Non-invasive myocardial work indices in ischemic heart disease

Abstract Background Myocardial work (MW) is a parameter of myocardial function which takes into account deformation as well as afterload. LV pressure-strain loops (PSLs) are a novel and reliable tool for the non-invasive assessment of MW. Purpose To evaluate MW indices in ischemic heart disease and their changes according to ejection fraction (EF) and type of myocardial infarction (MI) namely no-ST-segment elevation MI (NSTEMI) or ST-segment elevation MI (STEMI). Methods A total of 61 patients (mean age: 64.4±12 years) since at least 30 days from acute STEMI or NSTEMI treated with primary PTCA and 31 healthy subjects (controls) were enrolled. Patients with MI were divided into three groups according to the EF-based heart failure (HF) classification: a) group 1, HF preserved EF (HFpEF, EF >50%); 2) group 2, HF mid-range EF (HFmrEF, EF 40–49%); 3) group 3, HF reduced EF (HFrEF, EF <40%). Global Work Index (GWI), Global Constructive Work (GCW), Global Work Waste (GWW) and Global Work Efficiency (GWE), were estimated by LV PSLs using custom software. Results As shown in Table 1, GWE was significantly reduced in HFmrEF and HFrEF group (p=0.001) compared to both the controls and HFpEF group, while GWW was significantly higher (p<0.001) in the HFmEF group compared to controls and in the HFrEF group (p<0.001) vs all the other groups. GWI mmHg and GCW mmHg showed significantly compromised values in patients of HFmrEF and HFrEF groups compared to patients in HFpEF group and controls (p=0.001 and p<0.001 respectively). NSTEMI patients showed higher values of GCW compared to STEMI patients (p=0.003), and a trend towards better values of GWI, although not statistical significant. No significant differences were found about GWE and GWW. A strong correlation was found between indices of MW and LV volumes and EF (Table 2) Conclusions The non-invasive MW indices show a good correlation with traditional 2D parameters of myocardial systolic function in patients with ischemic heart disease. In addition, STEMI patients have lower constructive work than those with previous NSTEMI.