Left atrial strain predicts cardiovascular response to exercise in young adults with suboptimal blood pressure

To investigate the left ventricular response to exercise in young adults with hypertension, and identify whether this response can be predicted from changes in left atrial function at rest.

A total of 127 adults aged 18-40 years who completed clinical blood pressure assessment and echocardiography phenotyping at rest and during cardiopulmonary exercise testing, were included. Measurements were compared between participants with suboptimal blood pressure ≥120/80mm Hg (n = 68) and optimal blood pressure <120/80mm Hg (n = 59). Left ventricular systolic function during exercise was obtained from an apical four chamber view, while resting left atrial function was assessed from apical four and two chamber views.

Participants with suboptimal blood pressure had higher left ventricular mass (p = 0.031) and reduced mitral E velocity (p = 0.02) at rest but no other cardiac differences. During exercise, their rise in left ventricular ejection fraction was reduced (p = 0.001) and they had higher left ventricular end diastolic and systolic volumes (p = 0.001 and p = 0.001, respectively). Resting cardiac size predicted left ventricular volumes during exercise but only left atrial booster pump function predicted the left ventricular ejection fraction response ( $\beta$ = .29, p = 0.011). This association persisted after adjustment for age, sex, body mass index, and mean arterial pressure.

Young adults with suboptimal blood pressure have a reduced left ventricular systolic response to exercise, which can be predicted by their left atrial booster pump function at rest. Echocardiographic measures of left atrial function may provide an early marker of functionally relevant, subclinical, cardiac remodelling in young adults with hypertension.