Julio Garcia1,2,3,4,5, Hana Sheitt1, Michael S Bristow1,6, Carmen Lydell1,7, Andrew G Howarth1,3, Bobak Heydari1,3, Frank S Prato8, Maria Drangova8,9, Rebecca E Thornhill10, Pablo Nery11, Stephen B Wilton1, Allan Skanes12, James A White1,3. 1. Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada. 2. Department of Radiology, University of Calgary, Calgary, AB, Canada. 3. Stephenson Cardiac Imaging Centre, University of Calgary, AB, Canada. 4. Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada. 5. Alberta Children's Hospital Research Institute. 6. Department of Medicine, University of Calgary, Calgary, AB, Canada. 7. Diagnostic Imaging, University of Calgary, Calgary, AB, Canada. 8. Department of Medical Biophysics, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada. 9. Imaging Research Laboratories, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada. 10. Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada. 11. Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, ON, Canada. 12. Department of Medicine, University of Western Ontario, London, ON, Canada.
Abstract
BACKGROUND: Characterization of left atrial (LA) hemodynamics in paroxysmal atrial fibrillation (PAF) may provide valuable insights for thromboembolic risk. PURPOSE: To evaluate LA vortex formation and velocity distributions by 4D flow MRI and identify associations with age, LA/LV (left ventricle) function, and established risk scores. STUDY TYPE: Prospective clinical. POPULATION: Patients with PAF (n = 45, 46 ± 14 years) and healthy controls (n = 15, 54 ± 9 years) were enrolled. MRI SEQUENCES: 3T standardized cardiac MRI protocol inclusive of 4D flow MRI. ASSESSMENT: Flow analysis planes were prescribed at each pulmonary vein. Velocity distribution analysis and vortex size quantification by the Lambda2 (λ2 ) method were performed in the LA. STATISTICS: Pearson or Spearman's correlation coefficients, r, were calculated to identify relationships between 4D flow-derived LA parameters and age, LA/LV function, and CHA2 DS2 -VASc stroke risk score. Univariate and multivariate determinants of stroke risk were assessed using linear regressions. To compare parameters within multiple groups, one-way analysis of variance or Kruskal-Wallis was used. RESULTS: LA vortice sizes were observed in all subjects using λ2 showing inverse correlations with peak pulmonary vein inflow velocities (P < 0.05), and positive correlations with LA volume (P < 0.05). Vortex size was elevated in PAF at all phases of the cardiac cycle, being most prominent at end early diastole (3.98 ± 1.84 cm3 vs. 6.93 ± 3.11 cm3 , P = 0.001). Velocity distribution analysis showed a greater incidence of flow stasis among patients with PAF (P < 0.05). In univariate regression, vortex size was associated with the CHA2 DS2 -VASc risk score at peak systole (0.457 ± 0.038, P ≤ 0.001). However, in multivariate regression age was the dominant determinant of stroke risk (0.348 ± 0.012, P = 0.006). DATA CONCLUSION: This study demonstrated that LA vortex size is increased among low-risk patients with PAF and is associated with the CHA2 DS2 -VASc risk score. Age remained the dominant determinant of stroke risk. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:871-884.
BACKGROUND: Characterization of left atrial (LA) hemodynamics in paroxysmal atrial fibrillation (PAF) may provide valuable insights for thromboembolic risk. PURPOSE: To evaluate LA vortex formation and velocity distributions by 4D flow MRI and identify associations with age, LA/LV (left ventricle) function, and established risk scores. STUDY TYPE: Prospective clinical. POPULATION: Patients with PAF (n = 45, 46 ± 14 years) and healthy controls (n = 15, 54 ± 9 years) were enrolled. MRI SEQUENCES: 3T standardized cardiac MRI protocol inclusive of 4D flow MRI. ASSESSMENT: Flow analysis planes were prescribed at each pulmonary vein. Velocity distribution analysis and vortex size quantification by the Lambda2 (λ2 ) method were performed in the LA. STATISTICS: Pearson or Spearman's correlation coefficients, r, were calculated to identify relationships between 4D flow-derived LA parameters and age, LA/LV function, and CHA2 DS2 -VASc stroke risk score. Univariate and multivariate determinants of stroke risk were assessed using linear regressions. To compare parameters within multiple groups, one-way analysis of variance or Kruskal-Wallis was used. RESULTS: LA vortice sizes were observed in all subjects using λ2 showing inverse correlations with peak pulmonary vein inflow velocities (P < 0.05), and positive correlations with LA volume (P < 0.05). Vortex size was elevated in PAF at all phases of the cardiac cycle, being most prominent at end early diastole (3.98 ± 1.84 cm3 vs. 6.93 ± 3.11 cm3 , P = 0.001). Velocity distribution analysis showed a greater incidence of flow stasis among patients with PAF (P < 0.05). In univariate regression, vortex size was associated with the CHA2 DS2 -VASc risk score at peak systole (0.457 ± 0.038, P ≤ 0.001). However, in multivariate regression age was the dominant determinant of stroke risk (0.348 ± 0.012, P = 0.006). DATA CONCLUSION: This study demonstrated that LA vortex size is increased among low-risk patients with PAF and is associated with the CHA2 DS2 -VASc risk score. Age remained the dominant determinant of stroke risk. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:871-884.
Authors: Liliana Ma; Jérôme Yerly; Lorenzo Di Sopra; Davide Piccini; Jeesoo Lee; Amanda DiCarlo; Rod Passman; Philip Greenland; Daniel Kim; Matthias Stuber; Michael Markl Journal: Magn Reson Med Date: 2021-01-05 Impact factor: 3.737
Authors: Aaron T Hess; Rohan S Wijesurendra; Marco Spartera; Guilherme Pessoa-Amorim; Antonio Stracquadanio; Adam Von Ende; Alison Fletcher; Peter Manley; Stefan Neubauer; Vanessa M Ferreira; Barbara Casadei Journal: J Cardiovasc Magn Reson Date: 2021-03-22 Impact factor: 5.364
Authors: Marco Spartera; Antonio Stracquadanio; Guilherme Pessoa-Amorim; Adam Von Ende; Alison Fletcher; Peter Manley; Vanessa M Ferreira; Aaron T Hess; Jemma C Hopewell; Stefan Neubauer; Rohan S Wijesurendra; Barbara Casadei Journal: Eur Heart J Cardiovasc Imaging Date: 2021-12-18 Impact factor: 9.130
Authors: Mark T Mills; Ciaran Grafton-Clarke; Gareth Williams; Rebecca C Gosling; Abdulaziz Al Baraikan; Andreas L Kyriacou; Paul D Morris; Julian P Gunn; Peter P Swoboda; Eylem Levelt; Vasiliki Tsampasian; Rob J van der Geest; Andrew J Swift; John P Greenwood; Sven Plein; Vass Vassiliou; Pankaj Garg Journal: Wellcome Open Res Date: 2021-05-18