Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Jun 1991
Comparative StudyDoppler echocardiographic transmitral peak early velocity does not directly reflect hemodynamic changes in humans: importance of normalization to mitral stroke volume.
Doppler echocardiographic transmitral peak early velocity normalized to the time-velocity integral during diastole is equivalent to volumetric peak filling rate normalized to stroke volume. To compare the pathophysiologic validity of normalized and nonnormalized peak early flow velocity, pulsed Doppler echocardiography with simultaneous high fidelity left ventricular pressure measurements was performed in 52 patients with coronary artery disease. Left ventricular loading conditions were changed by intravenous administration of norepinephrine in 15 patients and synthetic atrial natriuretic polypeptide in 15 others. ⋯ Thus, nonnormalized peak early flow velocity does not directly reflect underlying hemodynamic changes in humans. Normalization to mitral stroke volume clarifies the dependence of peak early flow velocity on the determinants of early diastolic filling. When left ventricular early diastolic filling is evaluated by Doppler echocardiography, normalized peak early flow velocity should be taken into consideration.
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Systemic venous flow patterns are easily assessed by transthoracic echocardiography for evaluation of right heart dynamics. However, the transthoracic approach cannot be used in patients undergoing thoracic surgery. The present study describes a method for obtaining hepatic venous flow velocity with transesophageal Doppler echocardiography. ⋯ In conclusion, hepatic venous flow values are obtained more frequently and with better quality by transesophageal than by transthoracic echocardiography. The flow patterns and velocity integrals are similar with both methods and previous experience with transthoracic echocardiography should be applicable to the transesophageal technique. Transesophageal Doppler echocardiography therefore has potential for studying right heart dynamics during anesthesia and surgery.