The Cardiac Response to Exercise in Aortic Valvular Disease Before and After Ball Valve Replacement

Cardiac output, stroke volume, “exercise factor” and maximal arterial oxygen transport during upright exercise have been determined in seven patients with aortic valvular disease before and after successful ball valve replacement, in four patients with persistent heart failure after ball valve replacement and in four healthy subjects. Preoperatively the increment in stroke volume during exercise was subnormal, but the “exercise factor” was often within normal limits. Patients with heart failure showed definitely reduced “exercise factor” and maximal stroke volume. After successful ball valve replacement both the maximal stroke volume and “exercise factor” increased slightly, but insignificantly and with considerably scattered individual values. However, all patients with postoperatively increased “exercise factor” had also acquired a fall in Hb concentration. Thus the maximal oxygen transport capacity during submaximal exercise was not improved by the operation.