Abstract 17798: “The Left Main Coronary Artery - A Potential Hazard During Ablation of Left Atrial and Outflow Tract Arrhythmias”
Introduction: Left main coronary artery (LMCA) damage is an uncommon but catastrophic complication of cardiac ablation procedures. Tissue necrosis can occur within 5 mm of radiofrequency (RF) energy application, with highest risk within 2mm.
Hypothesis: We tested the hypothesis that the LMCA may be exposed to risk of injury in RF ablation procedures for left atrial and outflow tract arrhythmias. The anatomic relationship of the LMCA to these adjacent structures was assessed using analysis of computed tomographic coronary angiograms (CTCA).
Methods: We studied 100 patients (55 males, age 51±10 years) who were investigated for chest pain with CTCA acquired using General Electric Discovery CT 750 HD (GE Healthcare, GE Medical Systems, Milwaukee, WI) with slice thickness of 0.625mm. Measurements were made of the LMCA and adjacent structures, and the relationships between them were described by analysis of 2D images and 3D reconstructions using OsiriX open-source DICOM viewer (OsiriX; Pixmeo, Geneva, Switzerland).
Results: The LMCA coursed within 5 mm of the anterior left atrial (LA) endocardium and/or base of LA appendage (LAA) in 49% (within 2 mm in 17%) - see figure. LMCA was < 5mm from the pulmonary artery (PA) in 90% (within 2 mm in 43%) but was within 5 mm of the right ventricular outflow tract (RVOT) in only 1%. In 4% the LMCA coursed inferiorly, remaining within 5 mm of the left aortic sinus of Valsalva (LASV) at a vertical distance of >5 mm from the inferior margin of the LMCA ostium.
Conclusions: The LMCA is often intimately related to the anterior LA, LAA base, and PA and occasionally to the inferior part of the LASV, and is thus exposed to the risk of injury during ablation in these areas. The LMCA is rarely close to the RVOT.
Author Disclosures: K.A. Walsh: None. G.J. Fahy: None.
- © 2014 by American Heart Association, Inc.