Module 2.3 - Angina Pectoris & Myocardial Infarction

Question 1

What are the 4 types of angina?

Answer 1

1. Stable (chronic/classic)
2. Prinzmetal (varriant)
3. Unstable (preinfarction, rest or crescendo, ACS)
4. Microvascular (Syndrome X/metabolic syndrome)

Question 2

Describe stable angina. What are some common features of this type of angina?

Answer 2

• Pain is intermittent and predictable exhibiting the same onset, intensity and duration. Pain radiates
• Usually brought on by exercise, resolves with cessation of activity and rarely occurs at rest.
• EKG may show ST depression
• It is usually relieved by SL NTG.
• It results from the progression of obstruction of the lumen of the artery from atherosclerosis or less commonly from the microvasculature.

Question 3

Describe Prinzmetal angina. What are some common features of this type of angina?

Answer 3

• Caused by coronary spasm precipitated by an increase in intracellular calcium levels.
• Often occurs at rest.
• ST elevation is seen at time of event.

Question 4

Describe Unstable angina. What are some common features of this type of angina?

Answer 4

• Pain lasts longer than 30 minutes.
• Is more severe in intensity than stable angina.
• EKG shows ST depression.
• Non ST elevation myocardial infarction and unstable angina (UA) are closely related conditions.
• If there is no elevation in cardiac biomarkers (troponin) the syndrome is unstable angina
• Positive biomarkers = MI.
• The annual incidence of ACS is > 780,000 events with 70% being NSTEMI/UA.

Question 5

Describe microvascular angina. What are some common features of this type of angina?

Answer 5

• Pain mimics angina
• Exercise stress test (EST) is positive
• Angiogram is negative

Question 6

What are some important factors to review with assessing a patient for predisposing factors for CAD?

Answer 6

• Known CAD- How has it been treated in the past?
• Hypertension- current control, home readings
• HLD- treated for how long…?
• Metabolic syndrome
• Cigarette smoking- press for details! Remember, nicotine results in the release of catecholamines causing angina and tachycardia
• DM, T1 and T2- controlled? Examine home readings
• Male gender. After age 65 the incidence in men and women is equal
• Premature CAD in FH
• Sedentary lifestyle
• Classically, MI/ACS is precipitated by activities that increase oxygen demand by the myocardium – the four “E’s”, increased exercise, exposure to extreme weather conditions, eating a heavy meal, emotional stress

Question 7

What are some differential diagnosis for chest pain?

Answer 7

• Aortic stenosis
• Hypertrophic cardiomyopathy – sub endocardial ischemia may be worsened with exercise
• Coronary spasm
• Pericarditis – pleuritic chest pain caused by the inflammation
• Aortic dissection
• Cocaine use – can cause both coronary spasms and thrombus formation that can cause STEMI

Question 8

How do patients report angina pain?

Answer 8

Generally angina is more diffuse and vague than pain from an MI. May resolve with stopping activity (key factor)

Question 9

How do patients report pain from an MI?

Answer 9

• Approximately 15% of patients who experience an MI have no pain. Lack of pain is particularly common among diabetic patients and the elderly due to neuropathy.
• MI pain is vise like, crushing, gripping, substernal +/- radiation to jaw, back, shoulders, arms, abdomen, “elephant sitting on my chest”, it is a more deep-seated rather than superficial pain
• Other descriptors may include aching, cramping, grinding, burning, stinging, soreness, tearing or gnawing which makes the list of potential differential diagnoses longer
• Patients may have a difficult time describing pain and make a clenched fist over the sternum (Levine’s sign)
• Women may present with GI symptoms – angina should always be considered. Women under the age of 60 have reported a higher incidence of atypical signs.​

Question 10

Describe the grade I class of angina

Answer 10

• Ordinary physical activity does not cause angina such as walking or climbing stairs.
• Angina occurs with strenuous, rapid or prolonged exertion at work or recreation

Question 11

Describe the grade II class of angina

Answer 11

• Slight limitation of ordinary activity
• Angina occurs on walking or climbing stairs rapidly; walking uphill; walking or climbing stairs after meals; in cold, in wind, or under emotional stress; or only during the few hours after awakening.
• Angina occurs walking > 2 blocks on the level and climbing > 1 flight of ordinary stairs at a normal pace and under normal conditions.

