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Biomedical subjects

W Markiewicz

Publications and source records attributed to W Markiewicz.

At least 109 records · Page 6Linked to original sources
PubMed1979

Effect of large doses of morphine on experimental myocardial ischemia in cats.

The effect of large doses of morphine (1 mg/kg, i.v.) on experimental myocardial ischemia was evaluated in anesthetized open-chest cats. Myocardial ischemia was produced by intermittent coronary artery occlusion and assessed by measuring ST-segment elevation in multiple epicardial leads. The results obtained in the group of animals given morphine were compared with values obtained in animals given saline (control group), propranolol or nitrous oxide (reference groups). Morphine injected before coronary occlusion produced a significant increase in ST-segment elevation after left anterior descending coronary artery occlusion, whereas no significant change was noted in animals receiving normal saline or nitrous oxide. As expected, in the animals that received propranolol there was a pronounced decrease in ST-segment elevation. Our data suggest that large doses of morphine may increase myocardial ischemia when administered before coronary occlusion in the anesthetized open-chest cat.

Animals↗
PubMed1979

Echocardiography in infective endocarditis. Lack of specificity in patients with valvular pathology.

59 patients with suspected infective endocarditis on a natural valve were studied by M-Mode echocardiography to determine the specificity of the ultrasonic technique in detecting valvular vegetations. All echocardiograms were read independently by two observers who were unaware of the final diagnosis. Among 40 patients who later proved not to have infective endocarditis, two (5%) were diagnosed by echocardiography as having either possible or probably vegetation by at least one observer. Both patients with a false positive diagnosis of vegetation had pre-existing valvular pathology, the presence of which greatly complicated the interpretation of the echocardiogram. Inter-observer disagreement occurred in 5 of the 59 studies (8.5%). The results of this study suggest that caution should be exerted in the echocardiographic diagnosis of vegetation in patients with pre-existing valvular pathology.

Adolescent↗
PubMed1979

A comparison of static and dynamic exercise soon after myocardial infarction.

The cardiovascular response to treadmill exercise testing and to isometric handgrip was compared in 20 selected patients three to five weeks after acute myocardial infarction. The heart rate and the heart rate-systolic blood pressure product were significantly higher during treadmill exercise than during two minutes of isometric handgrip sustained at 25% of maximum voluntary contraction. No significant difference in systolic blood pressure was noted between the two types of exercise while diastolic blood pressure was higher during isometric exercise. Asymptomatic ST-segment depression was noted in two patients during the the treadmill test and was absent during handgrip. Angina pectoris was not noted during either type of exercise. Ventricular ectopic activity was slightly more frequent during treadmill exercise. Isometric handgrip at 25% of maximum voluntary contraction may be performed safely soon after myocardial infarction and provides useful guidelines for performing many customary physical activities requiring upper extremity isometric exertion during early convalescence.

Blood Pressure↗
PubMed1978

Contribuiton of M-mode echocardiography to cardiac diagnosis. An assessment in 1,000 successive patients.

The contribution of M-mode echocardiography to cardiac diagnosis was evaluated in a series of 1,000 successive patients. Among subjects in whom a presumptive clinical diagnosis had been made, echocardiography demonstrated totally unexpected findings in 10 per cent, supported the clinical diagnosis in 50 per cent and was entirely within normal limits in 19 per cent. Among patients with evidence of heart disease but no firm clinical diagnosis, echocardiography established the diagnosis in 23 per cent, including 20 per cent of all patients referred for evaluation of chest pain or arrhythmia of unclear etiology. "Missed" clinical diagnosis frequently involved patients with mitral valve prolapse, congestive cardiomyopathy, pericardial disease or asymmetrical septal hypertrophy of the heart. This study quantifies the amount of independent information contributed by echocardiography to cardiac diagnosis and demonstrates that this technic provides data of important clinical relevance in a surprisingly large number of cardiac patients.

Adult↗
PubMed1977

Echocardiographic detection of pericardial effusion and pericardial thickening in malignant lymphoma.

Serial echocardiographic examinations of the heart were obtained for 13 patients undergoing irradiation for malignant lymphoma. Eleven of these had been shown to have mediastinal adenopathy; none had clinically detectable pericardial disease. The pericardial effusion which had been echocardiographically evident in 6 patients prior to treatment disappeared during or subsequent to the course of radiotherapy. Small asymptomatic effusions appeared in 5 patients during the follow-up period. Pericardial effusions, detected easily by echocardiography, occur more commonly than hed been previously thought in patients with malignant lymphoma.

Adolescent↗
PubMed1977

Exercise testing soon after myocardial infarction.

