M Tayyab Student of Anesthesia

kmu

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Facts:The heart is about the size of a fist and weighs less than 1 pound

The average bpm is 72The average adult heart pumps about

6000-7500 liters of blood per day through 60,000 miles of blood vessels each minute at rest.

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StructureCovered by pericardium

ParietalVisceral (epicardium)

Outer heart layer: epicardiumMiddle heart layer: myocardiumInner layer: endocardium

Structure (continued)Four hollow chambers

Two upper, atriaTwo lower, ventricles

Divided by septum and valves

FunctionRight atrium

receives deoxygenated blood

Right ventricle pumps blood to lungs

Function (continued)Left atrium receives oxygenated bloodLeft ventricle pumps oxygenated blood to

bodyAV valve closure: S1 heart soundSemilunar valve closure: S2 heart soundCoronary circulation

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Aorta, arteries, arterioles, capillariesVenules, veins, superior and inferior vena

cavaThree layers

IntimaMediaAdventitia

FunctionCirculationPeripheral vascular resistance: viscosity,

length, diameterBlood pressure control

MechanicalConduction system

MechanicalSA node: pacemakerCardiac output (CO)Heart rate (HR)Stroke volume (SV): the volume of blood

pumped from one ventricle of the heart with each beat

CO = HR x SV

MechanicalCardiac reservePreloadStarling’s lawAfterloadContractility

Electrical properties:Action potentialPolarizationDepolarizationRepolarizationRefractory period

Filling and pumpingDiastole – ventricular fillingSystole –ventricles eject blood

SubjectiveHealth historyChest painSOBLeg painPillows to sleepMedicationsLifestyle: diet, alcohol use, exercise,

smoking, drugs

ObjectiveGeneral appearanceSkinWoundsPulsesJugular vein distentionEdemaBreathing

TEE (transesophageal echocardiogram)Monitor breathing, cough, gag reflexKeep NPO until gag reflex returns

Doppler sonography: is a medical imaging technique that uses ultrasound enhanced by the Doppler effect and is often provide helpful information about the flow and movement of blood and inner areas of the body Monitor BPWash extremities to remove gel after test

completed

X-rays/CT scan/EBCTElectron beam computed tomography (EBCT)

is used to determine coronary calcium Document client allergy to fish or shellfishPregnancy risk

Angiography/cardiac catheterizationMRI

Document presence of implanted electronic devices

Radionuclear scansIncrease fluids after the test

Telemetry/Holter monitorTeach about purpose: is a portable device

for continuously monitoring various electrical activity of the central nervous system for at least 24 hours (often for two weeks at a tim

Dry skinRemove hairAvoid getting unit wetWhen to phone the MD

24Dr Ibrahim Bashayreh

Coronary Artery DiseaseHeart AnatomyAtherosclerotic Plaque/AtheromaAngina PectorisMyocardial InfarctionSudden DeathOverall Management

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CAD is the largest killer of American males and females

13 million Americans have CAD1.1 million MI’s per yearEvery 26 seconds an American will suffer from a

coronary eventEvery 60 seconds an American will die because

of a coronary event@ 42% of those having a coronary event will die

from it@350K people die per year because of a coronary

event in the Emergency Department before even being admitted to the hospital

Death Rate in 2001: 177 in 100,000

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84% of those who die from CAD are 65 or older If under the age of 65, 80% mortality rate with the first

myocardial infarction Within 1 year of initial MI:

25% of men and 38% of women will die Within 8 years of initial MI:

50% of men and women under 65 will die An average of 11.5 years of life are lost due to an MI IMPORTANT:

50% of men and 64% of women who have died suddenly via CAD DID NOT HAVE ANY PREVIOUS SYMPTOMS

Sudden Death: Those with a previous history of MI have a 5-6 times

Sudden Death rate compared to the general population

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Start with anatomy…

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" Ischaemia " refers to an insufficient amount of  blood. The coronary arteries are the only source of  blood for the heart muscle. If this coronary arteries are blocked, the blood supply will reduce.

