UNLABELLED: A 4-month-old infant presented with incessant SVT and severe failure to thrive. At EP study, orthodromic-reciprocating tachycardia using an anteroseptal accessory pathway was identified. Detailed mapping on the right atrial septum failed to disclose a distinctly early site of atrial activation or a near-field pathway potential. Mapping in the noncoronary cusp of the aortic valve identified a discrete pathway potential that was successfully targeted for ablation. At 12-month follow-up after the procedure, there had been no recurrence of tachycardia. CONCLUSION: Myocardial fibers above the aortic valve cusps may constitute the atrioventricular bypass connection and can be identified and targeted for successful ablation even in infants.
UNLABELLED: A 4-month-old infant presented with incessant SVT and severe failure to thrive. At EP study, orthodromic-reciprocating tachycardia using an anteroseptal accessory pathway was identified. Detailed mapping on the right atrial septum failed to disclose a distinctly early site of atrial activation or a near-field pathway potential. Mapping in the noncoronary cusp of the aortic valve identified a discrete pathway potential that was successfully targeted for ablation. At 12-month follow-up after the procedure, there had been no recurrence of tachycardia. CONCLUSION: Myocardial fibers above the aortic valve cusps may constitute the atrioventricular bypass connection and can be identified and targeted for successful ablation even in infants.