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Biomedical subjects

R M Jeresaty

Publications and source records attributed to R M Jeresaty.

At least 19 recordsLinked to original sources

Left ventricular function in acute non-ischaemic mitral regurgitation.

Acute non-ischaemic mitral regurgitation (MR) has recently generated considerable interest because of its causal relationship to ruptured chordae tendineae and infective endocarditis, advances in its diagnosis by echo Doppler studies, and its management by afterload reduction and reconstructive surgery. It is fundamentally different from chronic MR because the previously normal, unprepared left ventricle (LV) and left atrium (LA) confront a sudden dramatic increase in volume. As the normal-sized left atrium suddenly receives a marked regurgitant flow, its pressure rises and is transmitted into the pulmonary capillaries causing pulmonary congestion and oedema. At onset, the LV function is usually well preserved and the pulmonary oedema does not reflect LV failure. In acute MR, the LV empties into the left atrium, thus reducing its radius and its systolic pressure, resulting in a decline in wall tension according to Laplace's law. With a reduction in LV wall tension, there is a marked increase in contractile shortening with marked increase in total LV output. The left ventricle may fail early in acute severe MR because it is forced to dilate rapidly before hypertrophy can occur, whereas in chronic MR both the LV diastolic volume and mass increase proportionately. With chronic persistence of MR, LV dysfunction and failure occur as a manifestation of the 'cardiomyopathy of overload'. Fortunately because of the low energy cost per unit of work in shortening, as opposed to that used for tension development, there is only a slight increase in myocardial oxygen consumption in acute MR. In patients with LV failure secondary to acute MR, the ejection fraction may be only slightly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Ventricular fibrillation during coronary angiography: reduced incidence with nonionic contrast media.

Ventricular fibrillation during coronary angiography with Renografin-76 has been attributed to the high osmolar ionic and calcium binding additive properties. Isovue-370 is a new low osmolar nonionic contrast medium lacking calcium binding additives. The present investigation compared the incidence of contrast media-induced ventricular fibrillation in patients undergoing coronary angiography with Renografin-76 to that with Isovue-370. Group I consisted of 2,000 consecutive patients undergoing coronary angiography with Renografin-76, and group II consisted of 2,000 subsequent consecutive patients in whom Isovue-370 was employed as the contrast medium. There was no significant difference between groups I and II with respect to volume of contrast media used per patient (125 +/- 35 vs. 140 +/- 45 ml), age (63.5 +/- 15 vs. 60 +/- 17 years), sex (74% male vs. 76% male), ejection fraction (55% vs. 55%), valvular heart disease (8% vs. 9%), prior coronary artery bypass graft surgery (5.8% vs. 5%), or extent of coronary artery disease. Contrast media-induced ventricular fibrillation occurred in 20 patients in group I (incidence 1%), whereas eight episodes occurred in group II (incidence 0.4%) (P less than 0.03). Thus the present investigation suggests that the incidence of ventricular fibrillation during coronary angiography can be significantly decreased by using low osmolar nonionic contrast media lacking calcium binding additives.

Angiography↗

Mitral valve prolapse: definition and implications in athletes.

Mitral valve prolapse is probably the most common cardiac valve disorder, affecting approximately 5% of the population. Although it is genetically determined, its clinical manifestations do not usually become evident before adulthood. In the setting of a cardiology referral center, a mitral valve prolapse syndrome, consisting of nonspecific symptoms, repolarization changes on the electrocardiogram and arrhythmias, has been identified. However, doubt has recently been expressed about the existence of such a syndrome. The prognosis of mitral valve prolapse is generally favorable but infrequent complications do occur and include transient ischemic attacks, progression of mitral regurgitation with or without ruptured chordae tendineae, infective endocarditis and sudden death. The symptoms and the complications are not usually related to physical activity. A permissive attitude toward participation of patients with mitral valve prolapse in competitive athletics is probably warranted; however, it would appear reasonable to disqualify athletes with mitral valve prolapse in the following circumstances: history of syncope; disabling chest pain; complex ventricular arrhythmias, particularly if induced or worsened by exercise; significant mitral regurgitation; prolonged QT interval; Marfan's syndrome; and family history of sudden death.

Adolescent↗

Mitral valve prolapse and ruptured chordae tendineae.

To determine the causes of ruptured chordae tendineae and a suspected etiologic role for mitral valve prolapse (MVP), the mitral valve in 25 consecutive and surgically proved cases of chordal rupture were examined. The diagnosis of MVP was made on the basis of redundancy and marked hooding of the mitral leaflets and on histologic changes. MVP was the underlying morphologic abnormality in 23 patients, only 1 of whom had infective endocarditis that was responsible for the rupture. Thus MVP was the only underlying morphologic abnormality in 22 of 25 patients (88%). Another finding in this study was the demonstration of auscultatory and angiographic or echocardiographic evidence of MVP in 4 patients, aged 4 to 11 years (mean 7), before chordal rupture; no patient had had endocarditis. The morphologic and historical evidence would indicate that MVP is probably the most common cause of so-called spontaneous chordal rupture.

Adult↗

Pulmonary function studies in patients with prolapse of the mitral valve.

We studied the pulmonary function and chest x-ray films of 20 nonsmokers with idiopathic prolapse of the mitral valve. Forty-five percent of these patients complained of dyspnea. Of the 16 chest films reviewed, 44 percent had radiographic evidence of pectus excavatum and 25 percent thoracic scoliosis. The most common pulmonary function abnormalities were increased residual volume (63 percent) and a reduced steady state diffusing capacity (50 percent of patients). There was no relationship between the presence of dyspnea and either chest wall deformity of abnormality of pulmonary function. These pulmonary function abnormalities may reflect a pulmonary parenchymal disorder possibly secondary to a connective tissue abnormality in the lung.

Adolescent↗