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Biomedical subjects

A Garson

Publications and source records attributed to A Garson.

At least 199 records · Page 11Linked to original sources
PubMed1980

Surgical treatment of supraventricular tachycardia in infants and children.

The technique, indications and results of surgical division of accessory atrioventricular connections in 10 infants and children with drug-resistant supraventricular tachycardia are described. The patients ranged in age from 6 months to 15 years. Four patients had associated congenital heart disease. Division of accessory connections were performed on free wall pathways in nine patients (seven right atrial, two left atrial) and on a septal pathway in one patient. Four patients had both anterograde and retrograde conduction over the accessory connection (manifest Wolff-Parkinson-White conduction) whereas six had only retrograde conduction (concealed Wolff-Parkinson-White conduction). The manifst Wolff-Parkinson-White conduction was abolished by surgical division in all four patients. In 8 of the 10 patients the procedure stopped the attacks of paroxysmal supraventricular tachycardia for follow-up periods ranging from 9 months to 3 1/2 years; no patient receives medication to date.

Adolescent↗
PubMed1980

Mechanisms of cardiac arrhythmias after the Mustard operation for transposition of the great arteries.

To determine the mechanisms of the cardiac arrhythmias frequently seen after the Mustard operation for transposition of the great arteries, intracardiac electrophysiologic studies were performed in 52 children 1 to 8 years after the Mustard operation. Sinus nodal automaticity as judged from the response to rapid atrial pacing was abnormal in 28 of the 52 children. Sinoatrial conduction (conduction of the sinus impulse to the atrium) was found to be abnormal in three of nine patients studied with the atrial extrastimulus method. Conduction of the sinus impulse from the high right atrium to the atrioventricular (A-V) node was abnormally delayed in only 2 of 41 subjects. The low lateral wall of the right atrium was depolarized late in 3 of 11 subjects (including the preceding 2). Two subjects showed delayed A-V nodal conduction and one delayed His-Purkinje conduction. The mechanism of supraventricular tachycardia induced in the laboratory was determined to be sinoatrial nodal reentry in four subjects and atrial muscle reentry in four. Two of the four with atrial muscle reentry had prolonged high right atrium to low lateral right atrium intervals during sinus rhythm. Thus, damage to the sinus node remains the most common cause of arrhythmias after the Mustard operation. In addition, delayed atrial conduction may predispose to atrial muscle reentrant tachycardia.

Adolescent↗
PubMed1980

Automated on-line measurement of electrophysiologic intervals during cardiac catheterization.

A small dedicated, computer-controlled waveform analyzer was used to automatically measure the R-R cycle length, low right atrium to His, and His to ventricle intervals obtained during electrophysiologic studies on 35 patients. These measurements were compared to intervals hand-measured separately and found to correlate well (0.92, 0.83, and 0.75, respectively). The sources of error, possible pitfalls, and future uses of this technique are discussed.

Adolescent↗
PubMed1980

Effect of chemical sympathectomy on myocardial cell division in the newborn rat.

Myocardial chemical sympathectomy was achieved by daily SC injection of 100 micrograms/g body weight of 6-OH-dopamine to each of 239 Holtzman newborn rat pups for the first seven days of life. Effective sympathectomy was verified by identifying a decrease in ventricular myocardial norepinephrine concentrations to 31% +/- 12 S.E. of control at 20 days of age. Activity of DNA polymerase was used to indicate the extent of myocardial cell division. Beginning at eight days of age, DNA polymerase activity was increased in the sympathectomized pups relative to control. The DNA polymerase activity was highest relative to control at 16 days (235% +/- 31 S.E.) and remained elevated beyond 20 days (188% +/- 30 of control). The DNA polymerase data was analyzed by covariance and was significantly greater in the 6-OH-dopamine rat pups (P < 0.001).

Animals↗
PubMed1980

Postoperative pericardial effusion and its relation to postpericardiotomy syndrome.

Postpericardiotomy syndrome often delays recovery from cardiac operation. Pericardial effusion is an important sequela of postpericardiotomy syndrome. To define the relationship between postpericardiotomy syndrome and pericardial effusion, we performed four to seven serial echocardiograms (echoes) between postoperative day 0 and postoperative day 10 in 40 children who had operation requiring pericardiotomy. We also performed daily physical examination on each patient for clinical evidence of postpericardiotomy syndrome. Echocardiographic signs of pericardial effusion developed in 21/40 patients (53%). The effusion was present by postoperative day 5 in 19/21 patients. Clinical signs of postpericardiotomy syndrome occurred in 18/40 patients (45%). Among the 18 patients with postpericardiotomy syndrome, 16 had echocardiographic evidence of pericardial effusion. Thus the sensitivity of the echocardiogram was 89%. The pericardial effusion always developed prior to and persisted through clinical symptoms. We conclude that (1) pericardial effusion is present in over 50% of the patients following cardiac surgery, (2) it develops early in the postoperative period, and (3) once present, the effusion is persistent and frequently followed by clinical evidence of postpericardiotomy syndrome.

Adolescent↗
PubMed1979

Prognosis for the newborn with transposition of the great arteries.

