Title: Circumferential Pulmonary Vein Isolation and Linear Left Atrial Ablation as a Single-Catheter Technique to Achieve Bidirectional Conduction Block: The Pace-and-Ablate Approach
Topic: Arrhythmias
Date Posted: 2/25/2010
Author(s): Eitel C, Hindricks G, Sommer P, et al.
Citation: Heart Rhythm 2010;7:157-164.
Clinical Trial: No
Study Question: Can conduction block in the atrium after radiofrequency catheter ablation (RFCA) be accurately assessed with a single catheter?
Methods: RFCA to achieve antral pulmonary vein isolation (PVI) in all patients and also block across posterior left atrial ablation lines in patients with persistent atrial fibrillation (AF) was performed in 147 patients (mean age 57 years) with AF. A single irrigated-tip ablation catheter was used for antral PVI and linear ablation. Global atrial capture during pacing at 10 volts from the ablation catheter along the ablation line was used to identify gaps where additional RFCA was necessary to attain complete exit block. PVI was then verified with a conventional ring catheter.
Results: Using the “pace-and-ablate” approach, complete PVI was achieved in 95% of patients and confirmed with a ring catheter in 94% of patients. Complete conduction block was achieved across 74% of the posterior left atrial ablation lines. There was freedom from AF in 84% of patients at 12 months.
Conclusions: Conduction block can be reliably achieved across circumferential and linear atrial ablation lines using a single ablation catheter that is used to confirm conduction block by the absence of atrial capture when pacing along the ablation line.
Perspective: Conventional PVI is performed using an ablation catheter and a ring catheter to monitor the pulmonary veins. The advantage of the 'pace-and-ablate' strategy used in this study is that only a single catheter is necessary in the left atrium. A disadvantage of this technique is that it does not identify the number or locations of the gaps in the ablation lines. Fred Morady, M.D., F.A.C.C.
Title: Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: Proposed Modification of the Task Force Criteria
Topic: Arrhythmias
Date Posted: 2/25/2010
Author(s): Marcus FI, McKenna WJ, Sherrill D, et al.
Citation: Circulation 2010;Feb 19:[Epub ahead of print].
Clinical Trial: No
Study Question: How can the sensitivity and specificity of the original Task Force criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) be improved?
Methods: One hundred eight patients with genetically confirmed ARVC/D were compared to normal subjects. Multiple parameters were analyzed and diagnostic criteria were selected based on receiver operating characteristic curves that identified optimal sensitivity and specificity.
Results: A definite diagnosis of ARVC/D is warranted in the presence of two major criteria, one major plus two minor criteria, or four minor criteria. The major criteria identified in this study were: 1) right ventricular (RV) akinesia, dyskinesia, or aneurysm by magnetic resonance imaging (MRI), echocardiography, or angiography; 2) fibrous replacement (>50%) of RV myocardium on biopsy; 3) T-wave inversion in V1-V3; 4) epsilon wave in V1-V3; 5) ventricular tachycardia (VT) with a left bundle branch block morphology and superior axis; 6) ARVC/D in a first-degree relative based on Task Force criteria or pathologic confirmation; and 7) the presence of an ARVC/D-related mutation. The minor criteria included (but were not limited to) an abnormal signal-averaged electrocardiogram, VT with a left bundle branch block morphology and inferior axis, and confirmed ARVC/D in a second-degree relative.
Conclusions: The updated Task Force criteria are likely to improve the accuracy with which ARVC/D is diagnosed based on structural, histological, electrocardiographic, arrhythmic, and genetic criteria.
Perspective: ARVC/D is characterized by fibrofatty replacement of the RV myocardium. In the past, thinning of the RV wall and fatty infiltration identified by MRI were felt to be reliable diagnostic criteria. However, normal subjects now are recognized as sometimes having fatty replacement without any fibrous component, and this has impaired the specificity of MRI. Fred Morady, M.D., F.A.C.C.
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