Abstract P094: Gender Difference of Left Ventricular Geometry and Prolonged QRS Duration on Electrocardiogram: MESA (Multi-Ethnic Study of Atherosclerosis)

Abstract

Backgrounds: Prolonged QRS duration (QRSd) on electrocardiogram (ECG) is commonly found in otherwise healthy individuals. However, geometrical factors of the ventricles that determine QRSd are poorly defined. T1 time by cardiovascular magnetic resonance (CMR) is good parameter to estimate extracellular expansion (ECE). Our objective was to evaluate the relationship between QRSd and CMR measures of tissue composition in a large community-based multiethnic population. Methods: A total of 1,615 participants (52% women; age range 44 to 84 years) of the MESA cohort were evaluated with T1 mapping by using 1.5-T CMR scanners. We excluded the participants with focal scar on delayed enhancement CMR and bundle branch block. Midventricular short-axis T1 maps were acquired before and at 12- and 25-min after administration of gadolinium contrast using Modified Look-Locker Inversion Recovery sequence. Results: Longer QRSd was associated with greater LV end diastolic volume (LVEDV) index (p <0.001), LV mass index (p <0.001), and stroke volume index (p <0.01) in both women and men. In addition, longer QRSd was associated with lower ejection fraction (p<0.001), circumferential shortening (p = 0.04), torsion (p <0.001), and longer post-contrast T1 times at 12 min indicating less ECE (p = 0.001) in women only. Longer T1 time remained significant after adjusting for LVEDV, LV mass and QRS voltage. Conclusions: In a large multiethnic population, longer QRSd was associated with lower ECE and LV dysfunction in women. However, these relationships were sex dependent and were absent in men.