Procedures were performed either under conscious sedation or general anesthesia. Using femoral venous and arterial access multipolar electrode catheters were positioned in the coronary sinus to GCV, the right ventricular (RV) apex and the His bundle region. For the patients © 2014 American Heart Association, Inc. Original Article Circ Arrhythm ElectrophysiolBackground-Catheter ablation for ventricular arrhythmia (VA) near the distal great cardiac vein (GCV) is often challenging, and data are limited. Methods and Results-Analysis was performed in 30 patients (19 men; age, 52.8±15.5 years) who underwent catheter ablation for focal VA (11 ventricular tachycardia and 19 premature contractions) with early activation in the GCV (36.7±8.0 ms pre-QRS). Angiography in 27 patients showed earliest GCV site within 5 mm of a coronary artery in 20 (74%). Ablation was performed in the GCV in 15 patients and abolished VA in 8. Ablation was attempted at adjacent non-GCV sites in 19 patients and abolished VA in 5 patients (4 from the left ventricular endocardium and 1 from the left coronary cusp); all success had VA with an initial r wave in lead I and activation ≤7 ms after the GCV (GCV-non-GCV interval). In 13 patients, percutaneous epicardial mapping was performed, but because of adjacent coronaries only 2 received radiofrequency application with VA elimination in 1. Surgical cryoablation was performed in 3 patients and abolished VA in 2. Overall acute success was achieved in 16 (53%) patients. After a median of 2.8 months, 13 patients remained free of VA. Major complications occurred in 4 patients, including coronary injury requiring stenting. Conclusions-Ablation for this arrhythmia is challenging and often limited by the adjacent coronary vessels. Success of anatomically guided endocardial ablation may be identified by a short GCV-non-GCV interval and r wave in lead I. Nagashima et al Ventricular Arrhythmias Near the GCV 907with a history of sustained VT, programmed ventricular stimulation was performed with ≤3 extrastimuli scanned to a minimum coupling interval of 180 ms after basic drives of 600 and 400 ms from 2 RV sites and burst pacing. If sustained VT was not reliably inducible, nonsustained VT or PVCs felt likely to be originating from the same site were targeted. Intravenous infusion of isoproterenol and epinephrine was administered as needed for arrhythmia induction. Mapping and ablation were performed using a 3.5-mm tip catheter (NaviStar ThermoCool or ThermoCool SF; Biosense Webster, Diamond Bar, CA) in 25 patients. In 5 patients, a 4-mm-tip nonirrigated catheter (NaviStar; Biosense Webster) was used initially for mapping (5 patients) and attempted ablation (3 patients) before switching to an irrigated tip catheter. Activation mapping of VT or PVCs used an electroanatomic mapping system (CARTO 3 or XP; Biosense Webster) with bipolar electrograms high-pass filtered at 20 to 30 Hz and low-pass filtered at 400 Hz. Bipolar electrograms were also band pass filtered from 30 to 500 Hz and digitally recorded along with ...

Background Efforts to reduce radiation from cardiac computed tomography (CT) are essential. Using a prospectively triggered, high-pitch dual source CT (DSCT) protocol, we aim to determine the radiation dose and image quality (IQ) in patients undergoing pulmonary vein (PV) imaging. Methods and Results In 94 patients (61±9 years, 71% male) who underwent 128-slice DSCT (pitch 3.4), radiation dose and IQ were assessed and compared between 69 patients in sinus rhythm (SR) and 25 in atrial fibrillation (AF). Radiation dose was compared in a subset of 19 patients with prior retrospective or prospectively triggered CT PV scans without high-pitch. In a subset of 18 patients with prior magnetic resonance imaging (MRI) for PV assessment, PV anatomy and scan duration were compared to high-pitch CT. Using the high-pitch protocol, total effective radiation dose was 1.4 [1.3, 1.9] mSv, with no difference between SR and AF (1.4 vs 1.5 mSv, p=0.22). No high-pitch CT scans were non-diagnostic or had poor IQ. Radiation dose was reduced with high-pitch (1.6 mSv) compared to standard protocols (19.3 mSv, p<0.0001). This radiation dose reduction was seen with SR (1.5 vs 16.7 mSv, p<0.0001) but was more profound with AF (1.9 vs 27.7 mSv, p=0.039). There was excellent agreement of PV anatomy (kappa 0.84, p<0.0001), and a shorter CT scan duration (6 minutes) compared to MRI (41 minutes, p<0.0001). Conclusions Using a high-pitch DSCT protocol, PV imaging can be performed with minimal radiation dose, short scan acquisition, and excellent IQ in patients with SR or AF. This protocol highlights the success of new cardiac CT technology to minimize radiation exposure, giving clinicians a new low-dose imaging alternative to assess PV anatomy.

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