PubMed Health⌕ Search

Biomedical subjects

D Avgoustakis

Publications and source records attributed to D Avgoustakis.

15 recordsLinked to original sources
PubMed1979

Early diastole in mitral valve disease.

Noninvasive findings from the study of early diastole in patients with mitral stenosis or mitral regurgitation are reported. Isovolumic relaxation time and the opening phase of the mitral valve are the main subintervals of early diastole. In mitral stenosis, a 3rd subinterval, the ECHO X-E phase, is described. Also, the effect of the cardiac cycle length on these intervals is studied, as well as the relationship between the opening snap, the O point of the apexcardiogram and the mitral echographic curve in early diastole.

Adolescent↗
PubMed1978

Effects of oxyfedrin: a beta-adrenoreceptor stimulant, on infarct size following acute coronary artery ligation.

Regional left ventricular blood flow and the extent of myocardial ischaemia were studied after acute coronary artery occlusion in open-chest dogs before and after infusion of oxyfedrin, a beta-adrenergic stimulant. Regional blood flow was measured with radioactive tracer microspheres and local tissue injury was estimated by the S-T segment elevation in epicardial electrocardiograms. Animals receiving oxyfedrin were divided into two groups: 1 and 2. Oxyfedrin was infused intravenously in a dose of 0.80 to 0.94 mg.kg-1 in dogs of group 1 and 1.45 to 1.60 mg.kg-1 in dogs of group 2. The rate of infusion in the animals of both groups was 0.61 mg.min-1. Oxyfedrin caused further S-T segment elevation over ischaemic myocardium and increased the extent of ischaemic injury in group 1 dogs. Conversely, in this same group of dogs, the blood flow was unchanged in low flow regions ( less than 0.3 cm3.g-1.min-1) and increased in higher flow areas, inside the ischaemic region. In the animals of group 2, oxyfedrin caused further S-T segment elevation over ischaemic myocardium and increased the extent of ischaemic injury. Concomitantly, blood flow was significantly reduced both inside and outside the ischaemic region. These observations in dogs of group 1 (ie increased blood flow inside the ischaemic region by infusion of oxyfedrin, in flow zones higher than 0.3 cm3.g-1.min-1, with a further S-T segment elevation over ischaemic myocardium, and an increase in the extent of ischaemic injury) may be explained by a primary effect of oxyfedrin on oxygen demands with secondary changes in blood flow.

Animals↗
PubMed1978

Noninvasive study of early diastole in mitral stenosis.

Cardiac events of early diastole were studied in 50 normal subjects and 46 patients with mitral stenosis (MS) by simultaneous recordings of the mitral valve echogram (MVE), phonocardiogram, and apexcardiogram (ACG). Left ventricular isovolumic relaxation time (IRT), measured between A2 and onset of the MVE opening motion, had almost the same values in normals 54 +/- 7 msec, and MS 51 +/- 16 msec. The interval between A2 and the ACG "O" point was approximately double that of IRT: 99 +/- 11 msec in normal subjects, 109 +/- 20 msec in MS. The normal MVE opening motion had a velocity 293 +/- 76 mm/sec and duration 45 +/- 6 msec, values significantly different (P less than 0.001) from 536 +/- 271 mm/sec, 23 +/- 7.5 msec found in MS patients. In atrial fibrillation the length of the cardiac cycle did not affect A2-O interval or mitral valve opening movement duration; however cycle length was clearly related to isovolumic relaxation time. This resulted in a variation in the interval between completion of the mitral valve opening (opening snap) and O point. This interval was longer after a short diastole and vice versa.

Adolescent↗
PubMed1978

Extent of the inferior myocardial infarction assessed by the frontal plane of the vectorcardiogram.

