Journal of cardiology
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Journal of cardiology · Jun 1988
[Effect of dobutamine on ventriculo-arterial coupling and ventricular work efficiency in patients with cardiac failure].
In nine patients with cardiac dysfunction (ejection fraction less than or equal to 50%), we evaluated the effects of dobutamine (5 micrograms/kg/min) on ventriculo-arterial coupling by monitoring direct arterial pressures and simultaneously-recorded M-mode echocardiograms guided with two-dimensional images. Left ventricular end-diastolic volume (EDV) and end-systolic volume (ESV) were calculated by the formula of Teichholz, and left ventricular end-systolic pressure (ESP) was approximately from the arterial dicrotic pressure. Arterial pressure was altered by phenylephrine or nitroprusside and the slope (Ees) and volume axis intercept (Vo) of the end-systolic pressure-volume relationship were determined as the contractile properties of the ventricle. ⋯ Dobutamine increased the Ees markedly (+41%, p less than 0.01) and decreased the Ea (-23%, p less than 0.01). These changes resulted in a substantial decrease in the ratio of Ea to Ees (-44%, p less than 0.01). The EW was augmented (+22%, p less than 0.01), but the PE was reduced (-33%, p less than 0.01) by dobutamine, while the PVA remained the same as in the baseline state.(ABSTRACT TRUNCATED AT 250 WORDS)
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Journal of cardiology · Jun 1988
Case Reports[Marked ST-segment elevation in the precordial and inferior leads in right ventricular myocardial infarction: a case report].
This is a report of right ventricular infarction complicated by inferior myocardial infarction in which marked ST-segment elevation was observed in the precordial and inferior leads. A 51-year-old man was admitted with chest pain of one-half hour duration. His admission ECG showed conspicuous ST-segment elevation in the precordial and inferior leads. ⋯ However, there has been no previous report of marked ST-segment elevation in the precordial and inferior leads. In right ventricular infarction, the currents of injury usually occur simultaneously in the right ventricular free wall and left ventricular inferior wall, and then are electrically opposed to each other. The diffuse and marked ST-segment elevation observed in this case is thus a rare phenomenon.
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Journal of cardiology · Jun 1988
[Correlation of left ventricular outflow obstruction with mitral regurgitation].
Our previous study of mitral regurgitation in obstructive hypertrophic cardiomyopathy suggested that left ventricular outflow obstruction due to systolic anterior motion of the distal residual anterior mitral leaflet may hydrodynamically induce mid-systolic mitral regurgitation. To test this hypothesis, we examined whether drug-induced left ventricular outflow obstruction in dogs might cause mitral regurgitation. Dobutamine, 20-60 micrograms/kg/min, induced the obstruction due to mitral systolic anterior motion with mitral-septal contact in 11 of 18 dogs. ⋯ The onset and the end of the pressure gradient were nearly simultaneous with those of the mitral-septal contact. After cessation of the infusion, the mid-systolic mitral regurgitation disappeared together with the obstruction. These results indicate a close relationship between left ventricular outflow obstruction and mid-systolic mitral regurgitation, and strongly support the hypothesis that the obstruction due to systolic anterior motion of the distal residual anterior mitral leaflet is responsible for mitral regurgitation.