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Circ Arrhythm Electrophysiol. 2014 Dec;7(6):1101-8. doi: 10.1161/CIRCEP.114.001745. Epub 2014 Sep 27.

Multiple autonomic and repolarization investigation of sudden cardiac death in dilated cardiomyopathy and controls.

Author information

1
From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.). thomas.pezawas@meduniwien.ac.at.
2
From the Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria (T.P., B.R., H.S.); Departments of Medicine (A.D.), and Departments of Medicine, Pharmacology, Neurology (D.R.), Division of Clinical Pharmacology, Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN; Health and Prevention Center, Sanatorium Hera, Vienna, Austria (R.W.); and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN (L.W., D.W.B.).

Abstract

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-up: pharmacological 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.

KEYWORDS:

(non-invasive) risk stratification; cardiomyopathy; dilated; implantable cardioverter defibrillator; sudden cardiac death or arrhythmic death

PMID:
25262115
PMCID:
PMC4329912
DOI:
10.1161/CIRCEP.114.001745
[Indexed for MEDLINE]
Free PMC Article

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