This commentary discusses the rationale for evaluating cardiac resynchronization therapy in patients with less severe heart failure, noting prior trials included 86-94% NYHA class III patients.
Does cardiac resynchronization therapy improve outcomes in patients with less severe heart failure?
This commentary discusses the rationale for extending cardiac resynchronization therapy to patients with less severe heart failure, as investigated in the MADIT-CRT trial.
This commentary refers to ‘Cardiac-resynchronization therapy for the prevention of heart-failure events’†, by A.J. Moss et al. , published in the New England Journal of Medicine , 2009; 361:1329–1338 Randomized clinical trials have firmly established the role of cardiac resynchronization therapy (CRT) in chronic heart failure patients in New York Heart Association (NYHA) class III or IV who have left ventricular dysfunction and a prolonged QRS complex. CRT improves symptoms, reduces the need for hospitalizations, and improves survival by reversal of left ventricular remodelling and by slowing of disease progression. In these CRT trials, patients were selected on the basis of the degree of heart failure. COMPANION1 included 86% class III and 14% class IV patients. CARE-HF included 94% NYHA class III and 6% class IV patients.2 Thus, the data on the beneficial effects of CRT, based on large trials, are restricted to class III and to a lesser degree to class IV patients. In contrast, in primary prevention implantable cardioverter defibrillator (ICD) trials, the spectrum of patients was broader. Although SCD-HeFT also selected heart failure patients in class III (30%), the majority were in class II (70%).3 The two post-myocardial infarction trials, MADIT and MADIT II, included an even broader spectrum of heart failure patients although primary inclusion was on the basis of ejection fraction and history of prior myocardial infarction. MADIT included 35% of patients in class I, and 65% in class II–III.4 In MADIT II, 37% of patients were in NYHA class I, 35% in class II, 24% in class III, and 5% in class IV.5 Since CRT induces progressive reverse left ventricular remodelling and slows disease progression in patients with NYHA class III or IV heart failure, it might also be beneficial in patients with less severe heart …
“Cardiac resynchronisation therapy was dramatically effective in this large study population, with a 34% reduction in the risk of all-cause mortality or heart failure. The benefit is dominated by a 41% reduction in heart failure events. This results validate a new indication for cardiac resynchronisation therapy in the prevention of heart failure in at-risk asymptomatic or mildly symptomatic cardiac patients. It seems likely that this preventive CRT-D therapy will have widespread application and utilisation.”
Günter Breithardt (Tue,) conducted a editorial in Heart failure. Cardiac resynchronization therapy was evaluated. This commentary discusses the rationale for evaluating cardiac resynchronization therapy in patients with less severe heart failure, noting prior trials included 86-94% NYHA class III patients.