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D Babalis

Publications and source records attributed to D Babalis.

13 recordsLinked to original sources
PubMed1992

Vascular endothelium, mechanical properties of the arterial wall and local angiotensin converting enzyme inhibition.

METHODS: An experimental model of in situ isolated carotid arteries was used to study the contribution made by angiotensin II (Ang II) towards the mechanical properties of the arterial wall in 12-week-old Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. The effects of local incubation with saralasin (Sar1-Thr8-Ang II, 10(-6) mol/l) and with lisinopril (5 x 10(-6) mol/l) on carotid compliance were compared to the effects of removing the endothelium and the effects of totally abolishing vasomotor tone with potassium cyanide (0.1 mg/ml). RESULTS: With an intact endothelium, local incubation with lisinopril increased carotid compliance by 23% in WKY rats (P less than 0.05) and by 14% in SHR (P less than 0.01). Under the same experimental conditions, saralasin increased carotid compliance by 24% in WKY rats and 23% in SHR relative to control values (P less than 0.05 and P less than 0.001, respectively). Removal of the endothelium induced significant increases in carotid compliance in WKY rats (17%, P less than 0.01) and in SHR (33%, P less than 0.001). After removal of the endothelium, there was no further increase in carotid compliance with lisinopril in either strain. In contrast, saralasin induced further significant compliance increases in both strains (+18%, P less than 0.001, and +11%, P less than 0.01, in WKY and SHR, respectively). After the artery had been poisoned with potassium cyanide, there was no further increase in compliance relative to values obtained with saralasin in either strain with or without the endothelium. CONCLUSIONS: These findings suggest that Ang II receptors have a major effect on the control of basal vasomotor tone of large arteries in both normotensive and hypertensive rats. Furthermore, the increase in carotid compliance induced by local incubation with saralasin and with angiotensin converting enzyme (ACE) inhibitors may involve similar mechanisms acting on smooth muscle angiotensin receptors.

Angiotensin II↗
PubMed1988

Cardiac hypertrophy and characteristic impedance in spontaneously hypertensive rats.

Characteristic impedance and systemic arterial compliance were evaluated in 12 anaesthetized spontaneously hypertensive rats (SHR) from analysis of phasic records of pressure and flow in the ascending aorta. Cardiac hypertrophy expressed as the ratio of the left ventricular weight to the body weight was not correlated with arterial blood pressure (systolic, diastolic or mean). In contrast, there was a significant relationship between the left ventricular weight to body weight ratio and the characteristic impedance, suggesting that increased arterial stiffness contributes to left ventricular hypertrophy in SHR.

Animals↗
PubMed1985

[Pathogenesis of tachycardia in hyperthyroidism. Value of Holter monitoring and the use of a beta-blocker].

The mechanisms of tachycardia in hyperthyroidism were investigated by means of Holter recordings of heart rate in 45 patients, 33 of whom had sinus rhythm and were left untreated. In the remaining 12 patients, recordings were taken after 3 days of treatment with either propranolol (120 mg/day; 6 patients) or pindolol (15 mg/day; 6 patients). Propranolol is a beta-blocker devoid of intrinsic sympathetic activity whereas pindolol possesses such activity. Changes in heart rate under the influence of each of these drugs were compared with those observed in 96 controls similarly treated. The difference in baseline heart rare between day and night was significantly higher (p less than 0.01) in patients with hyperthyroidism (17 +/- 1 QRS/min) than in controls (13 +/- 1 QRS/min). Day and night heart rates were increased by pindolol, the increase in night heart rate being significantly greater (p less than 0.05) in patients with hyperthyroidism (23.4 +/- 4.9%) than in controls (11.6 +/- 2.6%). These results suggest that sinus tachycardia in hyperthyroidism is related to an increase in the number of myocardial beta-adrenoceptors. They also indicate that thyrotoxicosis should not be treated with beta-blockers possessing intrinsic sympathetic activity.

Adolescent↗
PubMed1985

Relationships between single-vessel coronary artery obstructions and wall motion dysfunction analyzed by four computer-based methods.

