Chapter 19: Cardiac Flashcards
Pericardium
tough, fibrous, double-walled sac that surrounds and protects heart
Myocardium
muscular wall of heart; it does pumping
Endocardium
thin layer of endothelial tissue that lines inner surface of heart chambers and valves
How many pumps does the heart have?
2
Are valves uni or multidirectional?
Unidirectional
Do the valves work active or passively?
Valves open and close passively in response to pressure gradients in moving blood
What is the S1 sound?
Closing of AV valve
What is the S2 sound?
Closing of semilunar valve
When do you hear S3 and S4
S3 is after S2 and S4 is before S1
What is systole?
Ventricular contraction
What is diastole?
Ventricular relaxation
What is friction rubs?
Rubbing of the pericardium
Heart murmur grades
1-6
Grade 1 needs a bell and grade 6 can be heard with diaphragm
Physiologic murmur
a heart murmur that is primarily due to physiologic conditions outside the heart.
Ex: first trimester in pregnancy
Pathologic murmur
a pathologic murmur is produced by blood flowing through a narrowed blood vessel or hole in the heart.
S3 murmur
“Ventricular gallop”
S3 occurs when ventricles resistant to filling and ventricles have reached the elastic limit (dilated ventricles)
Occurs immediately after S2, when AV valves open and atrial blood first pours into ventricles
**Normal in children
S4 murmur
“Atrial gallop”
Occurs at end of diastole, at presystole, when ventricle resistant to filling
Atria contract and push blood into non compliant ventricle
This creates vibrations that are heard as S4
S4 occurs just before S1
Always a disease, never innocent
How do you characterize heart sounds?
Frequency, Loudness/Intensity, Duration, Timing
What impacts BP?
C.O, PVR, Viscosity, blood vessel elasticity, volume of circulating blood,
Should you hear blood circulating through normal cardiac chambers and valves?
Blood circulating through normal cardiac chambers and valves usually makes no noise
Reasons for murumr
Velocity of blood increases (flow murmur), for example, in exercise, thyrotoxicosis
Viscosity of blood decreases, for example, in anemia
Structural defects in valves, narrowed valve, incompetent valve
Unusual openings occur in chambers, dilated chamber, wall defect
Conduction
SA to AV to Bundle of His to Purkinje fibers to Apex then up ventricles
ECG: Electrocardiograph
P wave: depolarization of atria
P-R interval: from beginning of P wave to beginning of
QRS complex (time necessary for atrial depolarization plus time for impulse to travel through AV node to ventricles)
QRS complex: depolarization of ventricles
T wave: repolarization of ventricles
Stroke volume
Volume of blood that ejected from the left ventricle with each contraction