Cardiac resynchronization therapy. Indications and contraindications.

Progress in medical therapy wouldn't be possible without the contribution of the scientific community. Several randomized controlled trials have led to our current guidelines. Specifically, COMPANION and CARE-HF trials involved a turning point for cardiac resynchronization therapy, which became well recognized for the treatment of heart failure patients with QRS≥120ms, ejection fraction≤35%, and sinus rhythm to reduce hospitalizations and all-cause mortality. New indications were then established for atrial fibrillation, pacemaker-dependent, and mildly symptomatic patients, but new challenges should be addressed, namely reducing complication and nonresponder rates. To achieve this, further studies and new implant techniques are under investigation.