Cardiovascular: Physiology

What is stroke volume

Amount of blood pumped out of the left ventricle during systole

What affects stroke volume

Contractility

Afterload

Preload

What increases stroke volume

Increased contractility

Increased preload

Decreased afterload

Contractility increases with

Catecholamine stimulation via Beta 1 receptors

Increased intracellular Ca2+

Decreased Extracellular Na+

Digoxin

What happens when you activate protein kinase A

Phospholamban phosphorylation which increases Ca2+ ATPase and Increases Ca2+ storage in sarcoplasmic reticulum

Ca2+ channel phosphorylation which increases Ca2+ entry and Increases Ca2+ induced Ca2+ release

If you decrease the activity of Na+/Ca+ exchangers, what happens to calcium

increases

If you decrease the activity of Na+/K+ pumps, what hapens

Increase intracellular Na+

What happens if you have increased intracellular Na+

Increase intracellular Ca2+ concentration because you have a decrease in the Na+/Ca2+ exchanger

What is preload

Amount of blood left in the ventricle after diastole

What is preload approximated by

Ventricular end-diastolic volume

What is afterload approximated by

Mean arterial pressure (MAP)

What does the heart do to compensate for chronic afterload

Hypertrophy of the left ventricle

Arterial vasodilator decrease

Afterload

ACE inhibitors decrease

preload and afterload

ARBs decrease

preload and afterload

Myocardial oxygen demand is increased by

Increased contractility

Increased afterload

Increased heart rate

Increased vessel diameter

Wall tension follows Laplace's law, which states

Wall tension = Pressure x Radius

Stroke volume formula

EDV - ESV

Ejection fraction formula

(EDV - ESV) / EDV

Cardiac output formula

SV x HR

Pulse pressure formula

Systolic Blood Pressure - Diastolic blood pressure

Mean arterial pressure formula

CO x total peripheral blood resistance

Index of ventricular contractility

Ejection fraction

In the early stages of exercise, cardiac output is maintained by

Increased heart rate and increased stroke volume

In the later stages of exercise, cardiac output is maintained by

Increased heart rate

Pulse pressure is directly proportional to

Stroke volume

Pulse pressure is inversely proportional to

Arterial compliance

What increases pulse pressure

Hyperthyroidism

Aortic regurgitation

Aortic stiffening

Obstructive sleep apnea

Anemia

Exercise

What decreases pulse pressure

Aortic stenosis

Cardiogenic shock

Cardiac tamponade

Advanced heart failure

Force of contraction is proportional to

End diastolic length of cardiac muscle fiber (preload)

Increased cardiac contractility with

Catecholamines

Positive inotropes

Decreased contractility with

Loss of functional myocardium

Beta blockers

Nondihydropyridine Ca2+ channel blockers

Heart failure

_____ have the highest total cross-sectional area and lowest flow velocity

Capillaries

What increases volumetric flow rate

Increased flow velocity

Increased cross sectional area

What has less resistance: Vessels in series or Vessels in parallel

Parallel

Viscosity depends mostly on

Hematocrit

What increases inotropy

Catecholamines

Dobutamine

Milrinone

Digoxin

Exercise

What decreases inotropy

Heart failure with reduced ejection fraction

Narcotic overdose

Sympathetic inhibition

What increases venous return

Fluid infusion

Sympathetic activity

What decreases venous return

Acute hemorrhage

Spinal anesthesia

What increases total peripheral resistance

Vasopressors

What decreases total peripheral resistance

Exercise, arteriovenous shunt

Phases of the left ventricle

Isovolumetric contraction

Systolic ejection

Isovolumetric relaxation

Rapid filling

Reduced filling

Period between mitral valve closing and aortic valve opening; period of highest O2 consumption

Isovolumetric contraction

Period between aortic valve opening and closing

Systolic ejection

Period between aortic valve closing and mitral valve opening

Isovolumetic relaxation

Period just after mitral valve opening

Rapid filling

Period just before mitral valve closing

Reduced filling

What is heard at S1

Mitral and tricuspid valve closure

What is heard at S2

Aortic and pulmonic valve closure

What is heard at S3

Turbulence caused by blood from left atrium mixing with increased end diastolic volume

