ESTIMATION OF MYOCARDIAL WORK BY ECHOCARDIOGRAPHY IN PATIENTS WITH HEART FAILURE WITH PRESERVED EJECTION FRACTION

Heart failure (HF) is defined as the inability of the heart to pump blood to the body at a rate commensurate with its needs, or to do so only at the cost of high filling pressures. The new guidelines classify patients with HF in three categories: heart failure with preserved ejection fraction (HFpEF), defined by an LVEF ≥50%, heart failure with reduced ejection fraction (HFrEF) if the LVEF is <40%, and heart failure with mid-range ejection fraction (HFmrEF) if the LVEF is 40– 49%. Patients with heart failure are at a higher risk for subsequent repeat exacerbations of symptoms requiring hospitalization as well as cardiovascular death. The reference gold standard to diagnose HFpEF in patients is right-sided heart catheterization followed by invasive exercise testing if resting intracardiac pressures are normal. Patients with HFpEF are identified by elevated pulmonary capillary wedge pressure at rest (≥15 mm Hg) or during exercise (≥25 mm Hg) . Research suggests that LV systolic reserve disturbances may lead to the reduction of exercise capacity in patients with HFpEF. Traditional measurement of Left ventricular performance with ejection fraction (EF) is notably subjective, with many limitations and interobserver variability, while tissue Doppler Imaging has technical issues including preload and afterload dependence, and limitations in its ability to assess all planes of LV deformation. Recently, echocardiography parameters like speckle tracking imaging with global longitudinal strain (GLS) is being used to assess subtle myocardial dysfunction as this is a more objective measure but this too remains limited by its load dependency, as increase in the afterload may decrease the GLS and lead to false interpretations about LV contractility. To overcome these issues, a new echocardiographic tool called myocardial work (MW) has been developed to non-invasively measure the LV pressure–strain relationship. MW is calculated as LV pressure applied over strain and is a non-invasive method for LV performance evaluation. It incorporates both LV afterload and deformation. MW analysis is less load-dependent if compared with global longitudinal strain, and therefore could provide incremental information in the setting of HF patients. Thus, myocardial work is affected earlier as compared to global longitudinal strain. It is estimated by employing non-invasive brachial artery blood pressure and LV GLS. The estimated LV pressure curve is calculated using an empiric reference pressure curve. Along with MW, its components are also calculated, namely: global work index (GWI), global work efficiency (GWE), global constructive work (GCW) and global wasted work (GWW). Despite MW being an index of LV performance, there have only been a few studies of MW In HFpEF patients. These studies have shown that these patients have impaired GLS, enhanced WW and reduced myocardial work efficiency (MWE). MW analysis has been suggested to help differentiate patients with impending LV systolic decompensation. Research has also shown that low GWI is a predictor of severely impaired LV function, inadequate cardiopulmonary exercise, and increased NT-proBNP levels, all of which are markers of poor prognosis. They concluded that in HFpEF patients, GWW showed high accuracy to predict the first HFpEF hospitalization and its association with mortality. In addition, preclinical subtle myocardial damage in HFpEF could potentially be detected by MW. Despite the enormity of this subject, there have been a very small number of studies worldwide and none at all in India about the role of myocardial work in patients with HFpEF. Despite extensive search of literature, we could not find any study on the correlation between myocardial work parameters and the gold standard of HFpEF diagnosis, i.e pulmonary capillary wedge pressure. This avenue has the potential to alter algorithms for the prevention, investigation, diagnosis, treatment and follow up of patients with HFpEF, highlighting the need

for future large research in this field.

AIM To evaluate myocardial work indices and global longitudinal strain by echocardiography in patients with Heart failure with preserved ejection fraction. Primary objective: To evaluate myocardial work by echocardiography in patients with heart failure with preserved ejection fraction. Secondary objective: To study the correlation of myocardial work and global longitudinal strain(GLS) with NT Pro BNP levels and pulmonary capillary wedge pressure(PCWP).