Physiology Flashcards
Heart vessel that supplies anterior 2/3 of interventricular septum, anterolateral papillary muscle and anterior surface of left ventricle
Left anterior descending artery (LAD)
What variables maintain cardiac output during the early stages of exercise
Increased HR and SV
What variables maintain cardiac output during the late stages of exercise
HR only (SV plateaus)
What heart function is shortened by increased HR
Diastole
Effect of decreased diastole
Less filling time causing decreased cardiac output
Fick principle for calculating CO
CO = rate of O2 consumption/(arteriole O2 content - venous O2 content)
Method for calculating mean arterial pressure (MAP)
MAP = CO x TPR or MAP = 2/3 diastole + 1/3 systole
What is pulse pressure (PP)
PP = systolic pressure - diastolic pressure
Method for calculating stroke volume (SV)
SV = EDV - ESV
Variables that affect SV
Contractility, Afterload, Preload
Effect of increased contractility on SV
Increased SV
Effect of increased afterload on SV
Decreased SV
Effect of increased preload on SV
Increased SV
Effect of decreased contractility on SV
Decreased SV
Effect of decreased afterload on SV
Increased SV
Effect of decreased preload on SV
Decreased SV
Effect of catecholamine binding on contractility and SV
Both increased
Catecholamine MOA on increasing contractility and SV
Bind B-1 receptors leading to two outcomes:
1. Phosphorylate Ca channels
2. Phosphorylate phospholamban
Both increase Ca in SR through different mechanisms
Variable that approximates preload
EDV
Effect vasodilation has on EDV
Decreases EDV due to decreased venous return
Variable that approximates MAP
Afterload
Formula for calculating Ejection Fraction (EF)
EF = SV/EDV = (EDV - ESV)/EDV
Blood vessels that account for most TPR
Arterioles
Blood vessels that provide the most storage capacity
Veins
What does viscosity depend on most
Hematocrit
Condition that decreases blood viscosity
Anemia
Condition that increases blood viscosity
Polycythemia and hyperproteinemic (multiple myeloma)
Formula for calculating total parallel resistance
R = 1/(1/R1 + 1/R2 + 1/R3)
Effect of Vasopressors on TPR and CO for a given RA pressure or EDV
Increase TPR and decrease CO
Effect of increased contractility on pressure volume loop
Increased SV and Ejection fraction
Decreased ESV
Period between mitral valve closing and aortic valve opening
Isovolumetric contraction
Period between aortic valve opening and closing
Systolic ejection
Period between aortic valve closing and mitral valve opening
Isovolumetric relaxation
Period just after mitral valve opening
Rapid filling
Period just before mitral valve closing
Reduced filling
Sound made by mitral and tricuspid valve closure
S1
Sound made by aortic and pulmonary valve closure
S2
Area S1 loudest
Mitral area
Area S2 loudest
Left upper sternal border
Heart sound associated with increased filling pressures
S3
Heart sound made by left atrium pushing against stiff LV wall
S4
Heart sound that can be normal in children and young adults
S3
Heart sound considered abnormal at any age
S4
S4 heart sound is best heard at apex in what position
Left lateral decubitus position
JVP associated with atrial contraction
a wave
JVP associated with RV contraction
c wave
JVP associated with downward displacement of closed tricuspid valve during rapid ventricular ejection phase
x descent
JVP associated with increased right atrial pressure due to filling against closed tricuspid valve
v wave
JVP associated with RA emptying into RV
y descent
Cause of normal splitting between A2 and P2
Inspiration
Cause of wide splitting between A2 and P2
Conditions that delay RV emptying (pulmonic stenosis and RBBB) - splitting exaggerated during inspiration
Cause of fixed splitting
ASD - increased RA and RV volumes causes increased flow through pulmonic valve delaying closure regardless of breath
Cause of paradoxical splitting
Conditions that delay aortic valve closure (aortic stenosis and LBBB) - P2 closes before A2 - on inspiration P2 closer to A2 paradoxically eliminating split
Murmurs heard best in Mitral area
Mitral regurgitation
Mitral valve prolapse
Mitral stenosis
Murmurs heard best in Tricuspid area
Tricuspid regurgitation
Tricuspid stenosis
VSD
ASD
Murmurs heard best in Pulmonic area
Pulmonic stenosis
Murmurs heart best in LUSB
Pulmonic regurgitation
HCM
Aortic regurgitation
Murmurs heard best in Aortic area
Aortic stenosis
Maneuver that increases intensity of right heart sounds
Inspiration (increases venous return to RA)
Increases intensity of AR and VSD murmurs
Hand grip and rapid squatting
Maneuver that decreases intensity of most murmurs including AS
Valsalva and standing up
Maneuver that decreases intensity of hypertrophic cardiomyopathy murmurs
Hand grip and rapid squatting
Increases intensity of AS
Rapid squatting
Maneuver that increases intensity of hypertrophic cardiomyopathy murmurs
Valsalva and standing up
Maneuver that causes later onset of click/murmur in MVP
Hand grip and rapid squatting
Mnemonic for Systolic murmurs
MR VP TRAPS: Mitral Regurgitation VSD Pulmonic stenosis Tricuspid Regurgitation Aortic and Pulmonic Stenosis
Mnemonic for Diastolic murmurs
MS PAID:
Mitral Stenosis
Pulmonic and Aortic Insufficiency
D - just for diastolic
Continuous murmurs
Patent ductus arteriosus
Crescendo-decrescendo systolic ejection murmur, radiates to carotids with “pulsus parvus et tardus”, heard loudest at heart base
Aortic stenosis
Cause of AS in older patients > 60 years
Age-related calcification
Cause of AS in younger patients
Early-onset calcification of bicuspid aorta
Symptoms of AS
Syncope, Angina, Dyspnea on exertion (SAD)
Holosystolic, high-pitched “blowing murmur”, loudest at apex and radiates toward axilla
Mitral regurgitation
Common cause of MR
Ischemic heart disease, MVP, LV dilatation
Holosystolic, high-pitched “blowing murmur”, loudest at tricuspid area and increased with inspiration
Tricuspid regurgitation
Valvular pathology caused by rheumatic fever and infective endocarditis
Mitral or Tricuspid regurgitation
Late systolic crescendo murmur with midsystolic click best heard over apex and loudest just before S2
Mitral Valve Prolapse (MVP)
Valvular pathology seen in Marfan and Ehlers-Danlos syndrome, can be caused by rheumatic fever or chordae rupture and predisposes to infective endocarditis
Mitral Valve Prolapse
Holosystolic, harsh-sounding murmur, loudest at tricuspid area with hyperdynamic RV impulse and no change in arterial pulse pressure
Ventral Septal Defect (VSD)