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AimsThe optimum timing of cardiac resynchronization therapy (CRT) implantation is unknown. We explored long-term outcomes after CRT in relation to the time interval from a first heart failure hospitalization (HFH) to device implantation.Methods and resultsA database covering the population of England (56.3 million in 2019) was used to quantify clinical outcomes after CRT implantation in relation to first HFHs. From 2010 to 2019, 64 968 patients [age: 71.4 ± 11.7 years; 48 606 (74.8%) male] underwent CRT implantation, 57% in the absence of a previous HFH, 12.9% during the first HFH, and 30.1% after ≥1 HFH. Over 4.54 (2.80–6.71) years [median (interquartile range); 272 989 person-years], the time in years from the first HFH to CRT implantation was associated with a higher risk of total mortality [hazard ratio (HR); 95% confidence intervals (95% CI)] (1.15; 95% CI 1.14–1.16, HFH (HR: 1.26; 95% CI 1.24–1.28), and the combined endpoint of total mortality or HFH (HR: 1.19; 95% CI 1.27–1.20) than CRT in patients with no previous HFHs, after co-variate adjustment. Total mortality (HR: 1.67), HFH (HR: 2.63), and total mortality or HFH (HR: 1.92) (all P < 0.001) were highest in patients undergoing CRT ≥2 years after the first HFH.ConclusionIn this study of a healthcare system covering an entire nation, delays from a first HFH to CRT implantation were associated with progressively worse long-term clinical outcomes. The best clinical outcomes were observed in patients with no previous HFH and in those undergoing CRT implantation during the first HFH.Condensed abstractThe optimum timing of CRT implantation is unknown. In this study of 64 968 consecutive patients, delays from a first heart failure hospitalization (HFH) to CRT implantation were associated with progressively worse long-term clinical outcomes. Each year from a first HFH to CRT implantation was associated with a 21% higher risk of total mortality and a 34% higher risk of HFH. The best outcomes after CRT were observed in patients with no previous HFHs and in those undergoing implantation during their first HFH.

Anti-tachycardia pacing (ATP) is frequently used to terminate ventricular tachycardia (VT), however it is not always successful and may accelerate VT requiring defibrillation. REVRAMP is a novel concept of ATP that involves delivering pacing at a faster rate than VT, but instead of abruptly terminating pacing after eight beats, pacing is gradually slowed until VT continues or normal rhythm is restored. In a pilot study we show that REVRAMP can restore normal rhythm, and that if REVRAMP is unsuccessful, VT is not accelerated.

Excessive prolongation of PR interval impairs coupling of AV contraction, which reduces left ventricular pre-load and stroke volume, and worsens symptoms. His-bundle pacing allows AV-delay shortening while maintaining normal ventricular activation. HOPE-HF evaluated whether AV-optimized His pacing is preferable to no-pacing, in double-blind cross-over fashion, in patients with heart failure, left ventricular ejection fraction (LVEF) ≤40%, PR interval ≥200ms and either QRS ≤140ms or right BBB.Patients had atrial and His-bundle leads implanted (and an ICD lead if clinically indicated) and were randomized, to 6-months of pacing and 6-months of no-pacing utilizing a cross-over design. The primary outcome was peak oxygen uptake during symptom-limited exercise. Quality of life, LVEF and patients' holistic symptomatic preference between arms were secondary outcomes. 167 patients were randomized: 90% men, 69±10 years, QRS duration 124±26ms, PR interval 249±59ms, LVEF 33±9%. Neither peak VOHis-bundle pacing did not increase peak oxygen uptake but, under double-blind conditions, significantly improved quality of life and was symptomatically preferred by the clear majority of patients. Ventricular pacing delivered via the His bundle did not adversely impact ventricular function during the 6 months. This article is protected by copyright. All rights reserved.

Right ventricular (RV) dysfunction has been linked to a poor response to cardiac resynchronization therapy (CRT). We sought to determine whether cardiovascular magnetic resonance (CMR)-derived measures of RV function influence clinical outcomes after CRT.In this retrospective study, we used CMR to assess pre-implant RV volumes and RV ejection fraction (RVEF) in relation to clinical outcomes after CRT implantation.Among 243 patients (age: 70.3 ± 10.8 years [mean ± SD]; 68.7% male; 121 [49.8%]) with ischemic cardiomyopathy and 122 (50.2%) with nonischemic cardiomyopathy, 141 (58%) after CRT-defibrillation (CRT-D) and 102 (42%) after CRT-pacing (CRT-P), 101 (41.6.0%) patients died, 61 (25.1%) from cardiac causes and 24 (9.88%) from noncardiac causes, over 5.87 years (median; interquartile range: 4.35-7.73). Two (0.82%) patients underwent cardiac transplantation and four (1.64%) had a left ventricular assist device (LVAD). A total of 41 (16.9%) met the composite endpoint of sudden cardiac death (SCD), ventricular tachycardia, or ventricular fibrillation. In univariate analyses, no measure of RV function was associated with total mortality or the arrhythmic endpoint. RVEF was associated with cardiac mortality on univariate analyses (HR per 10%: 0.82, 95% CI 0.70-0.96), but not on multivariate analyses that included left ventricular ejection fraction.There is no relationship between measures of RV function, such as RV volumes and RVEF, and the long-term clinical outcome of CRT. These findings indicate that such measures should not be considered in patient selection.

Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Unrestricted educational grants Background Increasing evidence supports a link between myocardial fibrosis (MF) and ventricular arrhythmias. We sought to determine whether presence of MF on visual assessment (MFVA) and gray zone fibrosis (GZF) mass predicts SCD and ventricular fibrillation / sustained ventricular tachycardia after cardiac implantable electronic device (CIED) implantation. Methods In this prospective study, total fibrosis and GZF mass, quantified using cardiovascular magnetic resonance, was assessed in relation to the primary endpoint of sudden cardiac death (SCD) and the secondary, arrhythmic endpoint of SCD or ventricular arrhythmias after CIED implantation. Results Among 700 patients (age 68.0 ± 12.0yrs [mean ± SD]), 27 (3.85%) experienced a SCD and 121 (17.3%) met the arrhythmic endpoint over 6.93 yrs (median; interquartile range 5.82-9.32). MFVA predicted SCD (hazard ratio [HR]: HR:26.3 [95% confidence interval [CI] 3.70-3337]; negative predictive value: 100%). In competing risks analyses, MFVA also predicted the arrhythmic endpoint (subdistribution [sHR]: 19.9 [95% CI 6.40-61.9]; negative predictive value:98.6%). Compared with no MFVA, a GZF mass measured with the 5SD method (GZF5SD) > 17 g was associated with highest risk of SCD (HR: 44.6;95% CI 6.12-5685) and the arrhythmic endpoint (sHR: 30.3 [95% CI 9.60-95.8]). Adding GZF5SD mass to MFVA led to reclassification of 39% for SCD and 50.2% for the arrhythmic endpoint. In contrast, LVEF did not predict either endpoint. Conclusions In CIED recipients, MFVA excluded patients at risk of SCD and virtually excluded ventricular arrhythmias. Quantified GZF5SD mass added predictive value in relation to SCD and the arrhythmic endpoint.