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Biomedical subjects

A Garson

Publications and source records attributed to A Garson.

At least 145 records · Page 8Linked to original sources
PubMed1987

Pathologic features of myocardial hamartomas causing childhood tachyarrhythmias.

We have observed in 11 infants, aged 2 years or less, a distinct clinicopathologic lesion responsible for tachyarrhythmias that were fatal in 96% (25/26) of previously reported cases. Nine of the 11 patients, who underwent electrophysiologic mapping and surgical excision of the lesion, have survived, with follow-up periods ranging from 1 month to 6 years. The morphologic findings in these 11 patients and in the 26 cases cited in the literature are reviewed. Pathogenic considerations have included viral-induced lesion, cardiomyopathy, neoplasm, and developmental disorder of Purkinje cells. We believe this lesion to be a myocardial hamartoma. Supportive evidence includes prevalence in infants, tumorlike growth pattern without mitotic figures, and association of other developmental abnormalities. Through electrophysiologic mapping, this myocardial hamartoma is potentially accessible to surgical excision and long-term cure.

Child, Preschool↗
PubMed1987

Medicolegal problems in the management of cardiac arrhythmias in children.

Malpractice actions against pediatricians treating patients with arrhythmias have been recurrent in four general areas. Optimal medical management may not be widely recognized. Cases illustrating the following concepts are presented. Intravenous verapamil therapy in babies may cause apnea, hypotension, and bradycardia; continued episodes of atrial flutter in a child may cause sudden death; quinidine may be related to the death; children with "familial seizure disorders" may in fact have the long QT interval syndrome. The QT interval must be measured on the ECG in patients with unexplained seizures; "supraventricular tachycardia with aberration" is uncommon in children. Rapid heart rates with QRS complexes that are different from the sinus complexes are likely to be ventricular tachycardia. These situations must be recognized as potential problems and must be treated appropriately.

Arrhythmias, Cardiac↗
PubMed1986

Encainide for refractory supraventricular tachycardia in children.

Fifteen children, aged 5 days to 19 years (mean 4.7 years), with medically refractory supraventricular tachycardia were given oral encainide. In 10 of 15 children with "incessant" tachycardia (greater than 10% of the day), encainide alone controlled supraventricular tachycardia in 5 children; in combination with other antiarrhythmic agents, it partially controlled supraventricular tachycardia in 4 and was ineffective in 1. In 5 children with accessory atrioventricular connections, encainide eliminated supraventricular tachycardia in 3 and was ineffective in 2. Therapeutic encainide dosages ranged from 60 to 120 mg/m2/day (mean 90) (2.0 to 5.7 mg/kg/day). Encainide caused prolongation of the PR interval by 35%, RP interval by 17%, QRS interval by 44% and corrected QT interval by 10%. In 5 children with depressed left ventricular function administration of encainide, by controlling the arrhythmia, increased echocardiographic left ventricular shortening fraction from a mean of 24% to a mean of 36%. Three patients developed excessive QRS aberrancy, which was associated with wide QRS tachycardia in 2. No adverse reactions were noted in the absence of QRS aberration. Side effects were minor and noted in only 1 of 9 patients continuing to take the drug in 9 months of follow-up. Encainide was effective, or partially effective, in the control of resistant or incessant supraventricular tachycardia in 80% of children treated. Encainide allowed rapid resolution of arrhythmia-induced cardiomyopathy by controlling chronic supraventricular tachycardia.

Adolescent↗
PubMed1986

Transcatheter ablative techniques for treatment of the permanent form of junctional reciprocating tachycardia in young patients.

Five patients with medically refractory incessant supraventricular tachycardia due to a posterior septal, slowly conducting accessory connection underwent transcatheter closed chest ablative treatment. The tachycardia characteristics were consistent with the permanent form of junctional reciprocating tachycardia. In each patient the ablative attempts resulted in independent interruption of either the anterograde limb (atrioventricular node-His bundle conduction) or the retrograde limb (accessory connection) of the tachycardia circuit. Permanent retrograde pathway ablation was achieved in only one patient and followed separate permanent transcatheter His bundle ablation. In three of the other four patients the ablation attempt caused temporary interruption of retrograde conduction. Each patient had improved control of tachycardia related to the ablation attempt. Of the five patients, four required pacemaker implantation. With further refinements, selective ablation of the retrograde limb of the tachycardia circuit may be possible. This experience confirms the anatomic independence of the anterograde and retrograde limbs of the tachycardia circuit.

Adult↗
PubMed1986

Doppler echocardiography in the diagnosis and management of persistent fetal arrhythmias.

