Name the nodes of the heart
SA node, AV Node, Bundle of Hiss L and R, purkinje fibers
Name the internodal pathways
- Right atrium: anterior, middle, posterior
- Left atrium: Bachmanns bundle
What is the SinoAtrial node
- located at the RA wall
- has highest degree of automaticity
- native pacemaker of the heart
- initiates contraction
What is the AV Node
- the node between the atrium and ventricles
- impulse slows for .05 seconds to allow for ventricular filling in diastole
What are the purkinje fibers
- penetrate into the L and R ventricles
- rapidly conducts action potentials to ventricles, creating contraction
What does the P wave represent on ekg
The p wave represents atrial depolarization/contraction
What does the QRS complex represent
Ventricular depolarization/contraction
What is the R-R interval
1 cardiac cycle
What does T wave represent
Represents end systole
What is the PR interval
-from beginning of P wave -> onset of QRS complex
- normal duration is < 200 Msec
Normal QRS complex
- onset of QRS; Q wave -> end of R wave
- increased QRS timing is signs of Bundle branch block
- NL time: < 110 msec
What do
You call abnormal heart rhythms?
Arrhythmias
What are the Cells of the heart
Cardiomyocytes
What are the specialized functions of cardiomyocytes
- automaticity: ability to beat on its own
- excitable: accept and respond to electrical impulses
- conductive: can transfer electrical signals to other cardiac cells
- contractible: cells can contract in response to electrical impulses
What are the 3 phases of ventricular systole
1) isovolumic contraction timing
2) rapid ejection
3) reduced ejection
Need to know about IVCT
- begins at AV valve closure (end-diastole) and continues until SL valve opening (beginning of systole)
- ventricular volume is at its greatest due to ventricles filling
What happens during rapid ejection?
- SL valves are open
- Rapid ejection of blood occurs
- ventricular pressure rapidly increases
- ventricular volume rapidly decreases (ejected out of vent)
What happens during reduced ejection
- ventricular pressure rapidly decreases
- ventricle repolarizes (end systole)
What is normal sinus rhythm
When there is all waves formed at normal values
What is respiratory sinus rhythm
Your heart rate increases during inspiration and decreases during expiration
What will you see on a respiratory sinus arrhythmia ekg
The length of the cardiac cycle (R-R) will increase during inspiration
What is sinus bradycardia
- slow beating heart
- HR is < 60
What will you see on Doppler during sinus bradycardia
- HR < 60
- PR interval will be normal; A wave and A * velocity terminate on the R wave
- diastole is prolonged, especially diastasis (seen on mv inflow and TdI
What is sinus tachycardia
- HR > 100
