Cardiac Physiology Flashcards
Stimulating the beta-adrenergic receptors has what affect on the heart?
- increase in HR
- Increase in automaticity
- increase in contractility
Stimulating the alpha-adrenergic receptors has what effect on the heart?
There is no direct effect because the myocardium has no AA receptors. However this can cause vasoconstriction peripheral vessels.
The S1 heart sound occurs with the closure of what valves?
Mitral and Tricuspid (S1=M1,T1) “SMITTY”
The S2 heart sound occurs with the closure of what valves?
Aortic Pulmonic “STAP” s two a p
What is cardiac output?
The amount of blood ejected by the heart measured in L/min.
What is the CO formula?
SV x HR
What part of the cardiac cycle does S1 indicate?
Ventricular systole “S1S”
What is a “split S1”?
The S1 is comprised of two overlapped sounds M1 and T1, the closing of the mitral and tricuspid valves respectively. When both M1 and T1 can be heard the S1 is said to be split.
What can cause a split S1?
A delayed tricuspid valve closure can be caused by an RBBB.
What part of the cardiac cycle does the S2 indicate?
Ventricular diastole. Comprised of A2 and P2 sounds. “S2D”
What may cause an S2 split?
A normal S2 split can be heard during inspiration because P2 is delayed by increased venous return.
Describe the phases of atrial filling in a normal rhythm? (3)
There are three phases, rapid, slow and active.
How do the atrial filling phases correlate to heart sounds?
The rapid and active phases may produce heart sounds labeled as 3rd and 4th respectively.
What causes an S3 sound ?
“sudden distention of the ventricular wall due to rapid early filling”. p. 137 Darovic
What may cause an abnormal S3?
Enlarged failing ventricles with an elevated LVEDP
What may cause an abnormal S3?
Enlarged failing ventricles with an elevated LVEDP. Atrial blood rushes into an incompletely emptied LV.
What causes an S4 sound?
When ventricular filling is augmented by atrial contraction.
What is a summation gallop”
At heart rates normally found with heart failure, the S1, S2, and S3 and/or S4 may become almost synchronous in timing leading to a sound that is the sum of the parts. This summation sound is typically louder than the S1 and S2 . p. 138
Six causes of heart murmurs?
- rapid rate of flow across normal structures
- flow across a constricted area (aortic stenosis)
- flow across an abnormal structure w/o obstruction
- regurgitation r/t an incompetent valve
- flow into a dilated structure (PPH)
- blood shunted like an ASD
What characteristics are murmurs described by? (6)
- pitch- high or low
- quality - musical, harsh
- shape - crescendo, decrescendo, creshendo-decreshndo , plateau and variable
- location- where maximally heard and radiation
- timing - early, mid, late
- intensity - (loudness) Grades I-VI
Aortic stenosis murmur quality?
- Caused by ventricular outflow obstruction
- audible at 2nd ICS/RSB
3.. harsh - crescendo -decrescendo
Chronic Mitral regurgitation murmur quality?
- valvular issues cause incomplete closure and retrograde blood flow during ventricular systole
- high- pitched and blowing
- pansystolic
Acute Mitral valve regurgitation?
- life threatening due to damage to papillary muscle or chordae tendineae damage
- endocarditis, MI, blunt trauma
- leads to pulmonary edema
- decrescendo character
- low pitched and blowing
- usually loud (Grade V)
When in the cardiac cycle would diastolic murmurs be heard?
After S2 (during diastole)
Mitral stenosis
- low pitched, rumbling sound
- blood flow restricted from LA to LV
Aortic regurgitation
- blood refluxes into LV during diastole
- chronic or acute
- high pitched, blowing sound
Stroke volume formula/
EDV-ESV
What volume of blood is ejected from the LV with each contraction?
about 60ml
equates to an EF of 60%
What is the End Systolic Volume and how much is it?
The amount of blood left in the LV after contraction and is about 40ml
What causes an S3 sound?
blood contacting a COMPLIANT left ventricle
What causes an S4 sound?
Blood contacting a NON COMPLIANT LV
Where are S3 and S4 sounds heard best and how?
LLD, apex with bell
What causes the S1 sound?
Closure of the Tricuspid and Mitral valves
What causes the S2 sound?
Closure of the Aortic and Pulmonic valves
Causes of S3 heart sound?
heart failure, cardiomyopathy,
Causes of S4 heart sound?
HTN, Aortic stenosis, ACTIVE MI, “diastolic heart failure” (stiff LV).
What might aortic stenosis sound like?
- occurs after S1
- crescendo decrescendo sound
- may have ejection click
- heard best over aortic area, may radiate to neck
What might aortic regurgitation sound like?
- heard along left sternal border (Erbs point at 3rd ICS)
- heard in diastole after S2
3.peaks at the beginning of diastole then tapers off as the ventricles fill
What are some causes of mitral valve prolaspe?
Connective tissue diseases like Marfans or Ehlers-Danlos
What are the semilunar valves?
The aortic and pulmonic valves (SAP)
What are the atioventricular valves?
Tricuspid and Mitral (AVTM)
Where is the mitral region for murmur auscultation?
5th ICS at MCL usually radiates to axillae. Is at the location of the heart apex.
Where is the aortic region for heart murmur auscultation?
2nd ICS, RSB
Where is the pulmonic region for heart murmur auscultation?
2nd ICS at LSB
Where is the tricuspid region for heart murmur auscultation?
4th ICS, lower sternal border
Cause of S1 sound?
Closure of the Tricuspid and Mitral valves (atrioventricular valves).
Cause of S2 sound?
Closure of semilunar valves (aortic and pulmonic)
Cause of S3 sound?
blood contacting a COMPLIANT LV wall
Cause of S4 sound?
blood contacting a NON compliant LV wall
