Centerline Tracking for Quantification of Reverse Structural Remodeling of the Pulmonary Veins Following Cardiac Ablation Therapy

Abstract

Rationale and Objectives Patients with atrial fibrillation undergo structural remodeling resulting in increased pulmonary vein sizes. Studies have demonstrated that these changes are reversible following successful ablation therapy. To date, analyses of pulmonary vein structure have focussed on measurements at the pulmonary vein ostia and the full extent of reverse remodeling along the length of the pulmonary veins has not yet been fully characterized. Materials and Methods An automated, three-dimensional method is proposed which quantifies pulmonary vein geometry starting at the ostia and extending several centimeters into the veins. A centerline is tracked along the length of the pulmonary vein and orthogonal planes are computed along the curve. The method is validated against manual measurements on each of the four pulmonary veins for 10 subjects. The proposed methodology is used to analyze the pulmonary veins in 21 patients undergoing cardiac ablation therapy with pre- and post-operative CT scans. Results Validation results demonstrate that the automated measurements closely follow the manual measurements with an overall mean difference of 11.50 mm2. Significant differences in cross-sectional area at the two time-points were observed at all pulmonary vein ostia and extending for 1.5 cm (excluding the 1.0 cm interval) into the left inferior pulmonary vein, 3.0 cm into the left superior pulmonary vein, and 0.5 cm into the right superior pulmonary vein. Conclusions Quantitative analysis along the length of the pulmonary veins can be accomplished using centerline tracking and measurements from orthogonal planes along the curve. The patient study demonstrates that reverse structural remodeling following ablation therapy occurs not only at the ostia, but for several centimeters extending into the pulmonary veins.

Physiology: Beating stroke

“…There has never been a large, multicentre trial to assess cases of AF complicated by underlying disease, says Douglas Packer, a specialist in cardiovascular disease at the Mayo Clinic in Rochester, Minnesota. Packer hopes to fill that gap: he is the lead investigator of CABANA (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation), a study that plans to compare catheter ablation and drug treatment in 3,000 patients over a period of 2-5 years 3 . In a pilot study -presented at the 2010 American College of Cardiology Scientific Sessions -that followed 60 patients for a year, 65% of those who underwent ablation had no recurrence of symptoms, compared with only 41% of those taking anti-arrhythmia drugs.…”