TY - JOUR
T1 - Electroanatomical Remodeling of the Atria in Obesity: Impact of Adjacent Epicardial Fat
AU - Mahajan, Rajiv
AU - Nelson, Adam
AU - Pathak, Rajeev K.
AU - Middeldorp, Melissa E.
AU - Wong, Christopher X.
AU - Twomey, Darragh J.
AU - Carbone, Angelo
AU - Teo, Karen
AU - Agbaedeng, Thomas
AU - Linz, Dominik
AU - de Groot, Joris R.
AU - Kalman, Jonathan M.
AU - Lau, Dennis H.
AU - Sanders, Prashanthan
PY - 2018
Y1 - 2018
N2 - OBJECTIVES: The aims of the study were to characterize: 1) electrical and electroanatomical remodeling in patients with atrial fibrillation (AF) with obesity; and 2) the impact of epicardial fat depots on adjacent atrial tissue. BACKGROUND: Obesity is associated with an increased risk of AF. METHODS: A total of 115 patients with AF who underwent AF ablation were screened. After exclusion, 26 patients were divided into 2 groups (obese: body mass index [BMI] ≥27 kg/m2 and reference: BMI <27 kg/m2). They underwent cardiac magnetic resonance (CMR) imaging and electroanatomic mapping of the left atrium (LA) in sinus rhythm before AF ablation. Atrial and ventricular epicardial adipose tissue (EAT) were assessed by CMR. The following electrophysiological parameters were assessed: global and regional voltage, conduction velocity (CV), electrogram fractionation, and CV heterogeneity. In addition, the regional relationship between LA EAT depots and the electrophysiological substrate was evaluated. RESULTS: The BMIs of the obese and reference groups were 30.2 ± 2.6 and 25.2 ± 1.3 kg/m2, respectively (p < 0.001). There was no difference in the left ventricular ejection fraction and a nonsignificant increase in LA size with obesity. Obesity was associated with increase in all measures of EAT (p < 0.05), with a predominant distribution adjacent to the posterior LA and the atrioventricular groove. Obesity was associated with reduced global CV (0.86 ± 0.31 m/s vs. 1.26 ± 0.29 m/s; p < 0.001), with a nonsignificant increase in conduction heterogeneity (p = 0.10), increased fractionation (54 ± 17% vs. 25 ± 10%; p < 0.001), and regional alteration in voltage (p < 0.001). Although the global LA voltage was preserved, there was greater voltage heterogeneity (p = 0.001) and increased low-voltage areas (13.9% vs. 3.4%; p < 0.001) in the obese group compared with the reference group. The low voltage areas were predominantly seen in the posterior and/or inferior LA, which was similar to location of EAT on CMR imaging. Among various measures of obesity, LA EAT volume correlated best with posterior LA fractionation (r2 = 0.55 for LA EAT volume vs. r2 = 0.36 for BMI) and CV (r2 = 0.31 for LA EAT volume vs. r2 = 0.22 for BMI). CONCLUSIONS: Obesity is associated with electroanatomical remodeling of the atria, with areas of low voltage, conduction slowing, and greater fractionation of electrograms. These changes were more pronounced in regions adjacent to epicardial fat depots, which suggested a role for fat depots in the development of the AF substrate.
AB - OBJECTIVES: The aims of the study were to characterize: 1) electrical and electroanatomical remodeling in patients with atrial fibrillation (AF) with obesity; and 2) the impact of epicardial fat depots on adjacent atrial tissue. BACKGROUND: Obesity is associated with an increased risk of AF. METHODS: A total of 115 patients with AF who underwent AF ablation were screened. After exclusion, 26 patients were divided into 2 groups (obese: body mass index [BMI] ≥27 kg/m2 and reference: BMI <27 kg/m2). They underwent cardiac magnetic resonance (CMR) imaging and electroanatomic mapping of the left atrium (LA) in sinus rhythm before AF ablation. Atrial and ventricular epicardial adipose tissue (EAT) were assessed by CMR. The following electrophysiological parameters were assessed: global and regional voltage, conduction velocity (CV), electrogram fractionation, and CV heterogeneity. In addition, the regional relationship between LA EAT depots and the electrophysiological substrate was evaluated. RESULTS: The BMIs of the obese and reference groups were 30.2 ± 2.6 and 25.2 ± 1.3 kg/m2, respectively (p < 0.001). There was no difference in the left ventricular ejection fraction and a nonsignificant increase in LA size with obesity. Obesity was associated with increase in all measures of EAT (p < 0.05), with a predominant distribution adjacent to the posterior LA and the atrioventricular groove. Obesity was associated with reduced global CV (0.86 ± 0.31 m/s vs. 1.26 ± 0.29 m/s; p < 0.001), with a nonsignificant increase in conduction heterogeneity (p = 0.10), increased fractionation (54 ± 17% vs. 25 ± 10%; p < 0.001), and regional alteration in voltage (p < 0.001). Although the global LA voltage was preserved, there was greater voltage heterogeneity (p = 0.001) and increased low-voltage areas (13.9% vs. 3.4%; p < 0.001) in the obese group compared with the reference group. The low voltage areas were predominantly seen in the posterior and/or inferior LA, which was similar to location of EAT on CMR imaging. Among various measures of obesity, LA EAT volume correlated best with posterior LA fractionation (r2 = 0.55 for LA EAT volume vs. r2 = 0.36 for BMI) and CV (r2 = 0.31 for LA EAT volume vs. r2 = 0.22 for BMI). CONCLUSIONS: Obesity is associated with electroanatomical remodeling of the atria, with areas of low voltage, conduction slowing, and greater fractionation of electrograms. These changes were more pronounced in regions adjacent to epicardial fat depots, which suggested a role for fat depots in the development of the AF substrate.
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85058884921&origin=inward
UR - https://www.ncbi.nlm.nih.gov/pubmed/30573116
U2 - https://doi.org/10.1016/j.jacep.2018.08.014
DO - https://doi.org/10.1016/j.jacep.2018.08.014
M3 - Article
C2 - 30573116
SN - 2405-500X
VL - 4
SP - 1529
EP - 1540
JO - JACC. Clinical electrophysiology
JF - JACC. Clinical electrophysiology
IS - 12
ER -