The Benefit of Cardiac Resynchronization Therapy and QRS Duration: A Meta-Analysis

Indications for cardiac resynchronization therapy

Initial studies established patient selection criteria for cardiac resynchronization therapy (CRT) as left ventricular ejection fraction less than or equal to 35%, QRS greater than or equal to 120 ms, and New York Heart Association 3-4. Based on newer data, post hoc analyses, and meta-analyses, these criteria have been refined and guidelines updated, highlighting left bundle branch morphology and QRS greater than 150 ms in selecting patients with a likelihood of favorable outcomes. Guidelines will change as more data become available; the decision to apply CRT should be based on patient clinical profile and the balance of risk tolerance and likelihood of benefit.

The potential role of nonpharmacologic electrophysiology-based interventions in improving outcomes in patients hospitalized for heart failure

Hospitalization for heart failure (HHF) is commonly associated with symptomatic improvement in response to standard medical therapy, yet there remains a substantial risk of rehospitalization and death. Clinically stable outpatients and decompensated inpatients represent two types of patients with chronic heart failure. In the former, treatment of common heart rhythm disorders with nonpharmacologic electrophysiology-based interventions is of substantial benefit in select patients. The potential benefits of these interventions in the hospitalized setting are not well studied. In this review, current knowledge is discussed and future research directions are suggested with nonpharmacologic electrophysiology-based interventions to reduce the morbidity and mortality associated with patients with HHF.