Pressure-flow studies in man: The nature of the aortic flow pattern in both valvular mitral insufficiency and the prolapsing mitral valve syndrome

Abstract

In five normal patients and in six patients with various forms of mitral insufficiency, ascending aortic pressure-flow relationships were studied using the pressure gradient technique. Stroke volume, peak flow, mean aortic pressure, and the per cent of aortic flow during the first half of ejection were calculated in the control state, following amyl nitrite inhalation, and following the intravenous injection of 0.4 mg. of phenylephrine. In normal patients, an average of 52 per cent of flow occurred in the first half of ejection both during control and following phenylephrine, and increased to 60 per cent after amyl nitrite. A patient with the prolapsing mitral valve syndrome but without mitral insufficiency had flow curves similar to the normal. Two patients with moderate and severe mitral insufficiency, respectively, and a prolapsing mitral valve had a marked increase in flow during the first half of ejection (68 and 66 per cent) during control; the per cent of flow decreased with amyl nitrite and phenylephrine administration. Patients with mitral insufficiency secondary to either rheumatic heart disease or papillary muscle dysfunction had 58 to 64 per cent of flow during the first half of ejection during control; this pattern did not change significantly with amyl nitrite or phenylephrine.