Low peak oxygen uptake in relation to total heart volume as an early marker of sub-clinical diastolic dysfunction.

AIMS

Peak oxygen uptake (VOpeak) is closely related to total heart volume (THV) in healthy individuals. This study aimed to investigate (i) the association between VOpeak and THV in subjects with sub-clinical diastolic dysfunction, athletes, healthy controls, and patients with established heart failure with and without preserved ejection fraction (HFpEF and HFrEF), and (ii) whether VOpeak/THV-index can distinguish between subjects with sub-clinical diastolic dysfunction, HFpEF, HFrEF, and healthy controls.

METHODS AND RESULTS

Seventy participants were included: 15 with sub-clinical diastolic dysfunction (defined as showing only 1-2 echocardiographic signs of diastolic dysfunction, not meeting clinical diagnostic criteria), 10 athletes, 15 healthy controls, and 30 heart failure patients (15 HFpEF and 15 HFrEF). VOpeak was assessed by cardiopulmonary exercise testing and THV by cardiovascular magnetic resonance imaging. In sub-clinical diastolic dysfunction, THV was a weak determinant of VOpeak ( = 0.41, = 0.01), and even weaker in heart failure ( = 0.16, = 0.03). However, THV strongly predicted VOpeak in athletes and controls combined ( = 0.87, < 0.0001). VOpeak/THV did not distinguish healthy controls from sub-clinical diastolic dysfunction but could reliably discriminate between healthy controls and patients with heart failure.

CONCLUSION

Subjects with sub-clinical diastolic dysfunction may have an altered relationship between VOpeak and THV, approaching that of patients with established heart failure. Thus, this proof-of-concept study indicates that sub-clinical diastolic dysfunction constitutes a group of patients that may be of interest to follow over time to prevent continued deterioration of cardiac function. Furthermore, the VOpeak/THV ratio can be used to distinguish between healthy controls and overt heart failure.