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Biomedical subjects

G M Zavras

Publications and source records attributed to G M Zavras.

12 recordsLinked to original sources
PubMed1995

Pregnancy-induced increase of supraventricular arrhythmias in Wolff-Parkinson-White syndrome.

Six women suffering from Wolff-Parkinson-White syndrome and who were previously asymptomatic or nearly asymptomatic, were followed prospectively during and after their subsequent pregnancies. Three women experienced several attacks of supraventricular tachycardia (SVT) for the first time and the rest experienced an increase in their attacks. It seems that there is an increased tendency for SVT in pregnancy. Increased adrenergic sensitivity by estrogens, increased plasma volume, stress, and anxiety during pregnancy may be some of the causative factors.

Adult↗
PubMed1991

Histamine-induced coronary artery spasm: the concept of allergic angina.

Histamine, the main amine released during allergic reactions, can provoke coronary arterial spasm manifested as angina pectoris. This has been shown during clinical and laboratory studies. The effects of histamine on cardiac function are mediated via H1- and H2- receptors situated on the four cardiac chambers and coronary arteries. Coronary arteries of cardiac patients are hyperactive and contain stores of histamine which can initiate coronary artery spasm. Clinical observations indicate that angina pectoris or acute myocardial infarction can be provoked by acute allergic reaction. The coincidental occurrence of chest pain and allergic reaction accompanied by clinical and laboratory findings of classical angina pectoris seems to constitute the syndrome of allergic angina. The clinical symptoms of allergic angina include chest discomfort, dyspnoea, faintness, nausea, pruritus and urticaria. They are accompanied by signs such as hypotension, diaphoresis, pallor and bradycardia. There are also electrocardiographic findings indicating myocardial ischaemia, arrhythmias and conduction defects. Thus, in patients undergoing acute allergic reaction, the development of chest pain could be explained by the mechanism of coronary arterial spasm provoked by the release of histamine, which constitutes the syndrome of allergic angina.

Angina Pectoris↗
PubMed1990

Endocarditis, pyrexia of unknown origin and occult abdominal malignancy.

Two patients who presented with pyrexia of unknown origin were found to have carcinoma of the caecum without gastrointestinal symptoms. Blood cultures were positive for Escherichia coli, and in one patient the diagnosis of endocarditis was confirmed by echocardiography. This rare association may be fortuitous, but a common pathogenetic basis cannot be excluded.

Aged↗
PubMed1989

Systolic and diastolic septal and posterior wall echocardiographic measurements in normal subjects.

M-mode echocardiographic measurement of septal and left ventricular excursions and velocities was attempted in 109 subjects. Seventy subjects had adequate echocardiograms enabling detailed measurement. Two groups of subjects were studied: a group of normal adults aged nineteen to seventy-eight years and a group of normal juveniles aged nine to eighteen years. The posterior wall excursion (PWE), systolic septal excursion (SSE), diastolic septal excursion (DSE), and diastolic septal velocity (DSV) did not differ in these groups. There were significant differences in the posterior wall excursion during isovolumetric contraction (B-Ce, p less than 0.002), mean posterior wall velocity (PWV mean, p less than 0.002), and systolic septal velocity (SSV, p = 0.05) between the two groups. The measurements were obtained by using the recently published method of the specific points for labeling and description of the wall motion.

Adolescent↗
PubMed1989

Effects of nitroglycerin on myocardial excursions and velocities in the early hours of acute myocardial infarction.

The effects of sublingual nitroglycerin on septal and left ventricular wall motion were determined by echocardiography in the early hours of acute myocardial infarction (MI) in 20 patients admitted via a mobile coronary care unit. Left ventricular and septal echoes were obtained in 11 patients with acute anterior MI and in 9 with acute inferior MI before and after administration of 500 micrograms sublingual nitroglycerin. In the group with acute anterior MI, nitroglycerin did not significantly affect the B-C excursion, posterior wall excursion, and mean posterior wall velocity. Nitroglycerin significantly increased (P less than 0.01), however, the systolic septal excursion, systolic septal velocity, diastolic septal excursion, and diastolic septal velocity. In the group with acute inferior MI, nitroglycerin significantly increased the B-C excursion (P less than 0.01); posterior wall excursion (P less than 0.01); mean posterior wall velocity (P less than 0.01); systolic septal excursion (P less than 0.01); diastolic septal excursion (P less than 0.05), and diastolic septal velocity (P = 0.01) but did not affect the systolic septal velocity. All measurements were obtained by use of a method of labeling and describing specific points of the wall motion that has been described recently.

Administration, Sublingual↗
PubMed1989

Left ventricular excursions and velocities during coronary arterial ligation. Effects of nitroglycerin infusion in an experimental model.

To determine the effects of intravenous nitroglycerin on the velocities and excursions of the acutely ischemic myocardium, 20 open-chest dogs were studied by use of ultrasound. In 10 dogs with acute septal ischemia, the posterior wall excursion during contraction (B-C excursion), the mean systolic posterior wall velocity, and the posterior wall excursion remained unaltered. Nitroglycerin, however, increased all these parameters (P less than 0.01). In 10 dogs with acute posterior wall ischemia the B-C excursion (aneurysmal bulging) increased (P less than 0.01), but the mean systolic posterior wall velocity and posterior wall excursion decreased (P less than 0.01). Nitroglycerin increased even more the aneurysmal bulging (P less than 0.01) and the other parameters (P less than 0.01). Increased regional blood flow, reduced afterload, and mechanical pulling of the ischemic myocardium seem to be a possible mechanism. The measurements were obtained using the recently described method of the specific points.

Animals↗
PubMed1988

Unusual electrocardiographic manifestations in conditions with increased intrathoracic pressure.

Clinical, electrocardiographic and haemodynamic findings of 10 patients suffering from intrathoracic conditions were analyzed. Three patients suffering from left spontaneous pneumothorax, three from large left pleural effusion, three from traumatic rupture of the left diaphragm and one from sliding hiatus hernia were found to have electrocardiographic alternation, while their central venous pressure and pulmonary capillary wedge pressure were increased. With the correction of the condition the electrocardiographic alternation disappeared and the pressures returned to normal. The increase in direct or indirect pressure exerted on the global surface of the heart, as it is reflected in pulmonary capillary and venous pressures, seems to be the cause of the electrical alternation observed in these patients.

Arrhythmias, Cardiac↗