REGIONAL CARDIAC SYMPATHETIC DENERVATION IN PATIENTS WITH VENTRICULAR-TACHYCARDIA IN THE ABSENCE OF CORONARY-ARTERY DISEASE

Objectives. The aim of this study was to determine whether patients wi th ventricular arrhythmias in the absence of coronary artery disease a lso have abnormalities in sympathetic innervation. Background. We have previously shown by cardiac sympathetic scintigraphy using iodine-123 -metaiodobenzylguanidine (I-123-MIBG) that patients with ventricular t achycardia after myocardial infarction have regional cardiac sympathet ic denervation. It is not known whether patients with ventricular tach ycardia in the absence of coronary artery disease also have regional c ardiac sympathetic denervation. Methods. We performed cardiac I-123-MI BG and thallium-201 single-photon emission computed tomographic (SPECT ) scans at rest in 18 patients (mean age 47 +/- 18 years) with cardiom yopathy (n = 6), left ventricular hypertrophy (n = 1), valvular diseas e (n = 2) or a structurally normal heart (n = 9) who presented with mo nomorphic (n = 15) or polymorphic (n = 3) ventricular tachycardia. The se scans were compared with scans in 12 control patients without ventr icular tachycardia (mean age 30 +/- 17 years) who had cardiomyopathy ( n = 3) or a structurally normal heart (n = 9). Cardiac sympathetic den ervation was defined as myocardial areas having thallium uptake with r educed or absent I-123-MIBG uptake. Results. Twelve (67%) of 18 patien ts with ventricular tachycardia had regional cardiac sympathetic dener vation compared with 1 (8%) of 12 patients who did not have ventricula r tachycardia (p = 0.002). In the nine patients with a structurally no rmal heart and ventricular tachycardia, five (55%) patients had region al cardiac sympathetic denervation compared with zero of nine control patients with a structurally normal heart (p = 0.029). Five patients u nderwent right ventricular radiofrequency ablation for ventricular tac hycardia, and sympathetic denervation was adjacent to the ablation sit e in one of these patients. Conclusions. Patients with ventricular tac hycardia in the absence of coronary artery disease have abnormal cardi ac sympathetic innervation detectable by cardiac sympathetic scintigra phy. The role of regional cardiac sympathetic denervation in arrhythmo genesis remains to be determined.