Myocardial Vascular & Muscle Dysfunction

What are examples of myocardial vascular dysfunctions?

CAD

myocardial ischemia

stable/unstable angina

MI

What are examples of myocardial muscle dysfunctions?

arrythmias

valve disease

cardiomyopathy

CHF: left sided or right sided / systolic or diastolic failure

What is CAD?

steady buildup of plaque in the coronary arteries which leads to decreased myocardial blood flow

What are risk factors of CAD?

age

family hx

smoking

sedentary lifestyle

overweight or obese

hypertension or diabetes

dyslipidemia

What is atherosclerosis?

build up of cholesterol, lipid, cellular debris, and calcium plaques in medium and large arteries

What is stable plaque?

slow accumulation of lipid deposits

thick fibrous cap

unlikely to rupture

more arterial narrowing

What is unstable plaque?

rapid accumulation of lipid deposits

thin fibrous cap

prone to rupture

more arterial narrowing

What is a key symptom of myocardial ischemia?

stable angina

What are chief complaints of stable angina?

chest discomfort provoked by exertion

alleviated with rest or nitroglycerin

not reproducible with palpation

What are causes of stable angina?

blood vessel is occluded by plaque or muscle spasm

oxygen demand outpaces supply

ischemia occurs as result

Stable angina can also be seen in?

hypotension

massive blood loss

What are characteristics of MI?

cell death damages or destroys heart tissue

damage is irreversible

occurs with prolonged or unmanaged ischemia

What are characteristics of unstable angina?

decrease blood flow to heart

not severe enough to cause necrosis or heart attack

increases the risk of heart attach

occurs at rest or below usual ischemic baseline

What is myocardial ischemia?

myocardial blood flow is obstructed due to partial or complete blockage

can result in permanent damage if blood flow is not restored

What is a classic presentation for MI?

chest pain, pressure, tightness, squeezing

radiates to neck, jaw, shoulder, back or arms (L>R)

confused with heartburn or indigestion

pale and or diaphoresis

What is the cause of MI?

blood demand outweighs supply due to oxygen deprivation

What zone results in tissue becoming necrotic due to cell death and the extent of infarction depends on lesions and collateral circulation?

infarction (outer zone)

What zone results in its ability to return to normal and may become necrotic if blood flow isnt restored and can regain function within 2-3 wks if collateral circulation is adequately functioning?

injury (middle zone)

What zone results in no permanent changes and immediately surrounds zone of injury?

ischemia (inner zone)

What does the P wave represent?

function of upper chambers of the heart

What does the PR interval represent?

ability of the wires to conduct electricity from upper to lower chambers of heart

What does the QRS complex represent?

conduction of electricity throughout the lower chambers of the heart

What does the T wave represent?

repolarization

What does a ST elevation MI tell you?

elevated cardiac enzymes (troponin and CK) with ST segment elevation on EKG

complete artery blockage

What does a non-ST elevation MI tell you?

elevated cardiac enzymes (troponin and CK) without ST segment elevation on EKG
partial artery blockage

What are characteristics of a complicated MI?

dysrhythmia

damage to heart structures

thrombosis

often leads to HF

What are characteristics of uncomplicated MI?

small infarction

full recovery without significant decrease in CO at rest or with moderate activity

What are the 3 main cardiac enzymes?

troponin

myoglobin

creatine kinase (CK)

When is troponin released?

only when necrosis occurs

When is myoglobin released?

with any damage to muscle tissue including necrosis

When is CK released?

different subtypes are released depending on the tissue

What two cardiac enzymes are specific for MI?

troponin and CK

When does troponin levels peak?

24-48 hrs

When does myoglobin levels peak?

4-12 hrs

When does CK levels peak?

24 hrs

When does troponin return to baseline?

over 5-14 days

When does myoglobin return to baseline?

immediately

When does CK return to baseline?

after 48-72 hrs

When does serum levels increase with troponin and CK?

within 3-12 hrs from onset angina

When does serum levels increase with myoglobin?

withint 30-60 min after injury occurs

What are the 4 main focused for treatment with myocardial vascular dysfunction?

treat underlying cause

address dietary factors

pharmacologic management

exercise training and or cardiac rehab

What are the stages of change?

pre-contemplation (denial)

contemplation

preparation

action

maintenanace

termination (habit)

What are unmodifiable risk factors for CAD?

gender

age

family hx

What pharmacologic treatments are used to decrease oxygen demand?

beta blockers (ends in -lol)

calcium channel blockers

nitrates

What pharmacologic treatments are used to increase oxygen supply?

vasodilators (calcium channel blockers or nitrates)

clot distribution (thrombolytics, anti-platelets, anti-coags)

What are diagnostic testing used for CAD?

EKG, chest x-ray

echocardiogram

cardiac catheterization - angiogram

nuclear stress test

nuclear PET scan

What diagnostic test is used to test valve function, ventricular wall motion, and or estimates SV and EF?

echocardiogram (gold standard for heart)

What diagnostic test is used to visualize coronary arteries or open narrowed/blocked arteries?

cardiac catheterization-angiogram

What diagnostic test evaluates myocardial perfusion at rest, during exercise, or pharmacologically induced stress?

nuclear stress test

What diagnostic test evaluates myocardial perfusion and tissue function and able to differentiate between healthy and damaged tissue?

nuclear PET scan

What are the 3 types of valve disease?

stenosis

regurgitation

prolaspe

What are characteristics of valve stenosis?

