4300Strain parameters at rest and after exercise in symptomatically stable patients with improved heart failure - STRESS-HF
Authors: Saran M , Dwivedi S K , Sharma A , Chaudhary G , Chandra S , Sethi R , Vishwakarma P , Pradhan A , Bhandari M , Narain V S 
Published: October 2019

Abstract

Background
Optimal medical therapy (OMT) results in improvement in left ventricular (LV) ejection fraction (EF) and reduction in LV size in approximately 40% of patients of heart failure with reduced ejection fraction (HFrEF). Recent studies have proposed to continue treatment in all patients of this subgroup as improvement in LVEF does not indicate actual myocardial recovery. Global Longitudinal strain (GLS) is more sensitive marker of LV systolic function and better predictor of mortality than LVEF. GLS may identify probable patients in whom the therapy can be minimized or stopped.

Aim
To determine global longitudinal strain at rest and after exercise in patients with idiopathic dilated cardiomyopathy (DCM) who have improved LVEF ≥50% on guideline directed medical therapy (GDMT) and compare with resting & exercising LVEF on 3-dimesional (3D).

Material and methods
This Observational study was conducted in a tertiary care referral hospital, from February 2018 to October 2018. All patients with idiopathic DCM who had a documented LVEF of ≤40% in the past and improved LVEF (LVEF ≥50%) on GDMT were included in the study. Patients with secondary causes of HFrEF, poor echocardiographic window and inability to exercise were excluded from the study. Strain parameters were calculated at rest and after atleast 5 METS of exercise. GLS value of ≥ minus 12.6% was considered as mildly reduced strain, ≤ minus 8% as severely reduced strain and the values in between as moderately reduced strain. Post exercise, drop of >5% in absolute LVEF value or decrease in GLS >15% from baseline was considered as poor myocardial recovery.

Results
A total of 44 patients [mean age of 46.8±13.1 years and 24 males (54.5%)] constituted the study group. At the time of diagnosis, 31 (70.5%) patients were in NYHA class II and the remaining were in class III. Duration of GDMT ranged from 4 to 38 (median 12) months. Following improvement on GDMT, 25 (56.8%) were in class I and rest were in class II. Mean LVEF at diagnosis and after recovery was 33.6±4.9% and 55.1±4.5%, respectively with a mean absolute change in LVEF of 21.3±6.1%. At rest, mean 3D LVEF was 53±3.5% and GLS was −12.3±3.1. Mild, moderate and severely reduced strain was seen in 24 (54.5%), 13 (29.6%) and 7 (15.9%), respectively. After exercise, mean 3D LVEF was 51.5.±4.5% (mean decrease 1.5±2.1%) and mean GLS was −7±4.2% (mean decrease −5.3±4.6%). After exercise, none had a fall of LVEF >5% however 32 (72.7%) had a decrease of >15% in GLS. Seven (15.9%) patients had improvement in GLS, 4 (9.1%) had <15% decrease and 1 (2.3%) showed no change in GLS on exercise. The change in GLS on exercise was significant (p=0.001), but change in 3D LVEF was not significant (p=0.956).

Conclusion
Global longitudinal strain is a better marker for assessing myocardial recovery than LVEF in patients of heart failure with improved ejection fraction.

Acknowledgement/Funding
None