Case:
Our patient is a 61 year old man with a history of hypertension and symptomatic paroxysmal atrial fibrillation who underwent pulmonary vein. He remained symptom free with no evidence of recurrence of atrial fibrillation for 7 years following his initial ablation procedure. He then presented with persistent atrial fibrillation complicated by congestive heart failure and severely reduced left ventricular ejection fraction. He underwent electrical cardioversion and his left ventricular systolic function subsequently improved back to normal. A stress test revealed no evidence of ischemia. Given the hypothesis of a tachycardia mediated cardiomyopathy, and limitations of AV nodal blockers in the setting of profound sinus bradycardia, the decision was made to proceed with electrophysiologic testing and repeat ablation despite this single recurrence. Three dimensional electroanatomic mapping (CARTO 3, Biosense Webster, Diamond Bar, CA) of the left atrium suggested persistent isolation with voltage < .1 mV (entrance block) of the left and right sided pulmonary veins. Pacing revealed exit block within the right sided PVs. The left sided PVs showed exit block at paced cycle length of 600 ms with capture of the sleeve. At a paced cycle length of 1000 ms, there was conduction to the left atrium, albeit with significant delay (Figures 1 and 2).
We identified the site of electrical breakthrough in the LSPV using escape mapping.5 We then proceeded to re-isolate the PV and were subsequently unable to provoke non-pulmonary vein triggers, with and without Isuprel. We then proceeded to isolate posterior wall which demonstrated automaticity with exit block post-ablation.