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Ischemic heart disease (IHD): caused by coronary atherosclerotic plaque formation which leads to imbalance between O2 supply & demandresults in myocardial ischemia

Chest pain: cardinal symptom of myocardial ischemia caused by coronary artery disease (CAD)

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Ischemia / infarction

chest pain

Diastolic Dysfunction Systolic Dysfunction

cardiac output

catecholamines

MVO2

wall tension

LV diastolic pressurepulmonarycongestionpO2

(heart rate, BP)

High blood cholesterolHigh blood pressureSmokingObesityLack of physical activity

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Uncontrollable

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•Sex•Hereditary•Race•Age

Controllable•High blood pressure•High blood cholesterol•Smoking•Physical activity•Obesity•Diabetes•Stress and anger

Why would there be an insufficient blood supply to the heart?Remember that the coronary arteries are

the only source of fuel to the heartThe coronary arteries may become

partially/completely occluded:Atherosclerotic Plaques

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Focal accumulation of smooth muscle cells, foam cells, cholesterol crystals and lipid under the endothelium of the artery (within the Tunica Intima)

Given time, this plaque can protrude into the lumen of the vessel reducing blood flow

Often develops at branch points or curves within the vasculature blood is slowed and/or turbulent

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Where does the plaque begin? within the Tunica Intima, the innermost wall of the artery

What is a plaque made of? Superficial fibrous cap

made of smooth muscle cells, collagen, elastin and proteinsAlso contains

Macrophages, Foam Cells, T Cells

Foam cells are one of the first cells found at the site of the fatty streak, which is the beginning of atherosclerotic plaque formation in vessels

Necrotic Center of cholesterol crystals, lipids, Apolipoprotein B LDL

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As the atheroma within the coronary arteries enlarges, the blood flow to the heart decreases and therefore so does the O2 supply

The heart is not in danger of hypoxia until 50% of the vessel is occluded

As the heart senses a decrease in O2, there is attempted compensation:Increase Heart RateIncrease Blood Pressure Aggravation/Worsening of the atheroma

When 70% of the artery is occluded, Angina Pectoris will occur

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Classification = mainly 4 typesMyocardial infarction (MI)Sudden cardiac deathAngina pectoris Chronic IHD with heart failure

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At least 70% occlusion of coronary artery resulting in pain. What kind of pain? Chest pain Radiating pain to:

Left shoulderJawLeft or Right arm

Usually brought on by physical exertion as the heart is trying to pump blood to the muscles, it requires more blood that is not available due to the blockage of the coronary artery(ies)

Is self limiting usually stops when exertion is ceased

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Angina Pectoris can be Stable or Unstable:

Stable:The pain and pattern of events is

unchanged over a period of time (months years)

Unstable:The pain and pattern is changing, be it in

duration, intensity or frequencyA Myocardial Infarction waiting to happen

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Partial or total occlusion of one or more of the coronary arteries due to an atheroma, thrombus or emboli resulting in cell death (infarction) of the heart muscle

When an MI occurs, there is usually involvement of 3 or 4 occluded coronary vessels

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250,000 deaths per year.30% mortality within the first 2 hours45 Minutes of Ischemia:

Cardiac muscle death occursHow is the Diagnosis Made?

Electrocardiographic changesST elevation

Myocardial enzyme elevationCreatine kinase TroponinC Reactive Protein

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When there is an atheroma, as mentioned before there can be rupture resulting in thrombus formation because of the build up of platelets

When there is breakage of the thrombus there is emboli formation

An emboli can travel to the brain (cerebral infarct) can remain in the heart (myocardial infarct) or even travel to the extremities cutting off blood supply

As the area beneath the is disrupted atheroma hemorrhages, there can is increased risk of abscess formation and infection

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Infarction leading to inability of the heart to function properly leading to Heart Failure

Angina/PainCardiogenic shock Ventricular aneurysm and ruptureEmbolism FormationArrhythmias Myocardial Infarctions

can lead to Ventricular Fibrillation (shockable!)

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Sudden Death :250,000 deaths in the US per year are caused by

what is referred to as “sudden” cardiac death Sudden Cardiac Death is also known as a

“Massive Heart Attack” in which the heart converts from sinus rhythm to ventricular fibrillation

In V-Fib, the heart is unable to contract fully resulting in lack of blood being pumped to the vital organs

V-Fib requires shock from defibrillator “SHOCKABLE RHYTHM”

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Many people are able to manage coronary artery disease with lifestyle changes and medications.

