Cardiac Physiology Flashcards
avg stroke volume
70ml per beat
cardiac output
5L/min
3 factors that affect the stoke volume
preload
afterload
contractility
preload
directly affects stroke volume
degree of cardiac stretch at the end of diastole
blood volume at the end of diastole determines preload
afterload
pressure ventricles overcome to eject blood
left ventricle- pressure from systemic vascular system
right ventricle- pressure from the pulmonary vascular system
P wave
atrial contraction
QRS complex
ventricular contraction and atrial repolarization
T wave
ventricular repolarization
one small box on ecg =
0.04 seconds
one large box on ecg =
0.20 seconds
CKMB
creatine kinase MB
used to measure degree of myocardial injury Males:
Troponin T and I
measures degree of myocardial damage
Prothrombin time and INR
A prothrombin time test can be used to check for bleeding problems. PT is also used to check whether medicine to prevent blood clots is working. A PT test may also be called an INR test.
PT= measures the amount of time taken for clot formation after reagent tissue thromboplastin is added to the sample.
INR= just a set standard rate
Partial thromblastin time (PTT)
Partial thromboplastin time (PTT) is a blood test that looks at how long it takes for blood to clot. It can help tell if you have a bleeding problem or if your blood does not clot properly.
PTT= How well the the coagulation sequence is functioning by measuring the amount of time it takes for clot formation after partial thromboplastin is added.
what kinds of medications can cause a low PTT time
Blood thinners, such as aspirin and heparin, that make it hard for the blood to clot
Antihistamines
Vitamin C
homocystenine
a protein created in metabolism, high levels of it can cause a heart attack bc it can not be broken back down