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J M Dubroff

Publications and source records attributed to J M Dubroff.

4 recordsLinked to original sources
PubMed1985

Compliance, mass, and shape of the canine left ventricle after global ischemia analyzed with two-dimensional echocardiography.

End-diastolic pressure (EDP)-volume (EDV) curves were constructed for the left ventricle (LV) in 10 dogs on cardiopulmonary bypass before and after 45 min of normothermic ischemic arrest. LVEDV and mass were calculated from three perpendicular two-dimensional echocardiographic sections using a Simpson's rule algorithm. The echocardiographic method employed was specially developed in earlier work for physiologic studies in dogs. Postmortem pressure-volume curves were measured for comparison by direct saline infusion into sealed ventricles. LVEDV was plotted against LVEDP (0-20 mm Hg) and data were analyzed by two-way analysis of variance and also by exponential curve fitting to the relation EDP = alpha e beta EDV, where beta is the derived exponential constant reflecting slope and thereby ventricular stiffness. Postischemic EDP-EDV curves shifted to the left and the beta constant increased (beta = 0.02 +/- 0.005 (SE) vs 0.05 +/- 0.01, P less than 0.05). LV eccentricity, the ratio between long- and short-axis measurements, was unchanged (1.43 +/- 0.05 vs 1.46 +/- 0.06 postischemia, NS), but LV mass increased (105 +/- 7 vs 128 +/- 9 g postischemia, P less than 0.001). Postischemic LV mass by echo was not significantly different from measured postmortem LV mass (r = 0.87). The nonparallel alteration in the EDP-EDV curves, lack of change in LV shape (eccentricity), and increase in LV mass in the postischemic ventricle suggest that increased ventricular stiffness rather than direct encroachment by the edematous endocardium on chamber volume is responsible for postischemic changes in LV diastolic properties.

Animals↗
PubMed1983

Left ventricular ejection fraction during cardiac surgery: a two-dimensional echocardiographic study.

Although long-term effects have been studied, the immediate effect of surgery for acquired heart disease on left ventricular function is not well defined. Accordingly, 44 adults with acquired heart disease underwent intraoperative two-dimensional echocardiography with a gas-sterilized transducer before and immediately after cardiopulmonary bypass. Ejection fraction was measured by short-axis area change at the maximum left ventricular cross section (SAAC-EF) and also by a method using multiple sections. Correction of both mitral and aortic regurgitation produced a significant intraoperative decrease in ejection fraction from 0.49 +/- 19 (SD) to 0.32 +/- 0.16 (p less than .02) and from 0.41 +/- 0.13 to 0.30 +/- 0.17 (p less than .0005), respectively. Relief of aortic stenosis and mitral stenosis resulted in an intraoperative increase in ejection fraction from 0.45 +/- 0.10 to 0.55 +/- 0.09 (p less than .02) and from 0.41 +/- 0.05 to 0.50 +/- 0.07 (p less than .05), respectively. Ejection fraction after coronary artery bypass grafting was unchanged. Preload (end-diastolic area) was significantly decreased after correction of aortic regurgitation (p less than .02) but unchanged in other lesions. We conclude that (1) correction of pure mitral and aortic valvular lesions produces characteristic alterations in ejection fraction in the immediate postoperative period; (2) with the possible exception of patients with aortic regurgitation, the observed change in ejection fraction does not appear to reflect changes in preload; (3) noninvasive assessment of left ventricular function by two-dimensional echocardiography during cardiac surgery appears feasible and could provide data important for clinical decision making in the early postoperative period.

Aged↗
PubMed1982

Intraoperative 2-dimensional echocardiography: ejection of microbubbles from the left ventricle after cardiac surgery.

Although the presence of entrapped air in the left ventricle at surgery has long been a concern, its prevalence and clinical significance are unknown. Two-dimensional echocardiography provides a unique means for observing intracardiac microbubbles intraoperatively. Accordingly, intraoperative 2-dimensional echocardiograms obtained in 79 patients immediately after cardiopulmonary bypass were examined for the presence of microbubbles. Left ventricular microbubbles were detected in 14% of coronary artery bypass operations (n = 22), 50% of multiple valve replacements (n = 8), 67% of single valve replacements (n = 58), and 100% of atrial septal defect closures (n = 4), left atrial myxoma resections (n = 2), and mitral commissurotomies (n = 2). Microbubbles were not observed in patients undergoing coronary artery bypass with valve replacement (n = 4) or with removal of left ventricular aneurysm (n = 1). Continuous ejection of microbubbles from the left ventricle was frequently noted for extended periods of time and, although no patient in this study showed evidence of gross neurologic dysfunction, the possibility of subclinical organ damage exists. We conclude that 2-dimensional echocardiography is useful for detection of intracardiac microbubbles and therefore may be instrumental in their elimination.

Cardiac Surgical Procedures↗