Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)

2005   Vol. 6B   No. 4   p.249-253

The effects of sotalol on ventricular repolarization during exercise

LI Jian^*1, WANG Jian-an²

(¹Cardiology Department of Pu Nan Hospital, Pudong New District, Shanghai 200125, China)
(²Cardiology Department of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China)
^*E-mail: lj.zj@126.com; swordzj_cn@sina.com
Received Sept. 14, 2004; revision accepted Nov. 8, 2004

Abstract: Objective: Although after pacing animal and human studies have demonstrated a rate-dependent effect of sotalol on ventricular repolarization, there is little information on the effects of sotalol on ventricular repolarization during exercise. This study attempted to show the effects of sotalol on ventricular repolarization during physiological exercise. Methods: Thirty-one healthy volunteers (18 males, 13 females) were enrolled in the study. Each performed a maximal treadmill exercise test according to the Bruce protocol after random treatment with sotalol, propranolol and placebo. Results: Sotalol significantly prolonged QTc (corrected QT) and JTc (corrected JT) intervals at rest compared with propranolol (QTc 324.86 ms vs 305.21 ms, P<0.001; JTc 245.04 ms vs 224.17 ms, P<0.001) and placebo (QTc 324.86 ms vs 314.06 ms, P<0.01; JTc 245.04 ms vs. 232.69 ms, P<0.001). The JTc percent reduction increased progressively with each stage of exercise and correlated positively with exercise heart rate (r=0.148, P<0.01). The JTc percent reduction correlation with exercise heart rate did not exist with either propranolol or placebo. Conclusions: These results imply that with sotalol ventricular repolarization is progressively shortened after exercise. Thus the specific class III antiarrhythmic activity of sotalol, present as delay of ventricular repolarization, may be attenuated during exercise. Such findings may imply the need to consider other antiarrythmic therapy during periods of stress-induced tachycardia.

Key words: Sotalol, Exercise stress test, Ventricular repolarization
doi:10.1631/jzus.2005.B0249             CLC number: R5