Left ventricular volume and ejection fraction response to exercise in aortic regurgitation

Area of Science:

• Cardiology
• Cardiovascular Physiology

Background:

• Aortic regurgitation (AR) affects left ventricular (LV) function.
• Ejection fraction (EF) is a common measure, but may not fully capture LV performance in AR.

Purpose of the Study:

• To determine if LV volumes, in addition to EF, provide a more complete characterization of LV performance in asymptomatic and symptomatic patients with AR during exercise.
• To compare LV volume and EF responses to exercise between AR patients and healthy controls.

Main Methods:

• Studied 27 asymptomatic (Group 1) and 22 symptomatic (Group 2) AR patients, plus 10 controls.
• Utilized first-pass radionuclide technique and a multicrystal scintillation camera at rest and during bicycle exercise.
• Measured LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) using the area-length method.

Main Results:

• Controls showed increased LVEDV, decreased LVESV, and increased EF with exercise.
• Group 1 (asymptomatic AR) had elevated resting LVEDV and LVESV; LVEDV decreased with exercise (different from controls), while LVESV decreased (similar to controls).
• Group 2 (symptomatic AR) had reduced resting EF, abnormal EF response to exercise, unchanged LVEDV, and increased LVESV during exercise, with subgroups showing varied volume responses.

Conclusions:

• LV volumes at rest and during exercise offer more information on LV functional reserve in symptomatic AR than EF alone.
• Measuring LV volumes may help differentiate symptomatic AR patients with normal LVESV response from those developing worsening heart failure during exercise.