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Biomedical subjects

M C Hsiung

Publications and source records attributed to M C Hsiung.

At least 19 recordsLinked to original sources
PubMed1992

The value of transesophageal echocardiography in the diagnosis of cardiac metastasis.

To assess the diagnostic value of transesophageal two-dimensional echocardiography (TEE) as compared with transthoracic echocardiography (TTE), TTE and TEE were performed in eight consecutive patients (age range from 20 to 76 years, six male and two female) with clinical evidence of malignant tumors arising from the liver (n = 1), lung (n = 3), larynx (n = 1), osteogenic sarcoma (n = 1), lymphoma (n = 1), and yolk sac tumor in the anterior mediastinum (n = 1). In one case, the gastroscope could not be inserted because of tumor compression of the esophagus. Transesophageal echocardiography provided superior imaging in the detection of intracavitary metastatic lesions. In the case of right ventricular outflow tract tumor and greater vessel involvement, TTE may provide more imaging than TEE due to a blind area in this region by the transesophageal approach. In conclusion, TEE is complementary to TTE in the diagnosis of metastatic cardiac tumor.

Adult↗
PubMed1992

Application of echocardiographic color flow Doppler mitral regurgitation to the diagnosis of acute cardiac transplantation rejection.

Numerous noninvasive techniques have been examined for the detection of acute rejection following cardiac transplantation, but none has proven sufficiently sensitive to replace the endomyocardial biopsy. A prospective study was performed in 92 heart transplant patients in order to test the hypothesis that mitral regurgitant ratio by two-dimensional echocardiography with Doppler flow mapping could detect moderate or severe acute allograft rejection. There were 82 rejection episodes identified, of which 40% were associated with mitral regurgitation by echo-Doppler at the beginning of the episode. With augmentation of immunosuppression during a rejection episode, there was a progressive fall in the degree of mitral incompetence (P = 0.03). The sensitivity of color Doppler studies in identifying rejection was low (60% of all rejection episodes had no associated mitral incompetence at the beginning of the episode), but the likelihood of rejection progressively increased with higher degrees of mitral regurgitation (P less than 0.01), approaching 60% when the echo-Doppler regurgitant ratio exceeded 15%. Echo-Doppler studies do not provide sufficient sensitivity to be useful as a screening technique for acute cardiac rejection, but high or increasing echocardiographic mitral regurgitant ratio is predictive of acute rejection and should indicate prompt endomyocardial biopsy.

Adolescent↗
PubMed1992

Transesophageal color Doppler flow imaging in the evaluation of prosthetic cardiac valves.

To determine the value of transesophageal echocardiography in the assessment of prosthetic cardiac valves, 11 patients with clinically suspected cardiac prosthetic valve dysfunction were studied by transesophageal two-dimensional imaging, as well as by color Doppler flow mapping. Among these 11 patients, there were 10 with biological tissue valves and 3 with metallic valves (1 Bjork-Shiley, 2 St. Jude). Nine patients had replacement of mitral valves alone. The remaining two had received both mitral and aortic prostheses. The degree of mitral regurgitation was graded by transesophageal color Doppler according to the area of the regurgitant jet visualized. The degree of aortic regurgitation was graded by the jet height/left ventricular outflow height ratio method. All transesophageal studies were performed without complication and all were well tolerated. The pathological morphology of the cardiac prosthesis was clearly visualized by transesophageal two-dimensional imaging and subsequently proven at surgery. Of those tested, one patient was found to have a torn leaflet, one had a dislodged leaflet, one patient had paravalvular leakage, four had cusp vegetations, and five patients had prosthetic degeneration for other reasons. Mitral regurgitation was graded as absent in one patient, mild in two patients, moderate in two patients, and severe in six patients. Aortic regurgitation was graded as severe in both patients with aortic prostheses. We conclude that in patients with clinically suspected cardiac prosthetic dysfunction, transesophageal two-dimensional imaging combined with color Doppler can provide reliable information that corresponds to surgical findings.

Adult↗
PubMed1990

Detection of dysfunctioning mitral prosthetic regurgitation: transesophageal echocardiography in comparison with transthoracic echocardiography and angiography.

Transesophageal echocardiography has been increasingly used in addition to the transthoracic approach. It not only allows an unobstructed window for viewing the left atrium, but also provides high-quality imaging to improve diagnosis of prosthetic valve dysfunction. To determine the value of transesophageal echocardiography in detection of dysfunctioning mitral prosthetic regurgitation, 11 patients clinically suspected of dysfunctioning mitral prosthesis were studies by transthoracic, transesophageal echocardiography and was documented by a left ventricular angiography. There were 7 biological tissue valves and 4 metallic Bjork-Shiley valves. Compared with a left ventricular angiography, the transthoracic approach to 8 patients made an underestimation of the grade of regurgitation. The angiographic grading confirmed the transesophageal approach in all patients except one who was graded as mild regurgitation by left ventricular angiography, moderate regurgitation by transesophageal echocardiography, but no regurgitation by transthoracic echocardiography. Our results indicated that in patients with suspected mitral prosthetic dysfunction, a transesophageal echocardiography is more sensitive than a transthoracic echocardiography in detecting mitral regurgitation.

