Camilla Normand, Cecilia Linde, Jagmeet Singh, Kenneth Dickstein

This study compares and contrasts the recommended indications for cardiac resynchronization therapy (CRT) according to the most recent guidelines from international cardiology societies. CRT has been shown to reduce morbidity and mortality in selected patients with systolic heart failure. Cardiology societies provide guidelines regarding the indications for CRT. As evidence evolves, it is challenging for the guideline committees to review the impact of newer evidence in a timely fashion. Six of the most recent international guidelines providing recommendation concerning CRT implantation ranging from 2011 to 2017 were reviewed. These included guidelines from 2 European, 1 North American, 1 Canadian, and 1 Australian/New Zealand societies and the National Institute for Health and Care Excellence guidelines, specific to the United Kingdom. Although international societies provide consistent recommendations for most CRT indications, differences are found in recommendations for several important patient populations. Specifically, divergent recommendations exist regarding QRS duration, bundle branch morphology, patients in atrial fibrillation, choice of device type (CRT pacemakers vs. CRT defibrillators), and selected patients who are likely to be dependent on right ventricular pacing. The timing of publication of specific guidelines appears to play an essential role in explaining these disparities. Despite general consistency in international guideline recommendations, there remain certain patient populations for whom there are variations in recommendations concerning eligibility for CRT and selection of the most appropriate device in the individual patient.