A method for the evaluation of cardiac anatomy and physiology by injecting a radioactive substance, Technetium 99.
One of the most important indices that can be obtained from this examination is the value called ejection fraction (EF).
Ejection fraction is the percent of what enters the left ventricle and what leaves it during each heart beat. In a healthy heart, ejection fraction is about 55% or more. This means that 55% of the blood content included in the left ventricle at the peak of its filling phase (end diastolic) is expelled from it at the peak of the contraction (end systolic).
The lower the EF values the more severe is the functional impairment of the heart.
The examination can be performed at rest or during effort in order to evaluate changes in cardiac output under stress conditions.