Cardiac MRI Characterization of the Left Ventricle after Pulmonary Vein Isolation - Abstract
Background: Atrial fibrillation is a disease that is common in developed countries, which can cause impaired systolic function due to regional and global wall motion abnormalities. The symptoms hinder everyday life by dyspnoea and palpitations, which are classified by ERHA (European heart rhythm association score of atrial fibrillation). nMARQ™ was recently introduced as a means of pulmonary vein isolation (PVI); this single-shot device facilitates a quick and safe procedure that generates scar tissue in the left atrium to prevent the conduction of inappropriate electrical signals. Our aim was to characterize the left ventricle with the assessment of global and regional wall motion abnormalities before and after PVI by SENC (strain encoded cardiac imaging) in cardiac MRI. Methods: Twenty atrial fibrillation patients referred for PVI were prospectively enrolled in the study between December 20212 and March 2015 at the University of Duesseldorf with symptomatic atrial fibrillation ERHA III (severe symptoms, normal daily activity affected). Cardiac magnetic resonance imaging (cMRI) was performed using a 1.5-Tesla MR scanner one day before, one day after and three months after the patients underwent PVI with nMARQ. We conducted a standard balanced steady-state free precession (SSFP) sequence to assess left and right ventricular volumes. Strain-encoded (SENC) imaging was performed in four- and two-chamber views to assess the longitudinal strain on the left ventricle. Late gadolinium enhancement (LGE) imaging was performed 10 min after administration of a contrast agent. The one-month follow-up characterization of the left ventricle was conducted with the identical cMRI protocol described above. Results: No adverse events occurred. The average ejection fraction before PVI was 57%; the left ventricle had a diastolic volume of 135 mL and a systolic volume of 58 mL, and the myocardial mass was 155 g. Three months after PVI, the global and regional strain on the left ventricle were significantly reduced relative to pre-PVI levels (p<0.002 and p<0.03, respectively). Conclusion: In this study, the nMARQ system achieved safe PVI that improved quality of life (EHRA I)(no symptoms) in patients with atrial fibrillation. When atrial fibrillation was eliminated, we observed functional recovery of the left ventricle as measured by global and circumferential strain and restoration of the
sinus rhythm one month after PVI.