Atrial pacing in Fontan patients: The effect of transvenous lead on clot burden

Complex Congenital Heart Disease in the Adult

Congenital heart disease (CHD), a heterogeneous group of structural abnormalities of the cardiovascular system, is the most frequent cause of severe birth defects. Related to improved pediatric outcomes, there are now more adults living with CHD, including complex lesions, than children. Adults with CHD are at high risk for complications related to their underlying anatomy and past surgical palliative interventions. Adults with CHD require close monitoring and proactive management strategies to improve outcomes.

Lead Management in Patients with Congenital Heart Disease

Pediatric patients with congenital heart disease present unique challenges when it comes to cardiac implantable electronic devices. Pacing strategy is often determined by patient size/weight and operator experience. Anatomic considerations, including residual shunts, anatomic obstructions and barriers, and abnormalities in the native conduction system, will affect the type of CIED implanted. Given the young age of patients, it is important to have an "eye on the future" when making pacemaker/defibrillator decisions, as one can expect several generator changes, lead revisions, and potential lead extractions during their lifetime.

Cardiac Implantable Electronic Devices in the Fontan Patient

As a result of remarkable progress in operative techniques and cardiology care during childhood, Fontan patients continue to age and require team-based multidisciplinary expertise to manage complications encountered in adulthood. They face particular challenges in terms of altered hemodynamic stressors, cardiac and hepatic failure, and arrhythmias. Arrhythmias in Fontan patients are highly prevalent and associated with underlying anatomy, surgical technique, and postoperative sequelae. Diagnostic tools, treatments, and device strategies for arrhythmias in Fontan patients should be adapted to the specific anatomy, type of surgical repair, and clinical status. Great strides in our understanding of arrhythmia mechanisms, options and techniques to obtain access to relevant cardiac structures, and application of both old and new technologies have contributed to improving cardiac implantable electronic device (CIED) therapies for this unique population. In this state-of-the-art review, we discuss the various arrhythmias encountered in Fontan patients, their diagnosis, and options for treatment and prevention, with a focus on CIEDs. Throughout, access challenges particular to the Fontan circulation are considered. Recently developed technologies, such as the sub-cutaneous implantable cardioverter defibrillator carry the potential to be transformative but require awareness of Fontan-specific issues. Moreover, new leadless pacing technology represents a promising strategy that may soon become applicable to Fontan patients with sinus node dysfunction. CIEDs are essential tools in managing Fontan patients but the complex clinical scenarios that arise in this patient population are among the most challenging for the congenital electrophysiologist.

Hemodynamic Impact of Atrial Pacing in Patients with Fontan Physiology and Junctional Rhythm: A Cardiac Catheterization Study

Sinus node dysfunction is a common problem and adversely impacts patients who have undergone the Fontan operation. In Fontan patients with an adequate junctional escape rhythm, the benefit of atrial pacing to restore atrioventricular synchrony remains unclear. Data were collected retrospectively on all Fontan patients with junctional rhythm who underwent atrial pacing during cardiac catheterization. Hemodynamics were obtained at baseline and after atrial pacing for 5-10 min. Seven patients, mean age 10 years (3-21) were studied. The type of Fontan was extracardiac in 6 and lateral tunnel in one. Patients were paced at 10 bpm faster than their junctional rate. With pacing, there was a significant decrease in left atrial pressure from (mean ± SEM) 8.8 ± 2.6 to 5.5 ± 2.9 mmHg (p = 0.02), a significant increase in cardiac index from 2.7 ± 0.8 to 3.5 ± 1 L/min/m² (p = 0.01) and pulmonary blood flow from 2.1 ± 0.6 to 2.7 ± 0.7 L/min/m² (p = 0.001), and no significant change in pulmonary artery pressure, from 13.4 ± 2.8 to 12.4 mmHg ± 3.6 (p = 0.06) or pulmonary vascular resistance from 2.1 ± 0.86 to 3.25 ± 1.9 WU × M2 (p = 0.1). In Fontan patients with junctional rhythm, atrial pacing decreased the left atrial pressure, increased cardiac output and did not significantly change the pulmonary artery pressure. Our study supports further investigation into the utility of prophylactic atrial pacemaker implantation in Fontan patients with significant durations of JR on ambulatory monitoring.