scholarly journals Quantification of left atrial flow velocity distribution in atrial fibrillation using 4D flow MRI

2013 ◽  
Vol 15 (S1) ◽  
Author(s):  
Jacob U Fluckiger ◽  
Jeffrey J Goldberger ◽  
Daniel C Lee ◽  
Jason Ng ◽  
Richard Lee ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Left Atrial ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri

scholarly journals B-PO04-077 HEART RATE VARIABILITY AND LEFT ATRIAL HEMODYNAMICS IN ATRIAL FIBRILLATION MEASURED WITH 4D FLOW MRI

Heart Rhythm ◽  
2021 ◽  
Vol 18 (8) ◽  
pp. S310
Author(s):  
Amanda DiCarlo ◽  
Justin Baraboo ◽  
Mitchell A. Collins ◽  
Maurice Pradella ◽  
Patrick M. McCarthy ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Left Atrial ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri

Abstract 14026: Atrial Fibrillation is Associated with Altered Left Atrial 3D Hemodynamics and Increased Stasis

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Daniel C Lee ◽  
Michael Markl ◽  
Jason Ng ◽  
Maria Carr ◽  
Brandon C Benefield ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Stroke Risk ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
4D Flow Mri ◽  
4D Flow ◽  
Data Set ◽  
Ventricular Ejection Fraction ◽  
Flow Mri

Introduction: Clinical scores used for stroke risk estimation in atrial fibrillation (AF) have limited predictive accuracy. 4D Flow MRI can acquire blood flow in a volume data set encompassing the entire left atrium (LA) with quantification of blood velocity in 3 orthogonal directions for every voxel at multiple time points throughout the cardiac cycle (4D = 3D coverage + time). Hypothesis: 4D Flow MRI can assess 3D LA flow abnormalities in AF patients, which may potentially be linked to stroke. Methods: We performed 4D flow MRI in 30 volunteers (10 young, 20 older) and 70 patients with a history of AF: 40 in sinus rhythm (AF-sinus) and 30 in AF during MRI scan (AF-afib). The typical LA contained 3000 voxels and 18 phases per voxel. LA flow velocity histograms for each patient were quantified by mean LA velocity, median LA velocity, and the percentage of LA velocities < 0.2 m/s (%stasis). CHA2DS2-VASc scores were calculated for each patient. Results: Mean LA velocity, median LA velocity, and %stasis were significantly different between groups: young volunteers (0.26±0.02 m/s, 0.23±0.02 m/s, 37.3±7.6%), older volunteers (0.21±0.03 m/s, 0.20±0.03 m/s, 52.2±16.0%), AF-sinus (0.18±0.03 m/s, 0.17±0.03 m/s, 67.5±16.9%), and AF-afib (0.16±0.01 m/s, 0.14±0.03 m/s, 78.2±12.9%), p < 0.0125 for all comparisons. CHA2DS2-VASc had moderate but significant correlations with mean LA velocity (R 2 =0.27, p<0.001), median LA velocity (R 2 =0.23, p<0.001), and stasis% (R 2 =0.26, p<0.001). LA flow indices also correlated significantly with age, LA volume, and left ventricular ejection fraction (LVEF) as seen in the Table. Conclusions: Left atrial 4D flow MRI is a novel approach to identify patients with reduced LA blood velocities and increased LA stasis. Further study is needed to determine whether these measures can improve upon the CHA2DS2-VASc score for stroke risk prediction and enhance individual decisions on anticoagulation in patients with AF.

scholarly journals Altered left atrial 4D flow characteristics in patients with paroxysmal atrial fibrillation in the absence of apparent remodeling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmet Demirkiran ◽  
Raquel P. Amier ◽  
Mark B. M. Hofman ◽  
Rob J. van der Geest ◽  
Lourens F. H. J. Robbers ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Sinus Rhythm ◽  
Flow Velocity ◽  
Paroxysmal Atrial Fibrillation ◽  
Left Atrial ◽  
Peak Flow ◽  
Thrombus Formation ◽  
Clinical Value ◽  
4D Flow ◽  
Ssfp Cine

