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Biomedical subjects

B Siassi

Publications and source records attributed to B Siassi.

At least 73 records · Page 4Linked to original sources
PubMed1976

Antiarrhythmic effect of hypertonic sodium bicarbonate and sodium chloride in ouabain-induced arrhythmias.

Ouabain-induced tachyarrhythmias in cats can be abolished by bolus injection of NaHCO3 solution. This effect is consistent, rapid and of short duration. The antiarrhythmic effect appears to be due to high sodium concentration of this solution, as hypertonic NaCl solution with equal concentration of sodium exerts the same effect. Alkalinity and hyper-osmolality cannot account for the antiarrhythmic effect of NaHCO3 as respiratory alkalosis and mannitol solution with equal osmolality did not relieve the arrhythmias. Overdrive suppression is not responsible for this effect as the heart rate slows down during normalization of the cardiac rhythm. It is postulated that high Na+ concentration abolished ouabain-induced arrhythmias by competition with calcium ion in the myocardial cell sarcotubular system thus replacing it. This hypothesis is supported by the known effect of other agents such as sodium-EDTA and magnesium chloride, in digitalis-induced arrhythmias, which exert their antiarrhythmic properties by removal or displacement of calcium in the myocardial cells.

Animals↗
PubMed1976

Simplified vectorcardiographic method for assessment of pulmonary arterial pressure in children with chronic rheumatic mitral valve disease.

We previously reported that pulmonary artery pressures can be assessed in children with chronic rheumatic mitral valve disease by measuring right maximum spatial vector from Frank vectorcardiogram. To simplify the calculation, pulmonary artery systolic pressure was correlated with maximum negative deflection on Frank scalar X-lead (SX), maximum negative deflection on scalar Z lead (SZ), sum total of SX and SZ (SX+SZ) and combined SX and SZ. The patient material consisted of 30 children with chronic rheumatic mitral valve disease, aged 8-14 1/2 years. Eleven were male and 19 were female. Sixteen had mitral stenosis, 8 had mitral regurgitation, and 6 had combined mitral regurgitation and stenosis, documented by cardiac catheterization and angiocardiographic study. The results showed a significant correlation between pulmonary artery systolic pressure and SX (r=0.782). As calculation of SX is considerably easier and less time consuming than that of right maximum spatial vector, this simplified method is preferable to right maximum spatial vector for prediction of the pulmonary artery systolic pressure of children with pulmonary hypertension due to chronic rheumatic mitral valve disease.

Adolescent↗
PubMed1976

Incidence and clinical features of patent ductus arteriosus in low-birthweight infants: a prospective analysis of 150 consecutively born infants.

The incidence of persistent patency of the ductus arteriosus beyond the third day of life was prospectively determined in 100 preterm infants with birthweights of 2,000 gm or less and 50 infants with birthweights of 2,001 to 2,500 gm. The overall incidence was 21% and was inversely related to increasing gestational age and birthweight. The data suggest that immaturity is the major determinant of the persistent patency of the ductus arteriosus. Spontaneous delayed closure of the ductus occurred in 79% of patients that survived the immediate neonatal period. There was a high degree of association between the presence of a patent ductus arteriosus (PDA) and respiratory distress syndrome (RDS). Eight infants with severe RDS and PDA developed heart failure and four required surgical ligation of the ductus. None of the infants with birthweights greater than 2,000 gm who had PDA developed heart failure or required surgical ligation of the ductus arteriosus.

Birth Weight↗
PubMed1975

Surgical closure of patent ductus arteriosus in the premature infant with respiratory distress.

During the period from February, 1971 to February, 1973, 30 premature infants underwent surgical ligation of patent ductus arteriosus. The gestational ages ranged from 25 to 36 wk (mean 30), and the birth weights ranged from 760 to 2010 g (mean 1274). The patients were divided into two groups on the basis of the indications for assisted ventilation. Group I consisted of 21 patients with severe hylanine membrane disease who required assisted ventilation during the first 2 days of life and could not be weaned off the respiratory by 10 days of age. Group II was composed of nine infants who required intermittent positive-pressure breathing after a mean age of 8 days because of repeated apneic spells secondary to uncontrollable heart failure. All infants in Group II survived the operation and left the hospital well. Fourteen of the 21 patients in Group I survived; the seven deaths were all due to underlying severe pulmonary disease (bronchopulmonary dysplasia). The value of PDA ligation in premature infants with uncontrollable heart failure is demonstrated in this study; this procedure also appears to be beneficial in neonates with severe respiratory distress syndrome.

Aortography↗
PubMed1974

Direct monitoring of arterial blood pressure in depressed and normal newborn infants during the first hour of life.

Direct systolic, diastolic, and mean arterial blood pressure was continuously recorded during the first 64 min of life in 150 newborn infants. The data were analyzed at 4, 8, 16, 32, and 64 min. The highest blood pressure values were noted during the first few minutes of life in all newborn infants, with a rapid drop within 4 to 8 min. Decline in blood pressure was more gradual throughout the remainder of the observation period. Blood pressures of depressed newborn infants at birth (Apgar scores 6 or less at 1 and 5 min) were compared to those of normal newborn infants (Apgar scores 7 or greater at 1 and 5 min). The former demonstrated generally higher systolic pressures during the first 16 min and diastolic pressures at 4 min when infants were compared by their 1 min Apgar scores and higher diastolic pressures at 4 min when the infants were compared by their 5 min Apgar scores.

Acid-Base Equilibrium↗
PubMedDate not supplied

Use of femur length as a means of assessing M-mode ventricular dimensions during second and third trimesters of pregnancy in normal fetus.

Eighty-two normal fetuses were scanned from 18 to 41 weeks of gestation. The following M-mode measurements were correlated with the femur length: end-diastolic right ventricular (r = 0.93), left ventricular (r = 0.92), biventricular outer (r = 0.94), and biventricular inner (r = 0.94) dimensions; tricuspid (r = 0.93) and mitral (r = 0.92) valve opening excursion; right (r = 0.76) and left (r = 0.70) ventricular wall thickness; and interventricular septal thickness (r = 0.75). Polynomial regression demonstrated that linear regression best described the data from which the mean and 5% and 95% confidence limits for predicted M-mode measurements were computed for the femur length.

Diastole↗