Biomedical subjects

S D Moulopoulos

Publications and source records attributed to S D Moulopoulos.

At least 19 recordsLinked to original sources

PubMed1992

Coronary heart disease risk factors in Hansen's disease sufferers.

In the frame of an epidemiologic study of Hansen's disease (HD) sufferers, several risk factors have been investigated which might explain the high prevalence of coronary heart disease (CHD) among HD patients. The data analyzed in the present study are derived from 293 HD patients (157 men and 136 women). The patients, after having completed a WHO adopted questionnaire, were given a complete physical examination, a resting and an exercise electrocardiogram, and biochemical as well as hematological examinations. Coronary HD patients, when compared to noncoronary HD patients, showed statistically significant differences in the following parameters: (1) mean age, (2) mean concentration of the electrophoretic fraction of alpha-lipoproteins, (3) deviation from mean weight, (4) prevalence of hypertension, and (5) prevalence of the borderline lepromatous form of HD. However, the differences found when comparing other parameters, such as blood pressure, smoking, diabetes mellitus, total cholesterol, triglycerides, pre-beta and beta-lipoproteins, uric acid, erythrocyte sedimentation rate, ABO blood groups, etc., did not reach the level of significance. These findings suggest that HD sufferers are a special population subgroup with reference to CHD risk factors, differing in many ways from the general population.

Adult↗

PubMed1992

The circadian profile of extrasystolic arrhythmia: its relationship to heart rate and blood pressure.

This paper aims at examining whether there is an association between the circadian patterns of systolic blood pressure, heart rate and the incidence of ventricular ectopic beats, as well as to confirm that reducing the blood pressure by a diuretic may also reduce the ectopic frequency. Thirty-four ambulatory patients with ventricular ectopic beats and a systolic blood pressure of 131.33 +/- 17.46 mmHg had a 24-hour Holter electrocardiographic and blood pressure monitoring following 1 week off any antiarrhythmic and antihypertensive treatment. Then they received for one week a standard diuretic combination (amiloride 5 mg + hydrochlorothiazide 50 mg) at a dose depending on their systolic pressure value and their monitoring was repeated. The mean hourly values of systolic blood pressure, heart rate and ventricular ectopic beats were "normalized", i.e. expressed as (x-x)/SD, taking each patient's 24-hour average as zero and his own standard deviation as the unit of measurement. As a group, there was an independent positive correlation between blood pressure and ectopic beats, while the heart rate was a nonsignificant negative factor for ectopic beats. On an individual level, however, an independent positive significant correlation between blood pressure and ectopic beats was found in only 8 cases, with a negative one in 4 cases. While the blood pressure of the group ranged symmetrically around its daily average value, the corresponding ectopic beat curve was highly asymmetric, with a very high incidence (up to 2.56 +/- 0.52 SD) for a rather short time (only 9.41 +/- 3.56 hours above average) and a low incidence (up to 1.26 +/- 0.49 SD) for the remaining 14.59 hours below average. Sudden rises in ectopic beat (greater than 1 SD/hour) occurred 1 to 6 times per day in each individual, significantly (P less than 0.01) more often (20.31%) with a high (greater than 1 SD) blood pressure than with a low (less than -1 SD) one (8.99%) with intermediate frequencies at intermediate pressures. After treatment with the diuretic, the systolic blood pressure was reduced, the heart rate increased and the ventricular ectopic beat incidence reduced (significant changes). The mean change in systolic pressure in 25 patients with a reduction in ectopy was a significant (P less than 0.01) decrease (-5.21 +/- 8.70 mmHg) while in the remaining 9 cases there was a non significant increase (+1.68 +/- 7.63 mmHg). The heart rate was higher in both subgroups.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1992

Anatomical origin of pressure-related ventricular ectopic rhythms.

