Backgrounds: Esophageal damage during pulmonary vein isolation (PVI) may lead to esophageal fistula which still harbors high mortality. Recent implementation of contact-force (CF) measuring technology can reduce unnecessary collateral tissue damage avoiding too high CF application.

Objective: The aim of this study was 1) to evaluate the incidence of esophageal thermal lesions in clinical practice without esophageal temperature monitoring (ETM) during PVI under CF guidance, and 2) to evaluate the potential contribution of applied CF to the formation of endoscopic detected esophageal lesions (EDELs).

Methods: The study population consisted of consecutive 131 patients (75 men [57%]) who underwent PVI and additional left atrial procedures with radiofrequency (RF) ablation due to atrial fibrillation (AF) and atrial tachycardia. The point-by-point catheter ablations were performed with an upper limit of 30 Watts and a maximum CF of 40 grams on the posterior wall without ETM. An endoscopic investigation was performed within 120 hours following the index PVI and the incidence of endoscopic detected esophageal lesions (EDELs) was investigated. As the indices for applied RF ablation, CF, applied energy (J), force-time-integral (FTI) and force-power-time-integral (FPTI) were adopted. The ablation lesions were analysed according to the 4 predefined sites on the left atrial posterior wall around PVs (right postero-superior, postero-inferior, and left postero-superior, postero-inferior).

Results: All pulmonary veins were successfully isolated. Overall 6 patients out of 131 (4.6%, 3 females) developed EDELs after PVI. Out of these 6 patients with EDELs, 2 patients developed pericarditis with increased inflammatory response and pericardial effusion, which did not necessitate pericardial punctures. Between two patient groups with and without EDELs there were no significant differences in patients’ characteristics except for serum creatinine concentration (1.55±1.18 for EDELs(+) vs. 1.07±0.42 mg/dL for EDELs(-), P=0.016) and the incidence of obesity (Body-Mass-Index>30) (1/6 [17%] for EDELs (+) vs. 85/125 [68%] for EDELs (-), P=0.018). The periprocedural parameters including procedure duration, fluoroscopic duration, dose-area-product  and total RF duration (seconds) and total applied energy (J) on the posterior wall showed no significant differences between two groups. In the detailed site-dependent analyses, the duration of applied RF, the applied energy and applied average CF in 4 sites on the LA posterior wall also did not show significant differences. However, FTI and FPTI of the patients with EDELs in the left postero-inferior site were significantly higher as compared to those of the patients without EDELs (2973±3267 vs 1757±1262 g•s, P=0.042; 83547±105940 vs 43556±35255 g•J, P=0.022, respectively). In the other 3 posterior sites of PVs there were no significant differences in FTI and FPTI between the two groups.

Conclusion: The EDELs incidence was relatively low (4.6%) after CF guided PVI as compared to previous data without CF guidance, even without ETM. In our cohort the patients with esophageal thermal damages had higher RF related indices on the postero-inferior site of left PVs. Only the combined indices of applied CF and duration of RF showed these significances. Our data suggest that the CF measuring technology usage with incorporated indices should be used to enhance the procedural safety by reducing incidence of esophageal damage.