Heart Failure Flashcards
(9 cards)
Diastole:
relaxation and filling of the heart
Systole:
contracting and pumping out blood
Cardiac output (CO):
the amount of blood pumped out of the heart ((Ventricles) to the body per minute (normally ~3-5 liters)
CO = SV x HR, therefore CO can be increased as a result of increase SV/HR or both
Stroke volume (SV):
the amount of blood pumped out of the heart with each heartbeat (normally ~60-70ml)
Estimated SV = End diastolic Volume (EDV) - End systolic Volume (ESV)
EDV: the volume of blood in the ventricle when its full prior to contraction
ESV: the volume of residual blood left in the ventricle following contraction
Preload:
the volume of blood in ventricles at the end of diastole (EDV). Preload is determined by the amount of blood returned to the right side of the heart from the systemic circulation
Afterload:
resistance the left ventricle must overcome to circulate the blood. An increase in afterload will increase ESV (due to a decrease in SV and harder to eject the blood)
Inotropy:
force of ventricular contraction. Increase in sympathetic activity will increase contractility and thus SV - allows more complete ejection of blood so there will be a reduction in ESV. Inotropy also increases HR
Heart Rate (HR):
The number of beats per minute. Influenced by sympathetic input (can also be impacted by temperature and thyroxine levels)