Sympathetic denervation in patients with ischemic cardiomyopathy and risk on ventricular tachy-arrhythmias. A pilot study.

BACKGROUND: Patients with ischemic cardiomyopathy (ICM) are at risk for ventricular arrhythmias and are protected by an implantable cardioverter defibrillator (ICD). Visualization of cardiac sympathetic innervation may play an additional role to left ventricular ejection fraction (LVEF) in identifying those patients who will benefit from ICD therapy. The purpose of this study was to detect the role of sympathetic denervation in the genesis of ventricular arrhythmias in ICM patients. METHODS: Twenty patients with ICM and LVEF <30% were included in this pilot study. Included patients were equally stratified into two groups: no history of arrhythmias (group A) and recurrent arrhythmias (group B). All patients underwent cardiac sympathetic denervation (using carbon-11 labelled meta-hydroxy-ephedrine ([C-11]-mHED)), myocardial ischemia and viability detection. Patients were followed up to one year after the imaging studies. RESULTS: Mean age was 63 +/- 7.5 years. Mean global retention of [C-11]-mHED was 0.055 +/- 0,012 min(-1), and was not different between the two patient groups: 0.056 +/- 0.011 min(-1) vs. 0.054 +/- 0.013 min(-1) for group A vs. group B, respectively. During follow-up, seven patients developed ventricular arrhythmias, and four patients died. No difference in [C-11]-mHED retention was found between patients with and without ventricular arrhythmia during follow-up. However, size of denervated area was larger in patients who died during follow-up: 10 +/- 1 segments vs. 6 +/- 2 segments, P=0.002. CONCLUSIONS: Cardiac sympathetic innervation is impaired in patients with ischemic cardiomyopathy. All-cause mortality occurred in those patients with large areas of [C-11]-mHED defect.