(A) Comparative measures with corresponding SD of CTI length and pouch size between patients with straightforward (Group 1, black columns) and patients with prolonged radiofrequency ablation (RFA) time (Group 2, white columns). (B) Comparative qualitative assessment of prominent anatomic CTI features, and corresponding structural and morphological associations, between patients with straightforward (Group 1, black columns) and those with prolonged RFA time (Group 2, white columns). ‘Pouch’ is considered a profound CTI depression with TS depth ≥8 mm, based on the inferior SD margin around the mean TS depth value of the whole cohort. Long CTI is considered Telediastolic CTI length above the median length >41 mm; low LVEF is considered below the median value of 55%; dilated LA is considered median LA antero-posterior telediastolic diameter >43 mm. CTI, cavotricuspid isthmus; EV, Eustachian valve; ER, Eustachian ridge; LVEF, left ventricular ejection fraction; LA, left atrium; TD, tele-diastolic; TS, tele-systolic.