Page 56 - Clinical Pearls in Cardiology

44 Clinical Pearls in Cardiology

based on the average of at least two properly measured
blood pressure readings (at least two minutes apart) on
at least two separate occasions.
22. What are the factors that determine systolic blood
pressure?
Systolic blood pressure represents the ejection of blood
into the aorta during ventricular systole. It reflects the
stroke volume, the distensibility of the aorta, and the
velocity with which blood is ejected from the heart.

Determinants of systolic blood pressure (SBP)
• Stroke volume—increased stroke volume increases SBP (e.g.
aortic regurgitation)
• Distensibility of aorta—decreased distensibility increases SBP
(e.g. isolated systolic hypertension)
• Velocity of ejection—increased ejection velocity increases SBP
(e.g. hyperkinetic states like exercise)
Diastolic blood pressure represents the pressure
in the arterial system during diastole. It is largely
determined by the peripheral vascular resistance.
23. What is the difference between pulse pressure and
mean arterial pressure?
Pulse pressure is the difference between systolic and
diastolic blood pressure. It reflects the pulsatile nature
of arterial blood flow and is an important component of
blood pressure.
Mean arterial pressure (MAP) is the average pressure
produced during the cardiac cycle. It is calculated by
adding one third of the pulse pressure to the diastolic
pressure. MAP is the pressure that helps in the forward
movement of blood and it determines tissue perfusion.
Because it is a good indicator of tissue perfusion, the