Iatrogenic Cardiomyopathy in Patients with Right Anteroseptal Manifest Accessory Pathway

Introduction: We describe 2 patients with right anteroseptal accessory pathway (ASAP) who developed new cardiomyopathy due to worsening AV node conduction which resulted in more pre-excitation and frequent orthodromic reciprocating tachycardia (ORT). Methods and Results: Case 1: 48-year-old female with a history of normally functioning mechanical mitral valve, CABG, and pre-exitation that worsened after her open heart surgery. She presented with frequent palpitations with documented supraventricular tachycardia (SVT) and found to have a new cardiomyopathy with decrease in ejection fraction (EF) from 55% to 46% with dyssynchrony. Electrophysiological study confirmed a right ASAP and ORT. The pathway was successfully ablated from the antegrade approach after careful mapping. After ablation and six month follow up echocardiogram showed improvement of EF to 54% and the LV dyssynchrony resolved. Case 2: 51-year-old male with a history of frequent SVT with a recent unsuccessful ablations that resulted in worsening pre-exitation, more frequent SVT and new cardiomyopathy (EF from 60% to 40%). He was started on Amiodarone which resulted in significant sinus bradycardia, and intermittent pre-excitation and first degree AV block with no improvement in his ORT events. His Electrophysiology study confirmed ASAP which was successfully ablated from the antegrade approach after careful HIS mapping. After one month follow-up echocardiogram showed an improved ejection fraction to 60%. Conclusion: New cardiomyopathy due to dyssynchrony and symptomatic frequent ORT of right ASAP can develop in the setting of new iatrogenic diminished AV node conduction. Successful ablation will result in LV function recovery to baseline.