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Introduction: Reconduction across an ablation line is the most common reason for arrhythmia recurrence over time e.g. pulmonary vein (PV) and box lesion. Hybrid procedure combines the best of cardiac surgery (epicardial ablation of PVs and box lesion creation) and electrophysiologist (endocardial touchups if necessary to ensure any missed electrical gaps). This procedure is indicated for patients of longer duration of atrial fibrillation and with dilated left atrium. To create a transmural lesion, contact force (CF) between the ablation tip and cardiac tissue is one of the major determinant parameters for radiofrequency catheters. Low CF may lead to an inadequate lesion. However, if very high then is associated with increased risk of significant complications such as thrombus formation, catheter tip charring, steam pop formation and also cardiac perforation. Contact force monitoring is a significant new parameter for titration of the contact force for an adequate lesion creation.
Methods: All AADs were stopped 5 days before the procedure except for patients on Amiodarone. All 20 patients underwent PV isolation using epicardial bipolar radiofrequency clamps. Box lesion was made epicardially using bipolar radiofrequency isolator pen or cool rail. Then electrophysiologist checked for electrical isolation of the ablation lines by pacing maneuvers, voltage mapping (using electroanatomical mapping) and adenosine bolus administration. CF catheter was used for further ablation (if needed) to complete above lines, cavo-tricuspid isthumus line (CTI) and complex fractionated atrial electrogram (CFAE) ablation (table 1).
Results: Endocardial touchup was needed for 1 PV and 4 box lesions. It was also used for creation of CTI line in 4 patients.
Conclusion: Use of TS catheters is safe and feasible and also complementary to hybrid procedure setup for atrial fibrillation ablation.
Table 1: Patient Characteristics

Variables	Number
Patients (n) Gender (men/women) Age (years) BMI Tested pulmonary veins (n) Touch up needed in pulmonary veins (n,%) Tested box lesions (n) Touch up needed in box (n,%) Additional CTI ablation (n, %) Additional mitral line ablation CFAE ablation (n,%) Average procedure time (minutes) Medical History Hypertension (n, %) Diabetes (n, %) CAD (n, %) COPD (n, %) Medication Use Amiodarone Flecainide Sotalol Disease Characteristics Paroxysmal/persistent/permanent AF (n/n/n, %/%/%) AF duration (years, mean±SD) LVEF (%, mean±SD) LA volume (cc, mean±SD) Number of prior catheter ablation (n, %) Number of prior electrical/pharmacological cardioversions (n, %)	20 17/3 60.8±7.2 27.4± 3.4 80 1(1.2%) 20 4(20%) 4(20) 0 7(35) 242±57 8(40) 2 (10) 8(40.0%) 1(5) 1(9.0%) 6(55.5%) 2(18.1%) 8,9,3(40,45,15) 6.3±4.3 52±14 93±25 5(20) 14(70%)

AF indicates atrium fibrillation; BMI=body mass index; n=numbers; CTI= cavo tricuspid isthmus; CAD=coronary artery disease; CHF=congestive heart failure; LVEF=left ventricle ejection fraction; LA=left atrial; SD=standard deviation; AFl= atrial flutter.