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Biomedical subjects

J Morch

Publications and source records attributed to J Morch.

13 recordsLinked to original sources
PubMed1982

Assessment of right ventricular function during supine bicycle exercise after Mustard's operation.

Right ventricular (RV) performance during supine bicycle exercise was evaluated by gated equilibrium nuclear angiography in 19 clinically well children with d-transposition of the great arteries (d-TGA), 6.4 +/- 2.7 years after Mustard's operation. Comparisons were made between rest and peak exercise. The mean resting ejection fraction was 44 +/- 12% (range 30-75%) and was unchanged at peak exercise. Eight children had a normal ejection fraction response, whereas 11 children had either no increase or a decrease in ejection fraction. Relative end-diastolic volumes decreased from resting values in all patients who had an abnormal ejection fraction response. Among patients whose ejection fraction increased, the end-diastolic volume increased in three, decreased in four and was unchanged in one at peak exercise. Heart rate increased 84% (range 52-135%) and systolic blood pressure increased 16% (range 0-28%) at peak exercise. There was no correlation between exercise response and age at surgery or interval since surgery. These data indicate that clinically well children after Mustard's procedure may have abnormal right ventricular function under stress, raising concerns about the ability of the right ventricle to function as the systemic ventricle.

Adolescent↗
PubMed1975

Detection of acute myocardial infarction by technetium-99m polyphosphate.

Experimental work has shown that technetium-99m (99mTc) pyrophosphate accumulates in recently infarcted myocardium and can be detected by external imaging techniques. Twenty-two 99mTc polyphosphate myocardial studies were performed in 17 patients (in 3 after cardiac surgery) 3 to 20 days after myocardial infarction. Seventeen myocardial studies were performed in 17 control patients (in 6 after cardiac surgery). Twenty millicuries of 99mTc polyphosphate was injected intravenously 60 to 120 minutes prior to gamma camera imaging in several views. Myocardial images were processed by the Gamma-11 computer system using standardized background subtraction and contrast enhancement. Results of 16 myocardial studies performed 4 to 20 days after transmural myocardial infarction in 12 patients were positive in 13 instances and questionable in 1. The location of the myocardial infarction by imaging corresponded to location by standard electrocardiograhic criteria in 8 of the 10 patients with positive findings. In five patients with nontransmural myocardial infarction, results of myocardial imaging were positive in two, questionable in one and normal in one. In one patient with questionable findings results were normal when imaging was repeated 16 days after nontransmural myocardial infarction. Results of 17 control myocardial imaging studies were normal in 16 and questionable in 1. Therefore, 99mTc polyphosphate myocardial imaging appears promising in the detection and location of transmural myocardial infarction. Its accuracy in detecting nontransmural myocardial infarction may be increased with greater experience and development of sophisticated digital analysis techniques. The method may prove useful in clinical situations such as cardiac surgery in which standard diagnostic aids are difficult to interpret.

Acute Disease↗
PubMed1974

Late results of aortocoronary bypass grafts in 100 patients with stable angina pectoris.

From March 1969 to December 1972, 314 patients underwent elective aortocoronary saphenous vein bypass graft surgery at the Toronto General Hospital for the relief of stable disabling angina refractory to medical management. Inhospital mortality was 2.5%. Of these patients 100 agreed to return for follow-up hemodynamic and angiographic assessment at a mean interval of 19.7 months after operation. Seventy-four percent of patients were asymptomatic or had angina only with strenuous exertion at the time of follow-up. Seventy-five percent of the 142 grafts were patent, though a few had significant narrowings. Clinical improvement could be correlated with successful myocardial revascularization. Myocardial infarction was diagnosed by the presence of new Q waves after operation in 15% of patients. Many of these patients had patent grafts at follow-up and all were improved. Dyslipoproteinemia was not found to be a factor affecting late graft patency. Total left ventricular function was not shown to be improved by segmental revascularization. The trend toward improved survival in the intervening period for the total operated group is encouraging.

Adult↗