Figure 3.

Diagram showing the varied left atrial strain curves in HFpEF patients at different stages of heart failure, both at rest and during exercise. Stage A is characterized by decreased left atrial reservoir and conduit strain, preserved normal contractile strain during rest, and elevated strain values in the left atrial during all phases of exercise. Stage B is characterized by increasing contractile strain and decreased left atrial reservoir and conduit strain, which mainly occurs at rest. During exercise, the extent of the increase in the left atrial three-phase strain values decrease. Stage C and Stage D are characterized by all three left atrial phases (contractile, conduit, and reservoir) having significantly lower strain values. Additionally, there is a further decrease in the degree to which strain values increase during exercise in all three left atrial phases. HFpEF, heart failure with preserved ejection fraction; stage A, at risk for heart failure; stage B, pre-heart failure; stage C, symptomatic heart failure; stage D, advanced heart failure; LA, left atrial; LASr, left atrial reservoir strain; LAScd, left atrial conduit strain; LASct, left atrial contractile strain.