Abstract 14547: Strain Relaxation Index Predicts Heart Failure and Atrial Fibrillation Over a 10 Year Follow-Up Period: The Multi-Ethnic Study of Atherosclerosis
INTRODUCTION A novel strain relaxation index (SRI) is introduced to assess diastolic function by cardiac magnetic resonance (CMR), using myocardial deformation during LV relaxation. We investigate whether SRI predicts heart failure (HF) and atrial fibrillation (AF).
METHODS As a part of the Multi-Ethnic Study of Atherosclerosis (MESA), 1344 participants free of known cardiovascular disease (CVD) underwent tagged MRI in 2000-2002 (baseline). Harmonic phase analysis was used to compute mid-ventricular circumferential strains and strain rates. SRI was calculated as the difference between post-systolic and systolic times of the strain peaks, divided by the early diastolic strain rate peak (Figure). Normalization by the RR interval adjusted for varying heart rates. Over a 10-year follow-up period, we defined AF (n=52), HF (n=35), and AF or HF combined (n=73) as endpoints. Logistic regression and C-statistic assessed the performance of SRI to predict events over a 10-year follow-up period, adjusted to age, gender, ethnicity, BMI, smoking status, systolic and diastolic blood pressure, use of anti-hypertensive medication, HDL, total cholesterol and diabetes status.
RESULTS At baseline, participants were aged 65±10 yrs; 53% male; 29% Caucasian, 15% Chinese-American, 28% African American, 28% Hispanic; 47% hypertensive; and 14% diabetic. SRI (1.86±1.0 ms) showed independent prediction power for the endpoints, performing better for HF than AF. C-statistics for multivariate models are shown in the Table.
CONCLUSION We introduced SRI, a novel measure of diastolic function by tagged CMR. SRI is an independent predictor of HF and AF in a large population free of known CVD.
- © 2012 by American Heart Association, Inc.