AbstractThe pathophysiology behind thrombus formation in paroxysmal atrial fibrillation (AF) patients is very complex. This can be due to left atrial (LA) flow changes, remodeling, or both. We investigated differences for cardiovascular magnetic resonance (CMR)-derived LA 4D flow and remodeling characteristics between paroxysmal AF patients and patients without cardiac disease. In this proof-of-concept study, the 4D flow data were acquired in 10 patients with paroxysmal AF (age = 61 ± 8 years) and 5 age/gender matched controls (age = 56 ± 1 years) during sinus rhythm. The following LA and LA appendage flow parameters were obtained: flow velocity (mean, peak), stasis defined as the relative volume with velocities < 10 cm/s, and kinetic energy (KE). Furthermore, LA global strain values were derived from b-SSFP cine images using dedicated CMR feature-tracking software. Even in sinus rhythm, LA mean and peak flow velocities over the entire cardiac cycle were significantly lower in paroxysmal AF patients compared to controls [(13.1 ± 2.4 cm/s vs. 16.7 ± 2.1 cm/s, p = 0.01) and (19.3 ± 4.7 cm/s vs. 26.8 ± 5.5 cm/s, p = 0.02), respectively]. Moreover, paroxysmal AF patients expressed more stasis of blood than controls both in the LA (43.2 ± 10.8% vs. 27.8 ± 7.9%, p = 0.01) and in the LA appendage (73.3 ± 5.7% vs. 52.8 ± 16.2%, p = 0.04). With respect to energetics, paroxysmal AF patients demonstrated lower mean and peak KE values (indexed to maximum LA volume) than controls. No significant differences were observed for LA volume, function, and strain parameters between the groups. Global LA flow dynamics in paroxysmal AF patients appear to be impaired including mean/peak flow velocity, stasis fraction, and KE, partly independent of LA remodeling. This pathophysiological flow pattern may be of clinical value to explain the increased incidence of thromboembolic events in paroxysmal AF patients, in the absence of actual AF or LA remodeling.

scholarly journals LA velocities and stasis assessed by 4D flow MRI are closely associated with LAA peak velocities by Doppler TEE in patients with atrial fibrillation

2016 ◽  
Vol 18 (S1) ◽  
Author(s):  
Michael Mark ◽  
Nicholas Furiasse ◽  
Daniel C Lee ◽  
Jason Ng ◽  
James C Carr ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri

Assessment of left and right atrial 3D hemodynamics in patients with atrial fibrillation: a 4D flow MRI study

2016 ◽  
Vol 32 (5) ◽  
pp. 807-815 ◽  
Author(s):  
Michael Markl ◽  
Maria Carr ◽  
Jason Ng ◽  
Daniel C. Lee ◽  
Kelly Jarvis ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Right Atrial ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri ◽  
Left And Right ◽  
Mri Study

scholarly journals Left atrial blood stasis by 4D flow MRI correlates with stroke risk estimation by CHA2DS2-VASc score

2014 ◽  
Vol 16 (S1) ◽  
Author(s):  
Daniel C Lee ◽  
Michael Markl ◽  
Jacob Fluckiger ◽  
Jason Ng ◽  
James C Carr ◽  
...  
Keyword(s):  
Left Atrial ◽  
Stroke Risk ◽  
Risk Estimation ◽  
Blood Stasis ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri

Abstract 13383: Atrial Fibrillation Alters Both Left and Right Atrial 3D Hemodynamics

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Maria Carr ◽  
Jason Ng ◽  
Dan Lee ◽  
Kelly Jarvis ◽  
Susanne Schnell ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Flow Velocity ◽  
Thrombus Formation ◽  
Velocity Ratio ◽  
Right Atrial ◽  
4D Flow ◽  
Mean Velocity ◽  
Flow Mri ◽  
Whole Heart ◽  
Time Frames

Introduction: In patients with atrial fibrillation, pulmonary embolism and right atrial (RA) thrombus are less common than stroke and left atrial (LA) thrombus. Prior studies have linked thrombus formation to decreased blood flow velocity (stasis) promoting blood clotting. We hypothesized LA stasis is more evident than RA stasis. Methods: Whole heart 4D flow MRI was performed in n=70 subjects: 33 AF patients in sinus rhythm (SR) during imaging (AF-SR, age = 62±10 years), 29 AF patients in AF (AF-afib, age = 67±12 years), and 8 age-matched controls (age = 59±5 years). 3D segmentation (MIMICS, Materialise, USA) of the LA and RA geometry was performed to calculate the flow velocity distribution for all atrial voxels and cardiac time frames. Velocity histograms normalized by the total number of entries (figure 1A) were used to assess mean and median atrial velocities and the % of LA and RA with velocities <0.2m/s (stasis). Results: Compared to controls (LA = 0.20±0.2m/s, RA = 0.19±0.02m/s), both LA and RA velocities were significantly reduced in AF-SR (LA = 0.16±0.03m/s, RA = 0.16±0.04m/s, p<0.03) and even further in AF-afib patients (LA = 0.13±0.03m/s, RA = 0.13±0.04m/s, p<0.001). Atrial stasis was more pronounced in AF-afib (LA = 82±13%, RA = 80±16%, p<0.001) and AF-SR (LA = 72±15%, RA = 69±20%, p<0.04) than in controls (LA = 53±10%, RA = 53±13%). No significant RA vs LA differences were noted, Figure 1 shows significant associations (p<0.01) between LA and RA mean velocity (R2=0.40) and stasis (R2=0.36) in figure 1B. RA/LA mean velocity ratio (1.0±0.2, range=0.6-2.0) and RA/LA stasis ratio (1.0±0.3, range=0.3-2.2) were not significantly different. Conclusions: In both controls and AF patients, there was no evidence for increased stasis in the LA vs RA. Although stasis likely contributes to clot formation, other factors such as atrial geometry in combination with individual LA vs. RA flow differences may account for the more prevalent formations in the LA vs. the RA.

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