Multiple Autonomic and Repolarization Investigation of Sudden Cardiac Death in Dilated Cardiomyopathy and Controls

• Published in: Circulation. Arrhythmia and electrophysiology Vol. 7; no. 6; pp. 1101 - 1108
• Main Authors: Pezawas, Thomas, Diedrich, André, Winker, Robert, Robertson, David, Richter, Bernhard, Wang, Li, Byrne, Daniel W, Schmidinger, Herwig
• Format: Journal Article
• Language: English
• Published: United States American Heart Association, Inc 01.12.2014
• Subjects: Aged; Autonomic Nervous System - physiopathology; Baroreflex; Blood Pressure; Cardiomyopathy, Dilated - complications; Cardiomyopathy, Dilated - diagnosis; Cardiomyopathy, Dilated - mortality; Cardiomyopathy, Dilated - physiopathology; Cardiomyopathy, Dilated - therapy; Case-Control Studies; Death, Sudden, Cardiac - etiology; Death, Sudden, Cardiac - prevention & control; Decision Support Techniques; Defibrillators, Implantable; Electric Countershock - instrumentation; Electrocardiography; Female; Heart Rate; Humans; Male; Middle Aged; Patient Selection; Predictive Value of Tests; Primary Prevention - instrumentation; Prospective Studies; Risk Assessment; Risk Factors; Stroke Volume; Time Factors; Ventricular Function, Left; Young Adult; sudden cardiac death or arrhythmic death; dilated; implantable cardioverter defibrillator; cardiomyopathy; (non-invasive) risk stratification
• ISSN: 1941-3149; 1941-3084
• DOI: 10.1161/CIRCEP.114.001745

BACKGROUND—Prophylactic defibrillator implantation is recommended in dilated, nonischemic heart disease and left ventricular ejection fraction of ≤0.30 to 0.35. Noninvasive testing should improve accuracy in decision making of prophylactic defibrillator implantation. METHODS AND RESULTS—We enrolled 60 patients (median age, 57 years) with dilated cardiomyopathy and left ventricular ejection fraction ≤0.50, and 30 control subjects (median age, 59 years) with left ventricular ejection fraction >0.50. The protocol included an initial assessment, a second assessment after 3 years, and a final follow-uppharmacological baroreflex testing (baroreceptor reflex sensitivity), short-term spectral analysis of heart rate variability (low frequency/high frequency), and long-term time domain analysis (SD of all normal-to-normal R–R intervals), exercise microvolt T wave alternans, and signal-averaged ECG, and corrected QT-time. The median follow-up was 7 years. End points were cardiac death, resuscitated cardiac arrest, and arrhythmic death. Cardiac death was observed in 21 patients. Resuscitated cardiac arrest and arrhythmic death caused by ventricular tachyarrhythmias ≥240 per minute was observed in 7 and 10 patients, respectively. In the single time point analysis, microvolt T wave alternans, baroreceptor reflex sensitivity, and SD of all normal-to-normal R–R intervals at initial testing added significant information regarding cardiac death. Microvolt T wave alternans added information on resuscitated cardiac arrest or arrhythmic death at multiple time points (P<0.001). False-negative microvolt T wave alternans results were seen in 8% of patients. CONCLUSIONS—Noninvasive testing and left ventricular ejection fraction could not reliably identify patients with dilated cardiomyopathy at risk of fatal ventricular tachyarrhythmias. Therefore, the strategy to confine prophylactic implantable cardioverter-defibrillator implantation to patients with dilated cardiomyopathy and severely reduced LV function should be reconsidered.