The Effect of Contact Force in Atrial Radiofrequency Ablation: Electroanatomical, Cardiovascular Magnetic Resonance, and Histological Assessment in a Chronic Porcine Model.

Abstract Objectives This study sought to determine the effect of contact force (CF) on atrial lesion size, quality, and transmurality by using a chronic porcine model of radiofrequency ablation. Background CF is a major determinant of ventricular lesion formation, but uncertainty exists regarding the most appropriate CF parameters to safely achieve permanent, transmural lesions in the atria. Methods Intercaval linear ablation (30 W, 42°C, 17 ml/min irrigation) was performed in 8 Gottingen minipigs by using a force-sensing catheter with CF >20 g (high force) or  Results Mean CF was 22.6 ± 11.4 g and 7.8 ± 4.0 g in the high and low CF regions. Acute tissue edema was greater with high CF, both caudally (7.0 mm vs. 4.6 mm; p = 0.016) and cranially (6.9 mm vs. 4.6 mm; p = 0.038). There was no difference in chronic lesion size (voltage mapping) or volume (late gadolinium enhancement CMR) between high and low CF regions. There was no difference in scar density (assessed by low-voltage criteria and late gadolinium enhancement signal intensity) or histological transmurality between high and low CF regions. Conclusions Although high CF (>20 g) resulted in more acute tissue edema than low CF (