[Enhancement of the effect of captopril in the 1st 48 hours of treating refractory heart failure. A comparison with intravenous trinitrine].

The favourable haemodynamic effects of vasodilator drugs in refractory cardiac failure sometimes alter rapidly after the initial dose. This tachyphylactic phenomenon was looked for during captopril therapy in 14 patients with chronic cardiac failure resistant to digitalo-diuretic therapy and conventional vasodilator drugs. The average age of the patients was 64,4 +/- 3,8 years. Eleven patients had signs of congestive cardiac failure while the remaining three patients had only left ventricular failure. Four patients were classified as Stage III and the other ten Stage IV of the NYHA classification. Right heart catheter studies were performed with a Swan Ganz catheter and systemic pressures were measured by femoral artery catheterisation. Right and left pressures and cardiac output were measured under basal conditions, and 1 and 5 hours after a single dose of captopril (early and late periods). Captopril was given in between meals in 3 to 6 daily doses; in 10 of the 14 cases the dose was 50 mg 6 hourly. The haemodynamic parameters were recorded again during the early and late periods after the dose of captopril 24 and 48 hours after starting therapy. Captopril is a mixed vasodilator and is effective from the first hour of administration. It preferentially lowered pulmonary capillary pressure (PCP) from 29,6 +/- 0,92 mmHg to 21,4 +/- 1,04 mmHg (delta PCP: -27,7%, p less than 0,01). Mean systemic blood pressure (MBP) fell less from 92,4 +/- 3,51 mmHg to 76,6 +/- 3,4 mmHg (delta MBP: -17%, p less than 0,01).(ABSTRACT TRUNCATED AT 250 WORDS)