Ischemic Heart Disease

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Ischemic Heart Disease

• Hisham Alkhalidi

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Ischemic Heart Disease

• A group of related syndromes resulting from
  myocardial ischemia

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Ischemic Heart Disease

• The vast majority of ischemic heart disease is
  due to coronary artery atherosclerosis
• Less frequent contributions of
• vasospasm
• vasculitis
• Is it exactly the same as coronary artery disease
  (CAD)?
• Frequently yes

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Ischemic Heart Disease Angina pectoris

• Chest pain
• Can radiate down the left arm or to the left jaw
  (referred pain)
• Due to inadequate perfusion
• Duration and severity is not sufficient for
  infarction

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Ischemic Heart Disease Stable angina

• Occurring reliably after certain levels of
  exertion
• Typically due to atherosclerotic disease with
  75 (critical stenosis) fixed chronic stable
  stenosis

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Ischemic Heart Disease Unstable angina

• Unstable (occurring with progressively less
  exertion or even at rest)
• Results from a small fissure or rupture of
  atherosclerotic plaque triggering
• Platelet aggregation
• Vasoconstriction
• Formation of a mural thrombus that may not be
  occlusive
• Usually proceed MI

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Ischemic Heart Disease Variant angina

• Vessel spasm or Prinzmetal angina
• Without fixed atherosclerotic disease
• The etiology is not clear
• Responds promptly to vasodilators, such as
  nitroglycerin and calcium channel blockers

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Ischemic Heart Disease Myocardial infarction

• The severity or duration of ischemia is enough to
  cause cardiac muscle death
• Typically results from acute thromboses that
  follow plaque disruption

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Ischemic Heart Disease MI types

• Transmural
• Full thickness (gt50 of the wall)
• Subendocardial
• Inner 1/3 of myocardium
• Two mechanisms
• Fixed atherosclerosis but with increased demand,
  vasospasm or hypotension OR
• Evolving transmural with relieve of the
  obstruction (often multifocal)

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Ischemic Heart Disease MI, common locations

• In Right dominant coronary artery heart (90 of
  population)
• 2 cm proximal LAD (up to 50)
• anterior left ventricle
• anterior septum
• apex circumferentially
• Left circumflex ( up to 20)
• infarct involves lateral left ventricle except
  the apex
• 1st and last thirds of RCA (up to 40)
• posterior left ventricle
• posterior septum
• right ventricular free wall, sometime

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Ischemic Heart Disease

• Ischemia to myocardium rapidly (minutes) leads to
  loss of function and causes necrosis after 20 to
  40 minutes

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Ischemic Heart Disease Clinical picture of MI

• Severe, crushing substernal chest pain or
  discomfort that can radiate to the neck, jaw,
  epigastrium, or left arm
• Diaphoresis
• Nausea
• Dyspnea
• Can be silent (DM, old age)

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Ischemic Heart Disease ECG

• Changes such as
• Q waves (indicating transmural infarcts)
• ST-segment abnormalities
• T-wave inversion
• Arrhythmias

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Ischemic Heart Disease Laboratory evaluation

• Cardiac troponins T and I (TnT, TnI)
• Creatine kinase (CK, and more specifically the
  myocardial-specific isoform, CK-MB)
• Lactate dehydrogenase
• Myoglobin
• Troponins and CK-MB have high specificity and
  sensitivity for myocardial damage

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Ischemic Heart Disease Laboratory evaluation

• TnI and TnT are not normally detectable in the
  circulation
• After acute MI both troponins
• Become detectable after 2 to 4 hours
• Peak at 48 hours
• Their levels remain elevated for 7 to 10 days

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Ischemic Heart Disease Laboratory evaluation

• CK-MB is the second best marker
• CK-MB activity
• Begins to rise within 2 to 4 hours of MI
• Peaks at 24 to 48 hours
• Returns to normal within approximately 72 hours

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Ischemic Heart Disease Complications of MI

• At least 80 will suffer
• Cardiogenic shock (gt40 infarct of LV)
• Congestive heart failureCHF
• Arrhythmia
• Rupture of ventricle, free wall, septum, or
  papillary muscle
• Aneurysm formation,
• Mural thrombus, potentially source of emboli
• Pericarditis

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Ischemic Heart Disease MI death and
complications rates

• 25 die, presumably due to arrythmia
• 10 of the rest will die within a month
• 80-90 will develop complications
• Overall 30 die in the 1st year and then 10 per
  year

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Chronic ischemic heart disease

• Progressive heart failure due to ischemic injury,
  either from
• prior infarction(s) (most common)
• chronic low-grade ischemia

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Ischemic Heart Disease Sudden cardiac death

• Unexpected death from cardiac causes either
  without symptoms or within 1 to 24 hours of
  symptom onset (different authors use different
  time points)
• Results from a fatal arrhythmia, most commonly in
  patients with severe coronary artery disease

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Ischemic Heart Disease Acute coronary syndrome

• is applied to three catastrophic manifestations
  of IHD
• Unstable angina
• Acute MI
• Sudden cardiac death

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