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Acute Coronary Syndromes

At the end of this self-study the participant will:

• Describe the pathophysiology of Acute Coronary Syndromes

• List signs and symptoms of:– Stable angina– Unstable angina– Acute myocardial infarction

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What is ACS?• The term Acute Coronary Syndrome (ACS) includes a

constellation of syndromes: chest pain, unstable angina, non ST elevation MI (Non-STEMI) and ST elevation MI (STEMI).

• The American College of Cardiology (ACC) and American Heart Association (AHA) recommends that health care providers use the term ACS as a provisional diagnosis and once the diagnosis is made use the term that applies: Chest Pain Syndrome, Unstable Angina, Non-Q wave MI and Q-wave MI.

• Mortality rates and the risk associated with ACS is the greatest during the first 30 days after presentation and stabilizes to a lower rate after 30 days, validating the importance of early diagnosis and treatment.1

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ACS: Triad of I’s Ischemia vs. Injury vs. InfarctionAll represent an oxygen supply problem:• Ischemia = reversible• Injury = acute period of both ischemia and infarction• Infarction = irreversible cell death

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ACS• Unstable angina (U/A)

– a clinical syndrome usually resulting from disrupted atherosclerotic plaque, which subsequently results in an imbalance between myocardial oxygen supply and demand.

– U/A and Non-STEMI are closely related in presentation. – ECG may show ST depression,

• or be normal– Cardiac enzymes are normal – Ischemia is reversible

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ACS• Non-ST Elevation Myocardial Infarction (Non-STEMI)

– Differs from unstable angina mostly due to severity of ischemia

– Non-STEMI causes enough myocardial damage to release detectable cardiac markers indicating myocardial injury [Troponin I (TnI), Troponin T (TnT), and/ or Creatinine kinase( CK-MB)].1

– ECG changes may occur

• No sustained ST segment elevation.

– Can limit the area of infarction through medical and nursing interventions

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ACS• ST Elevation Myocardial Infarction (STEMI)

– a loss of cardiac myocytes as a result of prolonged ischemia due to a perfusion-dependent imbalance between supply and demand.

– Myocardial ischemia does not cause immediate cell death but rather it occurs over a finite period of time. It can take at least 4 to 6 hours for complete necrosis of myocardial cells

– This is dependent upon the presence of collateral blood flow into the ischemic zone or coronary artery occlusion.2

Examples of ST changes in STEMI

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ECG changes that commonly occur with increasing levels of coronary artery occlusion

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Signs and Symptoms Overview• Only 30-40% of all MI’s present with typical S & S’s.

• 60-70% exhibits less typical symptoms:

– Women exhibit less obvious symptoms than men

– If over age 75, syncope is the main symptom

– Diabetics express very non-specific symptoms

– What if you are a diabetic female over the age of 75?

• Cardiac risk factors must play an important role in deciding who receives a 12-lead ECG and who does not.

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Cardiac Risk FactorsFactors That Can’t Be

ChangedFactors that can be

changed or controlled

Heredity

Gender

Age

Smoking

Hypertension

Hypercholsterolemia

Obesity

Physical Inactivity

Stress

Diabetes

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History of Presenting Illness

• The most important diagnostic information is the patient’s “story”– Current symptoms– Time of onset– Pain assessment– Past medical history / medications

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“Typical” Signs and Symptoms of MI

• Chest discomfort:– Crushing, pressure,

tightness– Sustained– Unrelieved or partially

relieved by rest– Unrelieved or partially

relieved by nitroglycerin– Pain may radiate to other

areas

• Denial• Chest discomfort• Syncope/weakness• Cool/pale/diaphoretic• Dyspnea• Nausea/vomiting• Sense of impending

doom

Associated Signs and Symptoms of MI

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PQRST: Eliciting pain information• P: Placement/

provocation/ precipitating factors

• Q: Quality

• R: Radiation, relief and

reproducibility

• S: Severity (0-10 scale)

• T: Time of onset

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Women’s Issues

• Heart disease leading cause of death• Sharp rise in smoking-related illness• 1/3 of adult women are sedentary• 1 in 3 women are overweight• More nonfatal chronic conditions• Less available supports

– Because many chronic conditions are disabling, middle-aged and older women are about 80% more likely than men to report difficulties in taking care of themselves.

U.S. Dept. Health & Human Services, Special Profile Women’s Health, 1996.

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Cardiac Symptoms in the Elderly

• Acute or progressive dyspnea

• Extreme fatigue• Abdominal pain• Nausea & vomiting• Syncope• Congestive heart failure• Weakness/falls• Pain in other places (not

chest)Nowak, KA. Nurse Pract. 1997. 22:11-14.

AMI Statistics in the Elderly

• Higher in-hospital mortality

• Higher post-discharge mortality

• Do not have larger infarcts

FTT Collaborative Group. Lancet. 1994;343:311.White, HD, et al. Circulation. 1996;94:1826-1833.Miller, TD,et al. Circulation. 1997; 96 (suppl): Abstract 149.

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Diabetes & Acute MI• Independent predictor of mortality (mechanism

unknown)• Lowest mortality in patients who received fibrinolytics• Diabetic patients:

– Were older and more often female– Had more anterior MIs and triple vessel CAD– Presented later and were treated later

• Left ventricular function may differ from those w/o diabetes due to possible impaired left ventricular performance in non-MI zones

Mak, KH, et al. JACC. 1997; 30:171.Woodfield, SL, et al. JACC;1996; 29:35. Strandberg, LE, et al. J Int Med. 2000; 248:119Mak, KL & Topol, TJ. JACC. 2000; 35: 563-8

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Goal: Early Reperfusion Therapy• Reperfusion Therapy

– Defined as the initial strategy employed to restore blood flow to the occluded coronary artery by two standards of care• Fibrinolytic therapy• Primary percutaneous transluminal coronary

angioplasty (PTCA)• Outcomes Dependent Upon:

– Time to treatment– Early and full restoration of blood flow

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Next: ACS Diagnostics