CT Visualization and Histopathological Assessment of Cryoablation in Pulmonary Veins

Over 2 million adults in the United States are affected by atrial fibrillation (AF), a common cardiac arrhythmia that is associated with decreased survival, increased cardiovascular morbidities, and a decrease in quality of life. Atrial fibrillation can be initiated by ectopic beats originating in the myocardial sleeves surrounding the pulmonary veins [1]. Pulmonary vein (PV) isolation via radiofrequency ablation is the current gold standard for treating patients with drug-refractory AF [2]. However, cryoablation is emerging as a new minimally-invasive technique to achieve PV isolation. Cryoablation is fast gaining acceptance due to its minimal tissue disruption, decreased thrombogenicity, and reduced complications (RF can lead to low rate of pulmonary vein stenosis) [2]. One important question in regard to this technology is whether the PV lesion is transmural and circumferential and to what extent adjacent tissues are involved in the freezing process. As ice formation lends itself to image contrast in the body, we hypothesized that intraprocedural CT visualization of the iceball formation would allow us to predict the extent of the cryolesion and/or provide us with a measure of the adjacent tissue damage.