ACUTE CORONARY SYNDROME (ACS)

CHAPTER 4CARDIOVASCULAR—ACUTE CORONARY SYNDROME iii. Electrocardiographic (ECG) manifestations include

ST-segment depression and inverted T waves. These changes are transient and not always detected.

iv. Cardiac biomarkers are not elevated.

b.Non-ST-segment elevation myocardial infarction (NSTEMI) i. Pain and angina equivalents may be much the same as

in UA or may be of longer duration and more intense.

ii. Electrocardiographic (ECG) manifestations include ST-segment depression and inverted T waves, which may persist after resolution of ischemia and pain.

iii. Cardiac biomarkers are elevated.

c.ST-segment elevation myocardial infarction (STEMI) i. Electrocardiographic (ECG) manifestations include

ST-segment elevation in two contiguous leads (diag- nostic of STEMI), and abnormal Q waves appear as a result of alterations in electrical conductivity of the in- fracted myocardial cells.

ii. The imbalance between oxygen supply and demand is severe enough to cause tissue necrosis and the client requires emergency revascularization.

III. Etiology(Go et al, 2012; Mayo Clinic, 2010)

a.Coronary artery disease (CAD) common cause with plaque formation narrowing vessels and pieces of plaque breaking off, creating emboli, and coronary artery obstruction.

b.Risk factors—age (older than 45 for men, and 55 for women).

c.Presence of “metabolic syndrome” (e.g., fasting plasma glu- cose ≥100 mg/dL or undergoing drug treatment for elevated

glucose; HDL cholesterol <40 mg/dL in men or <50 mg/dL in women or undergoing drug treatment for reduced HDL cholesterol; triglycerides ≥150 mg/dL or undergoing drug treatment for elevated triglycerides; waist circumference

≥102 cm in men or ≥88 cm in women; BP ≥130 mm Hg systolic or ≥85 mm Hg diastolic or undergoing drug treat- ment for hypertension.

d.Being overweight or obese, lack of physical activity, smoking.

e. Type 2 diabetes and family history of chest pain, heart disease, or stroke.

IV. Statistics(National Heart, Lung and Blood Institute [NHLBI], 2011; Centers for Disease Control and Prevention [CDC], 2012)

a. Morbidity: There are an estimated 82.6 million Americans with some form of cardiovascular disease.

b.Coronary artery disease (CAD) accounts for 16.3 million;

angina, approximately 9 million.

c.400,000 new cases annually, most are over age 65.

d.Mortality: There were 812,000 deaths from cardiovascular disease in 2008; accounts for approximately 33% of total deaths.

e. Cost: Inpatient cardiovascular procedures and operations in 2009—echocardiogram $2.3 billion, diagnostic cardiac catheterization/coronary angiography $5.9 billion, angioplasty (PTCA) $11 billion, pacemaker procedures

$8.2 billion (Pfunter, 2012).

Angioplasty: See Percutaneous coronary interventions (PCIs), below.

Cardiac biomarkers: Substances that are released into the blood when the heart is damaged or stressed. Measurement of these biomarkers is used to help diagnose, monitor, and manage people with suspected ACS and cardiac ischemia. The current biomarker test of choice for detecting heart damage is tro- ponin (see below). Other cardiac biomarkers (e.g, CK, CK- MB, myoglobin) are less specific for the heart and may also be elevated in skeletal muscle injury, liver disease, or kidney disease (Lab Tests Online, 2012).

Coronary artery disease (CAD): Disease in which there is a narrowing or blockage of the coronary arteries that carry blood and oxygen to the heart muscle.

Myocardial infarction (MI): An occlusion or blockage of arter- ies supplying the muscles of the heart, resulting in injury or necrosis of the heart muscle (heart attack).

Occlusive thrombus: Blood clot which completely blocks a coronary artery.

Percutaneous coronary interventions (PCIs), also known as angioplasty: A nonsurgical procedure used to treat stenotic coronary arteries of the heart found in coronary heart disease.

During PCI, a cardiologist feeds a deflated balloon or other device on a catheter from the inguinal femoral artery or radial artery up through blood vessels until they reach the site of blockage in the heart. X-ray imaging is used to guide the catheter threading. At the blockage, the balloon is inflated to open the artery, allowing blood to flow. A stent is often placed at the site of blockage to permanently open the artery.

Non-ST-segment elevation myocardial infarction (NSTEMI):

Partial block of coronary arteries (nonocclusive thrombus).

