Effect of respiration on pansystolic regurgitant murmurs as studied by biatrial intracardiac phonocardiography

Abstract

Twelve patients have been studied in an attempt to delineate the effect of continuous accentuated respiration on the intracardiac murmurs of mitral and tricuspid insufficiency. External phonocardiographic and stethoscopic observations have been made in order to demonstrate the correlation between internal and external acoustical events and to derive some knowledge regarding the validity of Carvallo's observations. Of the eleven patients with mitral insufficiency, eight were studied by left atrial phonocardiography. In none did respiration result in an altered intensity of the murmur of mitral insufficiency when recorded in the left atrium. In eight patients with mitral insufficiency and associated tricuspid insufficiency, marked inspiratory augmentation of the regurgitant murmur was recorded in the right atrium. Thus, the two premises upon which Carvallo's sign rest are valid, namely, that respiration does not affect the intensity of the murmur of mitral insufficiency while inspiration results in augmentation of the tricuspid regurgitant murmur in every case when these murmurs are recorded at their source. The external phonocardiogram clearly demonstrated inspiratory augmentation of the tricuspid regurgitant murmur in four patients with tricuspid insufficiency. A less obvious but similar response was noted in an additional three patients. However, stethoscopic examination of these seven patients clearly demonstrated inspiratory augmentation of the systolic regurgitant murmur in every case. Thus, careful auscultatory examination may be more reliable than external phonocardiography in detecting changes in intensity of the tricuspid regurgitant murmur. In the eighth case of combined mitral and tricuspid insufficiency, neither the external phonocardiogram nor the stethoscopic observation demonstrated external augmentation of the regurgitant murmur. In this instance, the diagnostic value of intracardiac phonocardiography is clearly demonstrated. In addition, observations concerning the importance of selective augmentation of the regurgitant murmur in the diagnosis of tricuspid insufficiency have been discussed and an additional pitfall of confusing a long ejection murmur with a regurgitant murmur has been demonstrated. It is apparent from these studies that selective inspiratory augmentation of a pansystolic regurgitant murmur, when present, continues to be a useful sign of tricuspid insufficiency.