Marion Tipple

Effectiveness of oral sotalol for treatment of pediatric arrhythmias.

Sotalol is a beta blocker with class III activity. Few investigators have reported its use in pediatric patients. From August 1985 to May 1990, 66 patients (mean age 8.7 years; range 9 days to 24 years), including 14 infants aged less than 3 months, were treated with oral sotalol alone (n = 46) or in association with digoxin (n = 20). Supraventricular reentrant tachycardia was present in 38 patients (20 with documented preexcitation), atrial flutter in 10 and atrial ectopic tachycardia in 7. Three patients had other types of supraventricular tachycardia. Tachycardia was of ventricular origin in 6 patients and both of supraventricular and ventricular origin in the remaining 2. Mean dose of oral sotalol was 135 mg/m2/day given in 2 doses. Congenital heart disease was present in 28 patients, 14 with previous cardiac surgery, mostly at the atrial level. Prior treatment with 1 or more antiarrhythmic agent had been unsuccessful in 83% of patients. Mean duration of treatment was 13.3 months (range 2 months to 5 years). Overall, treatment was successful in 79% of cases. Highest rate of success was observed in patients with supraventricular reentrant tachycardia with or without preexcitation (89%) and in those with atrial ectopic tachycardia (85.5%). Atrial flutter could be controlled in 60% of cases. Sotalol seemed less effective in ventricular tachycardia with a complete control of the arrhythmia being achieved in only 17%; however, it decreased the number of runs of ventricular tachycardia and the number of ventricular premature complexes in 50% of patients. There were no adverse effects in 89% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy and Safety of Oral Sotalol in Early Infancy

Sotalol, a nonselective β blocking agent with additional Class III activity has been shown to be extremely elective in the treatment of supraventricular tachycardias in adults and children. Little information is available on its use in infants. From August, 1985 to April, 1990, 18 infants, 2 months of age or less, were treated with oral sotalol for supraventricular arrhythmias. Their age ranged from a few hours to 2 months, mean 5 weeks, at the start of treatment. Weights were between 2.58–5 kg, mean 3.9 kg and dosage 2–4 mg/kg/24 hrs given in two equal doses, 12 hourly. Sixteen infants had structurally normal hearts, one had multiple cardiac rhabdo‐myomas, and one was postoperative Mustard procedure for transpostion of the great arteries. Thirteen of 18 infants had reentrant forms of supraventricular tachycardia, six of these had overt preexcitation. Two infants had chaotic atrial tachycardia, two atrial flutter, and one with ectopic atrial tachycardia. Previous antiarrhythmic therapy had been unsuccessful in 12 patients. All infants, except one with chaotic atrial tachycardia, were successfully controlled with sotalol. Ten infants discontinued therapy between the ages of 7 and 18 months as it was felt to be no longer necessary. Mean duration of treatment was 12.8 months. Three had recurrences of their arrhythmia and were again successfully controlled by sotalol. Mild sinus bradycardia occurred in all infants. No other side effects were noted. Sotalol is an effective, safe drug for the treatment of supraventricular tachycardias in early infancy.

Double-blind placebo-controlled trial of corticosteroids in children with postpericardiotomy syndrome

SummaryThe objective of this study was to assess the efficacy of corticosteroids in hastening the recovery of children with postpericardiotomy syndrome, using a randomized double-blind placebo-controlled trial in a tertiary care referral center for pediatric cardiology and cardiac surgery. Twenty-one children, 6 months of age or older (mean age 3.9 years) with postpericardiotomy syndrome following open or closed heart surgery were administered either prednisone 2 mg/kg/day reducing to zero over 14 days (n=12) or placebo (n=9). Progress was monitored by daily clinical assessment and alternate day cross-sectional echocardiograms. The primary measures of efficacy were the number of patients in remission at 72 h and at 1 week. No difference in remission rates were found at 72 h, but at 1 week significantly more children treated with prednisone were in remission (placebo 3/9; prednisone 10/12,p=0.03). A trend to faster resolution of all symptoms and signs was seen in the prednisone-treated group but this was not associated with earlier hospital discharge. Enlargement of pericardial effusion was seen in two children treated with steroids. No complications of treatment were encountered. Prednisone hastens the recovery of children with postopericardiotomy syndrome. Pericardial effusions may increase in size despite the use of corticosteroids.

