Left atrial mechanics predict the success of pulmonary vein isolation in patients with atrial fibrillation.

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia with relevant impact on mortality and morbidity. Pulmonary vein isolation (PVI) is an established therapy in patients who remain symptomatic under optimal medical therapy. However, up to 70% of patients present with recurrence of AF after PVI. Therefore, identifying ideal candidates is an unmet clinical need. Left atrial (LA) fibrosis is associated with reduced LA function. Analysis of LA mechanics using 2D speckle tracking echocardiography (STE) might give more insight into LA substrates and be therefore of predictive value.

METHODS

This prospective single-center pilot study included 31 patients (mean age, 62.3 ± 9.1 years; 19 males) with AF who underwent PVI and 20 matched healthy controls (mean age, 60.6 ± 6.6 years; 10 males). 2D STE strain indices of LA reservoir (RLA), conduit, and, if feasible, contractile function, were analyzed before and 6 months after PVI. Assessment of the LV diastolic function was based on standard indices. Responders to PVI were defined as being asymptomatic and free of AF in a 7-day Holter-ECG after 6 months.

RESULTS

At baseline, all patients with AF had significantly lower reservoir and contractile function compared with controls. After 6 months, 17 patients (54.8%) were identified as responders. At baseline, the reservoir function was significantly higher in responders compared with nonresponders (32.7 ± 11.1 vs. 22.9 ± 10.9%; P = 0.019). Only in responders, RLA and contractile LA function improved and reached normal values whereas LA function remained unchanged in nonresponders. In a ROC analysis, a RLA value of ≥19.5% discriminated responders and nonresponders in patients with persistent AF with a sensitivity of 86% and a specificity of 100% (P = 0.012; area under the curve 0.943; CI, 0.81-1.0).

CONCLUSIONS

LA reservoir function helps to predict efficacy of PVI after 6 months. Only in responders, reservoir, and contractile function normalized within 6 months after PVI indicating a lower level of atrial remodeling at baseline. No deleterious effects of ablation were detected in nonresponders.