A correlation was made between the vectorcardiographic changes and the peak value of the L.D.H. in the serum of 21 patients with acute inferior (diafragmatic) M.I. The following vectorcardiographic variables showed changes proportional to the increase in serum L.D.H. The correlation was found to be statistically significant. The direction of the 0.025 sec vector (r = 0.63, P less than 0.005). The duration of the initial superior forces of the QRS loop (r = 0.87, P less than 0.001). The maximal leftward deviation of the initial superior QRS loop forces (r = 0.65, P less than 0.005). The maximal superior deviation of the initial QRS loop forces (r = 0.68, P less than 0.05). The ratio of the maximal superior deviation over the maximal inferior deviation of the QRS loop "QY/RY" (r = 0.76, P less than 0.001). The area under the initial superior forces of the QRS loop and over 0 degrees +/- 180 degrees axis in squared milimeters (r = 0.88, P less than 0.001). It is suggested that V.C.G. is a usefull means in assessing the extent of inferior M.I.

Female↗
PubMed1977

End-diastolic amplitude of mitral valve echogram in mitral stenosis.

By using simultaneous recordings of the mitral valve echogram and apex cardiogram, the mitral echogram amplitude was measured at the onset of left ventricular isovolumic contraction (MAIC). Twenty normal subjects and 68 patients with a reduced diastolic closure rate in the mitral valve echogram were studied. Of these patients, 53 had mitral stenosis, 6 aortic valvar stenosis, and 9 hypertrophic obstructive cardiomyopathy. In the normal subjects the MAIC ranged between 2 and 4 mm, average 2-7 mm, in the patients with aortic valvar stenosis or hypertrophic obstructive cardiomyopathy between 2 and 4 mm, average 2-9 mm, and in the patients with mitral stenosis between 6 and 17 mm, average 11-3 mm. The DE/MAIC ratio, where DE represents the opening amplitude of the mitral valve in early diastole, was between 3-3 and 6-5, average 5-1, in normal subjects; in the patients with aortic stenosis or hypertrophic obstructive cardiomyopathy the DE/MAIC ratio was between 2-7 and 6-5, average 4-2, and in the patients with mitral stenosis between 0-7 and 1-5, average 1-1. An excellent correlation was found between the DE/MAIC ratio and mitral valve area in the patients with mitral stenosis (r = 0-84, P less than 0-01) while the correlation between the diastolic closure rate and valve area was less satisfactory (4 = 0-62, P less than 0-01). These findings suggest that in cases with a reduced diastolic closure rate for reasons other than mitral stenosis, error can be avoided by using the DE/MAIC ratio.

Adolescent↗
PubMed1977

Re-entry ectopic ventricular rhythm caused by artificial pacing.

Two cases with coupled ectopic ventricular rhythm associated with artificial pacing are presented. The premature ventricular beats appeared at a fixed distance from the R of the previous electrical stimulus complex and when pacing was stopped ventricular arrest occurred. This provides strong evidence that the ectopic ventricular beats were dependent on the electrical stimulus and therefore that they were produced by its re-entry. It was observed that the re-entry phenomenon occurred at low rates. This arrhythmia even persisted after the permanent pacing and was successfully suppressed by procainamide in both cases.

Aged↗
PubMed1977

Rocking motion of the right cardiac cavities in Ebstein's anomaly. A specific cineangiographic sign.

In 7 cases of Ebstein's anomaly the right cineangiogram disclosed a big right atrium, the tricuspid valve positioned to the left of the spine and tricuspid regurgitation. The right atrial appendage was nearing the outflow tract of the right ventricle and the pulmonary artery so as the normal U appearance of the right aniograms was abolished. In addition to these signs a very characteristics and almost pathognomonic rocking motion of the radiopaque material, moving from the right atrium towards the right ventricle during ventricular diastole and backwards to the atrium during the next ventricular systole was observed. This sequence of motion gives the impression of a rocking hammock or pendulum.

Angiocardiography↗
PubMed1976

Length of main left coronary artery in relation to atherosclerosis of its branches. A coronary arteriographic study.

The relation between the length of the main left coronary artery and the presence of atherosclerosis in its branches or the presence of complete left bundle-branch block was studied by selective coronary arteriography in 43 persons. The length of the main left coronary artery was found to be significantly shorter in patients with coronary atherosclerosis than in subjects without angiographic evidence of coronary artery disease. In patients with electrocardiographic evidence of complete left bundle-branch block, the length of the left main coronary artery was significantly shorter than that in both previous groups. In view of these findings, it is suggested that a short main left coronary artery should be considered as a congenital factor predisposing to the development of coronary artery disease. The possible mechanisms leading to atherosclerosis of the left coronary arterial branches in the presence of a short main trunk are discussed.

