Diastolic stress echocardiography: from basic principles to clinical applications

Heart failure with preserved ejection fraction (HFpEF) looms as a major public heart challenge with increasing prevalence due to an ageing population. Diagnosis can be challenging due to non-specific symptomatology, low natriuretic peptide levels and equivocal diastology on resting echocardiography. Diastolic stress echocardiography represents a non-invasive option to refining the diagnosis in this subset of patients. Diastolic responses to exercise are most commonly measured with a non-invasive measure of left ventricular filling pressures (LVFP) estimated by the ratio of the early mitral inflow wave to early diastolic tissue velocity (E/e' ratio). This is measured pre- and post-exercise , and is highly feasible. An elevation of exercise E/e' >15 is classified as an abnormal response as per current guidelines. An alternative measure of exercise-related diastolic performance, the Diastolic Functional Reserve Index has also been proposed, but has not been as well studied as exercise E/e'. A number of studies have validated exercise E/e' as a measure of LVFP against invasively measured LVFP using simultaneous echocardiography-catheterisation studies. The independent prognostic value of exercise E/e' has also been well delineated in a number of studies. While diastolic stress echocardiography can be considered for all patients with suspected HFpEF, it is of particular value in patients with normal or equivocal diastolic indices on resting echocardiography.