In order to determine the origin of pressure-related ectopic rhythms, the main arteries were clamped in 11 anesthetized dogs, or the arteries or veins were transfused, while on or off metaraminol. The epicardial right atrial electrogram, the intracavity electrograms and the pressure of the two ventricles were recorded. Sinus rhythm was associated with 64/64 (100%) of the control periods off metaraminol, but only 19/50 (38%) of the clamping of the main arteries (P << 0.0005). In 14/27 aortic clampings ectopic beats appeared from the left ventricle and in 13/27 from the right one. In 4/23 clampings of the pulmonary artery ectopic beats appeared from the left ventricle and in 15/23 from the right one (P < 0.05). Sinus rhythm was associated with significantly lower left ventricular systolic pressure than any ventricular arrhythmia. The left ventricular systolic pressure associated with ectopic rhythms from the left ventricle was significantly (P < 0.005) higher than that associated with those from the right ventricle. The right ventricular systolic pressure during sinus rhythm was significantly (P < 0.005) lower than that during ectopic rhythm from any ventricle. It is concluded that a rise in the pressure of one ventricle tends to cause ventricular ectopic rhythms originating predominantly, but not exclusively, from this ventricle. The origin of ventricular ectopic rhythms from the right ventricle does not preclude that the arrhythmia may respond favorably to lowering of the systemic pressure.

Animals↗

PubMed1992

The effect of iodide on serum thyroid hormone levels in normal persons, in hyperthyroid patients, and in hypothyroid patients on thyroxine replacement.

OBJECTIVE: To clarify the duration and the extent of the antithyroid effect of iodides in hyperthyroidism, and to investigate whether iodides have an additional peripheral effect on the metabolism of thyroid hormones, as has been reported for some organic iodine compounds. DESIGN: The effect on the peripheral thyroid hormone levels of 150 mg of potassium iodide daily (equivalent to 114 mg of iodide) for 3-7 weeks was compared in 21 hyperthyroid patients and 12 healthy controls. A possible effect of iodide on the peripheral metabolism of thyroid hormones was investigated by assessing the serum levels of thyroid hormone in 12 hypothyroid patients on thyroxine replacement for 2 weeks. PATIENTS: There were 21 thyrotoxic patients, 12 healthy hospital controls, and 12 patients with complete or near-complete hypothyroidism, on thyroxine replacement. MEASUREMENTS: The following were measured before and at weekly intervals after iodide administration: (1) pulse rate, (2) serum T4, (3) serum T3, (4) serum TSH, (5) serum thyroxine-binding capacity (TBC), (6) serum rT3, (7) serum thyroxine-binding globulin (TBG), (8) the free-T4 Index, calculated as T4/TBC. RESULTS: In the hyperthyroid patients serum T4, T3 and rT3 decreased, whereas serum thyroxine-binding globulin and thyroxine binding capacity increased. Serum T3, however, did not become completely normal in all cases. After 21 days, serum T4 and T3 started increasing again in some cases, but other patients remained euthyroid even after 6 weeks. In the normal controls there was a small but significant and consistent decrease in serum T4, T3 and rT3 and an increase in serum TSH. Finally, in the T4-treated hypothyroid patients there was no consistent change, except for an increase of serum T4 at 1 and 14 days and a decrease of serum TSH the first day. CONCLUSION: Iodides in hyperthyroidism have a variable and unpredictable intensity and duration of antithyroid effect. Their antithyroid effect is smaller in normal controls. They have no important effect on the peripheral metabolism of thyroid hormones.

Adult↗

PubMed1992

Increased platelet activity in diabetic macroangiopathy.

In order to investigate the relationship between the in vivo platelet activity and diabetic macroangiopathy we have measured plasma beta-thromboglobulin (beta-TG) concentrations by means of a very sensitive radioimmunoassay in 55 diabetics, aged 47-80 years, and in 27 non-diabetic healthy controls (group A) of respective age and sex. Among diabetics 17 were free of vascular complications (group B) in terms of diabetic micro- or macroangiopathy, while the remaining 38 (group C) suffered from peripheral occlusive arterial disease (POAD) of the lower limbs. All subjects underwent a thorough clinical and laboratory investigation. The diagnosis of POAD was based upon the findings of Doppler ultrasound examination and was confirmed by selective arteriography. The mean plasma beta-TG concentrations were significantly higher in the two groups of diabetics compared to the non-diabetic controls (p < 0.001), whereas the highest beta-TG levels were found in diabetics with POAD (py 0.001), (beta-TG: mean +/- 1 SD ng/ml; group A: 26.50 +/- 13.14; group B: 55.88 +/- 26.56; group C: 106.50 +/- 52.65). These findings reveal an increased release reaction of platelets in diabetics and an enhanced in vivo platelet activity especially in POAD subjects. However, this may occur not only in cases with prominent macroangiopathy but also in the early stages of diabetic angiopathy when the vascular lesions cannot be traced clinically.

