Benefit of cardiac resynchronization therapy to a patient with a narrow QRS complex and ventricular dyssynchrony identified by tissue synchronization imaging.

This report described an 81-year-old woman with severe symptomatic heart failure, reduced ejection fraction, mitral regurgitation, and an electrocardiographic QRS width of 118 ms who had ventricular dyssynchrony identified by echocardiographic tissue synchronization imaging. Because of her severe heart failure symptoms on maximal medical therapy, referral to implant a defibrillator, and mechanical dyssynchrony, she underwent cardiac resynchronization-defibrillator therapy with lateral left ventricular lead placement. This resulted in an immediate 30% increase in stroke volume and 35% decrease in mitral regurgitation. Echocardiographic tissue synchronization imaging may play a role in identifying mechanical dyssynchrony in patients with narrow QRS duration who may potentially benefit from cardiac resynchronization therapy.