valve does fully open due to thickening, stiffness, or fusing together

forward blood flow is obstructed

chamber attempting to pump blood through a stenotic valve with hypertrophy

What are characteristics of valve regurgitation?

valve does not close fully or blood leaks backward as valve is closing

increase work to pump the same amount of blood

What are characteristics of valve prolaspe?

valve flap does not close smoothly or evenly

valves bulge into the atrium

tissue abnormalities, rupture of papillary muscles, or chordae tendinae can cause this

What are the 3 common types of cardiomyopathy?

dilated

hypertrophic

restrictive

What are the 3 less common types of cardiomyopathy?

ischemic

takotsubo (broke heart syndrome)

idiopathic

What is dilated cardiomyopathy?

ventricle walls become stretched out which results in significant systole dysfunction

What is hypertrophic cardiomyopathy?

thickened ventricular myocardium decreases available space inside ventricle which results in decreased filling during diastole

What is restrictive cardiomyopathy?

endocardial scarring of ventricles which results in decreased filling during diastole and decreased force during systole

scar tissue decreases compliance and contractility

What are the classifications of cardiac failure based on?

stage-severity-compensation

side of heart involved

cardiac output

duration

function affected

What are the types of cardiac failure based on stage-severity-compensation?

compensated or decompensated

What are the types of cardiac failure based on side of heart involved?

left sided

right sided

bilateral

What are the types of cardiac failure based on cardiac output?

low-output or high-output

What are the types of cardiac failure based on duration?

acute or chronic

What are the types of cardiac failure based on function affected?

systolic or diastolic

What HF has characteristics of:

L side of heart cannot pump blood to body

fluid from L ventricle backs up into lungs causing pulmonary edema

has dyspnea on exertion, orthopnea, restlessness, tachycardia, and pulmonary congestion

*pulmonary congestion: cough, crackles, wheezing, blood in sputum, tachypnea

left sided failure

What HF has characteristics of:

R ventricle cannot produce enough force to overcome pulmonary pressure

fluid from R side of heart backs up into venous system caused peripheral edema

has LE edema, abdominal swelling (ascites), JVD, increase peripheral venous pressure, and fatigue

right sided failure

What HF has characteristics of:

unable to fill ventricle

ventricles lose the ability to relax and expand

preserved ejection fraction

diastolic heart failure

What HF has characteristics of:

unable to pump enough blood out

ventricles lose the ability to contract and pump blood

reduced ejection fraction

systolic heart failure

What is another name for CHF?

pump failure

What HF has characteristics of:

heart cannot pump blood forward

fluid back up into the venous system of the lungs or peripheral circulation

may be unilateral or bilateral

CHF

What HF has characteristics of:

inability to pump enough oxygen-rich blood to periphery

left sided CHF

What HF has characteristics of:

inability to pump enough blood to lungs to pick up oxygen

right sided CHF

How does chronic or acute HF develop?

gradually as the heart struggles to keep up with demand

eventually the compensatory mechanism will not be enough to keep up with oxygen demand

What does chronic compensatory mechanism lead to?

end organ failure due to overuse

What needs to be known about acute heart failure?

it is a medical emergency and warrants an immediate 911 call if suspected

What HF has characteristics of:

reduced CO may be minor or asymptomatic

heat is able to compensate for HF

patients are at risk only if myocardial demand increases

danger to renal system

compensated HF

What HF has characteristics of:

“CHF exacerbation”

compensatory mechanism fails to maintain required CO

heart becomes dilated and weak and ultimately fails

renal function is compromised to due chronic overload

less CO means less blood to heart itself

decompensated HF

What are strategies to help the compensatory mechanism?

enlarging: cardiac muscle and heart chambers to increase contractility

ventricular hypertrophy “developing more muscle mass”: allows stronger contraction

pumping faster: increased HR means increases CO

T or F: does CHF cause a systemic change?

yes can affect the cardiovascular, pulmonary, musculoskeletal, neurochemical, nutrition, circulation and filtration

What is the outline of medical management for heart failure?

surgical intervention

diet

medications

treat underlying disease

reduce symptoms

exercise and or cardiac rehab

What pharmacological treatments are used to decrease workload for HF?

beta-blockers

ACE inhibitors

vasodilators

What pharmacological treatments are used to increase contractility for HF?

positive inotropes

What diagnostic tests are used for HF?

EKG, chest x-ray

echocardiogram

doppler US

cardiac catheterization-angiogram

nuclear stress test

nuclear PET scan

What diagnostic test is used to measure the speed and or direction of blood flow?

doppler US

What lab values should be monitored for HF?

cardiac enzymes

electrolytes

BNP

BUN & Creatinine

Where is BNP stored?

cardiac tissue

What does BNP release?

stimulation by high ventricular filling pressures and increased wall tension

What does BNP cause?

vasodilation, natriuresis, diuresis

What does BNP correlate with?

severity and prognosis of heart failure

What two things can be indicated if BNP is elevated?

heart failure or kidney failure (when filtered through kidneys)

What can cause electrolyte imbalances?

muscle weakness

palpitation and arrhythmias

altered level of consciousness

What is the normal range of sodium (Na+)?

136-145

What is the normal range of potassium (K+)?

3.5-5.3

What is normal range of CK? in males and in females?

normal: 30-170

males: 52-336

females: 38-176

What is normal range of troponin?

<0.03

What does increased and decreased levels of potassium cause?

increase: effect contractility

decrease: cause severe arrhythmias

What is normal range of BUN?

8-23

What two things can be indicated if BUN is elevated?

heart or renal (kidney)failure

What is normal range of creatinine?

<1.5