Trial: Beta-Blocker Therapy Induces Ventricular Resynchronization in Dilated Cardiomyopathy With Narrow QRS Complex

Authors: Takemoto Y, Hozumi T, Sugioka K, Takagi Y, Matsumura Y, Yoshiyama M, Abraham T, and Yoshikawa J.

Reference:  J Am Coll Cardiol, 2007; 49:778-783

Purpose:  To evaluate the effects of beta-blocker therapy on regional and global myocardial mechanics in addition to ventricular synchrony in patients with heart failure and normal QRS by using tissue Doppler and strain echocardiography.

Number of Patients: Conventional and strain echocardiography were performed in 15 healthy age-matched volunteers and in 25 patients with idiopathic dilated cardiomyopathy (IDC). Of these, 15 IDC patients on standard heart failure therapy were studied prior to and at 1 and 6 months after initiation of carvedilol therapy and compared to the controls.

Number of Centers: 1

Design:  Prospective

Authors Conclusion: Beta-blocker therapy stimulates increments in local contractility and reduction of intraventricular dyssynchrony. To our knowledge, this is the first report of cardiac resynchronization by medical therapy. Increased regional systolic function followed by cardiac resynchronization potentially underlies the beneficial effects of beta-blockers in heart failure.

Key words:  heart failure, resynchronization, beta-blocker

Comment:  This study demonstrates that pharmacologic agents can promote resynchronization, at least in patients with heart failure and a narrow QRS complex.  It highlights the importance of concomitant medical therapy in patients undergoing device-based resynchronization.

Ongoing Related Studies:

1. BOAT: Beta Blocker U[titration With optiVol After CRT
2. REVERSE: REsynchronization reVErses Remodeling in Systolic Left vEntricular Dysfunction

Summary written by Paul Friedman, MD