Question 12

Describe the grade III class of angina

Answer 12

• Marked limitation of ordinary physical activity
• Angina occurs on walking 1 to 2 blocks on the level and climbing 1 flight of stairs under normal conditions and at a normal pace

Question 13

Describe the grade IV class of angina

Answer 13

• Inability to carry on any physical activity without discomfort.
• Angina symptoms may be present at rest

Question 14

What are the 3 presentations of ACS?

Answer 14

1. Unstable angina
2. Acute non-ST elevation myocardial infarction (NSTEMI)
3. Acute ST-elevation myocardial infarction (STEMI)

Resting angina, new onset angina that markedly limits physical activity and angina increasing in duration, frequency and with less exertion suggest ACS

Question 15

What is unstable angina?

Answer 15

If the coronary flow is not severe enough or the occlusion in the artery is not severe enough to cause myocardial necrosis and a subsequent positive biomarker reading, the syndrome is classified as UA.

Question 16

What is a NSTEMI?

Answer 16

• Defined as the elevation of cardiac biomarkers and the absence of ST segment elevation on the ECG.
• Like STEMI can lead to cardiogenic shock.
• The short term occurrence of morbidity and mortality is less than STEMI.
• Long term occurrence is the same.

Question 17

What is a STEMI?

Answer 17

• Defined as a clinical syndrome of myocardial ischemia in association with persistent 12 lead ECG changes of ST segment elevation (injury pattern) causing necrosis and elevation of biomarkers.
• Compared to UA/NSTEMI there is a higher in hospital and 30 day morbidity and mortality.
• Can lead to arrhythmias, cardiogenic shock, and heart failure.
• Accounts for 20-30% of ACS cases annually.

Question 18

What are some atypical symptoms associated with an MI?

Answer 18

Female sex, DM, HF, ESRD and older age are traits that have been associated with less typical presentations of angina.

Question 19

The risk of death or progression to MI is elevated with what 5 high-risk ACS characteristics?

Answer 19

1. Recurrent and accelerating anginal symptoms despite adequate medical therapy – examine their compliance
2. New onset HF, pulmonary edema or shock (high Killip Classification**)
3. New or worsening mitral regurgitation
4. Newly diagnosed left bundle branch block (LBBB) on EKG - always compare to their earlier EKG if available
5. Ventricular arrhythmias – patients may present with ACS and move rapidly into VT or VF if they progress to STEMI

Question 20

What 12 lead EKG changes are associated with ACS?

Answer 20

• ​​UA and NSTEMI may present with ST-segment depression (ischemia). This finding in two contiguous leads is a sensitive indicator of myocardial ischemia especially if there are other symptoms.
• STEMI will present with ST-segment elevation (injury pattern)
• Approximately 30% of patients who experience MI show no immediate 12 lead EKG changes

Question 21

What cardiac enzymes are evaluated with ACS?

Answer 21

• Troponin is myocardial specific and is the preferred biomarker for ACS with troponin I rising slightly faster than troponin T (3 hrs. vs. 6 hrs.)
  
  • If the first troponin is negative, a second measurement should be drawn 6-8 hrs later before a final diagnosis is made.
• Other biomarkers include creatine kinase isoenzyme MB (CK-MB) and myoglobin with myoglobin rising within 1-2 hours and CK-MB rising 4-12 hours.
• CK-MB is an acceptable cardiac marker but lacks the specificity as it is also present in both skeletal and cardiac muscles.
• A CK-MB/total CK fraction would delineate cardiac muscle damage. A positive result is > 5% as this suggests injury.
• Because of the variability of the enzymes rising, serial enzyme testing (troponin) is needed every 6-8 hours regardless of the resolution of symptoms.

Question 22

What are some symptoms that indicate ACS from CAD?

Answer 22

Question 23

What is the treatment plan for patients presenting with ACS in an outpatient setting?

