Importance of Exercise Stress Testing in Unmasking Diastolic Dysfunction and Predicting Heart Failure with Preserved Ejection Fraction in Patients with Baseline Normal LV Function and Normal Pulmonary Function Test

Introduction: Echocardiography is most commonly used for detecting diastolic dysfunction which might be a predecessor of heart failure with preserved ejection (HFpEF). Exercise stress testing via treadmill test (TMT) followed by echocardiography can unmask diastolic dysfunction. Aim: To detect the prevalence of subclinical diastolic dysfunction in cases of un-explained dyspnoea and the risk factors associated with it. Materials and method: This cross-sectional study, done in a single tertiary care hospital, included patients from pulmonology and cardiology out patients? department with complaints of exertional dyspnoea, having normal baseline electrocardiogram, echocardiogram and normal pulmonary function test (N=318). Patients having comorbidities like chronic kidney disease, chronic liver disease, malignancy and individuals who did not give consent, were not included in the study. Included individuals were taken for exercise stress by TMT Bruce protocol stage 1. Post-exercise echocardiography was done to find out the number of patients showing diastolic dysfunction in post-exercise echocardiogram. Factors associated with unmasking of sub-clinical diastolic dysfunction were assessed by logistic regression analysis. Result: Post-exercise echocardiography revealed diastolic dysfunction in 99 individuals (31.13%). On further sub-analysis, hypothyroidism, type 2 diabetes mallitus were significant predictors of exercise-induced diastolic dysfunction. The appearance of diastolic dysfunction was assessed via the changes in mitral inflow E/A ratio and pulmonary vein systolic flow/diastolic flow (S/D) ratio in post-exercise echocardiogram.