Forty-six men under age 70, without clinical congestive heart failure or unstable angina pectoris, performed treadmill tests 3, 5, 7, 9 and 11 weeks after myocardial infarction. Patients were more frequently able to perform moderate exertion (2 mph, 14% grade) at 7 and 11 weeks than at 3 weeks following infarction. Ischemic ST-segment depression, usually unaccompained by angina pectoris, occurred in 45% of patients and was associated with a significantly increased incidence of subsequent coronary events. The presence of exercise-induced ventricular ectopic activity provided little independent prognostic information. No serious complications occurred in 210 tests. Exercise testing soon after myocardial infarction provides objective information concerning the capacity to resume physical activity, including return to work. Two tests, at 3-5 weeks and at 7-11 weeks, appear to provide most of the information contined in five tests performed during this time.

Aged↗
PubMed1976

Normal myocardial contractile state in the presence of quinidine.

Since quinidine is one of the few agents available to treat and prevent ventricular arrhythmias in ambulatory patients, its hemodynamic effects have been reevaluated. When given in therapeutic doses to anesthetized mongrel dogs, quinidine significantly reduced heart rate, aortic pressure and flow, but it did not significantly change the first derivative of the left ventricular pressure curve (left ventricular dp/dt) in nine dogs. A subsequent group of dogs was studied after vagotomy and practolol administration to block cardiac reflexes. This group showed significant reductions in heart rate, aortic pressure and left ventricular dp/dt, with the latter returning to predrug control values when preload, afterload and heart rate were maintained constant. These studies suggest that quinidine does not directly affect myocardial contractility when given in therapeutic doses. Furthermore, the reduction in heart rate in these animals provides support for a direct depressant effect of quinidine on the sinus node. The adverse effects of quinidine on cardiac function previously reported may be due to the use of toxic doses or are secondary to quinidine peripheral circulatory effects, rather than due to a direct reduction in cardiac contractile state.

Animals↗
PubMed1976

Mitral valve prolapse in one hundred presumably healthy young females.

Clinical, electrocardiographic, phonocardiographic, and echocardiographic examinations were performed in 100 presumably healthy young females. Treadmill testing and ambulatory electrocardiographic monitoring were performed in a selected group of these subjects. Phonocardiograms, recorded with the subjects supine at rest, after inhalation of amyl nitrite, and in the upright position, revealed a 17% incidence of nonejection clicks and/or late or mid- to late systolic murmurs (PHONO-MSCLSM). Echocardiographic studies were performed in the second, third, fourth, and fifth intercostal space with emphasis on the importance of transducer angulation on the chest. Studies obtained with the transducer perpendicular to the chest in the sagittal plane, or pointing cephalad at a time when both mitral leaflets and left atrium are recorded, are optimal to study the mitral valve systolic motion. With the transducer in this position, 21 subjects were found to have pansystolic or late systolic prolapse, as previously defined on the echocardiogram. The presence of these echocardiographic findings was statistically related to the presence of PHONO-MSCLSM. Other echocardiographic patterns were identified and their relation to PHONO-MSCLSM and transducer position is discussed. Ten subjects with both echocardiographic evidence of mitral valve prolapse and PHONO-MSCLSM were identified (group EP), while 18 other subjects had either echocardiographic or phonocardiographic findings suggestive of mitral valve abnormality (group EorP). Seventy-two subjects had no abnormality (group noEP). The incidence of various clinical, electrocardiographic, and echocardiographic findings in these three groups was determined. Some findings said to be common in patients with proven mitral valve prolapse were seen more frequently in group EP subjects. Echocardiographic and phonocardiographic findings suggesting mitral valve abnormalities were found more commonly than expected in a population of presumably healthy young females.

Adolescent↗
PubMed1976

Problems in assessing infarction size by epicardial mapping: preliminary studies with quinidine.

Some of the laboratory difficulties in assessing infarction size produced by intermittent coronary artery occlusion were demonstrated by using an epicardial mapping technique in anesthetized open-chest dogs. Intermittent occlusion of a left anterior descending coronary artery branch resulted in a marked elevation of the ST segment above the baseline in the areas of the myocardium supplied by this vessel. Repeated occlusions after administration of normal saline as a control produced less ST-segment elevation thn that noted during control occlusions; however, repeated occlusions after infusion of quinidine produced a further lessening in ST-segment elevation. The problems encountered in interpreting these results are emphasized. Long-term coronary occlusion studies were performed in order to correlate epicardial electrograms with histological findings of ischemia or myocardial necrosis. Our investigations show that epicardial mapping tended to underestimate the area of injury, and this limits the interpretation of drug intervention studies such as those in which quinidine is administered. Therefore, caution should be exerted when using epicardial mapping techniques to assess the effect of various pharmacological interventions on infarction size in open-chest dogs.

Animals↗