AHA: Scientific Statement for Arrhythmias in Repaired Tetralogy of Fallot

An AHA statement on mechanisms and treatment of arrhythmias in patients with repaired tetralogy of Fallot.

The American Heart Association has issued a scientific statement regarding the mechanisms and treatment of atrial arrhythmia (AA) and ventricular arrhythmia (VA) in patients with repaired tetralogy of Fallot (TOF), as reported in Circulation: Arrhythmia and Electrophysiology.

AAs are increasingly common in advancing age among patients with TOF. Catheter ablation is generally more effective compared with antiarrhythmic drugs for the treatment of atrial flutter and intra-atrial reentrant tachycardia. Initial rhythm control management is preferred vs a rate control strategy for moderate and complex congenital heart disease (CHD), including TOF.

Among patients with TOF, catheter ablation can reduce AA frequency, improve symptoms, and be an effective treatment option when conducted by specialists in TOF anatomy. Surgical AA ablation during pulmonary valve replacement (PVR) may reduce the risk for future arrhythmia and could be considered in individual scenarios with a multidisciplinary heart team.

Key recommendations for evaluating and managing patients with TOF and bradyarrhythmia include treating reversible causes of bradyarrhythmia, using ambulatory monitors to correlate symptoms, using atrial pacemakers for symptomatic sinus node dysfunction, and using dual-chamber pacemakers for complete or advanced atrioventricular block.

Preventing sudden death remains one of the largest challenges in the care of adults with CHD.

VAs can occur in adults with TOF throughout their life span, with monomorphic ventricular tachycardia (VT) the predominant form of VA. The main mechanism of arrhythmia is macro-reentry, and for patients with repaired TOF, reentry occurs with a critical circuit traversing well-defined anatomic isthmuses.

Sudden cardiac death (SCD) is a leading cause of death for adults with TOF, although the annual risk of SCD in adults with repaired TOF is too low to justify invasive risk stratification or implantable cardioverter defibrillator (ICD) implantation for all patients, according to the researchers. Studies have been inconsistent regarding which noninvasive risk factors are associated with SCD.

Univariate analyses have shown that older patient age, older age at initial repair, and older age at PVR are associated with an increased VA risk. In addition, the surgical era effect has been suggested as a potential risk factor for VA and SCD. The mechanisms may be associated with prolonged cyanosis or extensive right ventriculostomy, which has been associated with an increased risk of VA.

Other research has shown that a QRS duration of 180 milliseconds or longer was strongly associated with VT and SCD and that fragmentation of the QRS complex is more common in patients with right ventricular dysfunction, fibrosis, or dyssynchrony and therefore may help identify patients with a risk for VA.

Patients who have VA, especially polymorphic VT that is not responsive to catheter ablation, may benefit from β-blockade. ICDs can effectively terminate VA but do not prevent it and are associated with complications such as high rates of ICD shocks, lead dysfunction, and infection. Radiofrequency catheter ablation may help control recurrent monomorphic VT and prevent ICD shocks.

The combination of valve replacement with surgical ablation guided by intraoperative VT mapping has resulted in a significant decrease in the rate of spontaneous monomorphic VT postsurgery. An empirical surgical ablation line that connects the boundaries of the isthmus at the time of PVR may be an alternative to mapping-guided ablation.

Nonfatal but symptomatic and sustained VT may occur despite effective surgery and excellent functional status. For this group of patients, ablation may be an alternative to medical treatment and ICD therapy if procedural endpoints have been achieved.

“Preventing sudden death remains one of the largest challenges in the care of adults with CHD,” the researchers wrote. “Although there has been progress in noninvasive and invasive risk stratification, there remains no widely accepted algorithm to identify patients who are at greatest risk of arrhythmia and warrant more aggressive treatment.”

Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

References:

Krieger EV, Zeppenfeld K, DeWitt ES, et al; on behalf of the American Heart Association Adults With Congenital Heart Disease Committee of the Council on Lifelong Congenital Heart Disease and Heart Health in the Young and Council on Clinical Cardiology. Arrhythmias in repaired tetralogy of Fallot: a scientific statement from the American Heart Association. Circ Arrhythm Electrophysiol. Published online October 20, 2022. doi: 10.1161/HAE.0000000000000084