Thirteen fetuses with persistent arrhythmias underwent combined noninvasive echocardiographic evaluation utilizing M-mode, two-dimensional and pulsed Doppler echocardiography. This group (Group A) was compared with 14 fetuses in which only two-dimensional and M-mode echocardiographic evaluations were performed (Group B). In both groups correct prenatal interpretation of the arrhythmia was confirmed by postnatal electrocardiograms in all surviving fetuses. Although Doppler echocardiography was not more sensitive than M-mode echocardiography in the interpretations of the arrhythmia, Doppler tracings of sufficient quality to analyze rate and rhythm were easier to obtain in all cases and provided additional information about valvular incompetence and the functional state of the fetal heart. Cardiac malformations and hydrops fetalis were commonly associated with persistent arrhythmias. Congenital heart disease occurred frequently (6 of 11) with complete atrioventricular (AV) block. Pulsed Doppler echocardiography defined the AV contraction sequence, atrial and ventricular rates and AV valve insufficiency, allowing rapid interpretation of fetal arrhythmias.

Arrhythmias, Cardiac↗
PubMed1986

Fetal ventricular pacing for hydrops secondary to complete atrioventricular block.

The advent of ultrasound recording has expanded the capabilities for treatment of the fetus in utero. The diagnosis of specific disease processes has allowed for prenatal intervention by new techniques designed to improve fetal survival. The application of ventricular pacing in a hydropic fetus with complete atrioventricular (AV) block is reported. Complete AV block resulted from maternal collagen vascular disease. The application of ventricular pacing was to allow for further in utero development and for reversal of hydrops fetalis after improvement in cardiac output. Despite fetal death 4 hours after placement of the ventricular pacing lead, this procedure when applied earlier in the development of hydrops may allow for fetal survival. Ventricular pacing was accomplished without apparent trauma to mother or fetus and no evidence of fetal injury was seen at necropsy. Therefore, in the fetus who would otherwise die in utero before the point of viability ex utero, fetal ventricular pacing may be a rational alternative to current observation.

Adult↗
PubMed1986

Invasive electrophysiologic studies in children.

Although the technique of performing invasive electrophysiologic studies is similar in children and adults, the indications, interpretation, and management based on the studies are different. The major indications in children are determination of the specific diagnosis of an unknown arrhythmia and mapping prior to surgical treatment; chronic drug studies are performed for severely symptomatic patients, but technical considerations in the child limit the routine use of repeated drug trials. The greatest potential indication for invasive studies is in prognostication of symptomatic arrhythmias; this has not been possible in sinus node dysfunction and AV block, and the role in ventricular arrhythmias is under investigation. In the area of therapeutics, although drugs may have a similar effect in adults and children, the mechanism for the underlying arrhythmias may differ. The ventricular arrhythmias after congenital heart disease may have as their underlying cause the hypertrophic ventricle, not the pediatric substrate. Thus, some of the investigations originally performed in children eventually may contribute to a better understanding of arrhythmias in patients of all ages.

Arrhythmias, Cardiac↗
PubMed1985

Exercise testing in children with Wolff-Parkinson-White syndrome.

Exercise testing using a modified Bruce treadmill protocol was performed by 17 children with Wolff-Parkinson-White (WPW) syndrome. All had intracardiac electrophysiology studies as well. Endurance time, heart rate and blood pressure were normal during exercise. Ventricular premature complexes were seen with exercise in 2 patients and supraventricular tachycardia with exercise testing was seen in 2. Disappearance of the delta wave with exercise correlated with a long anterograde effective refractory period of the Kent bundle (360 to 390 ms). Children with partial normalization of the QRS during exercise had a longer anterograde effective refractory period of the Kent bundle than those in whom preexcitation persisted. In 1 patient, disappearance of the delta wave with exercise confirmed the diagnosis of WPW syndrome. Preexcitation was seen only after exercise in 1 patient. Exercise testing is of value in the evaluation of children with WPW syndrome; children with WPW syndrome who have total normalization of the QRS interval during exercise and few or no symptoms of tachycardia do not require electrophysiologic study.

Adolescent↗
PubMed1985

Chronic supraventricular tachycardia. A curable cause of congestive cardiomyopathy.

Two cases of congestive cardiomyopathy were proved to be due to chronic atrial automatic-focus tachycardia. Surgical elimination of the tachycardia resulted in normalization of cardiac function in both cases. We suggest that patients with congestive cardiomyopathy be carefully screened for supraventricular tachycardia. Patients with chronic supraventricular tachycardia should be treated aggressively to prevent myocardial dysfunction.

Cardiomyopathy, Dilated↗
PubMed1985

Surgical management of refractory supraventricular tachycardia in infants and children.

