ATrial Tachycardia PAcing Therapy in Congenital Heart

Congenital heart disease (CHD) affects approximately 1% of newborns in the US, with 25% of
those affected having critical conditions requiring open heart surgery within one year of
birth. Surgical and medical advances have allowed many patients to live beyond their fourth
and fifth decades of life. Unfortunately, cardiac arrhythmias are a relatively common sequela
due to cardiac anomalies and surgical scars in addition to residual volume and pressure load
on the heart. Atrial arrhythmias, including sinus node dysfunction and intra-atrial
re-entrant tachycardia (IART) are among the more common abnormalities found in adults with
repaired CHD. The presence of IART significantly increases morbidity and mortality, and
anti-arrhythmic medications have been shown to be a sub-optimal treatment strategy with the
majority of patients requiring multi-drug therapy. Catheter ablation procedures remain a
treatment option, but are less successful for some patient demographics. In the mid-1990's,
pacemakers with atrial anti-tachycardia pacing (ATP) capabilities were developed, primarily
for the management of atrial flutter and fibrillation in adults with structurally normal
hearts. Given the need for pacemakers in the CHD population to manage sinus node dysfunction
and atrioventricular node conduction block, the adoption of atrial anti-tachycardia
pacemakers began to gain favor. However, there is limited data available comparing the safety
and effectiveness of ATP therapy between various demographics of CHD patients. In the current
study, the investigators aim to determine if ATP is an effective treatment strategy for IART,
specifically within particular sub-populations of CHD patients. Additionally, investigators
hope to delineate any significant differences in efficacy of ATP treatment between adult and
pediatric congenital heart patients. The research team will accomplish our goals with a
retrospective, multi-center study in which data is collected from existing electronic medical
records and pacemaker interrogations. Following data collection, the investigators will
employ statistical analyses to determine if certain CHD demographics are statistically
significant predictors of ATP therapy outcomes.

The purpose of this prospective/retrospective study is to determine how effective atrial
anti-tachycardia therapies are with the congenital heart patients who are known to have
atrial arrhythmias. As this population ages, we know that arrhythmic burden increases and
medications are increased or changed for symptomatic improvement.

Patients will be enrolled at the time of anti tachycardia device (ATD) placement or when
device therapies are turned on. Patients will need a minimum of 5 years of clinical history
prior to implantation and after implantation (unless patient is very young). Data will be
collected both retrospectively and prospectively. The research team will consent patients at
the time of clinical evaluations and scheduled follow-ups (usually 3 - 6 months). If therapy
is effective, investigators will determine the specific programming which was successful. If
therapy was ineffective, investigators will also determine if a change in programing was made
and if this improved ATP efficacy. Investigators will also determine the arrhythmia burden.
Cardioversion and medications before and after ATD implantation will be the key determinants
of arrhythmia burden in this study.