Subclinical dysfunction in left atrial compliance after successful cryoballoon versus radiofrequency ablation for paroxysmal atrial fibrillation

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): The Medical Centre of Postgraduate Education. Purpose It has been suggested that cryoballoon ablation (CB) for paroxysmal atrial fibrillation (PAF) may lead to more extensive left atrial (LA) injury than radiofrequency ablation (RF), however, results are conflicting. The aim of our study was to estimate the LA function after successful CB and RF for PAF using transthoracic echocardiography (TTE). Methods 90 pts (66% males, mean age 57±10 years) successfully treated (no AF recurrences confirmed in serial 4–7 day ECG Holter monitoring) with RF (51%) or CB (49%) for PAF were prospectively studied. TTE with speckle tracking (STE) and tissue doppler was performed before and 12 months after the procedure in sinus rhythm. The peak longitudinal LA strain (LAS) during the reservoir (r), conduit (cd) and contraction (ct) phases were measured. The global LAS for each LA phase was calculated by averaging the values observed in all LA segments in the 4- and 2-Chamber views. We set the zero strain point as the time from the beginning of the QRS wave. The velocities of the early (e') and late (a') diastolic phases at the mitral annular septal and lateral corners were measured. Analysis of covariance was applied to compare changes over time with the baseline measurement as covariance and the type of ablation as the factor. The parallelism of the slopes of the covariance was tested. Results Parameters of LA function regarding the mode of ablation at 12 months after the procedure are shown in the table. Significant decrease in LAScd and e’ was observed in the CB subgroup with better preserved baseline values (≥16% and ≥12cm/s respectively). Conclusion Worsening of parameters reflecting LA compliance was observed 12 months after successful CB vs RF ablation for PAF. This might suggest subclinical dysfunction of LA after CB procedure. Clinical significance of this finding warrant further long-term observation.