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Background A percutaneous intravascular cardioverter-defibrillator (PICD) has been developed with a right ventricular (RV) single-coil lead and titanium electrodes in the superior vena cava (SVC)–brachiocephalic vein (BCV) region and the inferior vena cava (IVC). Objective To compare defibrillation thresholds (DFTs) of the PICD with those of a conventional ICD in humans. Methods Ten patients with ischemic cardiomyopathy and ejection fraction ≤35% were randomized to initial testing with either PICD or conventional ICD. A standard dual-coil lead was positioned in the RV apex. If randomized to PICD, the device was placed into the vasculature such that 1 titanium electrode was positioned in the SVC-BCV region and the second in the IVC. For PICD DFTs, the RV coil of the conventional ICD lead was connected to the PICD mandrel [shock vector: RV (+) to SVC-BCV (−) + IVC (−)]. When testing the conventional ICD, a subcutaneous pocket was formed in the left pectoralis region and the ICD was connected to the lead system and positioned in the pocket [shock vector: RV (+) to SVC (−) + active can (−)]. Each device was removed before testing with the other. A step-down binary search protocol determined the DFT, with the initial shock being 9 J. Results The mean PICD DFT was 7.6 ± 3.3 J, and the conventional ICD system demonstrated a mean DFT of 9.5 ± 4.7 J (N = 10; paired t test, P = .28). Conclusion The intravascular defibrillator has DFTs similar to those of commercially available ICDs.

Background Atrial fibrillation is associated with an increased risk of embolic events. The left atrial appendage (LAA) is believed to be an incubator for thrombus formation. LAA exclusion has been advocated to potentially reduce embolic events arising from the LAA. Objective The aim of the study was to determine the feasibility of a closed-chest surgical suture ligation of the LAA in man. Methods Thirteen patients undergoing either mitral valve surgery (n = 2) or electrophysiological study and radiofrequency catheter ablation for atrial fibrillation (n = 11) underwent ligation of the LAA with the LARIAT snare device. In patients having an ablation procedure, pericardial access was obtained prior to the patients undergoing radiofrequency catheter ablation. After transseptal catheterization, endocardial and epicaridal magnet-tipped guide wires were positioned under fluoroscopic guidance to stabilize the LAA. Transesophageal echocardiography (TEE) was used as guidance for positioning a marker balloon at the ostium of the LAA. An over-the-wire approach was used to guide the LARIAT snare device over the LAA to allow closure and suture ligation of the LAA. TEE and contrast fluoroscopy were used to confirm acute closure of the LAA. Results Both mitral valve replacement (MVR) patients had complete closure of the LAA determined by visual inspection. Ten of 11 patients having ablation underwent a successful closed-chest LAA ligation procedure with TEE and contrast fluoroscopy verification of closure of the LAA. Only one of 11 procedures was terminated owing to the lack of echocardiography guidance of the snare over the marker balloon. One patient with pectus excavatum did have ligation of his LAA; however, a thorascopic procedure was required to remove the snare from the LAA owing to compression of the LARIAT by the concave sternum. There were no other significant complications. Conclusions Catheter-based surgical suture ligation of the LAA is feasible in humans. This novel catheter approach may be appropriate for patients with atrial fibrillation who are ineligible for anticoagulation therapy. Further investigation is needed to demonstrate the long-term safety and efficacy of LAA closure.