Pulmonary Artery Banding: Results and Current Indications in Pediatric Cardiac Surgery

The results of pulmonary artery banding in 144 patients seen from 1971 to 1984 were reviewed. Age ranged from 1 week to 4 years (median, 8 weeks) and weight, from 1.1 to 16 kg (median, 4 kg). The patients were divided into three major groups: Group 1, defects without mixing disorders (ventricular septal defect, double-outlet right ventricle [DORV], atrioventricular septal defect); Group 2, defects with mixing disorders (transposition of the great arteries, DORV, single ventricle, tricuspid atresia); and Group 3, miscellaneous (mitral atresia, left ventricular hypoplasia, truncus complex). The diagnostic group influenced survival (p = 0.0035). In Group 1, 88.8% survived, but only 64.9% survived in Groups 2 and 3 combined. The presence of patent ductus arteriosus or coarctation of the aorta had no effect on survival (p = 0.61 and p = 0.7, respectively). The clinical condition at thirty days after pulmonary artery banding was good in 35.1% and fair in 46.9% of the patients. When the data were divided into the three periods 1971 through 1974, 1975 through 1979, and 1980 through 1984, which included 28, 49, and 67 patients, respectively, a significant improvement in survival was observed from the early (64.3%) to the late period (92.5%) (p = 0.0009). Patients weighing less than 4 kg had a significantly lower survival in the period 1971 through 1974 (37.5% versus 91.67%). No significant difference in survival was detected in the late period, 1980 to 1984 (90% versus 94.6%), between patients weighing less than and those weighing more than 4 kg. Pulmonary artery banding is clinically satisfactory in small infants and children with complex anomalies.

Treatment of grafts and major vessel thrombosis with low-dose streptokinase in children.

Low-dose streptokinase infusions have been used in 8 of our patients. Five of these were newborns who had major vessel occlusion. Four babies had extensive aortic thrombosis and hypertension producing congestive aortic thrombosis and hypertension producing congestive heart failure. One baby had caval and renal vein thrombosis and was in renal failure. Two infants with cyanotic heart disease and 1 with arteritis had occluded prosthetic grafts, which were reopened completely. Two grafts were between the subclavian and pulmonary arteries (Blalock-Taussig shunt), and one was between the abdominal aorta and right renal artery. In each patient, the thrombolytic agent was delivered directly to the area of thrombosis by three or four percutaneously inserted French catheters. The dose of streptokinase used was between 50 and 100 U/kg/hr. Therapy lasted for 2 to 11 days. Major bleeding was anticipated, and it occurred in 1 patient. Low-dose streptokinase infusion is a safe and effective treatment for a variety of thrombotic problems in infants and children.

Benign cardiac tumours, malignant arrhythmias.

Four cases of pediatric cardiac tumours (PCTs) associated with ventricular arrhythmias are reported. Sudden cardiac death attributable to the tumour occurred in two children. A third child received an implantable cardioverter defibrillator and the fourth had persistent ventricular arrhythmia despite medical therapy. Most PCTs are considered benign; however, the development of malignant arrhythmias may complicate the management of these tumours in some patients. The literature regarding the arrhythmogenic potential of PCTs and the use of implantable cardioverter defibrillators in these patients is reviewed. The series highlights the deficiency of prognostic information for this cohort.

Usefulness of the Electrocardiogram in Diagnosing Mechanisms of Tachycardia

Abstract. The electrocardiogram, despite its simplistic technological composition, remains a valuable tool in the diagnosis of pediatric arrythmias. In this article the characteristic features of different tachycardias are reviewed.

