Simultaneous endo-epicardial mapping of programmed atrial extrasystoles in patients undergoing cardiac surgery

Atrial extrasystoles (AES) are usually innocent, however they can also trigger (post-operative) atrial fibrillation (AF). It is unknown what the arrhythmogenic effect of AES is on 3-dimensional atrial conduction.

Therefore, the aim of this study was to examine the effect of programmed AES (PAES) provoked in the right atrium (RA) on both endo- and epicardial conduction.

Simultaneous endo-epicardial mapping of the RA was performed during PAES provoked from the RA free wall in patients undergoing cardiac surgery (256 electrodes). Areas of conduction block (CB) were defined as conduction delays of ≥12ms and endo-epicardial asynchrony (EEA) as activation time differences of exact opposite electrodes of ≥15ms.

Simultaneous endo-epicardial mapping of the RA during 15 PAES were analyzed and compared with sinus rhythm (SR) (n=12, 58% male, age 68±7 years). Eleven PAES were premature (>25% shortening cycle length (CL)), median preceding CL was 554.5ms [377.9–720.4] and median SR CL was 871ms [700.9–1021]. Amount of EEA (7.3% [2.6–17.8] vs 1% [1–2], p=0.002) and CB (9% [4.8–11.8] vs 1.4% [0.5–2.7, p=0.001) both increased during PAES compared to SR. Diabetes was the only cardiovascular risk factor associated with a higher incidence and degree of EEA and CB. Interestingly, CB during PAES was more severe in 4 patients (33.3%) who developed post-operative AF (11.9% [10.4–12.8] vs 5.4% [3.3–8.5], p<0.001).

Asynchronous activation of the atrial wall and conduction disorders, which play an important role in arrhythmogenesis, are enhanced during PAES compared to SR. Enhanced electropathology together with triggers provoked by heart surgery may initiate post-operative AF.

Type of funding source: None