The prognostic value of the left atrial strain rate determined using cardiovascular magnetic resonance feature tracking imaging in patients with severe idiopathic dilated cardiomyopathy

BACKGROUND: Left atrial strain rate (LASR) is rarely used as an indicator of cardiovascular disorder prognosis in dilated cardiomyopathy (DCM). In the present study, we aimed to explore the prognostic value of the LASR in patients with severe idiopathic DCM [left ventricle ejection fraction (LVEF) <35%] using cardiac magnetic resonance feature tracking (CMR-FT). METHODS: A retrospective cohort study was performed. At the time of enrollment, patients who underwent cardiovascular magnetic resonance (CMR) imaging were selected for the study. Left atrium (LA) strain rate was measured in patients with severe idiopathic DCM from four-chamber and two-chamber views using a 3.0-T CMR scanner. The study endpoint was defined as a combination of all-cause death, implantable cardioverter-defibrillator (ICD), hospitalization due to cardiac failure, and heart transplantation. Cox model analyses were used to assess the statistical significance of the risk factors. RESULTS: Fifty-eight patients with a confirmed diagnosis of severe idiopathic DCM were ultimately included in the analysis [mean age of 46 years; 41 (73%) men]. The median follow-up was 43 months (13–72 months). Adverse cardiovascular events occurred in 29 patients: all-cause death occurred in 15 participants (25.8%), ICD was performed in 5 participants (8.6%), heart failure hospitalization occurred in 8 participants (13.8%), and 1 participant (1.7%) underwent heart transplantation. From univariate analysis, the left atrium reservoir strain rate (LASRs) [HR 0.12; 95% CI (0.02, 0.55), P=0.007] and the left atrium booster pump strain rate (LASRa) [HR 3.21; 95% CI (1.08, 9.58), P=0.036] significantly predicted the association with cardiovascular events. In model 1 after adjusting for basic cardiovascular risk factors, including age, hypertension, diabetes mellitus, and N-terminal pro-brain natriuretic peptide (NT-proBNP), the LASRs [HR 0.12, 95% CI (0.02, 0.58), P=0.009] was assessed. The mitral valve regurgitation, LA maximum volume index, and LA diastatic volume index were added in model 2 based on model 1. LASRs [HR 0.13, 95% CI (0.02. 0.82) P=0.030] was the independent prediction factor after adjustment for model 1 and model 2. The LASRs had a good prognostic value with an area under the curve of receiver operating characteristic of 0.697 (0.617, 0.777) at 1 year, 0.716 (0.643, 0.788) at 3 years, 0.716 (0.651, 0.798) at 5 years and 0.703 (0.597, 0.809) at 7 years. CONCLUSIONS: LA reservoir strain rate and active strain rate were powerful prognostic markers. The LASRs by MRI-FT provided independent prognostic value in patients with severe idiopathic DCM.