Adult↗
PubMed1989

Progression of cardiac hypertrophy during long term calcium antagonist treatment with tiapamil.

Hypertension complicated by left ventricular hypertrophy is associated with increased morbidity as it leads to left ventricular systolic and diastolic dysfunction. Thus, in the treatment of hypertension, a desirable goal is the regression of left ventricular hypertrophy. Tiapamil, a new calcium antagonist, was evaluated in a 58 week open study to determine its effect on left ventricular mass in relation to its ability to lower blood pressure. Twenty adult patients with mild to moderate hypertension were entered into the study. Blood pressure was significantly reduced from 166 +/- 16/105 +/- 7 mmHg before treatment to 142 +/- 9/88 +/- 4 mmHg after 58 weeks. The posterior and interventricular septal wall thickness and left ventricular systolic dimension did not show any significant change by the end of the trial. On the other hand, left ventricular diastolic dimension, ejection fraction, and left ventricular mass increased significantly (P less than 0.05). Other laboratory parameters were not affected during treatment with the exception of a moderate decrease in the blood glucose. Side effects were mild and self-limiting, and no patients were withdrawn from the study. Although tiapamil appears to be an effective and well-tolerated drug in mild to moderate hypertension, it failed to reduce left ventricular mass.

Administration, Oral↗
PubMed1987

Color Doppler assessment of mitral regurgitation induced by supine exercise in patients with coronary artery disease.

Development of mitral regurgitation (MR) during acute myocardial ischemia is a well known occurrence. To assess the feasibility and clinical utility of detecting MR during exercise testing, color Doppler examinations were performed in 22 patients with angiographically proved coronary artery disease (CAD) and in 17 normal subjects before, during and after graded supine bicycle exercise. Not only was MR visualized using color Doppler during dynamic testing, but it was also slightly more sensitive (59% vs 54%) and specific (100% vs 88%) than the electrocardiographic response in identifying patients with CAD. When the appearance of MR or diagnostic electrocardiographic changes or both were used to identify patients with CAD, the sensitivity of exercise tolerance testing increased to 82%, although the specificity was 88%. In addition, exercise-induced MR was observed to be as sensitive and specific as exercise-induced wall motion abnormalities. Combining exercise-induced MR with wall motion abnormalities also increased the sensitivity to 82%, with the specificity remaining at 100%. With use of exercise-induced MR, wall motion abnormalities or electrocardiographic changes, the sensitivity and specificity of the exercise test in diagnosing CAD was 91% and 88%, respectively. The degree of MR as estimated by maximal area of regurgitation signals, as well as by its ratio to left atrial area, did not correlate with extent of CAD. However, the presence of exercise-induced MR suggested an increased likelihood of 3-vessel CAD because it was found in 9 of 11 patients with 3-vessel CAD, compared with 2 of 5 patients with 2-vessel and 2 of 6 patients with 1-vessel CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Demonstration of intracardiac tumor and its associated hemodynamic derangement by radionuclide angiography.

A case of malignant lymphoma primarily involving the heart is reported for the first time in which the tumor per se and its accompanying hemodynamic abnormalities were demonstrated by radionuclide angiography (RNA). The patient had severe and progressive failure of the right side of the heart of obscure origin. The tumor was pathologically proven to have involvement of the pericardium, right atrium, and right ventricle, causing significant tricuspid and pulmonic obstruction.

Heart Failure↗
PubMed1987

Color Doppler assessment of mitral regurgitation with orthogonal planes.

We evaluated 147 patients with adequate color Doppler and angiographic studies for mitral regurgitation. Sixty-five patients had no mitral regurgitation by both color Doppler and angiography and 82 patients had mitral regurgitation by both techniques. Thus the sensitivity and specificity of color Doppler for the detection of mitral regurgitation was 100%. Three two-dimensional echocardiographic planes (parasternal long and short axis, apical four-chamber view) were used to analyze variables of the mitral regurgitant jet signals in the left atrium. The best correlation with angiography was obtained when the regurgitant jet area (RJA) (maximum or average from three planes) expressed as a percentage of the left atrial area (LAA) obtained in the same plane as the maximum regurgitant area was considered. The maximum RJA/LAA was under 20% in 34 of 36 patients with angiographic grade I mitral regurgitation, between 20% and 40% in 17 of 18 patients with grade II mitral regurgitation, and over 40% in 26 of 28 patients with severe mitral regurgitation. Maximum RJA/LAA also correlated with angiographic regurgitant fractions (r = .78) obtained in 21 of 40 patients in normal sinus rhythm and with no evidence of associated aortic regurgitation. Other variables of the regurgitant jet such as maximal linear and transverse dimensions, maximal area, or maximal area expressed as a percentage of the LAA in one or two planes correlated less well with angiography. Color Doppler is a useful noninvasive technique that is not only highly sensitive and specific in the identification of mitral regurgitation but also provides accurate estimation of its severity.

Adolescent↗
PubMed1986

Doppler color flow mapping of the fetal heart.

The recently developed innovative technique of Doppler color flow mapping permits real time visualization of blood flow patterns superimposed on two-dimensional echocardiographic images of the heart. This study demonstrates, for the first time, the usefulness of this technique in characterizing fetal cardiac dynamics.

Blood Flow Velocity↗