Aged↗

PubMed1992

The role of mitral annulus motion in left ventricular function.

The dynamics between mitral annulus motion and left ventricular function were studied. Thirty subjects (10 normals, 10 with severe cardiac failure and 10 with mitral regurgitation) were examined. Left ventricular long and short-axis dimensions were measured in a two-dimensional apical four-chamber image. A volume was calculated as defined by cardiac cyclic changes of mitral annulus in size and motion. This volume had the approximate geometric configuration of a truncuated cone and was covered by mitral annulus motion at enddiastole and endsystole. Left ventricular ejection fraction was calculated echocardiographically using the prolate ellipsoid/area-length method. The volume defined by mitral annulus motion was 24 ml in normals, 16 ml in patients with cardiac failure and 48 ml in patients with mitral regurgitation while the ejection fraction was 51%, 19% and 53% respectively. Comparison between the volume of the truncuated cone and the ejection fraction in all 30 subjects revealed a statistically significant correlation (p less than 0.01). Thus, the bigger the volume determined by the mitral annulus motion during systole, the larger portion of the left ventricle is "atrialized", and a higher ejection fraction follows. Mitral annulus motion may provide new information about cardiac mechanics in normal and abnormal conditions.

Adolescent↗

PubMed1991

Increased mean serum thyrotropin in apparently euthyroid hypercholesterolemic patients: does it mean occult hypothyroidism?

Serum thyroid hormones and antithyroid autoantibodies (AAB) were assayed in 87 randomly selected hypercholesterolemic persons compared to 80 controls with normal serum total cholesterol (TC). Of the 87 hypercholesterolemic persons 22 (25%) had positive AAB compared to 5 (6%) controls. Furthermore, 8 of the hypercholesterolemic patients had a serum TSH level above 5 mU/l, i.e. the had subclinical hypothyroidism, not diagnosed before, whereas thyroid function was normal in all normocholesterolemic persons. The new and unexpected finding was that the hypercholesterolemic persons had on average a significantly higher serum TSH than the controls, and this was true even when persons with positive AAB were excluded. There was a significant correlation between TC and serum TSH. It is concluded that hypothyroidism may not be an all-or-none phenomenon, and that many hypercholesterolemic persons with thyroid tests within the conventional normal range may have a slight impairment of their thyroid function.

Female↗

PubMed1991

Treatment of hyperthyroidism with potassium iodide.

Potassium iodide was given to 17 cases of Basedow's disease in comparison to 12 normal controls for 5 weeks. In the thyrotoxic patients, the maximum decrease in serum T3 and T4 levels was observed 2 and 3 weeks, respectively, but in some cases remained normal even at 5 weeks. The euthyroid persons showed a small decrease in T4 and T3 and an increase in serum TSH.

Adult↗

PubMed1991

Effect of acute changes in aortic pressure on the coronary reserve.

STUDY OBJECTIVE: The aim was to evaluate the effect of acute changes in aortic pressure on the coronary reserve and hyperaemic response. DESIGN: Aortic pressure changes were induced either by intra-aortic balloon pumping or by the production of acute aortic regurgitation. A transient 20 s occlusion of the left anterior descending coronary artery was used as the hyperaemic stimulus. EXPERIMENTAL SUBJECTS: The experiments were performed on 19 open chest anaesthetised dogs, weight 13-32 kg. MEASUREMENTS AND MAIN RESULTS: During intra-aortic balloon pumping the mean diastolic aortic pressure increased by 24.7(SEM 2.9) mm Hg (p less than 0.001), while in aortic regurgitation it decreased by 47.7(11.1) mm Hg (p less than 0.01). At the peak hyperaemic response the driving coronary pressure was 121.4(2.8) mm Hg during intra-aortic balloon pumping and 59.8(11.5) mm Hg during aortic regurgitation. The peak hyperaemic flow increased by 12.0(3.8) ml.min-1 (p less than 0.01) during intra-aortic balloon pumping, compared to the values before pumping and decreased by 14.9(4.2) ml.min-1 (p less than 0.01) during aortic regurgitation, compared to the values before aortic regurgitation. The coronary reserve, expressed as the ratio of the hyperaemic to the resting flow, increased by 0.7(0.1) (p less than 0.001) during intra-aortic balloon pumping and decreased by 0.4(0.2) (p less than 0.05) during aortic regurgitation. A positive significant correlation coefficient was found at the peak hyperaemic response between the mean aortic pressure and the total forward effective coronary flow, and between the mean diastolic aortic pressure and the diastolic component of the coronary flow, during both intra-aortic balloon pumping and aortic regurgitation. CONCLUSIONS: The results suggest that coronary reserve increases during intra-aortic balloon pumping and decreases during aortic regurgitation; these changes could be attributed to the effect of the pressure changes on the hyperaemic flow.