G L O S S A R Y

There will be no ST elevation or Q waves on ECG, as trans- mural infarction is not seen. The main difference between NSTEMI and unstable angina is that in NSTEMI the severity of ischemia is sufficient to cause cardiac enzyme elevation.

Fibrolynics are not beneficial in NSTEMI due to increased risk of bleeding complications.

ST-segment elevation myocardial infarction (STEMI): A transmural infarction of the myocardium where the entire thickness of the myocardium has undergone necrosis. Usually due to an occlusive thrombus. This requires the use of throm- bolytics to lyse the thrombus.

Troponin (also known as Cardiac-specific Troponin I and Troponin T): Blood test used to help diagnose a heart attack, to detect and evaluate mild to severe heart injury, and to dis- tinguish chest pain that may be due to other causes. Troponins are the preferred tests for a suspected heart attack because they are more specific for heart injury than other tests and remain elevated for a longer period of time (Lab Tests Online, 2012).

Unstable angina (UA): Chest pain produced when the heart muscle is not getting enough blood flow is considered “un- stable” when it no longer follows the predictable patterns typical of “stable angina.” Unstable angina is called “unsta- ble” for two reasons: (1) symptoms occur in a more random and unpredictable fashion, and (2) it is most often caused by the actual rupture of a plaque in a coronary artery resulting in clot formation, with impairment of free blood flow to tis- sues. The imminent risk of a complete myocardial infarction is very high in unstable angina. Such a condition is quite

“unstable,” and for this reason is a medical emergency (Fogoros, 2011).

Care Setting

Client may have a short hospitalization during acute stage for stabilization and possible cardiac revascularization. The client who has sustained a STEMI or is judged to be at intermediate or high risk for MI will be hospitalized for further evaluation and therapeutic intervention.

Related Concerns

Angina, page 67 Dysrrhythmias, page 87 Myocardial infarction, page 75 Psychosocial aspects of care, page 729

Client Assessment Database

D I A G N O S T I C D I V I S I O N M AY R E P O R T

A

CTIVITY

/R

EST

•Sedentary lifestyle

•Weakness, feeling incapacitated after exercise

•Fatigue

•Activities and sleep disrupted by pain

C

IRCULATION

•History of heart disease, hypertension in self or family

•Palpitations

E

GO

I

NTEGRITY

•Stressors of work, family, others, and financial concerns

F

^OOD

/F

^LUID

•Nausea, “heartburn,” or epigastric distress

•Diet high in cholesterol and fats, salt, caffeine, liquor

N

EUROSENSORY

•History of dizziness, fainting spells, transient numbness, tin- gling in extremities (ischemia anywhere in the body can pro- duce transient neurological symptoms)

P

AIN

Note:Reports of pain location and severity differ between men and women.

•Substernal or anterior chest pain that may radiate to jaw, neck, shoulders, and upper extremities, often to left side more than right. Women may report pain between shoulder blades, back pain.

•Quality: Varies from transient and mild to moderate, heavy pressure, tightness, squeezing, burning. Women may report dull aching pain.

•Duration:Usually more than 15 minutes

•Precipitating factors:May be unpredictable or occur during rest or sleep

•Relieving factors:Pain may not be responsive to particular re- lief mechanisms, such as rest and anti-anginal medications

R

ESPIRATION

•Exertional dyspnea, which may resolve with rest or pain relief

•Smoking history

•Exertional dyspnea

•Tachycardia, dysrhythmias

•Blood pressure (BP) may be normal, elevated, or decreased

•Heart sounds: May be normal, late S₄or transient late systolic murmur may be evident during pain

•Moist, cool, pale skin, mucous membranes in presence of vaso- constriction

•Orthostatic blood pressure changes

•Apprehension, uneasiness

•Belching, gastric distention

•Facial grimacing, restlessness

•Placing fist over midsternum

•Rubbing left arm, muscle tension

•Autonomic responses, for example, tachycardia, blood pressure changes

Increased rate and rhythm, alteration in depth

M AY E X H I B I T

CHAPTER 4CARDIOVASCULAR—ACUTE CORONARY SYNDROME

D I A G N O S T I C D I V I S I O N

M AY R E P O R T

(continued)

T

EACHING

/L

EARNING

•Family history or risk factors of CAD: obesity, sedentary lifestyle, HTN, stroke, diabetes, smoking, hyperlipidemia

•Use or misuse of cardiac, antihypertensive, and over-the- counter (OTC) drugs

D

ISCHARGE

P

LAN

C

ONSIDERATIONS

•Assistance with homemaker or maintenance tasks

•Changes in physical layout of home