[Comparison of hemodynamic and coronary effects of 2 antianginal vasodilator drugs: nifedipine and trinitrine].

Twenty patients with coronary insufficiency had measurements taken while they were in normal rhythm (NR) and during atrial pacemaking (AP) before and after taking nifedipine (n: 12) or after intravenous perfusion of trinitrin (n: 8): measurements were taken of pulmonary capillary pressure (PCP), arterial femoral pressure (AFP), cardiac output (QC) and coronary sinus flow (QCS), coronary arterio-venous oxygen difference (DaVO2), myocardial oxygen consumption (MVO2) and the myocardial coefficient of extraction of lactates (K).--Under nifedipine in NR and AP, AFP was decreased and QC increased. QSC was increased in NR, but was not changed under AP. DaVO2 was shortened under both sets of conditions. MVO2 decreased only during AP. Nifedipine brought back to normal the lowering of K which occurred with pacemaking.--Under trinitrin, both in NR and under AP, AFP, PCP, QC, QSC and MVO2 were lowered. K and DaVO2 were unchanged.--A plethysmographic study in 13 patients showed that these haemodynamic effects could be explained by the arterial vasodilator action of nifedipine which occurred without changing the venous tone, and the mixed action of trinitrin.