Epiphenomenal Re-Entry and Spurious Focal Activation Detection by Atrial Fibrillation Mapping Algorithms.

OBJECTIVES: The purpose of this study was to validate the ability of mapping algorithms to detect rotational activations (RoA) and focal activations (FoA) during fibrillatory conduction (FC) and atrial fibrillation (AF) and understand their mechanistic relevance. BACKGROUND: Mapping algorithms have been proposed to detect RoA and FoA to guide AF ablation. METHODS: Rapid left atrial pacing created FC-fibrillatory electrograms-with and without AF induction in dogs (n = 17). Activation maps were constructed using Topera (Abbott, St. Paul, Minnesota) or CARTOFINDER (Biosense Webster, Irvine, California) algorithms. Mapping strategies included: panoramic noncontact mapping with a basket catheter (CARTOFINDER n = 6, Topera n = 5); and sequential contact mapping using 8-spline OctaRay catheter (Biosense Webster) (n = 6). Offline frequency and spectral analysis were also performed. Algorithm-detected RoA was manually verified. RESULTS: The right atrium (RA) consistently exhibited fibrillatory signals during FC. FC with and without AF had similar left-to-right frequency gradients. Basket maps were either uninterpretable (847 of 990 Topera, 132 of 148 Cartofinder) or had unverifiable RoA. OctaRay contact mapping showed 4% RoA (n = 30 of 679) and 63% FoA (n = 429 of 679). Verified RoA clustered at consistent sites, was more common in the RA than left atrium (odds ratio: 3.5), and colocalized with sites of frequency breakdown in the crista terminalis and RA appendage. During pacing, spurious FoA sites were identified around the atria, but not at the actual pacing sites. RoA and FoA site distribution was similar during pacing with and without induction, and during induced AF. CONCLUSIONS: Mapping algorithms were unable to detect pacing sites as true drivers of FC, and detected epiphenomenal RoA and FoA sites unrelated to AF induction or maintenance. Algorithm-detected RoA and FoA did not identify true AF drivers.

Left atrial appendage closure with the Watchman device using intracardiac vs transesophageal echocardiography: Procedural and cost considerations.

BACKGROUND: Imaging guidance for left atrial appendage (LAA) closure (LAAC) conventionally consists of transesophageal echocardiography (TEE) and fluoroscopy under general anesthesia (GA). Intracardiac echocardiography (ICE) can eliminate the need for GA, expedite procedural logistics, and reduce the patient experience to a simple venous puncture. OBJECTIVE: The purpose of this study was to define optimal ICE views and compare procedural parameters and cost of ICE vs TEE during LAAC with the Watchman device. METHODS: Optimal ICE views of the LAA for Watchman implant were delineated using Carto-Sound and 3-dimensional rendition of the LAA in 6 patients. Procedural and financial parameters of 104 consecutive patients with standard indications for LAAC undergoing Watchman implant using ICE guidance through a single transseptal puncture (n = 53 [51%]) were compared with those of TEE-guided implants (n = 51 [49%]) in 3 centers. RESULTS: Clinical characteristics were similar between the 2 groups. Total in-room, turnaround, and fluoroscopy times all were shorter using ICE (P <.05) under local anesthesia compared to the TEE group. Implant success was 100% in both groups without peri-device leaks or procedural complications. Follow-up TEE showed no significant peri-device leak in both groups. Total hospital charges for ICE with local anesthesia vs TEE were similar, as were total hospital direct and indirect costs. Professional fees were significantly lower with ICE and local anesthesia than with TEE because the charge of anesthesia staff was avoided. CONCLUSION: ICE-guided Watchman implant is safe, feasible, and comparable in cost to TEE during LAAC with a Watchman device but avoids GA and expedites procedure turnaround.