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Electrophysiologic findings after Fontan repair of functional single ventricle
C C Kürer1, C S Tanner, V L Vetter
1Department of Pediatrics, Children's Hospital, Philadelphia University of Pennsylvania School of Medicine, Pennsylvania 19104.
Insights
The Fontan procedure for single ventricle anomalies can cause significant cardiac arrhythmias. Electrophysiologic studies reveal abnormal sinus node function, prolonged atrial refractoriness, and inducible atrial arrhythmias in many patients.
Area of Science:
- Cardiology
- Electrophysiology
- Pediatric Cardiac Surgery
Background:
- The Fontan operation is a palliative procedure for complex congenital heart defects, creating a single ventricle physiology.
- Cardiac arrhythmias are known complications following the Fontan procedure.
Purpose of the Study:
- To evaluate the electrophysiologic effects of the Fontan procedure in patients with functional single ventricle.
- To identify specific electrophysiologic abnormalities and their prevalence post-Fontan repair.
Main Methods:
- Cardiac catheterization with electrophysiologic study in 30 patients post-modified Fontan repair.
- Assessment of sinus node and atrial pacemaker function, sinoatrial conduction, and atrial refractory periods.
- Atrial endocardial mapping and programmed atrial/ventricular stimulation to induce arrhythmias.
Main Results:
- 50% of patients showed abnormal sinus node or ectopic pacemaker automaticity.
- Prolonged sinoatrial conduction time and atrial refractory periods were observed in 50% and 43% of patients, respectively.
- Intraatrial conduction delays were found in 76%, and inducible supraventricular arrhythmias, primarily intraatrial reentry, occurred in 37% of patients.
Conclusions:
- The Fontan procedure is associated with significant electrophysiologic abnormalities, including impaired sinus node function and delayed intraatrial conduction.
- Intraatrial reentry is a common mechanism for inducible atrial arrhythmias after Fontan repair.
- These findings highlight the proarrhythmic substrate created by the Fontan circulation, necessitating careful long-term monitoring.
Abstract:
Cardiac arrhythmias are well recognized sequelae of the Fontan operation for complex congenital anomalies. In this study the electrophysiologic effects of the Fontan procedure were evaluated in 30 patients who underwent cardiac catheterization with electrophysiologic study 1.9 +/- 1.3 years (mean +/- SD) after modified Fontan repair for functional single ventricle. Abnormalities of sinus node or ectopic pacemaker automaticity were detected in 50% (15 patients) by determination of a prolonged corrected sinus node or pacemaker recovery time. Total sinoatrial conduction time was prolonged in 50% of the patients with normal sinus rhythm. Sinus node or ectopic atrial pacemaker function was entirely normal in only 43% of patients. The predominant atrial rhythm was normal sinus in 70% and ectopic atrial or junctional in 30%. Abnormalities of atrial effective and functional refractory periods were noted in 43% of patients and were most pronounced at faster paced cycle lengths. Atrial endocardial catheter mapping revealed intraatrial conduction delays between adjacent sites in 76% of the patients tested and in eight of nine patients with inducible intraatrial reentry. Programmed atrial stimulation induced nonsustained supraventricular arrhythmias in 10% of the 30 patients and sustained arrhythmias in 27%. Intraatrial reentry was the most common inducible arrhythmia and was present in seven of the eight patients with sustained and two of the three patients with nonsustained atrial arrhythmias. Atrioventricular conduction abnormalities were noted in 10% (three patients). No patient had inducible ventricular arrhythmias with programmed ventricular stimulation. The electrophysiologic findings after Fontan repair include abnormal sinus node function, prolonged atrial refractoriness, delayed intraatrial conduction and inducible atrial arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)