II. Risk Factors

III. Epidemiology

  1. Prevalence of CAD in U.S.: 27.6 million (11.5%) in U.S. (2014)
  2. Mortality: 370,000 per year in U.S. (2014)
  3. Incidence of Acute MI: 735,000/year in U.S. (2014)
    1. STEMI accounts for 30% of cases (typically younger patients)
    2. NSTEMI accounts for 70% of cases (typically older patients)
    3. Steg (2002) Am J Cardiol 90(4): 358-63 [PubMed]
  4. No prior coronary symptoms in >50% with fatal acute MI
  5. Coronary deaths account for up to 20% of all deaths in U.S.
  6. Average age of first Myocardial Infarction in U.S.
    1. Men: 65 years old
    2. Women: 72 years old
  7. References
    1. https://www.cdc.gov/nchs/fastats/heart-disease.htm
    2. https://www.cdc.gov/heartdisease/facts.htm

IV. Pathophysiology: Atherosclerotic Plaque

  1. Form over 10-15 years in response to vascular injury
    1. Significant Plaque present in 75% of age >25 years
  2. Lipid core (atheroma)
    1. Injured endothelium attracts Macrophages
    2. Macrophages resorb LDL Cholesterol fatty streaks
    3. Lipids transform Macrophages into foam cells
  3. Surrounding wall (fibroatheroma)
    1. Surrounds lipid core
    2. Composed of fibroblasts and Smooth Muscle Cells
  4. Acute MI or Acute Coronary Syndrome
    1. Occurs on Plaque rupture; results in vessel Occlusion

V. Pathophysiology: Postinfarction remodeling

  1. Early Phase (<72 hours)
    1. Infarct zone expansion
    2. Myocardial wall thinning and ventricular dilation
    3. Increased elevated myocardial wall stress throughout Cardiac Cycle
    4. Renin-Angiotensin System activated (increased BNP)
  2. Late Phase (>72 hours)
    1. Left ventricle generalized effects and ventricular dilation over time resulting in distorted ventricular shape
    2. Mural hypertrophy occurs in response to ventricular load (decreases rate of dilation, preserves contractility)
    3. Fibrous tissue replaces necrotic Myocytes in the first 4 weeks after Myocardial Infarction
    4. Ventricular effects do not improve with revascularization
  3. References
    1. Sutton (2000) Circulation 101(25):2981-8 [PubMed]

VI. History: Present Illness

  1. See Chest Pain
  2. Chest Pain
    1. Use the term "Chest Discomfort" in place of "Chest Pain" when asking the patient about symptoms
      1. Many patients will deny Chest Pain, but admit to chest pressure, chest tightness or discomfort
    2. Chest Pain characteristics (sharp, dull, pressure, tightness, tearing)
    3. Onset
    4. Duration
    5. Location (e.g. substernal, left or right, upper or lower)
    6. Radiation (right arm, left arm, neck, jaw or back)
    7. Severity (at onset, at worst, and now)
      1. Perceived pain intensity does not always correlate with disease severity
    8. Palliative (e.g. rest, Nitroglycerin)
    9. Provocative (e.g. walking or other physical exertion, deep breathing, eating, torso movement, direct pressure)
  3. Shortness of Breath
    1. Shortness of Breath on exertion
    2. Shortness of Breath at rest
    3. Orthopnea
  4. Nausea or Vomiting
  5. Near Syncope or light headedness
  6. Other Associated Symptoms
    1. Abdominal Pain
    2. Back pain
    3. Black stools (Melana) or Vomiting blood

VII. History: Past History

  1. See Chest Pain
  2. Coronary Artery Disease (prior PTCA or CABG?)
  3. Peripheral Arterial Disease
  4. Prior abnormal stress test
  5. Diabetes Mellitus
  6. Other risk factors
    1. See Coronary Artery Disease Risk Factors
    2. Hypertension
    3. Hyperlipidemia
    4. Tobacco Abuse
    5. Premature heart disease Family History (age <55 in father or brother, age <65 in mother or sister)

