Abstract 2444: Demonstration of Colorfully Visualized 3D Thickness of Left Atrial Myocardiun Obtained by 64ch Multi-detector CT: Implications for Catheter Ablation of Atrial Fibrillation
Background: Pulmonary vein (PV) isolation is useful for treatment of paroxysmal or persistent atrial fibrillation. However, this procedure is occasionally complicated with cardiac tamponade or atrio-esophageal fistula. To avoid such complications, radiofrequency ablation should not be applied to the thin left atrium (LA). For this purpose, we developed a novel visualization method to color LA wall thickness.
Method: 200 patients with ischemic heart disease or paroxysmal atrial fibrillation underwent 64ch multi-detector CT. Thickness of the septal, inferior, posterior, superior and lateral walls of LA was measured every 1.25mm interval. We subsequently reconstructed colorfully visualized 3D scanned image of the LA wall thickness using an analyzing software (CARDIQ, GE, USA).
Results: LA wall was not homogeneously thick as demonstrated in gradations of color ranging from 0.3 to 3.2 mm. Its thickness measured 2.2±0.7mm, 2.0±0.5mm, 1.8±0.8mm at 10mm apart from right superior PV, right inferior PV, and left superior PV, respectively (NS). However, LA wall near left inferior PV (1.0±0.3mm, p<0.0005) was significantly thinner than any other portions of LA. In addition, 80% of our cases had close contact of LA posterior wall with esophagus at its junction of left superior and inferior PVs. Hence, radiofrequency ablation of the inferoposterior portion of LA should be conducted with the uttermost care and attention.
Conclusions: Visualization of 3D wall thickness of LA by 64ch multi-detecdtor CT gives us precise information on where to ablate and where not to ablate for PV isolation. This method will certainly minimize occurrence of cardiac tamponade and atrio-esophageal fistula.