Effects Of Sotalol On Cardiovascular Physiology And Ventricular Repolarization During Exercise In Human Without Overt Heart Disease

[Background] During recent years, the focus on antiarrhythmic drug therapy has shifted from the widespread use of Class I antiarrhythmic agents to an increasingly frequent administration of Class III compounds. Moreover the P blockder has been proved to be able to decrease the mortality in cardiovascular incidence. Sotalol as an antiarrhythmic agent with both Class III and P -block activities is increasingly widely used and studied. Clinical trial has confirmed the efficiency of sotalol in treating a lot of atrial and ventricular arrhythmia, special for some serious ventricular arrhythmias which are obstinate to traditional antiarrhythmics. Although long-term use of sotalol has been proved to be both efficient and safe by several trials. But sotalol still has certain extent proarrhythmia effect, including its resulting in torsade de pointes(Tdp) and ventricular tachyarrhythmias. Domestic study on stalol is not adeqate. Extensive researches have been made abroad on the electrophysiology, hemodynamics, the efficiency of antiarrhythmia and side effects of sotalol. Most of the studies on its electrophysiology are animal experiments or studies6on human under slow pacing. Research on the electrophysiology of sotalol during exercise in human is not enough. There is only one article demonstrates the rate dependence effect of sotalol on ventricular repolarization during exercise in human. There is no study so far reporting the effects of sotalol on cardiovascular physiology during exercise in human from the aspect of safety.Exercise is an important physiological state for human. Series of physiologic changes during exercise are similar to changes under the condition of disease. To demonstrate the effects of sotalol on cardiovascular physiology and to explore the safety of sotalol therapy during exercise may be helpful to patients with structive heart disease and to patients who often need to exercise.[Purpose]oTo observe the effects of single dose of sota]ol on heart rate, systolic blood pressure, ventricular repolarization and intraventricular conduct, the cardiac oxygen consumption and working power reservation, exercise tolerance and so on.?To explore the safety of sotalol therapy during exercise on the basis of the observations above.[Method] A design of randomization, double blind, auto-control with placebo and propranolo] is employed in the study. Thirty-one patients without overt heart disease are enrolled in the study. Each of them performed treadmill exercise tests for 3 times at an interval of seven days after being treated with single dose of sota]ol(lOOmg), placebo or propranolol(3Omg).[ResultloSotalol significantly decreases the heart rate by 24% at rest and by 20% at peak of the exercise. But in comparison with propranolol, there is no significant difference between them.7?Sotalol significantly decreases the systolic blood pressure by 10% at rest and by 7% at peak of the exercise. But in comparsion with propranolol, there is no significant difference between them.?Sotalol significant prolongs the QTc and JTc intervals at rest in comparison with placebo(324.86?.4Oms vs.314.06?.58 ms in QTc, p