VIII. Symptoms

  1. See TIMI Risk Score
  2. See HEART Score
  3. See Angina Diagnosis
    1. Reviews the likelihood that Chest Pain is due to cardiovascular cause
    2. ACS is asymptomatic in 25% of Myocardial Infarctions
  4. Findings that most increase the likelihood of Acute Coronary Syndrome
    1. See Chest Pain
    2. Chest Pain radiation to the right chest or bilateral arms (or Shoulders)
    3. Exertional Chest Pain
    4. Chest Pain with diaphoresis
    5. Chest Pain associated with Vomiting (not only Nausea)
  5. Chest Pain due to Myocardial Infarction is similar to Angina
    1. Deep, poorly localized chest ache
      1. Worse with activity
      2. Better with rest and Nitroglycerin
    2. Radiation
      1. Arm, Shoulder, hand or upper back
      2. Radiation to right arm or bilateral arms is more suggestive of coronary syndrome
      3. May also radiate to neck, jaw or throat (less specific)
  6. Distinguishing features of Chest Pain due to Myocardial Infarction
    1. More intense than Angina
    2. More persistent than Angina (>30 minutes)
    3. Not fully relieved by palliative measures
      1. Rest
      2. Nitroglycerin (3 consecutive doses)
    4. Accompanied by systemic symptoms
      1. Vomiting
      2. Diaphoresis
      3. Apprehension
  7. Elderly Presentations of Acute Coronary Syndrome
    1. Most common presentations
      1. Dyspnea
      2. Syncope
      3. Generalized weakness
    2. Chest Pain is presenting symptom in only 24% of Acute Coronary Syndrome (ACS) age >75 years
      1. Contrast with 48% of younger adults who present with Chest Pain in ACS
    3. References
      1. Brieger (2004) Chest 126(2): 461-9 [PubMed]

IX. Signs

  1. Pallor
  2. Diaphoresis
  3. Tachycardia
  4. Signs of Congestive Heart Failure may also be present (higher risk findings)
    1. Rales on Lung Examination
    2. S3 Gallup Rhythm
    3. Jugular Venous Distention (esp. Right Ventricular Infarction)

XII. Types

  1. Type 1
    1. Myocardial Infarction with Plaque rupture or erosion with thrombus formation (classic)
  2. Type 2
    1. Myocardial Infarction with imbalance between oxygen supply and oxygen demand WITHOUT Plaque rupture
    2. Examples: Serious Arrhythmia, severe Anemia
  3. Type 3
    1. Sudden Cardiac Death before Troponins have time to rise
  4. Type 4 and 5
    1. Cardiac procedure (e.g. PCI, ) related Troponin elevation
  5. References
    1. Thygesen (2018) Circulation 138(2):e618-51 +PMID:30571511 [PubMed]

XIV. Complications

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Myocardial Infarction (C0027051)

Definition (MEDLINEPLUS)

Each year over a million people in the U.S. have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get help immediately. It's important to know the symptoms of a heart attack and call 9-1-1 if someone is having them. Those symptoms include

  • Chest discomfort - pressure, squeezing, or pain
  • Shortness of breath
  • Discomfort in the upper body - arms, shoulder, neck, back
  • Nausea, vomiting, dizziness, lightheadedness, sweating

These symptoms can sometimes be different in women.

What exactly is a heart attack? Most heart attacks happen when a clot in the coronary artery blocks the supply of blood and oxygen to the heart. Often this leads to an irregular heartbeat - called an arrhythmia - that causes a severe decrease in the pumping function of the heart. A blockage that is not treated within a few hours causes the affected heart muscle to die.

