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