Management of Junctional Rhythm in Patients After the Fontan Operation: A Multicenter Congenital Cardiology Survey

Permanent Cardiac Pacing in the Fontan Population: A Contemporary Review of Indications, Approaches, and Outcomes

Following the Fontan operation, electrophysiologic abnormalities requiring pacemaker implantation are common, consisting of sinus node dysfunction, complete atrioventricular block, and electromechanical dyssynchrony. Pacemaker implantation in this population can be challenging, as transvenous access to the cardiac chambers is often limited and may increase the risk of thromboembolism. Consequently, epicardial lead placement continues to be the default approach at most centers. Furthermore, permanent cardiac pacing has been associated with poor outcomes in this population (including an increased need for cardiac transplantation and death), even though it may be, depending on the approach, of great benefit for many individuals. Fortunately, improved understanding of the differential effects of cardiac pacing and novel approaches related to implantation have been developed and have increased their application to a growing number of patients. This review highlights the indications for pacing, methods to facilitate lead implantation, and associated outcomes in Fontan patients requiring permanent cardiac pacing.

Review of rhythm disturbances in patient after fontan completion: epidemiology, management, and surveillance

Purpose

The Fontan operation is commonly associated with alterations in heart rhythms, both tachycardic and bradycardic. Despite modifications to attempt to mitigate these complications, arrythmias still frequently occur. The purpose of this review is to examine the literature regarding the scope of the problem, therapeutic options, and current recommendations regarding screening and surveillance.

Recent findings

Modifications to the original Fontan procedure, antiarrhythmic medications, and improvements in catheter ablation procedures have improved the management of patients with arrhythmias following Fontan palliation. There is growing interest in the role of junctional rhythm in the role of Fontan dysfunction. While chronotropic incompetence has often been blamed for poor exercise testing, there is evidence that decreased performance may be related to ventricular filling and Fontan hemodynamics.

Summary

Tachyarrhythmias are an important cause of mortality and morbidity after the Fontan operation. Prompt and aggressive management of arrhythmias with the goal of maintaining sinus rhythm is vital. Management strategies such as anti-arrhythmic medications, ablation, anti-tachycardia pacing and Fontan conversion should be seen as complementary and used early to prevent hemodynamic deterioration. Bradyarrythmias likely also contribute to Fontan failure. Pacing is the primary management strategy with evidence supporting use of atrial pacing. However, ventricular pacing seems to often lead to deleterious effects. Current guidelines recommend surveillance with Holter monitor every 2-3 years in adolescents and every 1-2 years in adults. Future directions for research include further assessment of junctional rhythm and its management as well as further identifying patients in which pacing would be beneficial.

Impact of Atrial Pacing in Fontan Patients with Junctional Rhythm: A Prospective Echocardiographic Study

Sinus node dysfunction (SND) with junctional rhythm (JR) is common after the Fontan operation. Atrial pacing (AP) restores atrioventricular (AV) synchrony, but the placement of a pacemaker carries significant morbidity. To study the impact of AP on echocardiographic parameters of function in Fontan patients with SND and JR. Nine Fontan patients with AP for SND and JR were prospectively studied with echocardiography in the following conditions-baseline paced rhythm, underlying JR and, if possible, slow-paced rhythm below their baseline paced rate (~ 10 bpm faster than their JR rate). Cardiac index was significantly lower in JR (3 ± 1.1 L/min/m2) vs AP (4.2 ± 1.4 L/min/m2; p = 0.002). Diastolic function also significantly worsened with increased ratio of early diastolic systemic AV valve inflow velocity to early diastolic systemic AV valve annulus velocity (E/e' ratio) by tissue Doppler imaging (TDI) in JR (11.6 ± 4.6) vs AP (8.8 ± 2.2, p = 0.016). Pulmonary venous flow reversal was present in 7/9 patients in JR vs 0/9 in AP (p = 0.016). There were no significant differences in these echocardiographic measurements between the paced and slow-paced conditions. When compared to AP, JR was associated with a significant reduction in cardiac output and diastolic function, and an increased prevalence of pulmonary vein flow reversal. There were no differences between paced and slow-paced conditions, suggesting that AV synchrony rather than heart rate was primarily contributing to cardiac output. Further studies are needed to understand the chronic impact of JR on Fontan outcomes.