Other people with severe coronary artery disease may need angioplasty or surgery.

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Pharmaceuticals: Beta Blockers

Act either selectively or non-selectively on Beta receptors:Beta 1 cardiac muscle increase rate and contractionBeta 2 dilates bronchial smooth muscle

Ca++ Channel BlockersActs on vasculature blocking Ca++ and causing

vasodilation Nitrates

Vasculature vasodilation Anti-Hypercholesterolemia

HMG CoA Reductase Inhibitors reduction in “manmade” cholesterol thus helping to reduce atheroma formation

Antiplatelet Medication:Clopidogrel (Plavix)Aspirin

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1) Stenting2) Angioplasty (balloon)3) Bypass surgery

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Lifestyle:DietExercise Preventive treatment• Low fat, low cholesterol diet• Cessation of smoking• Red wine (in moderation)

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1. Gather information about all facets of the client’s activities, especially those that precede and precipitate attacks of anginal pain.2. Assess the risk factors in the client’s history and modifications possible to reduce risk.3. If chest discomfort is present at the time of the interview, further collection of data is delayed until pain and dysrhythmias are resolved.4. A complete physical assessment is performed to identify the presence of chest, epigastric, jaw, back, or arm discomfort which is then rated on a subjective scale of 1 to 10 in intensity. The client is questioned regarding nausea, vomiting, diaphoresis, dizziness, weakness, palpitations, and SOB

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1. Pain related to myocardial ischemia.2. Altered tissue perfusion: related to

imbalance between myocardial oxygen supply and demand.

3. Anxiety related to fear of death and knowledge deficit

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Goals1. Prevention of pain.2. Improved tissue perfusion as evidenced by absence of chest pain and absence of dysrhythmias.3. Reduction of anxiety and increased knowledge of disease process.

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1. The nurse must teach the client the link between symptoms and activity and the need to avoid activities known to cause angina, such as sudden exertion, exposure to cold, and emotional excitement.

2. Medications used in the treatment of angina include nitrates, beta-blockers, calcium channel blockers, and platelet antiaggregants. Administer cardiac medication as prescribed and be alert for adverse side effects, particularly their effect on blood pressure. Teach the client the symptoms to be aware of and what measures to take.

3. Encourage the client to remain on bedrest in order to decrease cardiac workload and oxygen consumption.

4. Administer oxygen therapy as prescribed.

5. Evaluate vital signs hourly to determine the hemodynamic effect of the drugs and the client’s tissue perfusion.

6. Nursing care should be planned so that minimal time is spent away from the bedside due to the high level of client anxiety, as well as the unstable condition of the patient.

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7. Clients with unstable angina are at high risk for myocardial infarction (MI) and sudden death. The nurse watches for development of heart failure and dysrhythmias.

8. Relieving pain is the top priority for the client with an acute MI, and medication therapy is administered to accomplish this goal.

9. Maintain patent IV for administration of fluids and vasodilators and anticoagulant therapy (Nitroglycerin and heparin). They relieve pain and they aid in minimizing permanent injury to the myocardium.10. Prepare for possible emergency heart catheterization or CABG.

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11. Whether CABG is planned as an elective procedure or performed on an emergency basis, the nurse should try to alleviate the client’s and the family’s anxiety and assist them in understanding the need for this life-saving procedure.

12. The nurse describes the postoperative course, emphasizing the close monitoring and use of sophisticated equipment. The client is encourage to tell the nurse about any discomfort post-op.

13. Encourage the client and family members to verbalize their fears and concerns.

14. Teach the client the nature of the illness and the facts needed to reorganize living habits in order to reduce the frequency and severity of anginal attacks, delay the progress of the disease, and avoid other complications.

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1. Verbalizes relief of chest pain.2. No signs of respiratory difficulties.3. Modifies lifestyle in order to prevent

future attacks.4. Demonstrates increased knowledge of

disease process and reduction in anxiety.

5. Absence of complications.

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2/11/2009 64

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