NIH: National Heart, Lung, and Blood Institute

Definition (NCI_FDA) Gross necrosis of the myocardium, as a result of interruption of the blood supply to the area, as in coronary thrombosis.
Definition (NCI_CTCAE) A disorder characterized by gross necrosis of the myocardium; this is due to an interruption of blood supply to the area.
Definition (NCI) Gross necrosis of the myocardium, as a result of interruption of the blood supply to the area, as in coronary thrombosis.
Definition (CSP) gross necrosis of the myocardium, as a result of interruption of the blood supply to the area.
Definition (MSH) NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).
Concepts Disease or Syndrome (T047)
MSH D009203
ICD10 I22 , I21
SnomedCT 66514008, 266288001, 155304006, 194796000, 233824008, 22298006
LNC LP98884-7, MTHU035551, LA14274-7, LA10558-7
English Myocardial Infarct, Infarctions, Myocardial, Myocardial Infarction, Myocardial Infarctions, Infarcts, Myocardial, Myocardial Infarcts, HEART ATTACK, Infarct, Myocardial, Infarction, Myocardial, MI, Myocardial infarction (MI), Attack heart (NOS), Infarct myocardial, cardiac infarction, Myocardial Infarction [Disease/Finding], attacking heart, heart attacks, attack hearts, infarctions myocardial, infarcts myocardial, myocardial infarctions, Infarction;heart, myocardial infarcts, Infarction;myocardial, AMI, attacks coronary, attacks hearts, coronary attack, disorder infarction myocardial, myocardial necrosis, syndrome myocardial infarction, heart attack, mies, Heart Attack, Attack - heart, Cardiac infarct, myocardial infarction, myocardial infarction (diagnosis), MI, MYOCARDIAL INFARCTION, MYOCARDIAL INFARCTION, MYOCARDIAL INFARCTION, (MI), INFARCTION (MI), MYOCARDIAL, -- Heart Attack, Cardiovascular Stroke, Cardiovascular Strokes, Stroke, Cardiovascular, Strokes, Cardiovascular, Myocardial infarct, Myocardial infarction, Heart attack, MI - Myocardial infarction, Cardiac infarction, Infarction of heart, Myocardial infarction (disorder), cardiac; infarction, infarction; myocardial, Cardiac infarction, NOS, Heart attack, NOS, Infarction of heart, NOS, Myocardial infarction, NOS, Heart Attacks, Infarctions (Myocardial), Myocardial infarction NOS, Attack coronary, heart infarction
German MYOKARDINFARKT, Koronarattacke, Herzanfall, MI, Herzanfall (NNB), HERZANFALL, Herzinfarkt, Myokardinfarkt
Dutch hartaanval, hartinfarct, hartaanval (NAO), MI, cardiaal; infarct, infarct; myocard, myocardinfarct, Hartinfarct, Infarct, myocard-, Myocardinfarct
French Crise coronaire, IM, Crise cardiaque SAI, Crise cardiaque, CRISE CARDIAQUE, INFARCTUS DU MYOCARDE, IDM (Infarctus Du Myocarde), Infarctus du myocarde, Infarctus myocardique
Italian MI, Attacco cardiaco, Attacco coronarico, Attacco cardiaco (NAS), Infarto del miocardio, Infarto miocardico
Portuguese Ataque coronário, Ataque do coração, Ataque cardíaco NE, EM, ATAQUE CARDIACO, ENFARTO DO MIOCARDIO, Enfarte do miocárdio, Infarto do Miocárdio
Spanish IM, Crisis coronaria, Ataque al corazón, Ataque al corazón (NEOM), Infarto miocárdico, ATAQUE CARDIACO, INFARTO DE MIOCARDIO, Infarto al Miocardio, ataque al corazón, infarto cardíaco, infarto de corazón, infarto de miocardio (trastorno), infarto de miocardio, Infarto de miocardio, Infarto del Miocardio
Japanese 心臓発作(NOS), 冠発作, 心臓発作, カンホッサ, シンゾウホッサNOS, シンゾウホッサ, シンキンコウソク, 冠状動脈梗塞, 心筋梗塞, 冠動脈梗塞, 心筋梗塞症
Swedish Hjärtinfarkt
Czech infarkt myokardu, Srdeční záchvat, Srdeční záchvat (NOS), IM, Koronární záchvat, Infarkt myokardu
Finnish Sydäninfarkti
Polish Świeży zawał serca, Zawał serca świeży, Zawał mięśnia sercowego, Zawał serca
Hungarian Coronaria roham, Szívroham (k.m.n.), Szívroham, Infarctus myocardii, Szívizom infarctus, MI
Norwegian Hjerteinfarkt, Hjerteattakk, Myokardinfarkt

Ontology: Acute Coronary Syndrome (C0948089)

Definition (MSH) An episode of MYOCARDIAL ISCHEMIA that generally lasts longer than a transient anginal episode that ultimately may lead to MYOCARDIAL INFARCTION.
Definition (NCI_CTCAE) A disorder characterized by signs and symptoms related to acute ischemia of the myocardium secondary to coronary artery disease. The clinical presentation covers a spectrum of heart diseases from unstable angina to myocardial infarction.
Definition (NCI) Signs and symptoms related to acute ischemia of the myocardium secondary to coronary artery disease. The clinical presentation covers a spectrum of heart diseases from unstable angina to myocardial infarction.
Concepts Disease or Syndrome (T047)
MSH D054058
SnomedCT 393587009, 394659003
Japanese 急性冠動脈症候群, キュウセイカンドウミャクショウコウグン
English Coronary Syndromes, Acute, Syndromes, Acute Coronary, Acute Coronary Syndromes, Acute Coronary Syndrome, Syndrome, Acute Coronary, Coronary Syndrome, Acute, Acute Coronary Syndrome [Disease/Finding], acute coronary syndromes, syndrome acute coronary, acute coronary syndrome (diagnosis), acute coronary syndrome, Acute coronary syndrome, Acute coronary syndrome (disorder), ACS - Acute coronary syndrome
Portuguese Síndrome Coronariana Aguda, Síndrome coronário agudo
Spanish Síndrome Coronario Agudo, síndrome coronario agudo (trastorno), síndrome coronario agudo, Síndrome coronario agudo
Finnish Akuutti sepelvaltimo-oireyhtymä
German Akutes Koronarsyndrom, akutes Koronarsyndrom
Italian Sindrome coronarica acuta
Swedish Akut koronarsyndrom
Czech Akutní koronární syndrom, akutní koronární syndrom
French Syndrome coronaire aigu, SCA (Syndrome Coronarien Aigu), Syndrome coronarien aigu
Polish Zespół wieńcowy ostry
Hungarian Acut coronaria syndroma
Norwegian Akutt koronarsyndrom, Koronarsyndrom, akutt, AKS
Dutch acuut coronairsyndroom