Effect of electrical posterior wall isolation on left atrial mechanical function

Pulmonary vein isolation (PVI) is a cornerstone of AF ablation. Posterior wall isolation (PWI) has become a frequently used adjunct to PVI. While there is data to suggest that PVI alone does not negatively impact left atrial function, the effect of PWI on left atrial mechanical function has not been definitively determined. Our aim was to determine if PVI plus PWI using a cryoballoon impacted left atrial mechanical function as measured by cardiac MRI.

We studied 28 patients who underwent ablation for AF. Fourteen patients had PVI alone and 14 patients had PVI plus PWI. All patients had cardiac magnetic resonance (CMR) before and after ablation. The primary outcome was change in LA ejection fraction (LAEF) as measured by CMR.

There were no statistically significant differences in the average patient age, height, weight, type of AF, or frequency of concomitant diseases between groups. No statistically significant differences in LAEF, LA max volume, LA min volume, or LA stroke volume were identified between baseline and follow up CMRs for the PVI only group nor the PVI plus PWI group. When utilizing linear regression analysis to compare change in LAEF, LA max volume, LA min volume, and LA stroke volume before and after ablation between groups, no statistically significant differences were identified.

Cardiac MRI did not demonstrate a significant change in left atrial mechanical function as measured by left atrial ejection fraction after pulmonary vein isolation alone nor after PVI plus posterior wall isolation.