The Utility Of The Left Atrial Coupling Index

Introduction Left atrial coupling index (LACi) is a novel imaging metric that integrates left atrial and ventricular functions. Methods We performed a secondary analysis of the TOPCAT trial based on the LACi. LACi was calculated as the left atrial volume index divided by the tissue doppler late myocardial velocity (a' velocity). Survival analysis methods included Cox proportional hazards regression and reverse Kaplan-Meier survival curves by quartile of LACi. Results Among 359 patients from the TOPCAT trial with available echocardiographic data for calculation of the LACi (age 69.2 +/- 9.7 years; 42.6% female), quartiles of the LACi were 0.01-0.025,0.25-0.38,0.38-0.54, and 0.54-3.10, respectively. LACi was associated with both age-adjusted all-cause mortality (HR 1.07 per 0.10 increase in LACi, 95% CI 1.003-1.14, p=0.04) and age-adjusted heart failure hospitalizations (HR 1.10, 95% CI 1.04-1.16, p=0.001). Patients with LACi in the quartile 4 had greater mortality during five years of follow-up (p=0.025; Figure Panel A), and patients with LACi greater than the median had increased heart failure hospitalizations during five years of follow-up (p=0.013; Figure Panel B). Conclusions The LACi was associated with increased mortality and increased heart failure hospitalizations independent of age in the TOPCAT trial.