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Biomedical subjects

M Pornin

Publications and source records attributed to M Pornin.

8 recordsLinked to original sources
PubMed1992

[Quantitative thallium myocardial tomoscintigraphy. Value of intravenous infusion of dipyridamole after negative submaximal exercise test].

Patients with suspected coronary artery disease are sometimes unable to exercise adequately (85% of age calculated maximal heart rate) to validate their ergometric stress test. Some groups suggest performing dipyridamole scintigraphy from the outset but then the information provided by exercise stress testing is lost. The aim of this study was to compare scintigraphies performed after exercise alone and after exercise combined with dipyridamole using a method of quantification. Thirteen patients with ischaemic heart disease without necrosis (coronary lesions greater than 75% luminal narrowing in: 7 right coronary, 10 left anterior descending, 3 left circumflex arteries and 1 left main coronary artery with 50% luminal narrowing) underwent exercise stress testing followed by Thallium imaging. One week later, the same exercise stress test was performed followed by an intravenous injection of dipyridamole and Thallium scintigraphy. The circumference of the radioactivity was traced and the surface of each segment calculated in three different short axis views, subdivided into 4 segments (anterior, lateral, inferior and septal walls). Any segment vascularised by a stenosed coronary artery was considered to be underperfused (105 segments). The ratios of the surfaces of underperfused/normal segments were compared using the two study protocols. Segments of the same wall in the 3 short axis views were grouped in the same myocardial zone. Thirty five myocardial zones were thus obtained: 25 zones were more underperfused after combining exercise and dipyridamole than after simple exercise stress (p = 0.014). The average increase in underperfusion after the combined exercise-dipyridamole was 12.4% compared with 5.5% after exercise alone (p = 0.03). Secondary effects were minimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1990

[Enoximone in the hemodynamic evaluation before heart transplantation. A new test].

A better selection of patients referred for cardiac transplantation should lead to better surgical results. The presence of severe and irreversible pulmonary hypertension is an important factor and its pretransplantation assessment requires pharmacodynamic testing with vasodilators and dobutamine. The aim of this study of 10 patients in congestive cardiac failure referred for cardiac transplantation was to evaluate enoximone in this indication by comparing it with sodium nitroprussiate (3 micrograms/kg/mn). Intravenous enoximone (total dose of 1.5 mg/kg) increased the cardiac index (+49%; p less than 0.01), slightly reduced the mean systemic blood pressure (-8%; p less than 0.05) whilst inducing a greater reduction in systemic arterial resistances (-36%; p less than 0.01); the fall in mean blood pressure was less than with sodium nitroprussiate (-23%; p less than 0.01). Myocardial oxygen consumption (rate-pressure product) did not increase in contrast to the effect of dobutamine (+21%; p less than 0.01). There was a significant reduction in pulmonary arteriolar resistances (p less than 0.01) with all three drugs but the interpretation of this response and its prognostic significance in patients with a low cardiac output and persistent pulmonary hypertension are discutable even when pulmonary arteriolar resistances are less than 6 Wood units. The value of using an inotropic agent such as Dobutamine or Enoximone is to unmask fixed pulmonary hypertension which may be missed in patients with low cardiac output even with vasodilator drugs, and also to mimic the haemodynamic result of transplantation. In this indication Enoximone may be used like Dobutamine but with the advantage of not increasing myocardial oxygen consumption and being probably less arrhythmogenic.

Adult↗
PubMed1990

[Phosphodiesterase inhibitors].

Phosphodiesterase III inhibitors constitute a new therapeutic group for congestive cardiac failure. They inhibit the degradation of cyclic adenosine monophosphate and increase the intracellular calcium. They have a double inotropic and vasodilator haemodynamics occurs without any increase in the myocardial effect. The improvement in the consumption of oxygen. The beneficial haemodynamic effect seems to last over a medium period of time, but the survival in the long term treatment is not yet known.

Electrophysiology↗
PubMed1988

[Short-axis thallium 201 tomography. Changes in the isotope fixation on the circumference of the left ventricle].

Several authors have studied variations in myocardial thickness on short-axis sections cut through healthy postmortem hearts. The circumferential profiles showed a series of minima and maxima, with a minimum at the septum, a maximum at the anterior interventricular junction and another at the anterolateral papillary muscle, a minimum at the inferior wall followed by a maximum at the posterior papillary muscle, then at the posterior interventricular junction, after which came a septal minimum again. When examined by short-axis thallium 201 tomography, the left ventricle does not look like a ring of even density. The purpose of this study was to try and explain the changes in density observed by variations in thickness and to devise a quantification method that would take anatomical features into account. 23 patients with normal coronary angiography underwent thallium 201 scanning after exercise. Circumferential profiles were drawn from short-axis sections with the angle on the abscissa and the number of sections on the ordinate. 29 other patients with a more than 75 p. 100 stenosis of coronary vessels (anterior interventricular artery 15, right coronary artery 10, circumflex artery 8, diagonal artery 4) had the same examination. The circumferential profiles of normal subjects closely resembled those of anatomical sections, with a minimum at the upper and anterior septal wall (the limit between the two areas being undefinable), a maximum at the anterolateral papillary muscle and adjacent myocardium, a minimum at the inferior wall and a maximum at the posterior papillary muscle and adjacent septum. These curves enabled us to determine the relative perfusion values of one area compared with another, which will serve as reference.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1986

[Abnormal origin of the left coronary artery. Pre- and postoperative hemodynamic and metabolic studies].

The authors report the case of an asymptomatic 45 year old man in whom an abnormal origin of the left coronary artery was discovered fortuitously. Coronary angiography was carried out for electrocardiographic signs of anterior myocardial infarction and showed the left coronary artery arising from the pulmonary artery: there was apical dyskinesia with alteration of global left ventricular function. The ostium of the left coronary artery was closed and a saphenous vein aorto-left anterior descending artery bypass was performed. There were no complications. Left ventricular function has not improved 8 months after surgery. The haemodynamic and coronary signs of myocardial ischaemia demonstrated preoperatively regressed after surgery: the coronary "steal" caused by the malformation which led to poor perfusion of the territory of the left coronary artery has therefore been corrected by surgery. This procedure should be carried out as early as possible in order to limit extension of the myocardial lesions.

Coronary Artery Bypass↗