Faculty Bibliography

This report describes a spontaneous coronary artery dissection occurring during exercise in a long-distance runner who otherwise had a normal coronary arteriogram. This syndrome has been reported before and the two previous cases are reviewed. Coronary dissection is a rare cause of death during exercise

OBJECTIVES: The goal of this study was to investigate the hydrodynamic cause of mitral-septal contact and obstruction in patients with hypertrophic cardiomyopathy. BACKGROUND: Mitral-septal apposition has been shown to be the cause of obstruction in patients with hypertrophic cardiomyopathy. With obstruction, characteristic continuous wave Doppler tracings show an increasing acceleration of flow. (Tracing is concave to the left.) METHODS: We studied 24 consecutive patients who had a Doppler echocardiographic pressure gradient > or = 36 mm Hg. We pursued two lines of inquiry. 1) Before the onset of obstruction, we systematically measured the angle between the direction of left ventricular Doppler color flow and the protruding mitral leaflet in early systole. 2) After the onset of obstruction, we qualitatively analyzed the concave contour of the continuous wave Doppler tracings in our patients and developed a hydrodynamic theory of the obstruction phase to explain the characteristic tracings. We present a mathematic model to support this concept. RESULTS: We measured 129 angles. Just before mitral-septal contact, the protruding mitral leaflet projects at a mean 40 degrees and 45 degrees relative to flow in the apical long-axis and apical five-chamber views, respectively. At mitral-septal contact, the obstructing leaflet projects at a mean 52 degrees and 58 degrees relative to flow in the same respective views. Even very early in systole, at leaflet coaptation, 11 of 23 patients had angles > 15 degrees relative to flow. After mitral-septal apposition, obstruction across a cowl-shaped orifice begins. During this stage, the obstructing leaflet projects at a mean 55 degrees and 63 degrees relative to flow. In 22 patients, the continuous wave Doppler tracing of the left ventricular outflow jet showed an increasing acceleration of flow. CONCLUSIONS: Just before mitral-septal contact, the protruding leaflets project at high angles relative to flow. At these high angles, flow drag, the pushing force of flow, is the dominant hydrodynamic force on the protruding leaflet and appears to be the immediate cause of obstruction. The high angle between flow direction and the protruding leaflet precludes significant Venturi effects. Even earlier in systole, at leaflet coaptation, flow drag is dominant in half of the patients, with angles relative to flow > 15 degrees. After obstruction is triggered, it appears from our data and model that the leaflet is forced against the septum by the pressure difference across the orifice. The increasing acceleration of Doppler flow is explained by a time-dependent amplifying feedback loop in which the rising pressure difference across the orifice leads to a smaller orifice and a higher pressure difference.

A case of staphylococcal endocarditis with the echocardiographic findings of mitral anular abscess is described. The anular mass resolved after 9 weeks of antibiotic therapy. This case illustrates that perivalvular abscess complicating infective endocarditis may respond to medical therapy.

Two-dimensional echocardiography at rest was used to analyze segmental wall motion abnormalities for detecting coronary artery disease in patients with and without a history of myocardial infarction. One hundred twenty-five echocardiograms were analyzed in a randomized, blinded fashion. They were obtained from 55 consecutive patients found to have significant coronary artery disease at angiography, 59 consecutive normal subjects and 11 patients with dilated cardiomyopathy. The overall sensitivity of two-dimensional echocardiography was relatively low at 67%. However, specificity was 99%. The sensitivity was higher in patients with past myocardial infarction than in those without myocardial infarction (81 versus 42%), as expected. Echocardiography can detect segmental wall motion abnormalities in some patients with coronary artery disease and no overt prior myocardial infarction. This was highlighted by nine such patients with coronary artery disease and no prior myocardial infarction or electrocardiographic Q waves who were found to have segmental wall motion abnormalities. A semiquantitative, two-dimensional echocardiographic segmental wall motion score was derived for 47 patients and was correlated with angiographic left ventricular ejection fraction (r = 0.71). This score differentiated patients with a normal ejection fraction (greater than 50%) from those with a depressed ejection fraction (less than 50%): 1.1 +/- 1.6 versus 6.9 +/- 3.1 (p less than 0.001). Almost all patients (92%) with an echocardiographic score of five or more had an abnormal ejection fraction of less than 50%. In patients with chronic congestive heart failure, the echocardiogram separated those with dilated cardiomyopathy from those with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of discrete subvalvular aortic stenosis with anomalous insertion of a papillary muscle to the base of the anterior mitral valve leaflet and continuous with the discrete subaortic stenosis is described. Two-dimensional echocardiographic and pathologic data showing the contribution of the anomalous papillary muscle to left ventricular outflow tract obstruction are presented.