Abstract: AIM: To observe the relationship among the effects, side-effects and serum concentration of sotalol in treatment of patients with arrhythmia. METHODS: 100 cases (male 53, female 47) of out patient department (OPD) with atrial or ventricular arrhythmia were select-ed. Every different doses of sotalol (80, 160, 240 mg°d^-1) were administrated two weeks in order.Samples of 3 ml peripheral venous blood were collected during the last day of the period of every different dose. The time of blood collecting was in the morning before administration and three hours after administration (i. e.peak and bot-tom serum concentration). RP-HPLC method was adopt-ed. ECG (including QT, QTc episodes and QTd) and Holter examination were performed.RESULTS: Total ef-ficiency of sotalol on arrhythmia :ventricular premature beats (VPB) was 85.7%, couple VPB and paroxysmal ventricular tachycardia was 73.3%, and atrial arrhythmia was 70%.The following resultswere still observed:bet-ter effects on the prevention to paroxysmal atrial fiberal-lation, ventricular rates being better controlled in atrial flutter and fiberallation.The average bottom value (ABV) of the effective serum concentration of the effective cases was 0.67±0. 21 mg°L^-1 and the peak value was 1.33± 0.51 mg°L^-1, but the ABV of the serum concentration was 0.69 ±0.22 mg°L^-1 and peak value was 1.36 ± 0.53 mg°L^-1 in ineffective cases.CONCLUSION: The most rational doses of sotalol ranges between 160 -240 mg°d^-1 with some advantages, such as lower side ef-fects, and effective to both atrial and ventricular arrhyth-mia.

Key words: sotalol, arrhythmia, serum concentra-tion, treatment effect