Hemodynamics

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Stroke volume

• 55-100 ml/beat
• Three factors that can affect it=
  • Preload: Max volume of blood in L ventricle (LVEDV = L ventricular end diastolic volume)2
  • Inotropy: ability of ventricle to contract
  • Afterload: force L ventricle must generate during systole to overcome aortic p to open aortic valve

Cardiac output

• Amount of blood d/c’d from L or R ventricle per minute

\[ \textrm{Cardiac Output} = (\textrm{Stroke Volume}) \times (\textrm{Heart Rate}) \]

• Average adult: 4-5 L/min

Ejection fraction

• Percent of blood emptied from ventricle during systole
• Average = 60-70%

\[ \textrm{Ejection Fraction} = \frac{\textrm{Stroke Volume}}{\textrm{Left Ventricular End Diastolic Volume (LVEDV)}} \]