Flipping syncope: The case of an adolescent athlete with syncopal episodes ultimately diagnosed with catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a channelopathy which can lead to fatal ventricular arrhythmias. The diagnosis can be challenging due to a wide variety of clinical presentations. In this case, we describe the unusual presentation and subsequent workup of a young patient who was ultimately diagnosed with CPVT.

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.

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.