Cardiac sympathetic nerve abnormality predicts ventricular tachyarrhythmic events in patients without conventional risk of sudden death.
OBJECTIVE
Patients with structural heart disease, severe left ventricular dysfunction, or history of cardiac arrest are at increased risk of sudden cardiac death. However, a useful marker for predicting sudden cardiac death is not clarified in low-risk patients without those conventional risks. We hypothesized that cardiac sympathetic nerve system (SNS) abnormality would be associated with ventricular tachyarrhythmic events in low-risk patients with ventricular tachycardia (VT).


METHODS
Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) scintigraphy was performed in 50 patients (mean+/-standard deviation, age 54 +/- 16 years, 52% males) with VT who did not have structural heart disease, severe left ventricular dysfunction, or history of cardiac arrest, and SNS activity was assessed from heart/mediastinal (H/M) ratio on delayed images.


RESULTS
Over 11 years of follow-up, three patients had sudden deaths (6%) and nine patients had sustained ventricular tachyarrhythmic events (18%). SNS abnormality, defined as H/M ratio <2.8, was predictive of sudden death or ventricular tachyarrhythmic events (45% in nine of 20 patients with SNS abnormality vs 16.7% in three of 30 patients without SNS abnormality, p = 0.005). After adjustment for potential confounding variables including slight left ventricular dysfunction, SNS abnormality remained independently predictive of ventricular tachyarrhythmic events with a hazard ratio of 5.3 (95% confidence interval = 1.4 to 20.8, p = 0.016).


CONCLUSIONS
SNS abnormality is a readily available and powerful predictor of recurrent ventricular tachyarrhythmic events in patients with VT who did not have conventional risk of sudden cardiac death. (123)I-MIBG scintigraphy can provide prognostic information of VT patients without conventional risk.
Akutsu
Yasushi
Y
Division of Cardiology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawaku, Tokyo, 142-8666, Japan. hzn01233@s02.itscom.net
Kaneko
Kyouichi
K
Kodama
Yusuke
Y
Li
Hui-Ling
HL
Kawamura
Mitsuharu
M
Asano
Taku
T
Tanno
Kaoru
K
Shinozuka
Akira
A
Gokan
Takehiko
T
Kobayashi
Youichi
Y
D019797:3-Iodobenzylguanidine; D000328:Adult; D016757:Death, Sudden, Cardiac; D005260:Female; D006321:Heart / Q000294:innervation*; D006801:Humans; D008297:Male; D011379:Prognosis; D011877:Radionuclide Imaging; D012306:Risk; D013564:Sympathetic Nervous System / Q000002:abnormalities* / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013997:Time Factors
D019797:3-Iodobenzylguanidine