Circulation
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Twenty-one patients without evidence of hypertrophy by M-mode echocardiography were studied by wide-angle two-dimensional echocardiography to determine if they had a form of hypertrophic cardiomyopathy that could not be detected by conventional M-mode echocardiography. Each patient was suspected clinically of having hypertrophic cardiomyopathy because of a distinctly abnormal ECG and either a family history of hypertrophic cardiomyopathy or cardiac symptoms. Patients were 5-49 years old (mean 16 years) and 16 of the 21 had no functional limitation. ⋯ Hence, some patients with hypertrophic cardiomyopathy may have substantial hypertrophy present in unusual locations of the left ventricular wall. Although electrocardiographic abnormalities suggested the presence of myocardial disease, conventional M-mode echocardiography (performed from standard parasternal positions) did not reliably identify such sites of hypertrophy, which were limited to regions of the left ventricle not accessible to the M-mode beam. Only wide-angle two-dimensional echocardiography permits definitive identification of these unusually located regions of cardiac hypertrophy and confirmation of the diagnosis of hypertrophic cardiomyopathy.
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The Medical Device Amendments of 1976 gave the Food and Drug Administration (FDA) new authority to regulate all medical devices. This regulation requires that manufacturers provide data supporting the safety and effectiveness of new and modified devices before marketing them, and eventually provide similar data even for devices now on the market. Those working in the cardiovascular field use a device every day of their professional lives; therefore, the Medical Device Amendments will have a significant effect on everyone in the field. We must understand the law so that we can provide scientific guidance to the FDA and to the medical device industry; in this article we aim to provide the necessary information.
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Randomized Controlled Trial Clinical Trial
Pulsatile cardiopulmonary bypass: failure to influence hemodynamics or hormones.
In a randomized trial of pulsatile vs nonpulsatile cardiopulmonary bypass for coronary artery surgery, we studied hemodynamic and hormonal responses. Anesthesia did not produce a response but, from the time of the incision, cortisol and antidiuretic hormone levels and plasma renin activity all increased. Cortisol levels continued to rise after surgery, whereas the other began to fall. ⋯ We did not see the changes ascribed to nonpulsatile bypass by others. There ws no difference between our pulsatile and nonpulsatile cases. High-flow cardiopulmonary bypass, vasodilating inhalation anesthesia and continuation of Inderal therapy may account for our results.
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We quantitatively analyzed the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire length of each of the four major coronary arteries in 27 necropsy patients with transmural acute myocardial infarction (AMI) and compared the findings with those in 22 control subjects. Of the 1403 5-mm segments examined in the 27 AMI patients, 484 (34%; controls 3%) were 76-100% narrowed in cross-sectional area by atherosclerotic plaques, 528 (38%; controls 25%) were 51-75% narrowed, 319 (23%; controls 44%) were 26-50% narrowed, and only 72 segments (5%; controls 28%) were less than or equal to 25% narrowed. ⋯ The number of severely narrowed 5-mm segments did not correlate significantly with the patient's age at death, the presence or absence of a history of angina pectoris or healed myocardial infarction, or with heart weight. The men, however, had a significantly greater number of severely narrowed 5-mm segments of coronary artery than the women (p less than 0.05), and the patients with associated transmural left ventricular scars had significantly more severely narrowed segments than did patients without transmural scars.