessary. Conclusions: HRRec decreases significantly with age. The performance of abnormal HRRec defined as < 13 bpm is inconsistent across age groups. To standardize the ability of HRRec to identify at least a 2.0-fold increased risk, lowering the cup-point to < 11 bpm for ages 50-59 and 60-69 and < 9 bpm for age 70-79 is required.

Abstract Background Implantable cardioverter defibrillators (ICDs) prevent sudden cardiac death in patients at high risk for ventricular arrhythmias, but conventional systems carry a risk of transvenous (TV) lead-related complications. The novel extravascular ICD (EV ICD) may reduce some of these complications, while offering anti-tachycardia pacing (ATP), pause prevention pacing, and a device of similar size and projected battery longevity as a TV ICD, by placing a lead substernally. The EV ICD Pivotal study demonstrated EV ICD safety and performance for termination of ventricular arrythmias at 6 months. Longer-term performance is unknown. Purpose To report the chronic safety and performance of the EV ICD system. Methods The extravascular implantable cardioverter defibrillator (EV ICD) Pivotal study was a prospective, international, single-arm, premarket clinical study. Patients with a class I or IIa indication for a single-chamber ICD per ESC or ACC/AHA/HRS guidelines were enrolled. Freedom from major system- and/or procedure-related complications at 18 mo was evaluated, as well as conversion of arrhythmias by anti-tachycardia pacing (ATP) or shock through all available follow up. Rates of ATP success were evaluated using the generalized estimating equation (GEE) and simple proportions. Results Implantation was attempted in 316 patients: 74.7% male, age 53.8±13.1 years, 82% primary prevention, left ventricular ejection fraction of 38.9%±15.4%, and New York Heart Association Class I (23.4%) or II/III (65.5%). Of 299 implanted patients (average follow up 16.2±7.2 mo), 19 experienced 80 spontaneous, appropriately treated arrhythmic episodes: 37 treated by ATP, 15 by ATP and shock, and 28 by shock alone with a Kaplan-Meier (KM) estimated 6.8% of patients experiencing appropriate therapy by 18 mo (Figure). Of discrete episodes treated with shock, 21/21 (100%) were successfully terminated. ATP was delivered in 12 patients, successfully treating 35/52 episodes (67.3%; GEE adjusted 59.0%). Inappropriate shocks occurred in 35 patients through all follow up, with a rate of 10.2% at 1 year. The KM estimate of freedom from major EV ICD system-or procedure-related complications rate through 18 mo was 91.9% (95% CI: 88.2% to 94.4%). The most common event was lead dislodgment (10 events in 9 patients) identified 0 to 120 days post-implant, predominantly due to anchoring technique. Conclusion The safety and effectiveness of a novel EV ICD system with a substernal lead extends through chronic follow up. Shocks were avoided in nearly half of all spontaneous episodes because of the availability of ATP.Figure

AbstractAimsIntraoperative defibrillation testing (DT) during implant or replacement of implantable cardioverter-defibrillators (ICDs) has been a matter of debate for many years. This debate was put to rest by the Simple and Nordic ICD trials, and the practice of testing during new implantations has essentially been almost abandoned. Old registries demonstrated an increased incidence of significant findings in DT during replacements. The aim of the present study was to evaluate frequency of significant findings and safety of DT in subjects undergoing device replacement.Methods and resultsA prospective observational multi-centre study included consecutive patients undergoing ICD generator replacement. The primary outcome was a failure to terminate induced ventricular fibrillation (VF) with a single shock 10 J below the maximal capacity of the device. Secondary outcomes included complications of DT. Patients were followed-up at 1- and 6-months post-procedure. A total of 92 patients were eligible, and consented to the study, of which 84 underwent DT during battery replacement. The median age was 68 years and 79.8% were males. Induction of VF was successful in 84 patients as was a successful conversion on the first attempt in all. There were no procedure-related complications. During follow up one patient had two appropriate ICD shock events. In four patients, ICD programming was changed. None suffered inappropriate shock. There was no evidence of lead malfunction. Two deaths occurred, none of which was related to arrhythmia.ConclusionThe present study found DT was not associated with complications in patients undergoing ICD generator replacement but produced no clinically important information.