Iatrogenic cardiomyopathy in patients with manifest right supero-paraseptal accessory pathways

We describe two patients with right supero-paraseptal accessory pathway (SPAP) who developed left ventricular dysfunction associated with an increased degree of ventricular pre-excitation and frequent orthodromic reciprocating tachycardia (ORT) due to worsening atrioventricular (AV) node conduction.

Case 1: 48-year-old female with a history of normally functioning mechanical mitral valve, CABG, and ventricular pre-excitation that worsened after her open heart surgery. She presented with frequent palpitations with documented supraventricular tachycardia (SVT) and found to have a new left ventricular dysfunction with decrease in left ventricular ejection fraction (LVEF) from 55% to 46% with dyssynchrony. An electrophysiological study confirmed a right SPAP and ORT. The pathway was successfully ablated from the antegrade approach after careful mapping. After ablation and 6-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 recent unsuccessful ablations that resulted in worsening ventricular pre-excitation, more frequent SVT, and new left ventricular dysfunction (LVEF from 60% to 40%). He was started on amiodarone which resulted in significant sinus bradycardia, intermittent ventricular pre-excitation, and first degree AV block with significant increase in ORT events. His electrophysiology study confirmed SPAP which was successfully ablated from the antegrade approach after careful mapping. After 1 month, follow-up echocardiogram showed an improved ejection fraction to 60%.

Left ventricular dysfunction due to dyssynchrony and symptomatic frequent ORT of right SPAP can develop in the setting of new iatrogenic diminished AV node conduction. Successful ablation will result in LV function recovery to baseline.