Animals↗

PubMed1991

Effect of adrenergic blockade on pressure-related ventricular arrhythmias.

This paper examines whether adrenergic blockade (B1) may prevent the arrhythmogenic effect of acute arterial pressure (AP) elevation. In 7 anesthetized dogs iv propranolol (0.2 mg/kg) was given and in another 2 dogs stellate ganglion excision was performed. Before and after these B1 manoeuvres the AP was repeatedly increased by either elevating an open-air arterial pressure reservoir or administering iv metaraminol and decreased by abating the pressure reservoir. In a continuous recording of AP and ECG the systolic (S) AP and the presence (or absence) of ventricular arrhythmia (A) was noted. Before B1 A was noted in 652/1715 (38.0%) 5-sec periods at a SAP of 160.3 +/- 69.9 mm Hg which was significantly higher than in the 1063 5-sec periods without A (104.2 +/- 54.3) in all experiments. Following B1 it was impossible to cause A in 3 experiments. In the remaining experiments the A incidence was reduced (significantly in 5/9 experiments) to a total of 253/983 (25.7%) periods (P less than 0.001). In the 5/9 experiments with post-B1 A, the mean SAP was higher with (185.0 +/- 97.9 mm Hg) than without A (113.7 +/- 59.9 mm Hg) (significantly in 2/9 experiments). Following fitting of the SAP distributions before and after B1 to their common distribution (i.e. the same AP), the incidence of A was higher before than after B1 in all experiments (significantly in 7/9). It is concluded that B1 has an antiarrhythmic action on AP-related A. This antiarrhythmic effect seems to be due partly to an antihypertensive effect of B1 and partly to an antiarrhythmic effect of B1 for a given AP.

Adrenergic beta-Antagonists↗

PubMed1991

Induced electrophysiological isolation of the myocardium prevents ventricular fibrillation.

STUDY OBJECTIVE: to investigate whether an encircling procedure without ventriculotomy, not involving the endocardium, may have a protective effect against ventricular fibrillation (VF), by achieving a physiological rather than anatomic entrenchment. DESIGN: the occurrence of VF was tested by DC application within an area entrenched by a circular "dotted" line formed by LASER (Nd-Yag) point by point applications. The result was compared with that from similar DC applications before the successful LASER entrenchment or beyond the restricted area. SUBJECTS: 16 anaesthetized mongrel dogs, weights 14-20 kg were used. MEASUREMENTS AND RESULTS: VF occurred 13/118 times by applying DC within the entrenched area and 86/114 times by applying the current outside this area or before the intervention (P less than 0.0005). The pacing threshold was significantly (P less than 0.001) increased within the circumscribed area (4.625 +/- 5.335 vs 0.859 +/- 0.947 mA). The maximal rate at which the ventricles could be driven by pacing at double threshold intensity was not significantly altered by the encircling procedure. Histological examination showed crater-like epicardial destruction with necrosis, loss of myocardial striation, haemorrhage, and polymorphonuclear infiltration, extending about 0.5 cm from the necrotic tissue. The subendocardial area was spared showing only hyperaemia, while the endocardium was intact. CONCLUSIONS: Encircling a small area by LASER point by point applications prevents the occurrence of VF when DC is applied within the restricted area, while permitting the conduction of paced beats. The size of the encircled area necessary to this effect is of importance, possibly reflecting the critical mass needed for the occurrence and maintenance of VF.

