The emerging role of cardiac resynchronization therapy in milder heart failure: are we implanting too late for response?

The role of cardiac resynchronization therapy in mild heart failure has become a focus of attention with the publication of recent clinical trials. We present a review of the data supporting implantation of cardiac resynchronization devices in early stage heart failure. In addition, we present evidence that may suggest patients are often implanted too late for clinical benefit, potentially contributing to the relatively high nonresponder rate seen in randomized trials and clinical practice.