Important Physio Stuffs Flashcards
S1
- first heart sound, closure of mitral then tricuspid valves: two bursts, a mitral M1 and a tricuspid T1 component
- Occurs during R-S segment of EKG, and during the isovolumetric contraction
S2
- second heart sound (sounds like dub)
- An aortic A2 and a pulmonary P2 component: resulting from closure of aortic and pulmonary valves
OS
opening snap
- opening of a stenotic mitral valve
S3
- third heart sound: early diastole, soon after S2
- during rapid ventricular filling phase
- normal in younger people
- may indicate ventricular enlargement associated with heart failure; reduced distensibility/compliance
- diastolic filling gallop or ventricular or protodiastolic gallop
- “protodiastolic gallop” : S1-S2-S3 (“Ken-tuck-y”)
S4
- fourth heart sound: heard late diastole, just before S1
- Associated with unusually strong atrial contraction
- Indicative of pathology, ventricular wall stiffness and decreased compliance associated with hypertrophy
- atrial sound that creates an atrial or presytolic gallop
“Gallop” S1, S2 + S3 and/or S4
- Presystolic gallop: S4 - S1- S2
- (“Ten-nessee”)
splitting of S2
best heart during inspiration
On right side of heart:
- Relatively negative intrathoracic pressure –>greater VR to RA/RV –> increased EDV –> greater RV ejection volume
- Additional time for RV ejection delays pulmonary valve closure (P2) more
- Enhances physiological splitting of S2
Effect on left side of heart:
- Relatively negative intrathoracic pressure –>retention of blood in dilated pulmonary v.v. –>reduced VR to LA/LV –> decreased LV EDV & ejection
- Less time for LV ejection accelerates aortic valve closure (A2) more
- Enhances physiological splitting of S2
What are variations in S1, S2 splitting?
Louder S1 with Tachycardia
Valves are farther from being closed when contraction occurs (slam shut) vs. more time at slower HR to slowly begin closure
Pathologic S1 split
Additional increase in delay between Mitral and Tricuspid closure (M1 , T1)
Ex: Right Bundle Branch Block
Paradoxical S2 Splitting
A2 and P2 heard during expiration, not inspiration
Fixed S2 splitting
A2 and P2 heard throughout respiratory cycle
Mitral stenosis:
Valve stiffening may result in opening snap (OS) after S2, early diastole
Venous Pulse
Contributions to venous pulse:
(1) Retrograde action of the heartbeat during cardiac cycle
(2) Respiratory cycle
(3) Contraction of skeletal muscles
- same three waves as the atrial waves:
- a wave: RA contraction, closely related to venous return
- c wave: RV pressure in early systole (when all valves are closed and isovolumetric contraction occuring - bulging of tricuspid valve into RA)
- v wave: RA filling (tricuspid closed)
- increase pressure subsequent to y minimum –> occurs as VR continues with reduced ventricular filling
abnormal changes in a wave?
- RA contraction:
- no a waves: atrial fibrillation
- large a waves: tricuspid stenosis, right heart failure
- cannon (very large) a waves: third degree complete heart block (AV dissociation)
what causes an abnormal v wave?
RA filling (tricuspid bulging): large v wave (c-wave): tricuspid regurgitation
work performed by heart
W = P x V + 1/2mv2 + tension heat
- kinetic energy: factors work per beat including acceleration
- W = total external work
- P= pressure volume work
- 1/2mv is kinetic energy
Tension Heat: KT(change in heat)
- greatest energy cost
- splitting ATP during isovolumetric onctraction
- isometric: no “work” without movement
- T= ventricular wall tesnsion (afterload)
- change in time: time in systole
What are three main determinants of myocardial O2 demand?
- ventricular wall stress
- heart rate
- contractility (inotropic state)
Cardiac Output
CO = HR X SV
- normal = ~ 5 L/min at
Determinants: Preload, Afterload, Contractility/Inotropy
What is measured in right-sided heart catheterization? what about left-sided heart catheterization?
- RA, RV and pulmonary wedge pressure (left atrial pressure, wedged into a small pulmonary a.)
- LA, LV; insertion of catheter into artery and advanced into the left heart to measure pressure
what would you see with aortic stenosis?
- increased heart sound between S1–>S2 due to narrowing of the aortic valve
- Left ventricular pressure would be abnormally high, due to increased pressure needed to get blood through the narrow segment
What would you see with mitral stenosis?
- would hear sounds before from S2–>S1: diastole phase: sounds are due to the difficulty getting blood through the AV valves
- would see elevated pressure in the left atrium
What would you see with aortic regurgitation?
- would see abnormally elevated aortic pressure due to blood flowing back through aortic valve into the left ventricle
- hear abnormal sounds during diastolic phase; due to blood leaking back through into the ventricle
What would you hear with mitral insufficiency?
- would hear relatively flat sound during systole due to the mitral valve leaking back through, would result in increased pressure in the left atrium during systole
Left Ventricular heart failure
increased LV pressure, increased LA pressure, increased pulmonary vv. pressure, pincreased pulmonary capillary hydrostatic pressure, results in increased filtration, increased pulmonary edema
What is the cause of pulmonary hypertension?
RV failure, results in RA failure, results in venous distension of the VC, results in hepatomegally, ascites and peripheral edema
what does increased afterload lead to?
increased afterload (aortic pressure) –> decreased outflow velocity, greater proportion of time in systole is spent in isovolumetric contraction
- decreased stroke volume
- increased end systolic volume: decreased ejection fraction
What does increased preload lead to?
- increased VR, increased EDV, increased contractility, increased SV, increased CO
- preload activates more Ca2+ release via stretch activated Ca2+ channels on sarcolemma