Phonocardiography in acute rheumatic carditis.

The diagnosis of early rheumatic carditis usually depends upon the detection of murmurs produced by acute valvulitis. It may be difficult to evaluate clinically the significance of certain murmurs occurring in patients with rheumatic fever, though the development of a loud apical pansystolic murmur in a patient already under observation usually presents no diagnostic problem. More frequently a systolic murmur is present when the patient is first seen: then the distinction between systolic murmurs of basal and of mitral origin may be difficult, and in the presence of fever, pain, and resultant tachycardia, it may be impossible to ascertain the significance of the murmur by auscultation alone. The undoubted presence of a mitral diastolic murmur is diagnostic of mitral valvulitis, but the faint short diastolic murmur that first appears is readily confused with a loud third sound or summation gallop, and the clinical distinction between diastolic sounds and murmurs may be uncertain. Similarly it may be difficult to be sure of the presence of the soft aortic diastolic " whiff " of acute aortic valvulitis. It was therefore decided to investigate these murmurs by phonocardiography. There have been very few reports of the phonocardiographic findings in acute rheumatic carditis. The mitral diastolic murmurs of acute valvulitis have been recorded by Schwarzchild and Feltenstein (1934), Johnston (1935), and McKee (1938). Taquini et al. (1940) investigated the mitral murmurs in a small group of patients with acute carditis: they concluded that the diastolic murmur they had diagnosed clinically in nine cases was due either to summation or near summation of the third and atrial sounds, or else that it was caused by prolongation of the third sound and was not therefore a true murmur. Tachycardia rendered interpretation difficult in some of their cases: although those phonocardiograms recorded at a slower heart rate are of small amplitude, a true diastolic murmur appears to be present in one of these tracings.