A medicamentous therapy of bradycardiac disturbances of heart rhythm can be performed on the one hand by stimulation of the sympathetic nerve, on the other hand by blockade of the parasympathetic system. An ester of the tropic acid, Ipratropiumbromide (IP), shall be used for answering the question to what extent the heart rate may be increased in such arrhythmias. In 10 patients (4 females and 6 males, m 60 +/- 9 years old) with asymptomatic bradycardiac arrhythmias (heart rate less than 60 per min in the routine ECG; 3 patients AV-block III, 1 patient AV-block II II, 6 patients sinus bradycardia) at first a 24-hour long-term ECG was recorded under ambulatory conditions, after this 1 mg IP was administered intravenously under continuous long-term ECG. After 4 days 10 mg IP orally thrice a day, in 3 patients also after 15 mg IP t.i.d. a repeated long-term ECG was performed. These were evaluated using the computer-assisted "multipass scanning" system. RESULTS 1 hour after 1 mg IP intravenously the m heart rate significantly increased about 17-87% (m 55%) in all patients (p less than 0.001). Proportionally to the increase of the heart rate it lasted 7-14 hrs. till the initial heart rate was reached again. 1-4 hours after intravenous injection in 2 patients sinus tachycardias developed as an expression of an increased sympathicotonia. 10 mg IP led to an increase of the heart rate of m 8% of the patients, during the day m 9%, during the night 4%.(ABSTRACT TRUNCATED AT 250 WORDS)