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Biomedical subjects

J L Pannier

Publications and source records attributed to J L Pannier.

At least 37 records · Page 2Linked to original sources
PubMed1981

Non-invasive evaluation of cardiac function in professional cyclists.

Cardiac dimensions and left ventricular function were investigated at rest with non-invasive methods in 14 professional road race cyclists and in 11 age-matched sedentary control subjects. The electrocardiographic findings were in agreement with previous studies in endurance athletes and the vectocardiographic data showed anterior displacement of the electrical forces. Echocardiographic dimensions at end-diastole showed higher values in the cyclists for left ventricular internal diameter, left ventricular posterior wall thickness, and interventricular septal thickness. Derived values for left ventricular volume and left ventricular mass were also much larger in the cyclists and there was excellent agreement between total heart volume measured with radiology and total measured by echocardiography. There was a significant correlation between maximal oxygen consumption and end-diastolic left ventricular diameter.

Adult↗
PubMed1980

Cardiac output distribution during induced static muscular contractions in the dog.

Previous experiments in the dog have shown that static contractions of the muscles of one limb elicit a reflex increase of resistance in the vessels of the opposite limb, along with an increase of systemic blood pressure. The aim of the present experiments was to examine whether this reflex can cause a redistribution of cardiac output from the resting areas, in favor of the working parts. In 17 anesthetized and ventilated dogs, static contraction of the muscles of the right thigh was elicited with electrodes inserted into these muscles. The carotid sinuses were kept at constant pressure and the vagi cut. During static contractions systemic blood pressure and cardiac output increased by 17.7 +/- 3.1 and 24.2 +/- 5.5%, respectively. The blood flow measured with an electromagnetic flowmeter decreased by 21.9 +/- 5.3% in the femoral artery of the resting limb and increased by 101 +/- 21% in the femoral artery of the "active limb". Data obtained in six dogs with injection of radioactive microspheres during stimulations show that blood flow decreased not only in the muscles of the rising limb (34 +/- 10%), but also in several other resting areas, such as skin (38 +/- 8%), kidney (24 +/- 8%), gut (38 +/- 6%), and tongue (23 +/- 3%). The results show that the reflex under study causes a redistribution of the cardiac output during static muscular contractions.

Animals↗
PubMed1980

Cardiorespiratory response to treadmill and bicycle exercise in runners.

Maximal aerobic power and related variables during submaximal work were determined on the bicycle ergometer and on the treadmill in nine long-distance runners and in nine control subjects. During submaximal work, heart rate and pulmonary ventilation were similar with the two exercise procedures in each group, but the runners had lower values than the control subjects. During maximal exercise, oxygen uptake and pulmonary ventilation reached higher levels on the treadmill than on the bicycle egometer. The difference in VO2max was not significant in the control subjects (4.4%), but was more pronounced (12.8%) and highly significantly (p < 0.01) in the runners. The intergroup differences for VO2max between runners and controls were more marked during treadmill running (17.3%) than during bicycle exercise (8.5%). It is concluded tht the differences between the VO2max values obtained on the bicycle ergometer and on the treadmill are influenced by the training conditions of the subjects and that bicycle ergometry leads to a marked underestimation of maximal oxygen uptake in runners.

Heart Rate↗
PubMed1980

Alteration in myocardial oxygen balance during exercise after beta-adrenergic blockade in dogs.

The effects of beta-adrenergic blockade upon myocardial blood flow and oxygen balance during exercise were evaluated in eight conscious dogs, instrumented for chronic measurements of coronary blood flow, left ventricular pressure, aortic blood pressure, heart rate, and sampling of arterial and coronary sinus venous blood. The administration of propranolol (1.5 mg/kg iv) produced a decrease in heart rate, peak left ventricular (LV) dP/dt, LV (dP/dt/P, and an increase in LV end-diastolic pressure during exercise. Mean coronary blood flow and myocardial oxygen consumption were lower after propranolol than at the same exercise intensity in control conditions. The oxygen delivery-to-oxygen consumption ratio and the coronary sinus oxygen content were also significantly lower. It is concluded that the relationship between myocardial oxygen supply and demand is modified during exercise after propranolol, so that a given level of myocardial oxygen consumption is achieved with a proportionally lower myocardial blood flow and a higher oxygen extraction.

Animals↗
PubMed1977

Regional blood flow in response to exercise in conscious dogs.

Regional blood flow was measured with the microsphere method in conscious dogs under resting conditions and during moderate exercise on the treadmill. With respect to total organ blood flow, exercise induced a marked increase in blood flow to the calf muscles and to the myocardium, and a significant decrease in the arterial blood supply to the liver. Slight changes in blood flow to the other organs under study (various skeletal muscles, skin, brain, kidneys, intestine) were not significant. Study of the blood flow distribution within the myocardium showed a slight decrease of the ratio of subendocardial to subepicardial blood flow in the left ventricular free wall in response to exercise, and within the brain there was a relative increase in the blood flow to the cerebellum.

Animals↗