PubMed Health⌕ Search

Biomedical subjects

I DuBrow

Publications and source records attributed to I DuBrow.

7 recordsLinked to original sources
PubMed1984

Etiology of atrioventricular-conduction abnormalities following cardiac surgery.

Atrioventricular-nodal-conduction abnormalities following cardiac surgery have been attributed to the potassium ion in cardioplegic solutions. To clarify the etiology of these rhythm problems, 15 dogs were subjected to (I) 60 min 4 degrees C potassium cardioplegic arrest; (II) 30 min normothermic ischemic arrest; or (III) cardiac hypothermia without ischemia. In sinus rhythm and during atrial pacing, A-H and H-V intervals, Wenckebach cycle length (WCL), atrial- and AV-nodal refractory periods (ARP and NRP) were measured at 37 degrees C before and 30 min after arrest (groups I and II) and at various myocardial temperatures (group III). Following cardioplegic arrest and reperfusion, all AV-nodal-conduction properties were unchanged from preischemic values. In contrast, unprotected ischemia significantly prolonged AV-nodal-conduction time (P less than 0.01) and myocardial hypothermia resulted in prolonged WCL (P less than 0.01), prolonged functional NRP (P less than 0.05), in addition to delayed A-H interval (P less than 0.05). The data suggest that properties of AV-nodal conduction are preserved following potassium cardioplegic arrest, but impaired by ischemic injury or persistent local cardiac hypothermia.

Animals↗
PubMed1983

Efficacy of pulmonary artery banding in infants with complete atrioventricular canal.

Total correction in infants less than 1 year old with complete atrioventricular (AV) canal carries a significant operative mortality. However, past reports suggest that the alternative palliative procedure, pulmonary artery banding (PAB), may be contraindicated in the presence of severe mitral insufficiency and/or a large left ventricular to right atrial shunt. Contrary to these previous reports, we report the results in 21 consecutive patients with congestive heart failure who underwent PAB at a mean age of 3.9 +/- 2.8 months and at a weight of 3.6 +/- 0.9 kg. (17/21 less than 6 months). Regardless of mitral valve competency, PAB was performed in conjunction with ligation of a patent ductus arteriosus (11 patients) and coarctation repair (two patients) with one death secondary to gastrointestinal bleeding (4.7% in-hospital mortality); one patient required early band readjustment because of hypoxemia. Repeat cardiac catheterization in 10 patients performed 4 to 41 months after PAB showed significant reduction in pulmonary hypertension and flow with no change in pulmonary vascular resistance. All infants were symptomatically improved after PAB and four have undergone successful total correction. Previous reports since 1977 indicate a significantly higher risk for total repair of complete A V canal before 1 year of age (36/147, 24%) than the risk for PAB in this series (p less than .05). Therefore, we believe that PAB is a rational alternative to total repair as the initial surgical treatment for symptomatic infants with complete A V canal, particularly when anatomic variants known to increase operative risk are recognized before cardiotomy.

Cardiac Catheterization↗
PubMed1982

The conduction system in Pompe's disease.

We report our findings in the microscopic examination of the conduction system in four infants with glycogen storage disease, one of whom had adequate electrophysiologic studies. The electrophysiologic studies in the latter case showed P-A and A-H intervals at the lower limits of normal, but the H-V interval was just above the normal mean. This suggests that the rapid conduction was not localized in the anatomic counterpart of the H-V interval. The short P-R interval in the ECG may be related to the enlargement of cells, which may in turn be related to increased glycogen content. The relationship of glycogen per se to the speed of conduction is unknown. We found that the summit of the ventricular septum bulged, probably because of the generally increased cell size, and that the topography of the atrioventricular conducting system was different from normal. This is possibly related both to an increase in the cell sizes of the specialized conducting tissue itself and to deforming effects of this bulging summit of the ventricular septum. New microscopic details of the components of the conducting system are described in these cases.

Cardiomegaly↗
PubMed1977

A new prenatal cardiac diagnostic device for congenital heart disease.

A unique case of congenital heart disease and complete heart block diagnosed by fetal electrocardiogram (ECG) and phonocardiogram recorded initially at 32 weeks gestation is presented. The slow, regular fetal heart rate of approximately 50 beats/min with bizarre QRS and a diamond-shaped murmur beginning with the fetal QRS complex made a diagnosis of complete heart block (CHB) and associated congenital heart disease highly probable. Direct fetal electrocardiograms (FECG) recorded during labor and vaginal delivery at term confirmed the diagnosis of completel atrioventricular block. Cardiac catheterization at 1 day of age showed multiple congenital heart anomalies. The infant developed signs of congestive heart failure and transvenous pacemaker was successfully placed; however, he died at 9 days of age of sepsis and renal failure.

Adult↗