Cardiac magnetic resonance of acute atrial ablation injury - impact of catheter-myocardium contact force

Background Catheter-myocardium contact force (CF) is a major determinant of ablation lesion generation in the atrium, with higher CF associated with greater energy transfer. Previous publications have suggested that acute atrial injury can be visualized with T2-weighted (T2W) cardiac magnetic resonance (CMR). This study therefore sought to compare T2W images of acute ablation lesions created at low and high CF. Methods Under general anesthesia, femoral venous access was obtained in eight male Gottingen minipigs. In two animals, pre-ablation T2W CMR imaging was performed. Using fluoroscopy, a decapolar reference catheter was placed in the coronary sinus and a force-sensing ablation catheter (SmartTouch, D curve, Biosense Webster) was advanced into the right atrium. Using an electroanatomical mapping system (Carto3-MEM) the geometry of the right atrium was obtained with a 20-pole circular mapping catheter (Lasso Nav, D curve, Biosense Webster). A linear ablation lesion was created from the SVC to the IVC (30W, 48°C, 8 ml/min irrigation). Different target contact forces (>20 g (high force) or <10 g (low force)) were used alternately at the cranial and caudal halves of the ablation line. After the ablation procedure, the animals were immediately transferred for T2W CMR imaging of the ablation lesion. Maximal wall thickness in the posterior right atrium was measured for the caudal and cranial portions of the ablation lines. Results