Animals↗

PubMed1990

Effect of 24-hour blood pressure and heart rate variations on left ventricular hypertrophy and dilatation in essential hypertension.

This study correlates variables derived from blood pressure (BP) and heart rate (HR) monitoring with the degree of left ventricular structural changes in essential hypertension. Forty patients with mild-to-moderate hypertension according to World Health Organization criteria underwent 24-hour ambulatory monitoring. Echocardiographic (posterior wall and interventricular septum thickness, left ventricular mass) or ECG (SV1 + RV5) indices of hypertrophy were significantly (p less than 0.01) correlated (positive correlations) with derivatives of BP monitoring (mean systolic and diastolic BP values) but not with HR derivatives. Echocardiographic indices of dilatation (left ventricular end-diastolic volume and diameter) were significantly (p less than 0.01 to less than 0.001) correlated (negative correlations) with derivatives of HR monitoring (mean HR values, mainly during the night) but not with BP derivatives. It is concluded that in essential hypertension, left ventricular hypertrophy depends on mean 24-hour systolic and diastolic BP values, whereas left ventricular dilatation appears to be more prominent in patients with bradycardia mainly during the night.

Adult↗

PubMed1990

Response of tertiary centres to pressure changes. Is there a mechano-electrical association?

STUDY OBJECTIVE: To investigate the mechanism of pressure related ventricular arrhythmias by examining them during atrioventricular (AV) block. DESIGN: Complete AV block, where all ventricular beats are ectopic, was induced by AV node ablation and/or by toxic digitalisation, and rhythm changes were studied while arterial blood pressure was repeatedly raised and lowered. SUBJECTS: 15 anaesthetised mongrel dogs, weight 15-28 kg, were used. AV block was induced in eight by chemical or mechanical ablation of the AV node. In five of these and in seven other dogs, 5.0-7.5 mg digoxin was also given. MEASUREMENTS AND RESULTS: Following AV block due to ablation, a heart rate increase (or no change) was found in 87.5% of 56 arterial pressure increases produced by elevation of an open arterial blood reservoir or by metaraminol infusion, but in only 21.8% of 55 pressure decreases caused by arterial bleeding (p much less than 0.001). Following AV block due to digitalisation, the equivalent figures were 96% of 50 pressure increases and 27.3% of 55 pressure decreases (p much less than 0.001). While arterial pressure was increased there was moderate acceleration of the escape rhythm, then appearance of premature ventricular beats, then non-sustained and finally sustained ventricular tachycardia. The reverse occurred, with some hysteresis, on decreasing the arterial pressure. In five of the digitalised animals, arterial pressure reduction to nearly zero caused reproducible sudden arrest, with resumption of the ordinary escape rhythm on increasing the pressure again. CONCLUSIONS: The findings suggest the possibility of two kinds of ectopic rhythm in AV block: the "normal" escape rhythm which is only moderately affected by arterial pressure changes; and an "abnormal" faster pressure dependent rhythm which is generated by high arterial pressure and abolished by pressure near zero, as if there were a mechano-electrical association. This abnormal rhythm may prevail completely in digitalis toxicity so that if cardiac arrest occurs, no automaticity can be expected to appear unless arterial pressure is raised.

Animals↗

PubMed1990

A self-learning approach to history-taking.

The present study examines the effectiveness of self-learning in interviewing skills training. Self-learning was carried out by self-evaluation of one's interviews by the use of an audiotape. Fifteen doctors specializing in internal medicine listened to their interviews and evaluated themselves against the suggested performance included in a rating scale. This procedure was repeated twice and composed the educational programme. Three main aspects of history-taking were involved: (1) eliciting patient information; (2) interviewing technique and (3) attitudes toward the patient. Comparison of performance at the first and third interview revealed significant improvement in all three aspects. Doctor-patient communication and written history performance were involved indirectly in the study but no significant improvement was revealed. The educational approach appeared simple and effective to the doctors. It is suggested that a brief programme of self-learning with feedback from audiotapes is both convenient and effective, improving essential aspects of history-taking performance.

Clinical Competence↗

PubMed1990

Experimental and clinical evaluation of a counterpulsation device.

