Pharmacologic management of supraventricular tachycardias in children. Part 1: Wolff-Parkinson-White and atrioventricular nodal reentry

Quinidine Therapy for Lennox-Gastaut Syndrome With KCNT1 Mutation. A Case Report and Literature Review

Mutations in the Potassium channel subfamily T member 1 (KCNT1) gene have been reported in a range of epileptic encephalopathies. Here we report the case of a 12-year-old male suffering from multiple types of epileptic seizures and cognitive decline from the age of 10. The patient had four types of epileptic seizures, including tonic seizures, atypical absence seizures, myoclonic seizures, and generalized tonic-clonic seizures. The electroencephalogram showed generalized slow spike-and-slow-waves, mutiple-spike-and-slow-waves, as well as short-term fast rhythms bursts. Thus, he was diagnosed with Lennox-Gastaut syndrome. The patient had failed to control seizures after using five first-line antiepileptic drugs. Whole exome sequencing revealed a missense KCNT1 mutation (c.625 C>T). Previous studies revealed that quinidine could block the KCNT1 channel. Therefore, we assumed that quinidine might be effective for him. Add-on treatment with quinidine was started when the patient was 12 years old. After an 8-month treatment, the frequency of seizures and epileptiform discharges were significantly reduced. In conclusion, quinidine therapy may offer a new choice for the treatment of Lennox-Gastaut syndrome with KCNT1 mutations.

Radiofrequency ablation of drug-refractory arrhythmias in small children younger than 1 year of age: single-center experience

The use of radiofrequency ablation (RFA) for the management of supraventricular tachycardia (SVT) in infants and small children remains controversial. The aim of this study was to evaluate the safety and efficacy of RFA in critically ill small children (<1 year of age) with drug-resistant tachycardia accompanied by arrhythmogenic cardiomyopathy and heart failure. The study included 15 patients age 5.3 ± 3.7 months. Wolff-Parkinson-White syndrome and atrial tachycardia were detected in eight (53.3 %) and seven (46.7 %) of patients, respectively. Patients with structural heart pathology, including congenital heart diseases and laboratory-confirmed myocarditis, were excluded from the study. Indications for RFA included drag-refractory SVT accompanied by arrhythmogenic cardiomyopathy and heart failure. Unsuccessful ablation was observed in two 1-month-old patients who underwent successful ablation 3 months later. The follow-up period ranged from 0.5 to 8 years (average 3.9). Only one patient (6.7 %) had tachycardia recurrence 1 month after RFA. The short- and long-term RFA success rates were 86.7 and 93.3 %, respectively. The study did not show any procedure-related complications. Heart failure disappeared within 5-7 days. Complete normalization of heart chamber sizes was documented within 1 month after effective RFA. A three-dimensional CARTO system (Biosense Webster, Inc., USA) was used in three patients with body weight >7 kg. The use of the CARTO system resulted in a remarkable decrease of the fluoroscopy time without vascular injury or other procedure-related complications in all cases. Our study suggests that RFA may be considered the method of choice for SVT treatment in small children when drug therapy is ineffective and arrhythmogenic cardiomyopathy progresses.

Antiarrhythmic Drug Therapy of Supraventricular Tachycardia

Pharmacologic therapy is commonly used for the acute treatment and termination of paroxysmal supraventricular tachycardia (SVT) and continues to be an important long-term option for some patients. Drug choice depends on the correct diagnosis of the arrhythmia and an understanding of its mechanism. Pharmacologic agents commonly used in the acute and chronic treatment of SVT are reviewed along with their effect on the various types of SVT. Drugs that are well tolerated with minimal side effects are preferred over agents with perhaps more efficacy but higher risk of toxicity.

Medications used to manage supraventricular tachycardia in the infant a North American survey

Supraventricular tachycardia is the most common pediatric arrhythmia, but there is no consensus and little evidence to guide its treatment. We sent a questionnaire to pediatric cardiologists in North America to assess the current practice pattern. Of 1534 surveys mailed, 352 (23%) were returned and 295 (19%) had complete data for analysis. In the acute setting, 11 different medications were chosen. The most commonly used in the infant without preexcitation were digoxin (42%), procainamide (21%), esmolol (13%), propranolol (10%), and amiodarone (8%). In the infant with preexcitation, propranolol (34%), procainamide (23%), esmolol (17%), amiodarone (11%), and digoxin (6%) were used. In the chronic setting, 8 different medications were chosen. The most commonly used in this scenario were digoxin (52%), propranolol (33%), amiodarone (4%), and sotalol (3%). In the infant with preexcitation, propranolol (70%), amiodarone (6%), digoxin (6%), atenolol (6%), and flecainide (5%) were used. Medication choices were influenced by additional electrophysiology training and preexcitation. Digoxin was used less in the setting of preexcitation. There are no comparative trials to explain the different medication choices. Although a number of medications may be efficacious, a randomized clinical trial is needed to offer further guidance.

Pediatric Radiofrequency Catheter Ablation Sedation Methods and Success, Complication and Recurrence Rates

BACKGROUND

There remains to be issues regarding radiofrequency catheter ablation (RFCA) in pediatric patients that are different to those involving adults. This study was performed to determine the efficacy and safety of RFCA in pediatric patients.