Answer 23

• 12 lead EKG should be done within 10 minutes of presentation
• Hemodynamic status assessment
• CBC, basic metabolic panel, glucose (fasting if possible), lipid panel should be obtained on all patients with suspected CAD
• Aspirin – 162-325 mg PO, chew and swallow. If the patient is allergic to aspirin, consider Plavix as an alternative if available
• Nitroglycerin SL 0.4 mg every 5 minutes
• Supplemental oxygen at 2-4 L/min per NC
• Bedside monitor to assess for life-threatening arrhythmias
• IV access for lab, medications, fluids
• Pulse oximetry
• Continuous pain assessment – consider morphine 2-4 mg IV to relieve chest pain or anxiety. Depending on your practice, this may not be available in an outpatient setting. ( Urgent care and ED - may repeat with 2-8 mg every 5-15 minutes until pain relieved unless adverse effects occur).

Question 24

What are the 4 potential early complications of a myocardial infarction?

Answer 24

1. Arrhythmias – Supraventricular and ventricular, conduction disturbances
2. Left ventricular dysfunction – CHF, Pulmonary Edema, cardiogenic shock
3. Cardiac tamponade, VSD – septal rupture
4. Right ventricular infarct – can occur in 30% of patients with inferior posterior infarct, can cause hemodynamic instability in 10% of patients

Question 25

What should the provider consider before ordering a cardiac stress test?

Answer 25

Cardiac stress testing is not only diagnostic it is prognostic with known or suspected. When choosing the appropriate type of stress test for a patient, the provider should consider the patient’s functional status or ability to physically exercise, what their resting EKG shows, the patient’s physical size, their cardiac history and their indication for the test.

Question 26

What type of patients should get cardiac stress testing?

Answer 26

For patients without known CAD – (not indicated if patients are asymptomatic):

• Stress testing should not be done as a screening test for patients without symptoms of reason to suspect CAD
• Patients with anginal symptoms who are at intermediate risk for IHD
• Patients with atypical symptoms and high risk for IHD.

For patients with known CAD:

• Post MI risk stratification
• Preoperative risk assessment
• Recurrent anginal symptoms despite medical therapy or revascularization
• Routine screening in patients after revascularization is controversial as there is no clear indication

Question 27

What are the contraindications for cardiac stress testing?

Answer 27

• Acute MI within the last 2 days
• Patients with continued unstable angina/pain with minimal exertion
• Arrhythmias that cause hemodynamic instability (hypotension, tachycardia, syncope)
• Severe aortic stenosis with symptoms
• Other diseases that include acute PE, myocarditis, pericarditis or aortic dissection

Question 28

What are the 3 types of cardiac stress testing?

Answer 28

1. Exercise treadmill – patient must be able to ambulate safely and achieve target heart rate – 85% of the maximum heart rate for age. This is the test of choice for evaluating patients with intermediate risk for CAD. The Bruce protocol is utilized that consists of 3-minute stages, each stage increasing in speed and incline. The following criteria are followed as to when to discontinue the test.

• Chest pain, fatigue or other adverse events occur (weakness, Dyspnea, syncope, ST segment elevation or depression of 1 mm or greater
• SBP 250 mm/hg
• Decrease in systolic BP greater than 10 mmHg
• Rise in DBP to higher than 90 mmHg or by more than 20 mmHg over the patient’s baseline
• Glassy eyed appearance, cold sweats or confusion

2. Thallium stress test - injection of an isotope is given prior to treadmill exercise. Patient’s heart is then scanned by a nuclear scanner to evaluate changes in cardiac function and wall motion.

3. Pharmacological stress test - for patients that are unable to exercise. Dipyridamole and adenosine are vasodilators that are commonly used in conjunction with cardiac imaging. Dobutamine is a positive inotrope that is commonly used with echocardiogram imaging. It may be augmented with atropine to reach target heart rate.

Question 29

What is an echocardiogram used for?

Answer 29

assess cardiac function, wall motion

Question 30

What is a doppler echocardiogram used for?

Answer 30

assessment of valvular regurgitation

Question 31

What is a transesophageal echocardiogram used for?

Answer 31

Generally used to evaluate patients with significant murmurs

Question 32

What are cardiac MRI’s used for?

