Cardiac resynchronization therapy in mildly symptomatic heart failure John Rogers, Jigar Patel, and J Thomas Heywood

Despite significant advances in the pharmacologic treatment of left ventricular (LV) systolic dysfunction, morbidity and mortality remain high.1 Device therapies, including pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT), have now been conclusively shown to improve symptoms and mortality when added to standard medical therapy.2-8 ICDs are indicated for New York Heart Association (NYHA) class II and III patients, but most studies with CRT have required patients to have at least moderate symptoms (NYHA class III-IV).9,10 This was a reasonable approach early on, because it allowed trials to be smaller, reserving this expensive therapy for those most likely to benefit.11