METHODS AND RESULTS

During the period from 1992 to 2003, 2,734 patients underwent RFCA and 131 pediatric patients who were < or =15 years old (70 males, mean age 12.0+/-3.1 years) were analyzed, retrospectively. The number of accessory pathways (APs) mediating atrioventricular re-entrant tachycardia was 93 (71.4%) and atrioventricular nodal re-entrant tachycardia (AVNRT) was 27 (20.5%). The most common indications for the RFCA were the ;patient's choice' in 94 (71.2%) and 'medically refractory tachycardia' in 29 (22.0%). The age-related indication of the ;patient's choice' was 80.4% (82 of 102) for those >10 years old and 40.0% (12 of 30) for those < or =10 years old (p=0.01). RFCA was performed without sedation in 87.3% (89 of 102) of the subjects >10 years old as compared to 20.0% (6 of 30) of those < or =10 years old (p=0.01). The success rate was 92.8% (90 of 97 APs) for the ablation of APs, and 96.3% (26 of 27) for that of AVNRT. The overall complication rate was 3.8% (5 of 131). During a mean follow-up duration of 13.1+/-2.5 months, the freedom of recurrence was 87.8% (79 of 90) for the arrhythmia associated with APs and 92.3% (24 of 26) for AVNRT.

CONCLUSION

RFCA in pediatric patients had a good success rate with acceptable recurrence and complication rates when compared to adult patient results. Therefore, RFCA could be considered as the first line of therapy for arrhythmias with concealed and manifested APs and AVNRT in pediatric patients.

Pediatric cardiac disorders

Although pediatric cardiac disorders are not commonly seen in the Emergency Department, they are important to identify to prevent further morbidity or mortality. Diagnosis may be complicated by the lack of classic complaints such as chest pain or palpitations that are commonly associated with cardiac disorders. In fact, presenting complaints associated with pediatric cardiac disorders, like "fussiness" or "difficulty feeding," may seem quite nonspecific. This article reviews pertinent issues concerning diagnosis and management of pediatric cardiac disorders including supraventricular tachycardia, congenital heart disease, prolonged QT syndrome, pericarditis, myocarditis, rheumatic fever, and endocarditis. It also reviews abnormal findings in pediatric electrocardiograms.

Radiofrequency catheter ablation in infants </=18 months old: when is it done and how do they fare?: short-term data from the pediatric ablation registry

BACKGROUND

The objective of this study was to determine the indications, the safety, and the efficacy of pediatric radiofrequency catheter ablation (RFCA) in infants.

METHODS AND RESULTS

Data from the pediatric RFCA registry were reviewed. Between August 1989 and January 1999, 137 infants, defined by age 0 to 1.5 years (median 0.7 years; weight 1.9 to 14.8 kg, median 10 kg), underwent 152 procedures in 27 of 49 registry centers (55%), compared with 5960 noninfants undergoing 6610 procedures during a comparable period. Structural heart disease was present in 36% of infants, compared with 11.2% of noninfants (P<0.0001). RFCA in infants was performed more commonly for drug resistance or life-threatening arrhythmias than in noninfants. No differences were found between infants and noninfants in success for all tachycardia substrates (87.6% versus 90.6%, P=0.11), for single accessory pathways (94.5% versus 91.5%, P=0.4), or for total (7.8% versus 7.4%, P=1) and major (4.6% versus 2.9%, P=0.17) complications. Neither success for infants with a single accessory pathway nor complications for the entire infant group were related to weight, age, center size, or the presence of structural heart disease. Centers that performed infant procedures, however, enrolled more patients overall in the registry than those that did not perform infant procedures, and successful procedures in infants were performed by more experienced physicians than failed procedures.

CONCLUSIONS

Compared with noninfants, RFCA in infants is usually performed for drug resistance or life-threatening arrhythmias, often in the presence of structural heart disease. The data support the use of RFCA by experienced physicians in selected infants.

Sotalol in treatment of pediatric cardiac arrhythmias

BACKGROUND

There is limited experience on sotalol use in the management of childhood arrhythmias. This study reviews the results of our experience with oral sotalol for treatment and prevention of tachyarrhythmias in children.

METHODS

The records of 62 patients (27 female, 35 male, mean age: 8.5+/-5.3 years) treated with sotalol for supraventricular or ventricular arrhythmias from 1994 to 1999 at our institution were reviewed. Demographic, clinical, echocardiographic, electrocardiographic (ECG), ambulatory ECG and electrophysiologic variables were collected.

RESULTS

Forty-two (63.6%) patients had re-entrant supraventricular tachycardia, eight patients (12.9%) had atrial tachycardia, one patient (1.6%) had junctional ectopic tachycardia, four patients (6.5%) had ventricular tachycardia, and seven patients (11.3%) had complex ventricular arrhythmias, as evidenced by surface or ambulatory ECG records; or revealed during the electrophysiological study. The mean sotalol dose was 3.9+/-1.2 mg/kg per day. In 15.5+/-13.9 months of sotalol use 50% (n=31) had complete relief of symptoms and/or arrhythmia and 29% (n=18) had partial relief. Sotalol was ineffective in 20% (n=13). Sotalol was more effective in re-entrant type supraventricular tachycardias (P=0.012). Sotalol was the first choice in 35.5% of patients. The sotalol therapy was initiated in inpatient settings in 40.3% (25 patients). Complications due to sotalol were seen in six patients (five patients developed bradycardia/pauses, and one patient had torsades de pointes) for which the sotalol dose was modified. In patients with sick sinus syndrome, a pacemaker was implanted and in another patient sotalol was stopped.

CONCLUSION

Sotalol, being an effective and safe drug particularly in children, is a good therapeutic alternative for the preventive treatment of childhood tachyarrhythmias.