COMMENTS AND RESPONSES Cardiac Resynchronization Therapy in Heart Failure

TO THE EDITOR: McAlister and colleagues (1), in their systematic review, concluded that cardiac resynchronization therapy (CRT) re-duces all-cause mortality and heart failure hospitalizations when added to medical therapy in selected patients with heart failure. Among some U.S. cardiologists, there appears to be a perception that patients with heart failure should receive a device with defibrillator ability and biventricular pacing function. It is likely that the report by McAlister and colleagues will further contribute to this perception and possibly influence practice trends. McAlister and colleagues used a comprehensive search strategy and intensive extraction and evaluation of data from pertinent stud-ies. However, their analysis could not overcome certain method-ologic deficiencies (for example, concealed randomization, lack of blinding or partial blinding, and intention-to-treat analyses) that af-fected several of the studies. Such deficiencies can lead to preferential management or treatment, resulting in better or improved outcomes that favor the intervention of interest (in this case, CRT). In addi-tion, the crossover design of several studies further restricted the already limited data available for evaluation of mortality rates and hospitalizations. Among the parallel studies noted in McAlister and colleagues