Successful radiofrequency catheter ablation of right-sided focal atrial tachycardia in a patient with Holt–Oram syndrome: a case report

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Background Holt–Oram syndrome (HOS) is a rare autosomal-dominant genetic disorder caused by mutations in the TBX5 gene. It is characterized by skeletal abnormalities of the upper limbs and congenital heart defects, most frequently atrial septal defect (ASD) and ventricular septal defect. Middle-aged individuals often develop conduction disorders and atrial arrhythmias, most commonly atrial fibrillation and atrial flutter, while focal atrial tachycardia (AT) remains relatively rare. We present the successful catheter ablation of a right anteroseptal focal AT in a patient with HOS and a history of surgical ASD closure. Case report A 22-year-old man was admitted due to recurrent episodes of supraventricular tachycardia, refractory to drug therapy. He has a history of HOS, patch closure of ASD at age three, and three hand surgeries. A 12-lead electrocardiogram showed narrow QRS complex tachycardia at 171 beats/min, regular RR intervals, and RP < PR interval. Transthoracic echocardiography revealed mostly normal findings, with mildly reduced left ventricle function and intact ASD patch with no residual shunt. Electrophysiology study showed no retrograde conduction over an accessory pathway. Programmed stimulation from the left atrium induced tachycardia with cycle length 280 ms, narrow QRS complexes, regular RR intervals, initial 1:1 AV (atrio-ventricular) ratio, and short VA interval (34 ms). Using the Carto 3 3D mapping system, activation mapping of the right atrium identified the earliest atrial activation near the His-Bundle area (5.9 mm distance from His bundle cloud). Radiofrequency ablation terminated AT within 2.5 s of the first application. Postablation tachycardia was not-inducible at baseline and under Isoproterenol. The patient was discharged from the hospital 1 day after ablation without antiarrhythmic therapy. After 21 months of follow-up, there were no recurrences of AT. Conclusion This case demonstrates that catheter ablation is a feasible, safe, and effective treatment option for focal AT patients with HOS and surgical ASD closure.