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Biomedical subjects

E G Abinader

Publications and source records attributed to E G Abinader.

At least 19 recordsLinked to original sources
PubMed1992

Doppler measurement of left ventricular isovolumic intervals: a study of feasibility and correlation with conventional techniques.

Pulsed Doppler echocardiography allows simultaneous recording of left ventricular inflow and outflow blood velocities obtained from the apical 5-chamber view. In this study the feasibility and accuracy of pulsed Doppler measurements of left ventricular isovolumic relaxation and contraction times were compared with those derived from two conventional techniques that combined phonocardiograms and M-mode echograms (phono-echo) and M-mode echograms and electrocardiograms (ECG-echo). Thirty-seven subjects--24 healthy volunteers and 13 cardiac patients--were examined. Isovolumic relaxation was consistently longer than isovolumic contraction time. Younger age was associated with shorter isovolumic intervals, while heart rate had a negative correlation with these parameters (r = -0.5). Pulsed Doppler measurements of isovolumic relaxation correlated well with phono-echo, r = 0.89, and ECG-echo, r = 0.75. Isovolumic contraction times measured by Doppler correlated better with those derived by phono-echo, r = 0.75, than those by ECG-echo, r = 0.4. Better correlations were found for both measurements in the normal subgroup than in the whole group. Difficulty was encountered in measuring isovolumic contraction time by Doppler and ECG-echo in the absence of presystolic A-wave, and in subjects with varying cardiac cycle lengths. Thus, pulsed Doppler measurements of left ventricular isovolumic relaxation times were feasible and consistent with the other methods, while isovolumic contraction intervals by Doppler were not.

Adolescent↗
PubMed1989

Doppler assessment of the effects of isometric stress on left ventricular filling in hypertensive young adults.

Doppler interrogation at the in-flow of the left ventricle was used to test the effects of isometric stress on ventricular filling in 7 hypertensive subjects with mild to moderate left ventricular hypertrophy, aged forty-two +/- seven years, compared with 9 matched healthy control males. In the hypertensive patients at rest, peak early diastolic (E) velocity was lower, and atrial (A) velocity higher, with lower E/A peak velocity ratios than in normals (p less than 0.05). These differences were more accentuated during isometric stress. Atrial filling fractions were higher in hypertensives (37 +/- 6%) than in normals (24 +/- 7%) at rest, p less than 0.05, and this difference increased during isometric stress (44 +/- 9% versus 30 +/- 11%). Thus, isometric stress accentuated the reliance of left ventricular filling on atrial contribution and may be applied for the detection of early ventricular filling abnormalities in patients with mild hypertension. The systolic blood pressure and the hypertrophic process were both important determinants of left ventricular diastolic filling.

Adult↗
PubMed1988

Corticosteroids in the management of sinoatrial block.

This report presented our experience in the treatment of sinoatrial (S-A) conduction disturbances with corticosteroids. Three patients with intermittent second-degree S-A block who failed to respond to atropine and isoproterenol were treated with prednisone for 6-17 weeks. Sustained improvement in S-A conduction following prednisone administration was confirmed by repeated Holter monitoring on and off therapy. Two patients eventually regained permanent sinus rhythm, while therapy led to marked diminution in S-A block in the 3rd patient. The possible mechanisms by which steroids may improve S-A conduction are discussed. Our observation is based on a small case series, each patient serving as his own control, and as such constitutes an indication for further confirmatory studies.

Atropine↗
PubMed1988

Aging and the effect of increased after-load on left ventricular contractile state.

Hemodynamic and contractile states were studied echocardiographically in 10 young (28 +/- 3 yr) and 10 elderly (67 +/- 4 yr) male subjects at rest and during upright isometric exercise which involved the hands, hips, legs, and lower back muscle groups (deadlift) at 30% of maximum voluntary contraction for 3 min. During deadlift, both groups showed similar and significant increases in blood pressure and heart rate, compared to the resting values. Ejection fraction at rest did not differ significantly between the two groups. During deadlift, it remained unchanged in the elderly white ejection fraction increased significantly in the younger subjects. No significant changes in left ventricular end-diastolic volume occurred in either group during deadlift. End-systolic volume remained unchanged in the elderly while it decreased significantly in the younger subjects. These data indicate that cardiovascular responses and contractile state in normal young men and normal exercise-trained elderly subjects were augmented during upright sub-maximal isometric deadlift exercise, utilizing large muscle mass. However, left ventricular contractility increased less in the elderly subjects compared to the younger subjects.

Adult↗
PubMed1988

Fetal arrhythmia associated with sinus node dysfunction--a case report.

Real time and M-mode echocardiography were used for evaluation of fetal bradycardia. Sinus bradycardia was revealed without structural abnormalities. An abdominal wall derived fetal electrocardiogram and the failure of the sinus rate to increase in response to maternal exercise or I.V. atropine suggested sinus node dysfunction. Postnatal evaluation revealed sinus bradycardia with blunted response to I.V. atropine and an abnormal sinus node recovery time. A gradual increase in heart rate was demonstrated in the neonatal period, possibly due to decrease in vagal tone.

Adult↗
PubMed1987

Quantification of atrial contribution to left ventricular filling by pulsed Doppler echocardiography and the effect of age in normal and diseased hearts.

Atrial filling fraction, or the fraction of stroke volume resulting from atrial contraction, was measured by Doppler echocardiography from the time-velocity integral of mitral anulus inflow with a method that allows separation of conduit or passive flow from flow resulting from the atrial contraction. The method was validated in 17 patients with externally programmable ventricular demand pacemakers by showing that the time-velocity integral of passive flow (excluding the A wave) during sinus or sequential atrioventricular pacing was almost identical to the time-velocity integral during ventricular pacing. Atrial filling fractions were then measured in 41 normal subjects, aged 20 to 80 years; 28 patients with echocardiographic evidence of concentric left ventricular hypertrophy; 24 with dilated cardiomyopathy (13 of whom had an ischemic origin); and 19 with acute myocardial infarction. Atrial filling fraction increased significantly with age in normal subjects (r = 0.77; p less than 0.001) and ranged from 12% in a 20-year-old man to 46% in a normal 80-year-old woman. In the hypertrophy group, atrial filling fraction had a weak relation with age (r = 0.47; p = 0.006), and the values were significantly higher than in normal subjects. In patients with cardiomyopathy or infarction, atrial filling fraction varied over a wide range and showed no relation to age. Thus, atrial filling fraction as determined by Doppler echocardiography is significantly altered by both age and left ventricular disease. Age-corrected nomograms are essential when assessing atrial filling fraction in individual patients.

Adult↗
PubMed1987

The usefulness of Doppler echocardiography in the management of rhabdomyoma diagnosed prenatally.

Cardiac rhabdomyoma diagnosed prenatally by cross-sectional echocardiography was confirmed after birth by Doppler echocardiography and cardiac catheterization in a baby with tuberous sclerosis. Doppler echocardiographic follow-up after 2 years revealed regression of tumour masses and concomitant disappearance of pulmonary regurgitation which was caused by the large tumour mass in the right ventricular outflow tract. In spite of a sizeable mass protruding into the left ventricular outflow tract, repeated Doppler examination failed to demonstrate any significant obstruction, thus avoiding repeated catheterizations and unnecessary surgery. Doppler examination of ventricular inflow revealed normal filling characteristics. Doppler and cross-sectional echocardiography was of great value in the management of this patient.

Echocardiography↗