The counterpulsation technique has been widely used for the assistance of the acutely failing left ventricle utilizing the intraaortic balloon pump. However, a variety of other counterpulsation devices are available. To evaluate a counterpulsation device several variables need to be considered: (1) experimental and clinical determination of the salutary effects of the device on the left ventricular ejection fraction, cardiac output, aortic pressures, left ventricular end-diastolic pressure, tension-time index, diastolic pressure-time index and endocardial viability ratio; (2) experimental and clinical estimation of the device biocompatibility, and (3) the clinical improvement of the assisted patients.

Counterpulsation↗

PubMed1989

Arrhythmogenic effect of high blood pressure: some observations on its mechanism.

An increase in aortic pressure is a reproducible way of causing ventricular ectopic rhythms. This study sought to determine whether it is the aortic pressure per se or the concommitant increase in afterload or preload that has a direct arrhythmogenic effect. Experiments were carried out in 17 anaesthetised dogs. For each 10 s period the pressure and the presence of a ventricular arrhythmia (at least one ectopic beat) were noted. In nine animals an aortic valve gradient was created (and released). The results were compared to those obtained by impeding the aortic flow at the ascending aorta. The mean systolic left ventricular pressure was significantly higher in the arrhythmia associated periods in 8/9 experiments when there was an aortic valve gradient and in 5/9 experiments when there was not. In 4/9 experiments the mean aortic pressure associated with arrhythmia was significantly lower with an aortic valve gradient than when there was no gradient and no arrhythmia. In 7/9 of these experiments, coronary sinus flow was measured volumetrically during the manoeuvres applied. The coronary flow was significantly lower when there was neither arrhythmia nor aortic valve gradient than when there was an arrhythmia (with or without an aortic valve gradient). In another eight experiments a pressure reservoir in the aorta was either raised or lowered while another pressure reservoir in the left atrium was moved in the opposite direction. Thus the mean aortic pressure could be increased while the left atrial pressure was decreased and vice versa. If the left atrial pressure was taken into account, the mean difference of the aortic pressure from its expected value, derived from the aortic v left atrial pressure regression equation, was significantly higher when there was an arrhythmia than it was when there was no arrhythmia in all eight experiments. On the other hand, the mean difference in the left atrial pressure from its expected value was significantly higher when there was an arrhythmia in 1/8, lower in 2/8 and not significantly different in 5/8 experiments. It is concluded that when the blood pressure is raised, it is the increase in afterload rather than an increase in aortic pressure itself or in the preload that has an arrhythmogenic effect on the ventricles.

Animals↗

PubMed1989

Mechanical assistance in cardiogenic shock.

Cardiogenic shock following myocardial infarction or surgical interventions with extracorporeal circulation, not responding to conventional treatment, is an "intractable" condition, unless mechanical assistance is applied. In today's practice mechanical assistance consists in counterpulsating an intraaortic balloon or, if this does not improve the condition, in using a left ventricle bypassing pump. In spite of the complexity of the procedures and the complications, a number of patients can recover with or without a subsequent corrective intervention or heart transplantation. The need for developing systems for chronic assistance to non-correctable hearts and the difficulties of the endeavour are pointed out.

Aged↗

PubMed1989

Comparison of the effect of amiodarone and benziodarone on thyroxine metabolism and surface ECG.

This study examined whether or not the electrophysiological effect of amiodarone on the heart is mediated through its action on thyroxine metabolism. Serum thyroid hormones and ECG were evaluated before and serially during amiodarone (15 subjects) and benziodarone (15 subjects) administration. Both amiodarone and benziodarone shifted the peripheral conversion of thyroxine (P less than 0.001 for amiodarone and P less than 0.001 for benziodarone) towards reverse triiodothyronine and away from triiodothyronine, whilst TSH levels initially fell and then rose with both drugs. After amiodarone the heart rate decreased (P less than 0.025), whilst the PR (P less than 0.005) and the QT interval (P less than 0.005) corrected for the heart rate increased. By contrast with benziodarone only the PR interval decreased (P less than 0.05). Since both drugs had roughly similar effects on thyroid hormone metabolism but different ones on the ECG, our results provide indirect evidence against the hypothesis that the antiarrhythmic effects of amiodarone are mediated through a decrease in the serum T3 presented to the peripheral tissues.

Adolescent↗