Arrhythmias in postoperative congenital heart disease

Associate Professor, Division of Pediatric Cardiology, Oregon Health & Science University, USA
Seshadri Balaji

The last 50 years have seen a growing population of children and adults with postoperative congenital heart disease. The two most common late problems in these patients are heart failure and arrhythmia, both of which are closely related to each other.
Patients with poor hemodynamic result after surgery are at high risk for arrhythmias. It is often hard to determine which of these two factors is primary. Successful management is rarely possible without addressing both sides of the equation. The keys to a proper diagnosis of the arrhythmia are vigilance and thoroughness. Aggressive approaches such as electrophysiologic studies, prophylactic pacing, drug therapy, catheter ablation and placement of a defibrillator may be necessary.
Pacing and defibrillator placement are often complicated by complex venous anatomy (including stenoses/obstructions) and loss of access to parts of the heart after surgery (e.g. Fontan operation). Also, ventricular pacing may lead to AV-synchrony which can lead to hemodynamic deterioration. Newer approaches, such as bi-ventricular pacing, may need to be considered in these patients.
The main approaches to tachyarrhythmias are: drug therapy, pacing (including antitachycardia pacing), catheter ablation and surgical ablation. Each approach has advantages and disadvantages. Patients may need more that one approach before success can be achieved.
While advances in therapy are much awaited, even more important is the hope of preventing arrhythmias, usually by surgical modifications. Examples are as follows. The total cavo-pulmonary Fontan has been shown to have better long term results compared to the classic atrio-pulmonary Fontan. It is hoped that the extra-cardiac conduit modification of the TCPC may be even better in the long run. Better knowledge of the anatomy and vascular supply of the sinus and AV nodes have significantly minimized the risk of bradyarrhythmias. Avoiding the use of tran-annular patches and minimizing the presence of pulmonary regurgitation after repair of tetralogy of Fallot can decrease the incidence of late arrhythmias and sudden death. It is hoped that such surgical modifications can decrease the arrhythmia burden significantly in the future and improve longevity and quality of life for our patients.
In summary, patients with arrhythmia after surgery for congenital heart disease represent a select population who need special and often expensive and time consuming approaches for successful management. Preventive approaches at the time of surgery may have a significant impact in the long term.