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Biomedical subjects

G A Bergeron

Publications and source records attributed to G A Bergeron.

At least 19 recordsLinked to original sources

Myocardial infarction, severe reversible ischemia, and shock following excess thyroid administration in a woman with normal coronary arteries.

In the absence of fixed coronary artery disease, thyrotoxicosis is rarely associated with acute myocardial infarction and/or ischemia. There are no known reports on the association of acute myocardial infarction with iatrogenic or factitious thyrotoxicosis in the absence of fixed coronary artery stenosis or coronary artery spasm. A 68-year-old woman, clinically in a state of thyrotoxicosis as a result of taking 0.3 g/d of exogenous thyroid replacement, sustained a severe, reversible myocardial ischemic event. Echocardiographic and scintigraphic evaluations demonstrated a large apical dyskinetic region. Subsequently, after the original dose of levothyroxine sodium was reduced to 0.15 mg and the patient became euthyroid, two-dimensional echocardiography and scintigraphic and cardiac catheterization studies demonstrated normal left ventricular contractility and normal coronary anatomy. Coronary artery spasm was not induced by ergonovine maleate therapy. Exogenous thyroid administration may directly influence myocardial oxygen supply and demand, exclusive of coronary artery disease and coronary spasm. A critical imbalance may then result in acute myocardial ischemia and reversible left ventricular segmental wall motion abnormalities.

Aged↗

Implications of normal left ventricular wall thickness in critical aortic stenosis.

It is standard practice for clinicians to consider echocardiographically-measured left ventricular wall thickness when estimating the severity of aortic stenosis. Most consider the degree of wall thickness above normal limits is in proportion to ventricular hypertrophy. Employment of wall thickness information to assess aortic stenosis severity, while generally reliable, can occasionally be misleading. Two cases are presented with findings of severe, critical aortic stenosis and normal wall thickness. In each case, left ventricular contractile function was markedly impaired and the patient markedly symptomatic.

Adult↗

Echocardiography in patients with acute cerebral events.

The question of the clinical and economic feasibility of echocardiographic screening for cardiac disease in patients with symptoms of acute cerebral events was assessed by recording M-mode and two-dimensional (2D) echocardiograms in 170 patients. Patients with transient ischemic attacks or cerebral infarctions were included. Of the patients with satisfactory echocardiograms, 96 (56%) had normal diagnostic findings; 74 (43%) had cardiac disorders possibly related to the acute cerebral event. There were 4 patients who fulfilled the standard criteria for mitral valve prolapse and 7 patients who were identified as having probable cardiac thrombosis or vegetation, or both. Thus, M-mode and two-dimensional echocardiography was of limited value in patients referred for these studies for screening to exclude mitral valve prolapse and cardiac thrombosis or vegetation. Although a diverse range of cardiac disorders was demonstrated that may be associated with cerebral ischemia, the overall low yield does not support such screening and should be reserved for selected patients.

Adult↗

Echocardiographic analysis of mitral valve motion after acute myocardial infarction.

To examine the effects of acute myocardial infarction on mitral valve diastolic velocity, echocardiograms were performed in 18 patients on admission, daily in the Coronary Care Unit, and at 3-day intervals during the remainder of hospitalization. These patients were divided into three groups based on the time interval between onset of symptoms and initial echocardiogram. Five of six patients admitted within 5 hours of onset of myocardial infarction had a triphasic response of mitral valve diastolic velocity with a transient rise above initial values, followed by a fall to below initial values, and then a slow rise during recovery. Seven of eight patients admitted 1-2 days after onset of myocardial infarction had a biphasic response, i.e., a fall from initial values and then a slow rise. Four patients admitted later in the course of myocardial infarction had a monophasic response, i.e. low initial velocity followed by a slow recovery. We conclude that in patients with myocardial infarction the mitral valve diastolic velocity following myocardial infarction shows a triphasic response which may appear biphasic or monophasic depending on the interval between myocardial infarction and admission. The temporal pattern of mitral valve diastolic velocity changes may reflect the dynamic alterations of myocardial function and compliance that are occurring after acute myocardial infarction and during the recovery period.

Adult↗

[Medical ethics].

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Abnormalities, Multiple↗