What is the pulse pressure in a patient with a systolic BP of 150 and a MAP of 90?
PP= 90 mmHg
equations you need:
MAP= 2/3 DBP + 1/3 SBP
PP= SBP- DBP
What is the basic equation for cardiac output?
What is the Fick principle?
CO= SV x HR
CO= rate of O2 consumption / (arterial O2-venous O2)
What medications affect a hearts contractility?
↑ contractility: Digoxin, catecholamines
↓ contractility: β blockers, non-dihydropyridine CCBs (verapamil and diltiazem)
What ionic changes affect a heart's contractility?
↑ contractility: ↑ intracellular Ca2+ or ↓ extracellular Na+
↓ contractility: acidosis (↑H+)
How can myocardial oxygen demand be decreased in circumstances where the heart is ischemic?
↓ heart rate
What can make the stroke volume increase for a given preload?
↑ contractility (sympathetic stimulation, inotropic drugs, ↑ intracellular Ca2+, ↓ extracellular Na+)
What factors affect stroke volume?
-↑ with squatting
- ↓ with ACEis and hydralazine
-↑ with exercise or ↑ blood volume (transfuction, IV fluids, pregnancy)
- ↓ with nitrates (venous vasodilators)
-↑ with catecholamines or digoxin
-↓ with heart failure, acidosis, hypoxia, β-blockers, CCBs
What is the heart ejection fraction?
1/2 How much the ventricle ejects from the amount in it
EF = SV/EDV ?