Aims Cardiac resynchronization therapy (CRT) for chronic heart failure with left ventricular systolic dysfunction (LVSD) consistently improves survival against optimal medical therapy alone. Limited data exist comparing the outcomes between CRT with pacemaker (CRT-P) and with defibrillator (CRT-D). We aimed to investigate the long-term prognosis of patients who received CRT-P or CRT-D.

Methods and results Data were prospectively collected from consecutive patients with standard indications for CRT, who were implanted at a single large tertiary centre between 2008 and 2012. All-cause mortality was compared between those patients who received either CRT-P or CRT-D. A subgroup analysis was performed in patients with ischaemic cardiomyopathy. During the period in question, 795 patients received CRT devices: 544 (68.4%) CRT-P and 251 (31.6%) CRT-D. The mean follow-up was 1072 W(SD 556) days. Overall, there was no survival benefit in those patients implanted with a CRT-D compared with CRT-P (hazard ratio 1.09, 95% confidence interval 0.84–1.41,

P U0.51). In patients with ischaemic chronic heart failure [n U530 (66.7%)], there was a trend for improved survival

Introduction

Chronic heart failure (CHF) remains a major health problem affecting up to 5.7 million people in the United States and is associated with significant morbidity and mortality.1 Several large randomized placebo-controlled trials have consistently demonstrated additional prognostic benefit of cardiac resynchronization therapy (CRT) over optimal medical therapy (OMT) in patients with CHF because of severe left ventricular (LV) systolic dysfunction (LVSD; LV ejection fraction <35%) and

electrical dyssynchrony (QRS duration greater than 120 ms).2–7

CRT can be provided with a device only for pacing (CRT-P) or with a combined defibrillator (CRT-D).8 Although implantable cardioverter defibrillators (ICDs) are also associated with a survival benefit beyond medical therapy,9,10 it is unknown whether there is a survival benefit of CRT-D versus CRT-P. CRT-D devices are

with CRT-D; however, this was not significant after adjustment. In a subgroup analysis, there were no differences in mode-specific mortality in those patients implanted with CRT-D compared with CRT-P.

Conclusion In this large consecutive patient cohort, we did not find a survival benefit of CRT-D compared with CRT-P. Patients indicated for CRT devices may not reliably benefit from the addition of a defibrillator.

J Cardiovasc Med 2017, 18:000–000

Keywords: cardiac resynchronization therapy, chronic heart failure, left ventricular systolic dysfunction

aLeeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, bLeeds Teaching Hospitals NHS Trust and cClinical Trials Research Unit, Leeds Institute of Clinical Trials Research, Leeds, UK

Correspondence to Klaus K. Witte, MD, Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre (MCRC), Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, LIGHT building, Clarendon Way, Leeds LS2 9JT, UK

Tel: +44 113 3926108; e-mail: k.k.witte@leeds.ac.uk

Received 24 July 2017 Revised 2 September 2017

Accepted 28 September 2017

more expensive and are more complex to follow-up,

whilst they are also associated with a higher complication and reoperation rate.11,12 The lack of clear data around

the benefit of an ICD approach to CRT means that international guidelines extrapolate the benefit from ICD into the CRT population. It is, however, the case that optimal therapy of the CHF syndrome, including with CRT, significantly reduces the risk of sudden arrhythmic death.13

Until 2015, the United Kingdom guidelines for CRT did not mandate CRT-D implantation for patients with nonischaemic CHF and also included physician discretion to implant CRT-D or CRT-P in patients with ischaemic heart disease. It is on this background and in the absence of trial data that we aimed to establish whether there were significant differences in outcomes between the two approaches in patients receiving CRT devices.