Prognostic value of left atrial size and function by cardiac magnetic resonance in non-ischemic cardiomyopathy.

Abstract

To evaluate left atrial (LA) function and strain parameters by cardiac magnetic resonance imaging (CMR) in patients with non-ischemic cardiomyopathy (NICM) and evaluate the association of these parameters with long-term clinical outcomes. We retrospectively included 92 patients with NICM and 50 subjects with no significant cardiovascular disease (control group). We calculated LA volumes using the Simpson area-length method to derive LA ejection fraction and expansion index. LA reservoir (ƐR), conduit (ƐCD), and contractile strain (ƐCT) were measured using dedicated CMR software (cvi42, Circle Cardiovascular Imaging Inc., version 5.14). An adjusted multivariate regression analysis was performed to determine the association of LA parameters with death and heart failure hospitalization (HFH). NICM patients were older with male preponderance. The mean age for NICM patients was 59.6 ± 15.9 years, 64% males, and 73% whites versus 52.2 ± 12.4 years, 34% male and 64% white for controls. LA strain patterns were significantly lower in NICM patients when compared to controls. During a median follow-up of 58.9 months, 12 patients (13%) died and 33(35.9%) had a HFH. None of the clinical or CMR factors were significantly associated with death. On multivariate analysis, after adjusting for age and significant univariate variables, ƐR was the only variable significantly associated with the HFH (OR 0.98, CI 0.96-1.0). Unadjusted and adjusted Cox proportional hazard models divided by the median ƐR (~ 18%) showed a significant difference in HFH over time (χ2 statistic = 21.1; P value = 0.03). In NICM patients, all LA strain components were reduced. ƐR was found to be significantly associated with HFH.