Biomedical subjects

A L Klein

Publications and source records attributed to A L Klein.

96 records · Page 6Linked to original sources

PubMedDate not supplied

Experimental and numerically modeled effects of altered loading conditions on pulmonary venous flow and left atrial pressure in patients with mitral regurgitation.

Pulmonary venous flow measured by pulsed-wave Doppler transesophageal echocardiography reflects the effects of mitral regurgitation on left atrial pressure contour. To assess the relationship between pulmonary venous flow and left atrial pressure in patients with mitral regurgitation under altered loading conditions, we studied 25 patients with 3+ or 4+ mitral regurgitation and a control group by measuring pulmonary venous flow with transesophageal echocardiography and left atrial pressures after administering saline solution (n = 6), nitroglycerin (n = 6), phenylephrine (n = 6), or nitroprusside (n = 7). After administration, the left atrial pressure v wave increased in the group given phenylephrine, concomitant with an increased diastolic flow. In contrast, the left atrial pressure v wave decreased in the group given nitroglycerin, concomitant with a decreased diastolic flow. Changes in diastolic flow were closely related to changes in the left atrial pressure v wave under all loading conditions (r = 0.91; p < 0.0001). Numeric modeling of left atrial pressure and pulmonary venous diastolic flow corroborated the experimental findings. We conclude that changes in pulmonary venous diastolic flow are closely related to changes in the left atrial pressure v wave in mitral regurgitation, under altered loading conditions.

Adult↗

PubMedDate not supplied

Transesophageal echocardiography in the critical care unit.

Transthoracic echocardiography may be of limited value for patients in intensive care units because of suboptimal patient positioning, surgical wounds, and mechanical ventilation. By contrast, transesophageal echocardiography provides a new window for cardiac imaging, even in critically ill patients. We report our indications based on findings comparing transesophageal and transthoracic echocardiography in 112 studies in intensive care units. The transesophageal approach diagnosed 131 significant findings, compared to only 95 (73%) found transthoracically. Transesophageal echocardiography was superior to the transthoracic approach in patients with significant (higher than 2+) mitral regurgitation, with improved detection in 10 (9%) cases (p less than 0.05). Transesophageal echocardiography also provided additional information in the evaluation of vegetations, diseases of the aorta, visualization of the left ventricle, intracardiac masses, intracardiac thrombi, and congenital heart disease. Transesophageal echocardiography provides a useful diagnostic tool for evaluation of critically ill patients.

Critical Care↗

PubMedDate not supplied

Doppler echocardiographic assessment of constrictive pericarditis, cardiac amyloidosis, and cardiac tamponade.

Doppler echocardiography is useful in assessing diastolic dysfunction. Pulsed-wave Doppler echocardiographic interrogation of the atrioventricular valves and the central veins has been used in conjunction with respiratory monitoring to characterize abnormal diastolic function of the heart in diseases such as constrictive pericarditis, restrictive cardiomyopathy, and cardiac tamponade. Constrictive pericarditis has distinct Doppler flows with marked respiratory variation because the pericardial shell separates the intracardiac pressures from intrathoracic pressure. This is not the case with restrictive cardiomyopathy, as in cardiac amyloidosis. Cardiac amyloidosis shows a spectrum of the Doppler flows which evolve as the disease progresses from abnormal relaxation in the early phase to pseudo-normal in the intermediate phase and to restrictive in the advanced phase. Doppler echocardiography can be used to assess the hemodynamic significance of pericardial effusion and to detect cardiac tamponade.

Amyloidosis↗

PubMedDate not supplied

Doppler echocardiographic assessment of aortic regurgitation: uses and limitations.

Completely satisfactory standards for assessing the severity of aortic regurgitation have not yet been formulated. Invasive and noninvasive methodologies have inherent limitations that prevent any single procedure being considered as a gold standard. Nevertheless, Doppler echocardiography, using the full range of imaging modalities, including pulsed-wave and continuous-wave Doppler and Doppler color-flow mapping, may detect and semiquantify the severity of aortic regurgitation with a high degree of accuracy. This article describes the application, methodology, and limitations of the Doppler indices currently used to assess aortic regurgitation.

Aortic Valve Insufficiency↗

PubMedDate not supplied

The Maze procedure: surgical therapy for refractory atrial fibrillation.

Although atrial fibrillation is well tolerated by most patients, in some patients the consequences may be severe. The Maze procedure is a new open-heart operation that creates a carefully designed maze of incisions in the atrial myocardium; this maze then acts as an electrical conduit to channel atrial impulses from the sinoatrial node to the atrioventricular node. The Maze procedure has been shown to restore sinus rhythm and atrial systole (thus reducing the risk of thromboembolism), improve hemodynamics, alleviate palpitations, and eliminate the need for antiarrhythmic and anticoagulant drugs. We describe our first patient to undergo this operation.

Aged↗

PubMedDate not supplied

Tumor encasement of the heart simulating pericardial effusion.

A 56-year-old woman with breast carcinoma was referred for an urgent two-dimensional echocardiogram. An anterior and posterior echo-free space suggesting pericardial effusion and a new right atrial mass were detected. A few hours later the patient died suddenly. Necropsy revealed neoplastic encasement of the heart without pericardial effusion.

Adenocarcinoma↗