Cardiac resynchronization: a brief synopsis part I: patient selection and results from clinical trials.

Heart failure continues to affect large populations within the industrialized nations. Previous therapies have been directed at increasing myocardial contractility or decreasing vascular resistance but have not addressed the mechanical dysfunction within certain subpopulations with heart failure. Biventricular pacing has been shown to improve both acute hemodynamic parameters and long-term functional capacity in patients with ventricular dysynchrony and suffering from severe heart failure. From this data, the therapy is indicated for use in patients with depressed ejection fraction, bundle branch block, and either NYHA class III or class IV heart failure, regardless of whether or not there is a separate indication for ICD placement. Recent studies suggest that biventricular pacing may remodel the failing heart. Future studies could expand the previously mentioned indications to patients suffering from mild symptoms of heart failure. This article reviews the current demographics involved within this population, the acute hemodynamic benefits experienced from biventricular pacing, the long term function benefits experienced from the therapy, and other possible benefits from the therapy.