Effect of pressure loading, volume loading and surgery on left ventricular chamber and myocardial stiffness in congenital heart disease, with a reevaluation of normal pediatric values

This study assessed the effect of pressure load, volume load and surgery on left ventricular chamber stiffness (b) and myocardial stiffness (k). A normal range for chamber stiffness and myocardial stiffness was also established. A total of 44 patients were studied: 8 were control subjects, 12 had volume load and 24 had pressure load. At cardiac catheterization simultaneous high fidelity pressures (P) and left ventricular volumes (V) were obtained in one diastolic cycle. From the relation P = aVb, operant chamber stiffness (b) was estimated for each patient. Similarly, the relation between stress (sigma) and radius (B) was approximated by sigma = cBf and the myocardial stiffness (k) derived for each patient. Mean values for chamber or myocardial stiffness for the diagnostic groups were not significantly different but differed within the operative groups. Mean values for b and k were greater in the post-open heart surgery group than in the post-closed heart surgery or nonsurgical group. Although the mean values for chamber stiffness and myocardial stiffness for the diagnostic groups were not different, there were more abnormal patients in the pressure load group (9 of 24) than in the volume load group (2 of 8) when the normal range was obtained from the control group. Thus, left ventricular operant chamber and myocardial stiffness are often preserved with volume loading, less frequently with pressure loading and rarely after open heart surgery.

A variant of unknown significance in the GLA gene causing diagnostic uncertainty in a young female with isolated hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is genetically heterogeneous, and largely caused by mutations in genes encoding sarcomere proteins. However, GLA mutations causing Fabry disease, an X-linked lysosomal storage disorder, may also present with isolated HCM. As HCM genetic testing panels are increasingly being used clinically, variants of unknown significance (VUS) are encountered, leading to challenges in interpretation. We present an illustrative case: a 10-year-old girl with isolated HCM who, on testing with a HCM multi-gene panel, was found to carry a maternally inherited p.W24R variant in GLA. Attempts to evaluate the significance of this variant, by direct biochemical testing of patient specimens, gave inconclusive results. Subsequent in vitro protein expression studies suggested that the variant is unlikely to be pathogenic. This case highlights diagnostic dilemmas that can be provoked by VUS in general, and specifically raises a question whether GLA sequencing should be included in first-line diagnostic testing for female children with isolated hypertrophic cardiomyopathy.

Postpericardiotomy syndrome: no evidence for a viral etiology.

BACKGROUND Postpericardiotomy syndrome has been considered a disorder induced by viral infection. This conclusion is based on serologic criterions, but these may be unreliable following either cardiopulmonary bypass or transfusion therapy. Previous studies have not verified the proposed etiology either by isolation of viruses, or by detection of their genome. We sought, therefore, to clarify the role, if any, of viruses in this syndrome. METHODS AND RESULTS We studied prospectively 149 children aged from 6 months to 16 years who were undergoing open heart surgery. Blood samples were collected from all prior to operation, and again 7 to 10 days post-operatively, and 47 were sampled at the time of development of symptoms of pericardial involvement. Serums were analyzed for the presence of IgM and IgG antibodies to cytomegalovirus, herpes simplex virus, and Epstein-Barr virus. The polymerase chain reaction was used for amplification when assessing the genome of the enteroviruses. Cultures for viruses were established on samples of stool, urine, and throat swabs collected 7 days post-operatively, and at the time of postpericardial symptoms. Pericardial fluid obtained from 5 patients with the syndrome was cultured for viruses, and tested for enterovirus genome. On the basis of clinical and echocardiographic findings, 34 children were determined to have definite evidence of the syndrome, 13 were considered to have possible evidence, and the results from these patients were compared to those from patients with no pericardial symptoms, the latter being matched for age and transfusion status. We isolated viruses from one or more sites in five patients with definite evidence (16%), from one (9%) of those with possible evidence, and from seven (19%) of the controls. All serums and pericardial samples were negative for enterovirus genome. IgM antibodies were found in only 5 patients, three with symptoms of pericardial involvement and two without. Rates of seroconversion to IgG for the viruses were lower in the patients with symptoms of pericardial involvement compared to controls, but were strongly influenced by transfusion status. CONCLUSION Our study has provided no evidence to support a viral etiology for the postpericardiotomy syndrome.