Background We investigated the prevalence and the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs) originating from the para‐Hisian area. Methods Among 250 patients with idiopathic VAs, 8 (3.2%) had an ablation site in the para‐Hisian region. For comparison with right ventricular (RV) para‐Hisian VAs (n=6), 27 patients with VAs originating from the posterior RV outflow tract (RVOT) were studied. Results Para‐Hisian VAs had an R wave in leads I and aVL. The VAs originating from the site below the His bundle region were determined to have a superior axis (n=4, 50%). A His potential was recorded at the proximal bipole of the successful ablation site in 6 patients. RV para‐Hisian VAs had a narrower QRS width (114±12 ms vs. 139±12 ms, P=0.003), as well as a higher incidence of R waves in lead aVL (83.3% vs. 0%, P<0.001) and QS waves in lead V1 (83.3% vs. 22.2%, P=0.004) compared to posterior RVOT VAs. A greater R wave amplitude in lead I (1.15±0.34 mV vs. 0.34±0.18 mV, P=0.001) and a smaller R wave amplitude in the inferior leads (0.68±0.23 mV vs. 1.58±0.55 mV, P<0.001), with a higher R wave amplitude ratio in leads II/III (4.2±2.0 vs. 1.1±0.2, P=0.01) were the major ECG characteristics. Conclusions Para‐Hisian VAs have distinctive electrocardiographic features and can be successfully eliminated without disturbance of atrioventricular conduction.

A half of patients with persistent AF refractory to LA ablation successfully converted to AT or SR during automated CFAE-guided ablation at the RA. The most common critical sites for AF termination were the CT and RA appendage and septum. Patients with AF termination during procedure whether LA CFAE only or after RA CFAE ablation had better outcome with less late recurrence of atrial tachyarrhythmia compared to those without AF termination.

This study evaluated the feasibility and accuracy of three-dimensional rotational angiography (3DRA) to determine the anatomy of the left atrium (LA) and pulmonary veins (PVs) compared with cardiac computed tomography (CCT) and trans-thoracic echocardiography (TTE). One hundred two patients (56.1 ± 9.9 years, 86 males) with an indication for atrial fibrillation ablation were prospectively enrolled. Intra-procedural 3DRA was performed with power injected contrast medium (20 cc/s for 4 s, 240°) in the LA. 3DRA images of the LA and PVs were assessed qualitatively and then compared quantitatively. LA volume measured by 3DRA, CCT and TTE were compared. The majority of 3DRA acquisitions were optimal in delineating the right-side LA-PV (95 % for right superior PV and 96 % for right inferior PV) and left inferior PV anatomy (91 %), whereas it was optimal in only 63 % of left superior PV and 73 % of the LA appendage. The circumferences of PV ostia identified by 3DRA and CCT were correlated in four PVs (r = 0.57 for right superior PV, r = 0.67 for right inferior PV, r = 0.60 for left superior PV, and r = 0.52 for left inferior PV, p < 0.001). The mean LA volume measured by 3DRA (120 ± 32 mL) was greater than that found by CCT (109 ± 35 mL) or TTE (64 ± 23 mL), but the 3DRA LA volume measurements correlated well with those of CCT (r = 0.83, p < 0.001) and TTE (r = 0.69, p < 0.001). Intra-procedural 3DRA provided anatomical accuracy of LA and PVs comparable to those of CCT. However, optimal delineation of the left superior PV and LA appendage was limited. The LA volume determined by 3DRA was well correlated with those of CCT and TTE, despite different absolute values of each.

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