Sixty-seven children underwent attempted surgical correction of refractory supraventricular arrhythmias using a combination of intraoperative electrophysiologic mapping followed by surgical division or cryoablation of an aberrant conduction pathway or atrial ectopic focus. The patients ranged in age from 4 months to 18 years (mean 11.4 years). Fifty-five patients (82%) had an abnormal conduction pathway crossing the atrioventricular junction (Kent bundle). Thirty-six (65%) of these 55 patients had classic Wolff-Parkinson-White syndrome with a delta wave of pre-excitation on the surface electrocardiogram. Nineteen (35%), however, demonstrated only retrograde conduction across the Kent bundle and had a normal surface electrocardiogram when tachycardia was not present. Kent bundles were isolated to the following locations: right anterior or lateral in 19 (34.5%), left posterior or lateral in 22 (40%), posteroseptal in 10 (18%), anteroseptal in 2 (4%) and both right and left in 2 (4%). Follow-up evaluation of as long as 8 years (mean 34.9 months) has shown seven immediate failures and one late recurrence of arrhythmia (14.5%). Recent refinements in technique and the use of cryoablation for septal aberrant pathways have improved these results. There have been two failures (8%) in the last 25 attempts. Twelve patients underwent surgery for an atrial ectopic focus by the following techniques: cryoablation in seven patients, excision in one patient and both excision and cryoablation in four patients. At a mean follow-up of 16.6 months, there was one late recurrence in the group with an atrial ectopic focus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Wolff-Parkinson-White syndrome and supraventricular tachycardia during infancy: management and follow-up.

The records of 90 patients with Wolff-Parkinson-White syndrome who presented with supraventricular tachycardia in the first 4 months of life were reviewed. Among these, 63% were male. Structural heart disease was present in 20%, most commonly Ebstein's anomaly. All patients presented with a regular narrow QRS tachycardia, and pre-excitation became evident only when normal sinus rhythm was established. Only one infant had atrial flutter and none had atrial fibrillation. Type A Wolff-Parkinson-White syndrome was most common (49%), with heart disease occurring in only 5% of these patients. In contrast, heart disease was identified in 45% of those with type B syndrome. Initially, normal sinus rhythm was achieved in 88% of the 66 infants treated with digoxin with no deaths. Normal sinus rhythm resumed after electrical countershock in 87% of the 15 infants so treated. Maintenance digoxin therapy was used in 85 patients. The Wolff-Parkinson-White pattern disappeared in 36% of the patients. Four infants died of cardiac causes during the mean follow-up period of 6.5 years. Two of these four infants had congenital heart disease; the third, with a normal heart initially, developed ventricular fibrillation and died from a cardiomyopathy considered related to resuscitation. The remaining infant, with a normal heart, died suddenly at 1 month of age. All were receiving digoxin. A wide QRS tachycardia later appeared in three patients, all with heart disease, one of whom died.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1985

Treatment of atrial automatic tachycardia by ablation procedures.

Sixteen cases of atrial focus tachycardia are described clinically, electrophysiologically and hemodynamically. In each case multiple attempts at drug treatment (average 2.5 drugs) had failed. After delineation of the electrophysiologic mechanism, the patients were treated by surgical removal or cryoablation or catheter electroablation of the focus. In two of four patients catheter ablation was successful and without complication. Surgical treatment was successful in 13 of 14 patients. Left ventricular function, which had been abnormal in 10 patients, normalized in all but 1 patient whose echocardiographic shortening fraction improved from 10 to 27%. There have been no recurrences in a follow-up period of 6 months to 5 years (mean 2.2 years). It is recommended that any atrial automatic focus tachycardia that produces hemodynamic compromise undergo definitive treatment. Patients with chronic tachycardia rates of more than 140 beats/min should be followed up closely.

Adolescent↗
PubMed1985

Prevention of sudden death after repair of tetralogy of Fallot: treatment of ventricular arrhythmias.

The majority of sudden deaths after repair of tetralogy of Fallot have been presumed to be due to ventricular arrhythmia; however, it remains to be demonstrated that antiarrhythmic medication reduces the incidence of sudden death. Since 1978, ventricular arrhythmias have been treated aggressively; these include any ventricular arrhythmia on routine electrocardiogram and more than 10 uniform premature ventricular complexes per hour on 24 hour electrocardiogram. A review was undertaken of 488 patients followed up for more than 1 month after repair of tetralogy of Fallot (mean follow-up time 6.1 years); 13.5% had ventricular arrhythmia on routine electrocardiogram. Ventricular arrhythmia appeared from 2 months to 21 years postoperatively (mean 7.3 years). Ventricular arrhythmias were significantly (p less than 0.01) related to: longer follow-up duration, older age at follow-up, older age at operation and higher postoperative right ventricular systolic and end-diastolic pressures. Ventricular arrhythmia on routine electrocardiogram occurred in 100% of those who later died suddenly compared with 12% of those who did not die (p less than 0.01). Treatment for ventricular arrhythmia was given to 46 patients and considered "successful" if there were fewer than 10 uniform premature ventricular complexes per hour on 24 hour electrocardiogram. A successful drug was found in 44 of the 46: 30 of 34 given phenytoin, 6 of 9 given propranolol, 1 of 7 given quinidine, 1 of 2 given disopyramide, 8 of 9 given mexiletine and 4 of 5 given amiodarone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