The Left Atrial V-Wave After Mitral Valve Replacement

Abstract

Abnormal ν-waves in the left atrium were observed after mitral valve replacement in the absence of clinical or angiographical signs of mitral regurgitation at rest. the ν-waves were accentuated during exercise and it was considered important to establish whether mitral regurgitation was responsible or not. A method for left ventricular angio-graphy during exercise was developed. A comparison of left atrial ν-waves in patients with intact mitral valves was made.

The v-wave was related to the mean left atrial pressure in patients after mitral valve replacement and in patients with intact mitral valve function. It was observed that these two groups of patients had the same relationship between u-wave and mean pressure in the left atrium and thus the marked u-waves seen after mitral valve replacement were of the expected amplitudes, as predicted from the left atrial mean pressure.

Left ventricular angiography during exercise was per- formed in five patients and a slight but haemodynamically insignificant regurgitation through the prosthesis was observed in two patients. Regurgitation through or around the prosthesis was not considered responsible for the high u-wave amplitudes either at rest or during exercise.

The various factors possibly contributing to the generation of the u-wave and their relative importance are discussed. These factors were the inflow of blood into the left atrium, propagation of the pulmonary arterial pulse wave and different actions of the mitral valve (regurgitation, ballooning, movement of the valvular plane). Thus, mitral regurgitation is only one of several factors contributing to the generation of a u-wave in the left atrium.