Aim: Left atrial isomerism (LAI) is an uncommon congenital heart disease, which is combined with a range of intracardiac abnormalities. Atrial arrhythmia is common in LAI. We hypothesized that permanent pacing will decrease arrhythmia recurrence in adult patients with LAI.
Methods and results: Patients with LAI and permanent pacing were identified from the Royal Brompton Adult Congenital Heart Database. Hospital records were reviewed, and patients' current status was assessed with clinic reviews including standard and Holter ECGs, and transthoracic echocardiograms. Four patients who underwent permanent pacing at the age of 27.5+/-11.7 years fulfilled inclusion criteria, namely permanent pacing in the setting of LAI. All 4 had sick sinus syndrome-with sustained supraventricular arrhythmia in 3-requiring several hospitalizations for arrhythmia management prior to pacing. All 4 patients remained free of clinical arrhythmia and hospital admission at a mean follow-up of 67.0+/-59.5 months from pacing. The latest ECG revealed paced rhythm in all. NYHA functional class remained stable. There were no pacemaker related complications at implantation or during follow-up.
Conclusion: Adults with LAI benefit from pacemaker implantation, which reduces recurrence of supraventricular tachycardia and maintains atrioventricular synchrony. Future studies need to determine the preferred pacemaker mode and optimal timing for pacing.