Cardiac Cycles & Sounds Flashcards
What happens between P and Q on an ECG?
atrial ctx
What happens at R on an ECG?
ventricle is depolarized
ventricle begins ctx
AV valve closes
What is the dicrotic notch on the aortic pressure line indicative of?
when the aortic valve closes upon ventricle relaxation
Which part of the heart reaches the highest pressure upon ctx?
ventricle
Which part of the heart reaches the lowest pressure upon relaxation?
ventricle
What happens as a result of the ventricular pressure being the lowest?
blood flows into the heart
What is happening during isovolumetric ctx?
ventricular ctx
AV valves have closed
aortic/pulmonic valves are not open yet
What is happening during isovolumetric relaxation?
ventricular relaxation
aortic/pulmonic valves have closed
AV valves are not open yet
True or False: blood is continually returning to the R atrium?
True
What is happening during the A wave of jugular vein pressure?
atrial ctx
What is happening during the C wave of jugular vein pressure?
the AV valve has closed, causing a temporary steep increase in jugular V. pressure
What is happening during the V wave of jugular vein pressure?
blood continually returning to the atria starts backing up in the jugular V. increasing pressure gradually
Why does aortic pressure continue to drop after the aortic valve closes until the aortic valve opens up again?
peripheral run-off
What happens at the point of the cardiac cycle where the ventricular pressure exceeds the aortic pressure?
aortic valve opens
What causes the 1st heart sound?
the AV valve closes and blood bounces against it, causing an audible vibration of the cardiac tissue
What causes the 2nd heart sound?
the aortic and pulmonic valves close and blood bounces against them
-backflow is created d/t gravity after the ventricular pressure was cut off when the valve closed
What causes the 3rd heart sound?
blood rapidly filling the ventricles after the AV valves re-open
- normal in kids (thinner chest walls)
- may not be heard in adults
What causes the 4th heart sound?
the ventricle being “topped off” during atrial ctx
- normal in kids
- not generally heard in adults
What causes a heart murmur?
- blood moving in the wrong direction
- blood having a hard time moving in the direction it should be
What causes a systolic murmur?
- blood moving back into the atria
- blood not going into the aorta or pulmonary trunk
What causes a diastolic murmur?
- blood moving back into the ventricles from aorta
- blood not moving into ventricles from atria