Angiography↗
PubMed1976

The contribution of right ventricular angiocardiography to the diagnosis of tricuspid valvular stenosis (Observations made on 3 patients).

The right ventricular angiocardiographic findings, in the anterioposterior projection, are described on three patients with tricuspid valvular stenosis. During diastole, the tricuspid valve was delineated as an arcline contour, placed between the non opacified right atrium and the opacified right ventricle, and it was displaced to the left of the spine. Its mobility was diminished. Right ventricular angiocardiography seems to be a useful method for the diagnosis of the tricuspid valvular stenosis and the estimation of the pathology and the functional condition of the tricuspid valve. The method is recommended for further evaluation.

Adult↗
PubMed1976

Haemodynamic alterations of the left ventricle during right atrial pacing.

The left ventricular haemodynamic alterations during right atrial pacing were studied in 12 cases. Cardiac index varied little: during maximal rate however, its mean value was slightly lower than the resting one. Stroke index decreased inversely to the heart rate. The course of these indices did not separate the normal from abnormal cases. Ventricular function curves (VFCs) were constructed by relating the changes of left ventricular (LV) end-diastolic pressure (EDP) to those of stroke index (SI). In 4 normal cases the curves were steep, showing a fall of EDP with relatively large decrease of SI; in 3 cases of congestive myocardiopathy they were flat, showing fall of EDP in two and increase in one, with relatively small decrease of SI; in 5 patients with effort angina LVEDP initially decreased. This initial fall of VFCs was steep in two with normal and flattened in three with impaired resting LV function. Increase of EDP, evidently due to development of ischaemia, followed in all; it exceeded resting EDP in two out of three cases developing angina and in one out of two not developing angina. Our findings support the view that the increase of LVEDP is due to decrease of both myocardial contractility and compliance.

Adult↗
PubMed1976

Mechanical alterations of the left ventricle during right atrial pacing.

The effect of increasing heart rate by right atrial pacing on the peak value of the first derivative of left ventricular (LV) pressure(dp/dt) and the maximal velocity of the contractile element (KVmax) was studied in 12 cases. Peak dp/dt was poor as regards its sensitivity in reflecting the changes of contractility, due to its strong dependence on LV end-diastolic (EDP) and systolic pressure. KVmax increased constantly in the 4 normals and in 2 cases of ischaemic heart disease which did not develop angina; the increase exceeded 90 ml sec-1 in the former and one of the latter cases in which resting LV function was normal. In contrast, it decreased during the development of ischaemia in two of the three cases which developed angina; in the third case, in which also resting LV function was seriously impaired, the course of KVmax was almost flat. A similar flat course was observed in the three cases of congestive myocardiopathy. the above alterations of KV max were independent of the EDP and proportional to the basic contractility and its anticipated changes during pacing.

Adult↗
PubMed1975

The significance of intraventricular electrocardiogram in artificial heart pacing. Observations made on 232 patients.

From 1972-1975, 232 consecutive patients suffering from A/V block were paced intravenously in the Cardiac Department. Medical School, University of Athens. Of these, 124 were female and 108 male. Their age range was between 49 and 85 years. Besides fluoroscopic and threshold control, the intraventricular electrocardiogram (E.C.G.)., recorded from the tip of the electrode, was used as a guide for the accurate positioning of the catheter-electrode in the right ventricle. An injury pattern with an elevation of the ST segment of at least 3 mV and characteristic and steady morphology was obtained when the electrode tip was satisfactorily impacted in the right position. As a consequence of this, an initial stimulation threshold below 0.7 mA was obtained in all cases and pacing failure, due to catheter displacement was noted in only 11 cases (5%), without any apparent increase in the incidence of right ventricular perforation.

Action Potentials↗