Objectives To study whether young adults with elevated blood pressure have an altered left ventricular stress response and whether this is determined by cardiac structure.

Methods We recruited 148 young adults (mean age 27±5 years) with a range of blood pressures for cardiovascular phenotyping at rest with cardiac magnetic resonance. A subgroup (n=49) then underwent exercise stress echocardiography while exercising at 40%, 60%, and 80% of peak exercise capacity. Myocardial stress response was assessed from changes in ejection fraction and biochemistry (post-exercise copeptin release). Results were compared in participants with systolic or diastolic BP e 120/80 mm Hg (n=62, mean BP 129/77 mm Hg) vs. those with systolic and diastolic BP <120/80 mm Hg (n=84, mean BP 110/66 mm Hg).

Results Resting left ventricular ejection fraction was similar between groups with higher or lower blood pressure. However, during physical exercise, despite similar achieved work load, higher blood pressure was associated with lower ejection fraction at 40% and 60% exercise load (73.9±3.25 vs. 80.0±4.54%, p<0.001 and 75.2±6.59 vs. 79.4±4.70%, p=0.026 respectively) as well as lower submaximal contractile reserve (10.4±5.92 vs. 19.0±6.90%, p<0.001 and 11.5±8.34 vs. 17.5±7.31%, p=0.029 at 40% and 60% respectively). Furthermore, increases in post-exercise plasma copeptin level were predicted by lower ejection fraction at 40% workload (beta=−0.329, p=0.045). Blood pressure was associated with variation in left ventricular mass index (55.6±10.0 vs. 52.0±9.6 g/m2, p=0.041 and 0.68±0.13 vs. 0.62±0.12 g/ml, p=0.007) and wall thickness (7.21±1.31 vs. 6.62±1.44 mm, p=0.015) but measures were within clinically normal ranges and did not predict variation in myocardial stress response.

Conclusions x0013_Young adults with modest blood pressure elevation have a significantly lower systolic response to exercise. The association between this altered stress response and daily functional limitations in young adulthood, as well as cardiovascular disease progression and event risk, requires further study.