[Arrhythmia in patients with hypertrophic cardiomyopathy during an exercise test with 24-hour Holter monitoring].

Thirty patients with hypertrophic cardiomyopathy (HCM), (20 men and 10 women, age 16-55, mean 37 +/- 8 years) underwent exercise test done on bicycle twice to estimate effort tolerance before drugs. In all patients a 24-hour ekg Holter monitoring was also performed. During exercise test heart rhythm disturbances were noticed in 2 patients (7%). One had a 2-second sinus arrest, in the other ventricular bigeminity was observed. Twenty two patients (79%) had rhythm or conduction disturbances in Holter monitoring. In 2 (7%) rhythm generation and conduction abnormalities, in 7 (23%)-supraventricular and in 13 (43%)-ventricular arrhythmia. Ten of them (33%) had Lown class IVa and IVb arrhythmia. In conclusion we suggest that exercise test done on bicycle ergometer is a safe method to estimate effort tolerance in patients with HCM and usually does not induce rhythm disturbances. Holter monitoring is more effective than exercise test in revealing cardiac arrhythmia.