[Effect of vasodilator agents on the character and incidence of cardiac arrhythmia in chronic heart failure].

In 50 patients with chronic congestive heart failure (CCHF, III or IV class), aged 62.8 +/- 9.1 years, who were treated with digoxin (Dx) and furosemide (F) (investigation A), continuous 24-hour ecg registration was performed according to Holter. Next, this treatment was extended by two-week administration of nifedipine (N) or isosorbide dinitrate (S) (investigation B), followed by one-month addition of captopril (Cp) (investigation C). During the last two weeks Dx, F, N or Dx, F, S were administered with Cp being withdrawn (investigation D). At the end of each stage of the treatment ecg registration was repeated according to Holter. At the same time, during the investigation A there were performed determinations of blood serum sodium, potassium and digoxin concentrations, two-dimensional echocardiography and evaluation of submaximal exercise tolerance. In 96 per cent of patients with CCHF, treated with Dx and F, cardiac rhythm disturbances were found. In 53.3 per cent life-threatening ventricular arrhythmias occurred, including unstable ventricular tachycardia in 11.1 per cent of patients. Addition of N or S to the classical treatment did not decrease either patient number or amounts of cardiac rhythm disturbances in individual classes according to Lown. Also Cp did not affect numbers of patients with cardiac rhythm disturbances, but it decreased numbers of patients with life-threatening ventricular arrhythmias from 53.3 per cent to 28.9 per cent (from 24/45 to 13/45). At the same time, Cp significantly decreased numbers of ventricular arrhythmias in class 3 and 4a (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)