Abstract 4136900: Left-to-right ventricular volume ratio as a predictor of cardiovascular events: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background: The left ventricle (LV) and right ventricle (RV) are closely connected anatomically and functionally. Therefore, relative volume alterations signify pathologic disequilibrium even when within the normal range for chamber volumes. We aimed to define the prognostic value of volumetric imbalance between the LV and RV in the general population. Methods: The study sample consisted of 4073 asymptomatic participants from the Multi-Ethnic Study of Atherosclerosis who had a cardiac MRI at baseline. The left to right ventricular volume ratio (LRVR) was defined as LV volume/RV volume at end diastole. LRVR was categorized into balanced reference category 0.8-1.3, low (RV predominance) <0.8, and high (LV predominance) >1.3. Multivariable cox regression models were used to study the association between LRVR and heart failure (HF), atrial fibrillation (AF), and death. Results: The mean age of participants was 61.3±10 years, with 52% females. Participants were followed for a median of 17.8 years for HF, 16.7 years for AF, and 17.1 years for death. During follow up, 239 (5.9%) participants developed HF, 772 (19%) developed AF, and 906 (22.2%) died. When compared with the reference balanced LRVR group, those with high LRVR had increased risk of HF (HR 2.55; 95% CI 1.7-3.8; p <0.01), AF (HR 1.57; 95% CI: 1.2-2.06; p<0.01), and death (HR 1.63; 95% CI: 1.29-2.07; p<0.01) after adjusting for demographics and traditional cardiovascular risk factors. Participants with low LRVR had increased risk of HF (HR 1.88; 95% CI 1.1-3.2; p=0.02) and death (HR 1.51; 95% CI 1.12-2.04; p<0.01) in crude models. Adjusting for risk factors maintained increased risk of HF and death, but statistical significance was lost. Low LRVR was not associated with increased risk of AF. In a subgroup of participants with both absolute RV and LV volumes within normal ranges, high LRVR was still associated with increased risk of HF, AF, and death after adjusting for risk factors. Conclusion: In healthy asymptomatic participants at baseline, LV volume exceeding RV volume by at least 30% is associated with increased risk of HF, AF, and death. This relationship is independent of cardiovascular risk factors and absolute dilatation of either ventricle.