Arrhythmias
Malcolm Serran
Research Student
Stephenson Cardiac Imaging Centre
Guelph, Ontario, Canada
Malcolm Serran
Research Student
Stephenson Cardiac Imaging Centre
Guelph, Ontario, Canada
Dina Labib, MD, PhD, FSCMR
PhD student
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Alena Yakimenka, MD
Internal Medicine Resident
Libin Cardiovascular Institute of Alberta, University of Calgary; Cumming School of Medicine, Canada
Steven Dykstra, MSc, BSc
PhD Student
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Yoko Mikami, MD, PhD
Core Laboratory Manager
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Jacqueline Flewitt, MSc
Research Collaborations Coordinator
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Patricia Feuchter, MSc, MRT
MRI Research Technologist
Libin Cardiovascular Institute of Alberta, University of Calgary, Canada
Sandra Rivest, RN
Research nurse
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Andrew G. Howarth, MD, PhD
Clinical Co-director
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Carmen P. Lydell, MD
Clinical Co-director
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
F. Russell Quinn, MD
Clinical Associate Professor
Cumming School of Medicine, University of Calgary, Alberta, Canada
Stephen B. Wilton, MD, MSc
Associate Professor
Cumming School of Medicine, University of Calgary
Calgary, Alberta, Canada
James White, MD
Professor of Cardiology
Stephenson Cardiac Imaging Centre
Calgary, Alberta, Canada
Left atrial (LA) contractile health has been proposed as a prognostic marker for atrial fibrillation (AF) recurrence following pulmonary vein isolation (PVI). The predictive value of phasic LA strain amplitude by CMR feature tracking in this role has been poorly explored. In a large series of patients undergoing pre-procedural CMR imaging prior to first time PVI we explored if phasic LA strain amplitude and strain rate (SR) markers were associated with AF recurrence.
Methods:
204 consecutive patients referred for pre-procedural CMR prior to first-time PVI were recruited. 146 patients were in sinus rhythm at time of CMR and had acceptable image quality for strain analysis. Cine images were analyzed using cvi42 (Circle Cardiovascular Inc., Calgary) for bi-planar LA volumes at maximum (LAmax), minimum (LAmin), and pre-atrial contraction (LAprekick) from 2- and 4-chamber views. Reservoir, conduit, and booster global longitudinal strain (GLS) amplitude and SR were calculated from the same views using feature tracking. Multi-chamber volumetric and functional measures were assessed by body surface area and sex-corrected Z-scores to address recognized sex-related differences in these markers. This was achieved through the recruitment of 101 healthy subjects for matched cine imaging. Patients were followed for the primary outcome of clinical AF recurrence. Optimal cut points for each strain marker were determined by ROC curve analysis and entered separately into multivariable models adjusting for age and comorbidities to test independent associations with AF recurrence.
Results: Over a median follow up of 2.5 years, AF recurrence developed in 64 patients (44%). Baseline characteristics stratified by sex, are presented in Table 1. Using Z-score based analysis, females showed similar left ventricular (LV) cavity volumes and ejection fraction (EF) to males, with smaller right ventricular (RV) volumes and higher RV EF. LAmax, LAmin and LAprekick volumes were significantly higher in females with consistently worse phase specific GLS amplitudes and SR’s. Of all six LA strain markers, LA booster GLS amplitude and SR showed significant associations with the primary outcome by univariable Cox regression. Respective optimal cut-off Z-scores for these markers were -2.4 and 2.0, with corresponding Kaplan-Meier curves shown in Figure 1. Adjusting for age, hypertension, and pre-procedural use of anti-arrhythmic medications, these GLS thresholds remained significantly associated with the primary outcome, with adjusted hazard ratios (95% CI) of 0.45 (0.24-0.84; p=0.01) for booster GLS amplitude, and 2.07 (1.15-3.72; p=0.02) for booster GLS SR (Table 2).
Conclusion:
This is the largest study to date exploring associations of phasic LA strain with AF recurrence following first-time PVI. Sex-specific Z-score defined LA booster strain and SR were independently associated with this important adverse clinical outcome. Future prospective large-scale studies are warranted to confirm these findings.