Remote monitoring of cardiovascular implantable devices in the pediatric population improves detection of adverse events.

With the exponential growth of cardiovascular implantable electronic devices (CIEDs) in pediatric patients, a new method of long-term surveillance, remote monitoring (RM), has become the standard of care. The purpose of this study was to determine the usefulness of RM as a monitoring tool in the pediatric population. A retrospective review was performed of 198 patients at the University of Iowa Children's Hospital who had CIEDs. Data transmitted by RM were analyzed. The following data were examined: patient demographics; median interval between transmissions; detection of adverse events requiring corrective measures, including detection of lead failure; detection of arrhythmias and device malfunctions independent of symptoms; time gained in the detection of events using RM versus standard practice; the validity of RM; and the impact of RM on data management. Of 198 patients, 162 submitted 615 RM transmissions. The median time between remote transmissions was 91 days. Of 615 total transmissions, 16 % had true adverse events with 11 % prompting clinical intervention. Of those events requiring clinical response, 61 % of patients reported symptoms. The median interval between last follow-up and occurrence of events detected by RM was 46 days, representing a gain of 134 days for patients followed-up at 6-month intervals and 44 days for patients followed-up at 3 month-intervals. The sensitivity and specificity of RM were found to be 99 and 72 %, respectively. The positive and negative predictive values were found to be 41 and 99 %, respectively. RM allows for early identification of arrhythmias and device malfunctions, thus prompting earlier corrective measures and improving care and safety in pediatric patients.

Nonfluoroscopic and radiation-limited ablation of ventricular arrhythmias in children and young adults: a case series.

The purpose of this study was to report the feasibility and procedural technique of minimal or no fluoroscopy in the ablation of ventricular arrhythmias in the pediatric population. A retrospective review was performed of all patients <21 years old who underwent ablation of ventricular arrhythmias using three-dimensional (3D) mapping with no or minimal fluoroscopy at a single institution. Five patients underwent electrophysiology studies for ventricular tachycardia or frequent premature ventricular complexes. Three patients had right-sided arrhythmias, and two patients had left-sided arrhythmias. Electro-anatomic mapping with the 3D EnSite NavX system and radiofrequency ablation was used in all patients. No fluoroscopy was used in the patients with right-sided arrhythmias. The two patients with left-sided arrhythmias had 1.0 and 1.9 min of fluoroscopy, respectively. The mean procedure time was 168 min (range 95 to 270). There has been no recurrence at mean follow-up of >1 year. Three-dimensional mapping systems have allowed pediatric electrophysiologic procedures to be performed with minimal to no fluoroscopy in patients with challenging arrhythmias, including ventricular arrhythmias. The decrease in radiation exposure decreases the risk of long-term adverse sequelae resulting from radiation exposure, which is especially important in children.

Safety and efficacy of atrial antitachycardia pacing in congenital heart disease.

BACKGROUND: Intra-atrial reentrant tachycardia (IART) is a common sequela in the congenital heart disease (CHD) population, and it significantly increases morbidity and mortality. Atrial antitachycardia devices (ATDs) capable of atrial antitachycardia pacing (ATP) therapy have been used to manage IART in the CHD population, but there are limited data on their safety and efficacy. OBJECTIVES: To determine whether ATD implantation was associated with reduced direct current (DC) cardioversions and to compare ATP success between different CHD diagnoses and ATP programs. METHODS: A single-center retrospective chart review was performed on CHD patients with ATDs. Demographic data were collected in addition to the number of DC cardioversions required before and after ATD implantation; data on ATP efficacy and the specific ATP program utilized; and adverse events related to ATD implantation or subsequent ATP treatments. RESULTS: ATD implantation in 91 CHD patients was associated with a significant reduction in DC cardioversions (P < .01). Overall, 72% of IART episodes were successfully terminated by ATP. Patients with levo-transposition of the great arteries experienced lower rates of ATP success than the remainder of the cohort (P < .01). There was no evidence of degeneration to ventricular arrhythmia or death directly attributed to ATP. CONCLUSION: ATD implantation was associated with reduced DC cardioversion burden. Patients with levo-transposition of the great arteries may experience lower ATP efficacy than patients with other CHDs; however, a larger patient population is required to better determine subgroup efficacy. These results support the safety and efficacy of ATP in the CHD population.

Atrial Antitachycardia Pacing in Complex Congenital Heart Disease: A Case Series.

