Background: Performance of ambulatory electrocardiography (AECG) may provide data useful for counseling patients regarding prognosis and for selecting potential patients for defibrillator implantation, but this practice remains controversial.
Methods: We reviewed clinical and AECG data on 355 patients diagnosed with dilated cardiomyopathy (DCM). Predictors of survival were identified in a multivariable analysis using a Cox proportional hazard model. Ability of the derived model to predict outcomes was tested using a second cohort of 144 patients.
Results: Nonsustained ventricular tachycardia (NSVT) was present on AECG in 31% of the subjects. Ambulatory electrocardiography provided 3 independent predictors of mortality: NSVT (relative risk [RR], 1.63; 95% confidence interval [CI], 1.06-2.51; P = .02), mean heart rate (RR, 1.03; 95% CI, 1.02-1.04; P = .0001), and heart rate range (RR, 0.990; 95% CI, 0.982-0.997; P = .008). Performance of the multivariable model was validated (area under the curve = 0.83) on a second cohort of patients.
Conclusion: Ambulatory electrocardiography provides useful prognostic information in patients with DCM, identifying 3 independent predictors of mortality.