TY - JOUR
T1 - The hemodynamic and atrial electrophysiologic consequences of chronic left atrial volume overload in a controllable canine model
AU - Ruaengsri, Chawannuch
AU - Schill, Matthew R.
AU - Lancaster, Timothy S.
AU - Khiabani, Ali J.
AU - Manghelli, Joshua L.
AU - Carter, Daniel I.
AU - Greenberg, Jason W.
AU - Melby, Spencer J.
AU - Schuessler, Richard B.
AU - Damiano, Ralph J.
N1 - Publisher Copyright:
© 2018
PY - 2018/11
Y1 - 2018/11
N2 - Objective: The purpose of this study was to determine the effects of chronic left atrial volume overload on atrial anatomy, hemodynamics, and electrophysiology using a titratable left ventriculoatrial shunt in a canine model. Methods: Canines (n = 16) underwent implantation of a shunt between the left ventricle and the left atrium. Sham animals (n = 8) underwent a median sternotomy without a shunt. Atrial activation times and effective refractory periods were determined using 250-bipolar epicardial electrodes. Biatrial pressures, systemic pressures, left atrial and left ventricle diameters and volumes, atrial fibrillation inducibility, and durations were recorded at the initial and at 6-month terminal study. Results: Baseline shunt fraction was 46% ± 8%. The left atrial pressure increased from 9.7 ± 3.5 mm Hg to 13.8 ± 4 mm Hg (P <.001). At the terminal study, the left atrial diameter increased from a baseline of 2.9 ± 0.05 cm to 4.1 ± 0.6 cm (P <.001) and left ventricular ejection fraction decreased from 64% ± 1.5% to 54% ± 2.7% (P <.001). Induced atrial fibrillation duration (median, range) was 95 seconds (0-7200) compared with 0 seconds (0-40) in the sham group (P =.02). The total activation time was longer in the shunt group compared with the sham group (72 ± 11 ms vs 62 ± 3 ms, P =.003). The right atrial and not left atrial effective refractory periods were shorter in the shunt compared with the sham group (right atrial effective refractory period: 156 ± 11 ms vs 141 ± 11 ms, P =.005; left atrial effective refractory period: 142 ± 23 ms vs 133 ± 11 ms, P =.35). Conclusions: This canine model of mitral regurgitation reproduced the mechanical and electrical remodeling seen in clinical mitral regurgitation. Left atrial size increased, with a corresponding decrease in left ventricle systolic function, and an increased atrial activation times, lower effective refractory periods, and increased atrial fibrillation inducibility. This model provides a means to understand the remodeling by which mitral regurgitation causes atrial fibrillation.
AB - Objective: The purpose of this study was to determine the effects of chronic left atrial volume overload on atrial anatomy, hemodynamics, and electrophysiology using a titratable left ventriculoatrial shunt in a canine model. Methods: Canines (n = 16) underwent implantation of a shunt between the left ventricle and the left atrium. Sham animals (n = 8) underwent a median sternotomy without a shunt. Atrial activation times and effective refractory periods were determined using 250-bipolar epicardial electrodes. Biatrial pressures, systemic pressures, left atrial and left ventricle diameters and volumes, atrial fibrillation inducibility, and durations were recorded at the initial and at 6-month terminal study. Results: Baseline shunt fraction was 46% ± 8%. The left atrial pressure increased from 9.7 ± 3.5 mm Hg to 13.8 ± 4 mm Hg (P <.001). At the terminal study, the left atrial diameter increased from a baseline of 2.9 ± 0.05 cm to 4.1 ± 0.6 cm (P <.001) and left ventricular ejection fraction decreased from 64% ± 1.5% to 54% ± 2.7% (P <.001). Induced atrial fibrillation duration (median, range) was 95 seconds (0-7200) compared with 0 seconds (0-40) in the sham group (P =.02). The total activation time was longer in the shunt group compared with the sham group (72 ± 11 ms vs 62 ± 3 ms, P =.003). The right atrial and not left atrial effective refractory periods were shorter in the shunt compared with the sham group (right atrial effective refractory period: 156 ± 11 ms vs 141 ± 11 ms, P =.005; left atrial effective refractory period: 142 ± 23 ms vs 133 ± 11 ms, P =.35). Conclusions: This canine model of mitral regurgitation reproduced the mechanical and electrical remodeling seen in clinical mitral regurgitation. Left atrial size increased, with a corresponding decrease in left ventricle systolic function, and an increased atrial activation times, lower effective refractory periods, and increased atrial fibrillation inducibility. This model provides a means to understand the remodeling by which mitral regurgitation causes atrial fibrillation.
KW - atrial fibrillation
KW - mitral regurgitation
UR - http://www.scopus.com/inward/record.url?scp=85054745629&partnerID=8YFLogxK
U2 - 10.1016/j.jtcvs.2018.05.078
DO - 10.1016/j.jtcvs.2018.05.078
M3 - Article
C2 - 30336917
AN - SCOPUS:85054745629
SN - 0022-5223
VL - 156
SP - 1871-1879.e1
JO - Journal of Thoracic and Cardiovascular Surgery
JF - Journal of Thoracic and Cardiovascular Surgery
IS - 5
ER -