Answer 32

Cardiac MRIs can be obtained as an outpatient with contrast and vasodilator stress can detect changes in perfusion of the cardiac muscle.

Question 33

What are coronary angiograms used for?

Answer 33

It is the gold standard to determine CAD

Question 34

What 3 types of medications can be used to reduce myocardial ischemia in patients with angina?

Answer 34

1. Nitrates
2. Beta Blockers
3. Calcium channel blockers

Question 35

How should patient’s be instructed to take nitrates?

Answer 35

Encourage the use of SL or buccal spray 5 minutes before exertion that has caused angina in the past. Patients should be educated that when experiencing an episode of CP, SL NTG should be taken x 1. If pain persists, call 911 before the second dose of SL NTG.

Question 36

What brand and dosage of nitrates are prescribed to patients with angina?

Answer 36

• Isosorbide dinitrate (Isordil) 5-40 mg TID (most common)
• Nitroglycerin sustained release 2.5 – 6.5 mg every 8-12 hours
• Nitroglycerin transdermal patches (Nitro-Dur; Nitro-Derm) 5-40 mg daily – 12-14 hrs. on, 10-12 hr. holiday

Question 37

What brand and dosage of beta blockers are prescribed to patients with angina?

Answer 37

• Metoprolol (Lopressor) 50 mg BID , titrate to 100 mg BID-TID or Toprol XL 50-100 mg daily
• Carvedilol (Coreg) 5.25 mg BID, titrate to 25 mg BID
• Nadolol (Corgard) 20 mg daily titrate to 40-80 mg daily
• Atenolol (Tenormin) 25 mg daily, titrate to 100 mg daily
• Propranolol – 40 mg daily, titrate to 180-240 mg daily in divided doses

Question 38

What brand and dosage of calcium channel blockers are prescribed to patients with angina?

Answer 38

• They are not the first line drugs for patients with ACS and should be used only in patients with normal LV function. If patients cannot tolerate beta blockers:
  
  • Diltiazem – short-acting or extended release forms are available. Daily doses 180 mg to 540 mg depending on the specific drugs
  • Dihydropyridine calcium channel blockers (amlodipine) can be used as adjunct therapy with beta blockers. Both amlodipine and felodipine have been used, cause less reflex tachycardia and are affective in relieving angina with vasodilation of coronary arteries

Question 39

What are the outpatient post-MI management goals for a patient?

Answer 39

• See the patient immediately in the clinic after discharge from the hospital and PRN.
• Consider stress testing 3-4 weeks after an MI
• Repeat EKG at 3 months then every 1-2 years afterward
• Continue pharmacological therapy
  
  • Beta Blocker daily-up to 3 years post MI or if LVEF < 40%
  • Aspirin indefinitely
  • ACE inhibitor for patients with left ventricular dysfunction (LVEF < 40%) and most patients with STEMI
• Cardiac Rehabilitation for patients with recent event or procedure
• Monitor lipoprotein profiles
  
  • Statin therapy daily with high-intensity statins – atorvastatin (Lipitor) 80 mg daily; Rosuvastatin (Crestor) 20-40 mg daily
• Patient/family teaching
  
  • Smoking cessation
  • Diet –review recommendations from AHA
  • Diabetes management- Hemoglobin A1C < 7%
  • Exercise-avoid extremes.
  • Flu and Pneumococcal vaccine recommended for all patients with cardiovascular disease

Question 40

What are the implications for the elderly patient with an MI?

Answer 40

• 80% of deaths related to MIs occur among patients older than 65 years of age.
• Approach should take into account the patient’s general health, weight and renal function
• Majority of patients have non-diagnostic ECGs or present with an NSTEMI
• Patients > 75 years are more likely to experience a “silent” MI (no chest pain/angina). They may exhibit confusion, lightheadness, and syncope, shortness of breath or GI symptoms as their presenting complaint.
• Patients > 85 years are more likely to develop a left bundle block (LBBB) or congestive heart failure (CHF)
• Older patients do better with PCI than thromboembolic therapy
• The risk of hemorrhagic stroke is increased in patients > 85 years with thromboembolic therapy
• Dose of Clopidogrel (Plavix) is adjusted for age and type of therapy