What is head at S4

TUrbulence caused by blood entering stiffened left ventricle

Where is S1 heard the loudest

Mitral area

Where is S2 heard the loudest

Left upper sternal border

Where is S3 heard the loudest

Apex with patient in left lateral decubitus position

What is an S3 sound associated with

Increased filling pressures

Dilated ventricles

Where is S4 heard the loudest

Apex with patient in left lateral decubitus position

What is an S4 heart sound associated with

High arterial pressure

Ventricular noncompliance

What is the other name for jugular venous pulse

Right atrial pressure

A wave in JVP

atrial contraction

A wave is absent in

Atrial fibrillation

C wave in JVP

ventricular contraction

X descent in JVP

Atrial relaxation due to rapid ventricular ejection

V wave in JVP

Increased atrial pressure due to increased volume against tricuspid valve

Y descent in JVP

Atrium emptying into ventricle

A prominent Y descent on JVP is noted in

Constrictive pericarditis

An absent Y descent on JVP is noted in

Cardiac tamponade

What happens to LV, ESV, and SV in aortic stenosis

LV: Increased

ESV: Increased

SV: Decreased

What happens to EDV and SV in aortic regurgitation

EDV: Increased

SV: Increased

What is lost in the waveform in aortic regurgitation

Dichrotic nothc

What happens to LA pressure, EDV, ESV, and SV in mitral stenosis

LA Pressure: Increases

EDV: Decreases

ESV: Decreases

SV: Decreases

What is lost in mitral regurgitation

Isovolumetric phase

What happens to ESV, EDV, and SV in mitral regurgitation

ESV: Decreases

EDV: increases

SV: Increases

What causes ESV to decrease in mitral regurgitation

Decreased resistance and increased regurgitation into LA during systome

What causes EDV to increase in mitral regurgitation

Increased LA volume/pressure from regurgitation leading to increased ventricular filling

What causes increased SV in mitral regurgitation

Forward flow into systemic circulation plus backflow into LA

What causes physiologic splitting of S2

Inspiration causes a drop in intrathoracic pressure, increasing venous return to RV, causing increased RV stroke volume, causing the pulmonic valve to close after the aortic (delayed closure)

Decreased pulmonary impedance can also occur during inspiration, which contributes to

Delayed closure of pulmonic valve

What causes wide splitting of S2

Conditions delaying RV emptying:

- Pulmonic stenosis

- RBBB

What causes fixed splitting of S2

Atrial septal defect

What causes paradoxical splitting of S2

Conditions that delay aortic valve closure

- Aortic stenosis

- LBBB

Normal order of semilunar valve closure is reversed in what conditions

Paradoxical splitting P2 occurs before A2

When can paradoxical splitting be heard

On expiration

What can you hear in the aortic area

Aortic stenosis

Flow murmur (physiologic murmur)

Aortic valve stenosis

What can you hear at the left sternal border

Diastolic murmur

- Aortic regurgitation

- Pulmonic regurgitation

Systolic murmur

- Hypertrophic cardiomyopathy

What can you hear in the pulmonic area

Systolic election murmur

- Pulmonic stenosis

- Atrial septal defect

- Flow murmur

What can you hear in the tricuspid area

Holosystolic murmur

- Tricuspid regurgitation

- Ventricular septal defect

Diastolic murmur

- Tricuspid stenosis

What can you hear in the Mitral area (apex)

Holosystolic murmur

- Mitral regurgitation

Systolic murmur

- Mitral valve prolapse

Diastolic murmur

- Mitral stenosis

With a Standing Valsalva maeuver, what happens to:

- Cardiovascular changes

- Murmurs that increase with maneuver

- Murmurs that decrease with maneuver

Changes: Decreased preload

Murmurs increased: Mitral valve prolapse & Hypertrophic cardiomyopathy

Murmurs Decreased: Most murmurs

With a Passive Leg Raise maeuver, what happens to:

- Cardiovascular changes

- Murmurs that increase with maneuver

- Murmurs that decrease with maneuver

Changes: Increased preload

Murmurs increased: Most murmurs

Murmurs Decreased: Mitral valve prolapse & Hypertrophic cardiomyopathy

With a Squatting maeuver, what happens to:

- Cardiovascular changes

- Murmurs that increase with maneuver

- Murmurs that decrease with maneuver

Changes: Increased preload, Increased afterload

Murmurs increased: Most murmurs

Murmurs Decreased: Mitral valve prolapse & Hypertrophic cardiomyopathy

With a Hand grip maeuver, what happens to:

- Cardiovascular changes

- Murmurs that increase with maneuver

- Murmurs that decrease with maneuver

Changes: Increased afterload leading to increased reverse flow across aortic valve

Murmurs increased: Most other left sided murmurs (Aortic regurgitation, mitral regurgitation, and Ventriclar septal defect)

Murmurs Decreased: Aortic stenosis & Hypertrophic cardiomyopathy

With a Inspiration maeuver, what happens to:

- Cardiovascular changes

- Murmurs that increase with maneuver

- Murmurs that decrease with maneuver

Changes: Increased venous return to right heart & decreased venous return to left heart

Murmurs increased: Most right-sided murmurs

Murmurs Decreased: Most left sided murmurs

Which heart murmurs are heard in systole

Aortic stenosis

Mitral/tricuspid regurgitation

Mitral valve prolapse

Ventricular septal defect

Which heart murmurs are heard in diastole

Aortic regurgitation

Mitral stenosis

Which heart murmurs are continuous

Patent ductus arteriosus

Which murmur has a crescendo-decresendo systolic ejection murmur and soft S2

Aortic stenosis

Which murmur has holosystolic, high pitched "blowing murmur"

Mitral/tricuspid regurgitation

Which murmur has a late systolic crescendo murmur with midsystolic click

Mitral valve prolapse

Which murmur is a holosystolic, harsh sounding murmur heard loudest in the tricuspid area

Ventricular septal defect