Backward transmission of the left atrial V wave and premature pulmonary valve closure

Abstract

The concept that premature pulmonary valve closure may result from severe mitral insufficiency is presented. Five patients with severe mitral valve insufficiency had pulmonary arterial mean pressure which exceeded simultaneously recorded right ventricular mean systolic pressure. A high delayed pressure wave was present in the pulmonary artery of these subjects, and in four subjects the pulmonary arterial pressure rose above the right ventricular pressure. In two of the five, the timing and morphology of this pressure wave were suggestive of early closure of the pulmonary valve by retrograde transmission of the left atrial “V” wave through the pulmonary vessels. Catheterization revealed low cardiac indices, marked left atrial systolic pressure elevation, and elevated pulmonary artery pressure. All subjects had high total pulmonary resistance, while pulmonary arteriolar resistance was normal in three and only moderately elevated in two. The respective roles played by pulmonary arteriolar resistance, compliance of the left atrium and pulmonary vasculature, the state of left ventricular function, and amount of mitral regurgitation in the production of this phenomenon are discussed.