Among the congenital heart disease (CHD) population, intra-atrial reentrant tachycardia (IART) is a common sequela resulting from anatomical anomalies and surgical scars that significantly increases morbidity and mortality. Atrial antitachycardia pacing (ATP) delivered by atrial antitachycardia devices (ATDs) has been used to treat IART in the CHD population. However, there remains limited data on the safety and efficacy of ATP, as well as on comparisons of its effects amongst different CHD subtypes. The purpose of the current study is to describe the clinical history and ATP efficacy in three patients with unique forms of complex CHD. During this study, a single-center review of three patients with ATDs was performed. One patient with each of the following CHD anomalies was selected for inclusion: systemic left ventricle, systemic right ventricle, and single ventricle. Data collected included ATP success rates, medications in use, direct current (DC) cardioversions, and any complications related to the ATDs. Study findings revealed the patient with a systemic left ventricle had an ATD implanted for approximately 9.5 years, with 695 of 956 (73%) episodes successfully converted. Unsuccessfully treated episodes were generally asymptomatic and self-terminating in this patient. The patient with a systemic right ventricle had an ATD implanted for approximately 16 years, with 333 of 348 (96%) episodes being successfully converted. The patient with a single ventricle had an ATD implanted for approximately 12.5 years, with 404 of 416 (97%) episodes successfully converted. The patients with biventricular physiology were able to forgo DC cardioversion after receiving their ATDs. However, due to medical noncompliance as well as multiple episodes of IART, which presented with 1:1 conduction or low rates, the single-ventricle patient still required DC cardioversions post-ATD implantation. In conclusion, this study's findings demonstrate that, while ATP can be effective in a wide variety of CHDs, experiences can vary based on individual arrhythmia substrates, cardiac anatomy, and medical compliance. Additionally, challenges remain in IART detection in patients with especially complex CHD anatomies.

Transcatheter cryothermal ablation of junctional ectopic tachycardia in the normal heart.

BACKGROUND: Junctional ectopic tachycardia in the normal heart is rare and often is resistant to pharmacologic management. Transcatheter ablation using radiofrequency energy places the AV node at risk. OBJECTIVES: The purpose of this study was to report our experience with transcatheter cryothermal ablation using three-dimensional mapping in six patients with junctional ectopic tachycardia. METHODS: A review of clinical and electrophysiologic data was performed on all patients with structurally normal hearts who underwent cryothermal ablation for treatment of junctional ectopic tachycardia at two institutions. RESULTS: Six patients (age 7.7-36.5 years) underwent attempted transcatheter cryothermal ablation using three-dimensional mapping. Only one patient had achieved arrhythmia suppression on medical management. Cryothermal mapping (-30 degrees C) localized the junctional focus while normal conduction was monitored. The junctional focus was high in the triangle of Koch in four patients and was low in one patient. The sixth patient had only one run of junctional ectopic tachycardia during the procedure and therefore received an empiric cryoablation (-70 degrees C) lesion. Subsequent cryoablation lesions were delivered at and around the junctional focus. In one patient, cryomapping eliminated the junctional focus but resulted in transient complete AV block; therefore, cryoablation was not performed. All patients who received the cryoablation lesions had elimination of their junctional ectopic tachycardia at 6-week follow-up. The patient who did not receive a cryoablation lesion remained in a slower junctional rhythm at follow-up. CONCLUSION: Cryoablation of junctional ectopic tachycardia is safe and effective. Nonetheless, proximity to the His-Purkinje system may preclude success. Empiric cryoablation can be effective; cryotherapy may not yield immediate success, but a delayed salutary effect can follow.

Successful transcatheter cryoablation in infants with drug-resistant supraventricular tachycardia: a case series.

PURPOSE: Drug-resistant supraventricular tachycardia can cause hemodynamic instability, especially in infants. There are no case-series reports of transcatheter cryoablation treatment for infants with drug-resistant supraventricular tachycardia. Our purpose is to report our experience with transcatheter cryoablation in three infants with drug-resistant supraventricular tachycardia. METHODS: We reviewed clinical and electrophysiologic data from infants who underwent cryothermal ablation for drug-resistant supraventricular tachycardia (SVT) at our institution. RESULTS: Three patients (age 10-42 days) underwent transcatheter cryothermal ablation over a 1-year period. None had arrhythmia suppression on medical management, and all had hemodynamic instability from persistent SVT episodes. Cryothermal mapping (-30 C) localized the suspected foci. All foci were adjacent to the AV node. Cryoablation lesions were delivered at and around mapped foci. In one patient, cryothermal energy application eliminated the SVT but resulted in transient right bundle branch block that resolved later. Two patients had hemodynamically insignificant episodes of SVT in the immediate post-ablation period that resolved with standard antiarrhythmic treatment. One died of sepsis but remained SVT free for 10 days after the procedure without antiarrhythmic medications. Neither of the two surviving patients had SVT recurrence at 6-month follow-up off medications. CONCLUSIONS: In our series, transcatheter cryoablation was an effective treatment for drug-resistant SVT in infants. We encountered some early nonsustained post-procedure SVT; however, such episodes did not predict procedural failure.