Failure of intravenous metoprolol to limit acute myocardial infarct size in a nonreperfused porcine model.

The usefulness of intravenous beta-adrenergic receptor blockade in limiting infarct size when neither reperfusion nor collateral flow occurs is unknown. The effect of intravenous metoprolol on limiting myocardial infarct size was therefore examined in a nonreperfused porcine model. Closed-chest techniques were used to occlude the left anterior descending coronary artery, after which animals were randomized at 20 minutes to receive intravenous metoprolol, 0.

Relationship of left atrial pressure and pulmonary venous flow velocities: importance of baseline mitral and pulmonary venous flow velocity patterns studied in lightly sedated dogs.

Prior clinical and animal studies have shown a markedly different relationship between left atrial pressure and the systolic fraction of pulmonary venous flow but have not discussed possible reasons for this discrepancy. To examine the possibility that these disparate results are due to differences in baseline mitral and pulmonary venous flow velocities, we recorded both velocities with left atrial and left ventricular pressure under different loading conditions in eight lightly sedated normal dogs. With constant atrial pacing at 85 beats/min, mean left atrial pressure was increased from 5.

Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction.

Objectives: The purpose of this study was to determine whether left atrial size and ejection fraction are related to left ventricular filling pressures in patients with coronary artery disease.

Background: In patients with coronary artery disease, left ventricular filling pressures can be estimated by using Doppler mitral and pulmonary venous flow velocity variables. However, because these flow velocities are age dependent, additional variables that indicate elevated left ventricular filling pressures are needed to increase diagnostic accuracy.

Pulmonary venous flow velocity: relation to hemodynamics, mitral flow velocity and left atrial volume, and ejection fraction.

Abnormal pulmonary venous flow velocity patterns are present in multiple cardiac disease states, but the determinants of pulmonary venous flow velocity have not been fully elucidated. To determine the relative importance of several proposed factors that could influence pulmonary venous flow, anatomic, hemodynamic, and Doppler mitral and pulmonary venous flow velocity data were compared in 50 consecutive patients undergoing cardiac catheterization for clinical reasons. Pulmonary venous diastolic flow velocity was most strongly related to left ventricular isovolumetric relaxation time (r = -0.

Diastolic mitral regurgitation with atrioventricular conduction abnormalities: relation of mitral flow velocity to transmitral pressure gradients in conscious dogs.

Diastolic mitral regurgitation is a common finding that can be detected with use of Doppler echocardiographic techniques in patients with atrioventricular (AV) conduction abnormalities. With use of simultaneous hemodynamic and Doppler techniques, mitral flow velocity, mitral valve motion and transmitral pressure gradient were studied during 50 cardiac cycles each of spontaneous or atrial paced first- and second-degree AV block in five lightly sedated dogs. Diastolic mitral regurgitation was detected during atrial relaxation on all beats in which ventricular contraction was delayed greater than 190 ms.