What is the normal response of diastolic function of the left ventricle during exercise testing?

The normal response of diastolic function of the left ventricle during exercise testing is characterized by an increase in both E' and A' velocities. During exercise, the heart encounters increased demands for blood flow, which stimulates enhanced filling of the left ventricle.

E' velocity reflects the early diastolic filling of the left ventricle, and it corresponds to the relaxation phase of the heart when blood enters the ventricle. As the individual exercises, the heart rate increases, and there is a more rapid return of blood to the heart, necessitating quicker relaxation and filling. This leads to a rise in E' velocity.

A' velocity, on the other hand, is associated with the late diastolic filling phase due to atrial contraction. During exercise, with increased heart rate and faster cardiac output demands, the contribution from atrial contraction (represented by A' velocity) also increases to help maintain stroke volume.

Thus, in a healthy heart, both E' and A' will increase to enhance diastolic function and accommodate the body's elevated requirements during exercise. This response is essential for an effective hemodynamic adaptation to physical activity.