Holter monitoring was performed in 55 patients (24 women, 31 men), mean age 50.7 +/- 11.3 who underwent ECG-triggered extracorporeal shock wave lithotripsy (ESWL). Patients were divided into two groups A--30 with history of cardiac disease and B--25 control. The heart rate was significantly higher before and after ESWL in the first group. The number of premature ventricular contractions was higher during ESWL in the same group. No other cardiac complication was observed.