We analyzed regional wall motion in 238 patients by using cineangiograms recorded in the 30 degrees right anterior oblique projection. The sample was divided into three groups: a normal group (n = 71), a group with isolated obstruction of the left anterior descending coronary artery and previous anterior myocardial infarction (n = 85), and a group with isolated obstruction of the right coronary artery and previous inferior myocardial infarction (n = 82). Both anterior and inferior groups also had motion abnormality within the corresponding anterior or inferior wall as judged by the qualitative analysis of cineangiograms. Four quantitative methods were compared: a long axis method and a center of mass method using internal reference systems, a method derived from the Stanford model and an area-based method using external reference systems. Normal regional values were determined from the normal group to evaluate the specificity and sensitivity of the methods. The area-based method was the most sensitive in the anterior infarction group, whereas the center of mass method was the most sensitive in the inferior infarction group. We conclude that there is no evidence that any method, among those tested, is superior to others for every expected location of wall motion abnormality.

Adult↗
PubMed1984

Ventricular function and arterial compliance in patients with congestive cardiomyopathy.

In order to study the interrelationship between left ventricular afterload, estimated from the mean left ventricular wall stress, and the mechanical properties of the aorta, we have simultaneously measured systemic arterial compliance and left ventricular wall stress in 19 patients with congestive cardiomyopathy. The strong linear relationship between the ejection fraction of the left ventricle and systemic arterial compliance, and between left ventricular wall stress and systemic arterial compliance, suggests that systemic arterial compliance is an important determinant of left ventricular afterload and thus of left ventricular function.

Adult↗
PubMed1984

[Value of long-term electrocardiography in patients with cerebral ischemic accidents].

Continuous 24 hour electrocardiography (Holter monitoring) was performed in 226 patients aged 20 to 85 years (mean 61 years) presenting with focal signs of a cerebrovascular accident (CVA). The technique was the same in all patients; the study was limited to paroxysmal atrial arrhythmias. Eighty four of the 226 patients examined had atrial arrhythmias which were already known in 39 patients before Holter monitoring. In the other 187 cases, the following results were obtained: 1) 9 patients (4,8%) had paroxysmal atrial fibrillation (AF), 2) 6 patients (3,2%) had paroxysmal atrial tachycardia (PAT), 3) 11 patients (5,9%) had runs of atrial extrasystoles, 4) 19 patients (10%) had isolated atrial extrasystoles (IAE). When patients with underlying cardiac disease constituting a diagnostic indicator for arrhythmia were excluded, the following incidences were obtained: AF = 3,7%, PAT = 2,7% and runs of atrial extrasystoles = 4,3%. The majority of these arrhythmias occurred in elderly patients in whom atrial arrhythmias are known to occur and may be asymptomatic. There were practical consequences of these results, i.e. antiarrhythmic and anticoagulant therapy in 12 patients (6,4%) alone. As Holter monitoring is also associated with a number of false negative results with respect to paroxysmal atrial tachycardia, we do not believe that this investigation should be offered routinely to patients with CVA in the absence of other clinical or electrocardiographic indications.

Adult↗
PubMed1983

Systemic arterial compliance in patients with non obstructive cardiomyopathy (NOCM), and coronary artery disease (CAD).

Arterial compliance had been estimated in three groups of patients: control, NOCM, and CAD, from analysis of the arterial pressure curve. In the three groups, a simple first order Winkessel model had been validated during normal and post extrasystolic beats. The measured arterial compliance depends mainly on i the diastolic pressure, ii, the mechanical properties of the aorta and major arteries. For the same range of age and diastolic pressure, the arterial compliance was not significantly different in the three groups of patients. Because of the significant variations of the arterial compliance during slight modifications of the diastolic pressure, the lack of difference in the compliance of control, NOCM, and CAD patients may be attributed to similar arterial mechanical properties.

Adult↗
PubMed1982

[Effect of nitroglycerin and N-ethoxycarbonyl-3-morpholinosydnonomine on the walls of large arteries].

Systemic arterial compliance was measured in 20 patients with left ventricular failure due to congestive cardiomyopathy. The method consisted in evaluating arterial compliance by analysing the exponential fall of the arterial pressure curve on a simple visco-elastic model. In the patient group, significant correlations were found between arterial compliance and age (r = 0,64 ; p less than 0,01) and arterial compliance and systolic blood pressure (r = -0,58 ; p less than 0,001). These relationships suggest that arterial compliance depends on the height of the systolic blood pressure and/or the elasticity of the arterial walls. Two groups of patients were defined : Group I (10 patients) given a single oral dose of 7,5 mg of nitroglycerine (Lenitral), and Group II (10 patients) giben a single oral dose of 4 mg N ethoxycarbonyl-3-morpholinosydnonomine (Molsidomine). There was no significant difference in the hemodynamic parameters or arterial compliance between the two groups before administration of these drugs. However, systolic blood pressure was significantly lower (p less than 0,01) and compliance significantly higher (p less than 0,05) after treatment in Group II. In Group I, nitroglycerine caused a significant increase in compliance (p less than 0,01), a significant decrease in systolic (p less than 0,02) and mean blood pressure (p less than 0,05) whilst heart rate, cardiac output and total systemic resistance remained unchanged. In Group II, Molsidomine caused a significant increase in arterial compliance (p less than 0,01), a decrease in systolic (p less than 0,001), diastolic (p less than 0,01) and mean blood pressure (p less than 0,01) and in cardiac output (p less than 0,01), whilst heart rate and total systemic resistance remained unchanged. This study shows that both drugs studied had significant effects on the walls of the large arteries.

