Final answer:
Left ventricular ejection fraction (LVEF) is the best indicator of left ventricular systolic function in patients with congestive heart failure.
Step-by-step explanation:
The best indicator of left ventricular systolic function in patients with congestive heart failure is Left ventricular ejection fraction (LVEF). Ejection fraction is the portion of blood pumped out of the heart with each contraction. It is calculated by dividing stroke volume (SV) by end-diastolic volume (EDV) and is expressed as a percentage. In congestive heart failure, a reduced ejection fraction indicates impaired left ventricular systolic function.