To determine the prognosis for the newborn with transposition of the great arteries, the clinical course of 112 consecutive neonates with dextrotransposition was reviewed. Patients were managed with balloon atrial septostomy at initial cardiac catheterization, palliative operation if needed in the 1st year of life and Mustard's intraatrial baffle repair. The 1st month of life was the period of greatest risk (8 percent mortality rate). Between balloon septostomy and baffle repair, 14 of 103 patients at risk (14 percent) either died or had a cerebrovascular accident. The mortality rate at baffle repair was 14 percent (10 deaths in 71 patients), and there were 3 late postoperative deaths. Actuarial analysis of the data indicates that with this plan of management, approximately 50 percent of newborns with transposition of the great arteries will survive 5 years with excellent function and an additional 15 to 20 percent will survive with one or more medical handicaps.

Cardiac Catheterization↗
PubMed1979

Electrophysiologic effect of digitalis on sinoatrial nodal function in children.

Despite the prevalence of digitalis usage in children, the electrophysiologic effects of digitalis on sinoatrial (S-A) nodal function is unknown in this age group. The purpose of this study was to determine the effect of digitalis on sinoatrial conduction time as well as on S-A nodal automatically. Ten subjects (mean age 10.5 years) underwent electrophysiologic assessment of S-A nodal function before and 30 minutes after administration of ouabain (0.01 mg/kg). Total S-A conduction time increased in each subject and the mean value after ouabain (182 msec +/- 13 standard errors of the mean [SEM]) was significantly higher (P less than 0.01) than before (149 msec +/- 11). The sinus cycle length was variable after ouabain (P greater than 0.1). The corrected sinus nodal recovery time also was variable (P greater than 0.1), decreasing substantially in three subjects. Mechanisms of the effect of digitalis on the S-A node and atrium are proposed and discussed. It is concluded that digitalis prolongs the S-A conduction time in children with normal S-A nodal function. By prolonging the S-A conduction time, digitalis may artifactually shorten corrected S-A nodal recovery time in some patients.

Adolescent↗
PubMed1979

Wolff-Parkinson-White syndrome in children: electrophysiologic and pharmacologic characteristics.

Intracardiac electrophysiologic studies were performed on 28 infants and children, ages 1 month to 18 years, with the Wolff-Parkinson-White syndrome to try to determine 1) the electrophysiologic characteristics of the accessory connection and 2) the mechanisms of associated supraventricular dysrhythmias. Although the antegrade refractory periods of the normal conduction system were shorter than those found in adults, those of the accessory connection were slightly longer. Reciprocating supraventricular tachycardia (SVT), which had been a clinical problem in 26 of 28, could be induced in the laboratory in all 26 subjects. The mechanism involved reentry with antegrade conduction through the atrioventricular (AV) node and retrograde through the accessory connection in 22. Eleven of these 22 had a wide QRS during tachycardia due to a bundle branch block. Three other subjects had wide QRS tachycardia, but the mechanism involved antegrade conduction through the accessory connection and retrograde through the AV node. The other patient had AV node reentry tachycardia. Two patients did not have clinical SVT, and in these two, SVT could not be induced. Neither patient had retrograde conduction through the accessory connection. The site of the accessory connection could be identified in 26 subjects by the sequence of retrograde activation of the atrium during SVT or ventricular pacing. Digitalis shortened the refractory period of the accessory connection in five of the eight patients studied.

Adolescent↗
PubMed1978

Parental reactions to children with congenital heart disease.

Informal discussions with 260 families of children with congenital heart disease are reported. Parents raised questions concerning etiology, timing of the diagnosis, pathophysiology and symptomatology, and need for restriction. Depending upon the stage and seriousness of the disease, common parental behavior was observed. A psychological process similar to mourning is required at the time of diagnosis and at the time of corrective surgery in order to promote the family's adaptation to the child with congenital heart disease. Management suggestions are included.

Adaptation, Psychological↗
PubMed1978

Premature ventricular contractions in normal children.

To document the assumed benign prognosis of premature ventricular contractions in children, we followed 17 patients with PVCs and without other heart disease for a mean of seven years (range one to 19 years). Data were collected from the history, physical examination, 15-lead ECG, and treadmill exercise test. Eight of the 17 children still had PVCs at the most recent follow-up. Of these eight children, seven were asymptomatic. The physical examination remained normal in all except one, who developed signs of mitral prolapse. Light exercise abolished the PVCs in all children. We believe that if a careful clinical examination discloses no abnormalities, and if the PVCs are unifocal and disappear with exercise, this dysrhythmia is, in fact, benign in children, and requires no further cardiovascular examination.

Adolescent↗
PubMed1978

Oral propranolol treatment in infants and children.

To determine the effectiveness of oral propranolol in children, we administered 0.5 to 4.0 mg/kg/day of the drug to 64 children (age one day to 20 years); 41 with cardiac dysrhythmias, six with isiopathic hypertrophic subaortic stenosis, and 17 with paroxysmal hypoxemic spells associated with right ventricular infundibular obstruction. A new liquid form of propranolol (10 mg/ml) was administered to 37 of the younger patients, and tablets were given to the other 27. Propranolol improved the dysrhythmia in 31 of 41 patients, being notably effective in supraventricular tachycardia and ventricular tachycardia associated with a prolonged QT interval. The drug also eliminated symptoms attributed to IHSS in six of six patients and abolished hypoxemic spells in 12 of 17. The liquid and tablets were equally effective; and the liquid had the advantage of allowing for accurate dose changes in younger children. We conclude that oral propranolol is an excellent drug for use in pediatric patients with certain types of cardiac disease.

Adolescent↗