Adult↗
PubMed1982

[Evaluation of left ventricular function in diabetics by studying systolic time intervals].

Systolic time intervals were measured before and four minutes after maximal exercise stress testing in 54 patients without obvious cardiac disease. Twenty seven patients (average age 46 years) had diabetes of over 5 years standing (group II); group I comprised 27 normal controls (average age 46 years). All patients underwent maximal treadmill stress testing using the Bruce protocol and the maximal heart rate was achieved without any signs of coronary insufficiency. No significant difference was observed in the basal systolic time intervals of the two groups. The difference was not significant 4 minutes after the stress test. However, when the changes before and after exercise were compared, the patients in group I had a significant increase in heart rate (p less than 0,001), a reduction in the duration of electromechanical systole (QB2; p less than 0,02) in the preejectional period (PEP; p less than 0,001) and in the PEP/LVET ratio: p less than 0,01, whilst left ventricular ejection time (LVET) remained unchanged. The patients in group II only showed an increase in heart rate (p less than 0,01) and LVET (p less than 0,001). The differences in the systolic time intervals after exercise between these two groups probably reflect a degree of cardiac dysfunction which is not apparent at rest.

Adult↗
PubMed1981

Detection of residual myocardial function in acute transmural infarction using postextrasystolic potentiation. A computerized angiographic study.

Twelve subjects without clinical or hemodynamic heart failure, admitted for a first untreated anterior transmural myocardial infarction, were evaluated within the first 24 hours after the onset of symptoms. Pulmonary angiography was performed while a right ventricular extrastimulus was delivered every fourth beat at 50% of the RR interval to systematically analyze the basal and the postextrasystolic left ventricular frames. Left ventriculograms were quantitatively processed to determine the ejection fraction (EF) and the percentage of the end-diastolic circumference showing hypokinetic (%HK) or akinetic (%AK) areas. Left ventricular angiography was performed 1 month later in all cases at the same paced atrial heart rate to compare this final angiogram to the basal and the electrically induced postextrasystolic initial beats. During the 1-month period of the study none of these subjects had complications such as recurrent chest pain, heart failure or rhythm disturbances, and no drug administration was necessary. Comparing the basal cycle of the initial angiogram and the final cycle, a poor correlation was found between the corresponding values of EF (r = 0.34), %HK (r = 0.38) and %AK (r = 0.48). The correlations were much better when a comparison was made between the postextrasystolic cycle of the initial angiogram and the final cycle (EF, r = 0.84; %HK, r = 0.96; %AK, r = 0.95). These results indicate that, from the first day after a TMI, the analysis of the postextrasystolic frame allows accurate estimation of the final left ventricular function and regional wall motion abnormalities. Postextrasystolic potentiation may be useful in the acute state of transmural infarction to discriminate potentially reversible ischemic from definitely jeopardized areas.

Acute Disease↗
PubMedDate not supplied

Effect of antihypertensive treatment on lipids and fibrinogen: Greek multicentre study of cilazapril.

The effect cilazapril (CLZ) treatment on serum lipids and fibrinogen was studied in 114 hypertensive patients for 18 weeks. Blood pressure, heart rate, lipid profile and fibrinogen were measured before and at the end of the study in all patients. Satisfactory blood pressure control was seen in 68% of the patients (group A) after 4 weeks of treatment with 5 mg CLZ monotherapy, while a single dose of chlorthalidone, 25 mg daily, was added to the therapeutic regimen of the remaining 32% of patients (group B) to achieve blood pressure control. We conclude that CLZ has a slight beneficial effect on the lipid profile and a significantly beneficial effect on fibrinogen, but its combination with a diuretic reverses this beneficial effect.

Antihypertensive Agents↗