Background-We identified a gene (PRKAG2) that encodes the ␥-2 regulatory subunit of AMP-activated protein kinase (AMPK) with a mutation (Arg302Gln)

Sawaya SE, Rajawat YS, Rami TG, Szalai G, Price RL, Sivasubramanian N, Mann DL, Khoury DS. Downregulation of connexin40 and increased prevalence of atrial arrhythmias in transgenic mice with cardiac-restricted overexpression of tumor necrosis factor.

VOM signals are consistently present in recurrent AF. VOM may rarely play a role in PV reconnection. However, VOM ethanol infusion can be useful in patients with recurrent AF after PVAI, assisting in achieving redisconnection of reconnected left PVs.

Objective To investigate incidence and timing, risk factors, prognostic significance, and electrophysiological mechanisms of atrial arrhythmia (AA) after lung transplantation. Background Although new-onset AA is common after thoracic surgery and is associated with poorer outcomes, prognostic and mechanistic data is sparse in lung transplant populations. Method A total of 293 consecutive isolated lung transplant recipients without known AA were retrospectively reviewed. Mean follow-up was 28±17 months. Electrophysiology studies (EPS) were performed in 25 patients with AA. Results The highest incidence of new-onset AA after lung transplantation occurred within 30 days postoperative AA, (25 % of all patients). In multivariable analysis, postoperative AA was associated with double lung transplantation (OR 2.79; p=0.005) and lower mean pulmonary artery pressure (OR 0.95; p=0.027). Patients with postoperative AA had longer hospital stays (21 days vs 12 days; p<0.001). Postoperative AA was independently associated with late AA (HR 13.52; p<0.001) but not mortality (HR 1.55; p=0.14). In EPS, there were 14 patients with atrial flutter alone and 11 with atrial flutter and fibrillation. Of all EPS patients, 20 (80%) had multiple AA mechanisms, including peritricuspid flutter (48%), perimitral flutter (36%), right atrial incisional reentry (24%), focal tachycardia from recipient pulmonary vein (PV) antrum (32 %), focal PV fibrillation (24%), and left atrial roof flutter (20%). Left atrial mechanisms were present in 80% (20/25) of EPS patients and originated from the anastomotic PV antrum. Conclusions Postoperative AA was independently associated with longer length of stay and late AA but not mortality. Pleomorphic PV antral arrhythmogenesis from native PV antrum is the main cause of AA after lung transplantation.

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Objectives To test the technical feasibility of robotic catheter ablation of left ventricular (LV) tachycardia (VT) using the Hansen Sensei® Robotic system (HRS). Background Catheter ablation of VT can be technically challenging due to difficulty with catheter positioning in the LV and achieving stable contact. The HRS has been used in atrial fibrillation but its utility in VT is unclear. Methods Twenty-three patients underwent LV VT mapping and ablation with the HRS via a trans-septal, trans-mitral valve approach. Nineteen patients underwent substrate mapping and ablation (18 had ischemic cardiomyopathy, one had an apical variant of hypertrophic cardiomyopathy). Four patients had focal VT requiring LV VT mapping and ablation. Procedural endpoints included substrate modification by endocardial scar border ablation and elimination of late potentials, or elimination of inducible focal VT. Results Mapping and ablation were entirely robotic without requiring manual catheter manipulation in all patients and reaching all LV regions with stable contact. Fluoroscopy time of the LV procedure was 22.2 ± 11.2 minutes. Radiofrequency time was 33 ± 21 minutes. Total procedure times were 231 ± 76 minutes. Complications included a left groin hematoma (opposite to the HRS sheath), 1 pericardial effusion without tamponade that was drained successfully, and transient right ventricular failure in a patient with previous left ventricular assist device. At 13.4 ± 6.7 months of follow-up (range 1–19 months), recurrence of VT occurred in 3/23 patients. Conclusions Our initial experience suggests that the HRS allows successful mapping and ablation of LV VT.