Prognostic influence of left atrial strain in heart failure patients with intermediate ECG criteria for cardiac resynchronization therapy

Abstract

Abstract Background Heart failure (HF) patients with left bundle branch block (LBBB) with QRS width ≥150ms is class I indication for cardiac resynchronization therapy (CRT), whereas it is still controversy to CRT response in HF with QRS width 120-149ms or non-LBBB as intermediate ECG criteria in routine echocardiography. Left atrial (LA) adverse remodeling is a prognostic marker in patients with heart failure. Nevertheless, the prognostic significance of LA strain (LAS) imaging in HF patients with intermediate ECG criteria is not well understood. Purpose The objective of this study was to determine the prognostic value of LA deformation analysis in patients undergoing CRT implantation who met the intermediate ECG criteria. Methods We studied 94 patients who were defined routine CRT indication by the clinical guidelines. LAS was calculated as the average strain using apical two- and four-chamber views. The predefined endpoint was death, hospitalization due to worsening HF for 5 years after CRT implantation. Results Of the 94 patients, LAS is feasible in 76 patients (81%) with aged 69 ± 11 years, 30±8% of LV ejection fraction. 46 patients (61%) fulfilled intermediate ECG criteria. The predefined endpoint occurred in 43 patients (57%). The median LAS was 15%. LAS below 15% were associated with a high probability of unfavorable outcomes over 5 years (Log-rank, p = 0.002). After adjusting for left ventricular ejection fraction, LAS remained significantly associated with poor outcomes (hazard ratio 0.92, 95% confidence interval 0.87-0.97, p<0.001). There is no difference in the probability of poor outcomes between LBBB with QRS width ≥150ms and intermediate ECG criteria. Patients with intermediate ECG criteria and LAS <15% had worse outcome than in those with LBBB with QRS width ≥150ms and in those with intermediate ECG criteria patients with LAS ≥15% (Log-rank: p = 0.046, p = 0.029, respectively). Conclusion Baseline LA functional deterioration by deformation analysis was significantly associated with poor outcome after CRT implantation regardless of the ECG criteria for CRT indication and has promise for clinical utility.