SAM 5

What are the two phases of the cardiac cycle?

Systole and diastole

What is systole?

Contraction

What is diastole?

Relaxation

What happens during atrial systole?

Atria contract and fill ventricles

What happens during ventricular systole?

Ventricles contract and eject blood

What are the two types of heart valves?

AV and semilunar

Which AV valve is on the right?

Tricuspid

Which AV valve is on the left?

Mitral

Which semilunar valve is on the right?

Pulmonary

Which semilunar valve is on the left?

Aortic

What do heart valves prevent?

Backflow

What ensures one-way blood flow?

Pressure differences and normal valves

What is cardiac output?

Blood pumped per unit time

What is the formula for cardiac output?

CO = HR × SV

What is stroke volume?

Blood ejected per heartbeat

What is the formula for stroke volume?

SV = EDV − ESV

What is end diastolic volume?

Volume in ventricle at end of diastole

What is end systolic volume?

Volume left after systole

What is ejection fraction?

SV ÷ EDV

What are the three determinants of stroke volume?

Preload contractility afterload

What is preload?

Heart muscle stretch before contraction

What determines preload?

Ventricular filling and venous return

What happens when preload increases?

Stroke volume increases

What increases preload clinically?

IV fluids

What is contractility?

Strength of heart contraction

What happens when contractility increases?

Stroke volume increases

What increases contractility?

Sympathetic stimulation

What decreases contractility?

Heart failure

What is afterload?

Resistance against ventricular ejection

What happens when afterload increases?

Stroke volume decreases

What increases afterload?

Hypertension and aortic stenosis

What is the Frank-Starling law?

More preload causes stronger contraction

What is the key limitation of Frank-Starling?

Excessive preload becomes harmful

What is mean arterial pressure?

Average arterial pressure

What is the formula for MAP?

MAP = CO × SVR

What happens to MAP when CO increases?

MAP increases

What happens to MAP when SVR increases?

MAP increases

What happens to MAP when SVR decreases?

MAP decreases

Where is most systemic vascular resistance?

Arterioles

Where is most blood volume stored?

Systemic veins

What is vascular compliance?

Volume a vessel holds at a given pressure

What is inotropy?

Contractile state

What is chronotropy?

Heart rate

What is dromotropy?

Conduction speed

What is lusitropy?

Relaxation speed

What does increased sympathetic tone cause?

↑ HR and ↑ contractility

What does increased parasympathetic tone cause?

↓ HR and ↓ conduction

What is the basic blood flow pathway?

Veins → atria → ventricles → arteries

Where does oxygenated blood enter the left heart?

Pulmonary veins

Where does the left ventricle eject blood?

Aorta

Where does the right ventricle eject blood?

Pulmonary artery

What is oxygen delivery?

CO × arterial O2

What happens when cardiac output decreases?

Compensation activates

Why can compensation become harmful in heart failure?

It increases pressure and volume

What activates RAAS?

Decreased renal perfusion

Where is angiotensinogen produced?

Liver

Where is renin released?

Kidney

What does renin convert angiotensinogen into?

Angiotensin I

What converts angiotensin I to angiotensin II?

ACE

What are the major effects of angiotensin II?

Vasoconstriction and sodium retention

What does angiotensin II stimulate?

Aldosterone ADH and thirst

What does aldosterone promote?

Sodium retention

What does chronic RAAS activation cause?

Fibrosis and remodeling

What are the natriuretic peptides?

ANP BNP and CNP

Where is ANP produced?

Atria

Where is BNP produced?

Ventricles

What stimulates ANP and BNP release?

Wall stress

What do ANP and BNP do?

Natriuresis vasodilation and ↓RAAS

Which natriuretic peptide is diagnostically important?

NT-proBNP

What does the Wiggers diagram show?

ECG pressure volume valves and sounds

What are the major phases of the cardiac cycle?

Atrial systole contraction ejection relaxation filling

What does S1 represent?

Mitral and tricuspid closure

When does S1 occur?

Start of ventricular systole

What does S2 represent?

Aortic and pulmonic closure

When does S2 occur?

End of ventricular systole

What does S3 represent?

Ventricular filling

What does S4 represent?

Atrial contraction against a stiff ventricle

What are S3 and S4 called?

Gallop sounds

Which disease was associated with S4?

Feline hypertrophic cardiomyopathy

Which disease was associated with S3?

Canine dilated cardiomyopathy

What is a mid-systolic click associated with?

Chronic degenerative valve disease

What commonly causes split S2?

Delayed pulmonic closure

What are the three ways to describe a murmur?

Location timing and loudness

What is the point of maximal intensity?

Where the murmur is loudest

What does an apical murmur suggest?

AV valve region

What does a basilar murmur suggest?

Aortic or pulmonic region

When does a systolic murmur occur?

Between S1 and S2

When does a diastolic murmur occur?

Between S2 and next S1

When is a murmur continuous?

During systole and diastole

What disease causes a continuous washing-machine murmur?

PDA

How are murmurs graded?

I to VI

What is a grade I murmur?

Barely audible

What are grade II-III murmurs generally like?

Focal and audible

What is characteristic of a grade IV murmur?

Radiates from PMI

What is characteristic of grade V-VI murmurs?

Palpable thrill

What is the most common murmur in older small-breed dogs?

Degenerative mitral valve disease

What type of murmur do most cats have?

Systolic

What should you use to rank murmur differentials?

Location timing and loudness

What can murmurs and pulses help determine?

Likely cardiac disease