Risk Assessment of Ventricular Arrhythmias in Patients with Nonischemic Dilated Cardiomyopathy by Strain Echocardiography

Background: Indications for prophylactic implantable cardioverter-defibrillator implantation in patients with nonischemic dilated cardiomyopathy (DCM) are based on left ventricular (LV) ejection fraction (LVEF), although LVEF has limited ability to predict arrhythmias. It has recently been shown that strain echocardiography can predict ventricular arrhythmias in patients after myocardial infarction. The aim of this study was to evaluate whether strain echocardiography may help in the risk stratification of ventricular arrhythmias in patients with DCM. Methods: Ninety-four patients with nonischemic DCM were prospectively included. By speckle-tracking strain echocardiography, global longitudinal strain was calculated as the average of peak longitudinal strain from a 16-segment LV model. The time interval from electrocardiographic peak R to peak negative strain was assessed in each LV segment. Mechanical dispersion was defined as the standard deviation of time to peak negative strain from 16 LV segments. Results: After a median of 22 months of follow-up (range, 1-46 months), 12 patients (13%) had experienced arrhythmic events, defined as sustained ventricular tachycardia or cardiac arrest. LVEF and global longitudinal strain were reduced in patients with DCM with arrhythmic events compared with those without (28 +/- 10% vs 38 +/- 13%, P = .01, and 6.4 +/- 3.3% vs 12.3 +/- 5.2%, P < .001, respectively). Global longitudinal strain showed greater area under the curve than LVEF to identify arrhythmic events in receiver operating characteristic curve analyses (P = .05). Patients with arrhythmic events had increased mechanical dispersion (98643 vs 56618 ms, P < .001). Mechanical dispersion predicted arrhythmias independently of LVEF (hazard ratio, 1.28; 95% confidence interval, 1.11-1.49; P = .001). Conclusions: Global longitudinal strain is a promising marker of arrhythmias. Mechanical dispersion predicted arrhythmic events in patients with DCM independently of LVEF. Strain echocardiography may help in the risk stratification of patients with DCM not fulfilling current implantable cardioverter-defibrillator indications. (J Am Soc Echocardiogr 2012;25:667-73.)