Role ofmyocardial constructive work in the identification of responders to CRT

Abstract

Aims: Cardiac resynchronization therapy (CRT) plays a pivotal role in the management of patients with heart failure (HF) and wide QRS complex. However, the treatment is plagued by numerous non-responders. Aim of the study is to evaluate the role myocardial work estimated by pressure-strain loops (PSLs) in the comprehension of physiological mechanisms associated with CRT and in the prediction of CRT response. Methods and results: Ninety-seven patients with symptomatic HF (ejection fraction: 27± 6%, QRS duration 164± 18ms) undergoing CRT implantation according to current recommendations were retrospectively included in the study. Standard 2D and speckle tracking echocardiography were performed before CRT and at the 6-month follow-up (FU). PSL analysis allowed the calculation of global and regional myocardial constructive work (CW) and wasted work (WW). A> 15% reduction in left ventricular (LV) end-systolic volume at FU defined CRT-positive response (CRT-PR). At FU, 63 (65%) patients responded to CRT. Global CW (CWtot) was significantly increased in CRT-responders. At multivariate analysis, CWtot> 1057mmHg% (OR 14.69, P= 0.005) and septal flash (OR 8.05, P= 0.004) were the only significant predictors of CRT-PR. CWtot was associated with the entity of CRT-induced myocardial remodelling in both ischaemic (r= -0.55, P< 0.0001) and non-ischaemic patients (r=0.65, P< 0.0001). ACWtot< 1057mmHg% identified 85% of non-responders with a positive predictive value of 88%. Conclusion: Patients with higher CWtot exhibit a favourable response to CRT. These data encourage further studies for the assessment of the myocardial substrate related to the functional response to CRT.