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Biomedical subjects

V Stanek

Publications and source records attributed to V Stanek.

13 recordsLinked to original sources

[Effect of prolonged administration of beta-blockers on the hemodynamics of patients who have sustained a myocardial infarct].

The effect of prolonged treatment with the beta-blocker trimepranol on left-ventricular function was assessed in patients who survived myocardial infarction. Pulmonary arterial catheterization with a floating catheter was used for hemodynamic investigation. Hemodynamic parameters were compared in the treated (20 patients) and control (20 patients matched for age and infarction site) groups. The treated patients showed a reduction in heart rate and cardiac output at rest, as well as stress-induced elevation of the pulmonary arterial pressure and peripheral resistance. Patients with pulmonary hypertension often demonstrated changes of the pressure curve in the pulmonary artery as a possible manifestation of stress-induced mitral regurgitation. Prolonged treatment with trimepranol is associated with increased incidence of pulmonary hypertension in myocardial infarction survivers. The clinical significance of this observation is yet to be established by further studies. Stress-induced mitral regurgitation associated with a mitral subvalvular dysfunction may occasionally be the cause of elevated pulmonary blood pressure.

Cardiac Output

Longterm follow-up of patients with pulmonary thromboembolism. Late prognosis and evolution of hemodynamic and respiratory data.

Seventy-six patients with various forms of pulmonary thromboembolic disease were followed-up for 1 to 15 years. All were free of other cardiopulmonary disease at the time of the first examination which was performed at least two months after the last pulmonary embolism. Catheterization was repeated in all survivors on average 4.8 years later. Severe chronic pulmonary hypertension (mean pulmonary artery pressure (PPA greater than 30 mm Hg) did not occur after a single episode of acute embolism, was infrequent after single subacute or recurrent emboli (8 of 9 patients), and was common after occult emboli (12 of 13 patients). Mortality in all clinical groups correlated with PPA and with the presence of right heart failure. In survivors, no correlation was found between the longterm changes of PPA and age, duration of disease, interval between catheterizations, PaO2, or cardiac output. Pulmonary hypertension progressed further in patients with initial PPA greater than 30 mm Hg. In contrast, none of the patients with normal or borderline PPA at the initial examination developed severe pulmonary hypertension during the follow-up. Since the future course of patients could be predicted from the first examination, repeated hemodynamic investigation proved to be of minor prognostic value.

Adult

[Lung perfusion distribution study by means of 133Xe].

A method for studying regional lung perfusion employing 133Xe is described. Simple radioisotope apparatus with two catheters was used; every isotopic diagnostic department is equipped with it. The possibility of the clinical use of this method was demonstrated in 28 patients with mitral stenosis and in 11 healthy persons. A statistically significant dependence between regional movement of the perfusion to the upper regions of the lungs and the degree of hemodynamics changes in mitral stenosis was noted. Study of the distribution of persusion may be used as a simple method for appraising the hemodynamic changes in mitral stenosis. This method is simple and not burdensome for the patient. It may be recommended first of all in repeated examinations and long-term observations over patients.

Diffusion

[Hemodynamic observations in acute myocardial infarct].

A haemodynamic study was conducted in 96 patients with acute myocardial infarction. The method of right heart catheterization at the bedside using the Swan-Ganz floating balloon-tipped catheter is safe and feisible. An elevation of pressure in the pulmonary circulation was revealed in patients with transmural myocardial infarction and in those without clinical signs of heart failure. The pressure elevation is detected the more often the sooner after the onset of infarction the examination is conducted. To evaluate fast pressure changes heart catheterization is essential and cannot be substituted by any other technique of examination Digoxin administration during the acute phase of myocardial infarction fails to produce any significant reduction of the pulmonary circulation pressure, but a prompt reduction of the pulmonary circulation pressure can be achieved by way of Phentolamine infusion. The pulmonary circulation pressure measurements during the acute phase of myocardial infarction are believed to be an indispensable component of examinations for the heart failure therapy.

Acute Disease

Central haemodynamics during exercise in patients with restrictive pulmonary disease.

Pulmonary precapillary hypertension present only during exercise is the first stage of corpulmonale. Examination of the reaction of central haemodynamics to exercise is the only way to detect it. In a model situation like unilateral pulmonary artery occlusion (UPAO) in healthy subjects, an increase in pulmonary artery pressure (Ppa) during exercise is a linear function of restriction of the pulmonary vascular bed and blood flow increase. Central haemodynamics during exercise in younger subjects after pneumonectomy (PNE) resemble the situation with UPAO provided the remaining lung is intact. In older patients after PNE the same rise of blood flow is associated with a considerably greater rise of Ppa. PNE patients compared to healthy individuals increase their cardiac output during exercise more by increasing stroke volume. Patients with pulmonary fibrosis show a disproportionate rise in Ppa in relation to flow. This is due to reduced distensibility of the pulmonary system. Hypoxia also seems to be involved in pulmonary hypertension during exercise. Pulmonary wedge pressure rises at work but remains within the normal range, even in patients having marked hypoxaemia at rest and during exercise. In idiopathic intersitial pulmonary fibrosis (IIPF), pulmonary hypertension during exercise is greater than in other forms of pulmonary fibrosis. Inhalation of oxygen during exercise in patients IIPF leads to a reversal of hypoxaemia but the decrease of Ppa is small and due to a passive decrease of cardiac output. Finally right ventricular function in restrictive pneumopathies is discussed.

Heart Ventricles