myocardial ischemia

(noun)

An imbalance between myocardial oxygen supply and demand.

Related Terms

Examples of myocardial ischemia in the following topics:

  • Myocardial Ischemia and Infarction

    • Ischemic heart disease (IHD), or myocardial ischaemia, is a disease characterized by ischaemia, or reduced blood supply to the heart muscle, usually due to coronary artery disease and myocardial infarction.
    • Acute chest pain- acute coronary syndrome, unstable angina or myocardial infarction
    • An EKG is performed, looking for changes that are characteristic of a myocardial infarction.
    • Atherosclerosis reduces blood flow to the heart muscle, causing ischemia.
    • Distinguish between the effects of myocardial ischemia and infarction on the heart

  • Coronary Artery Disease

    • A distinction should be made between myocardial ischemia and myocardial infarction.
    • Ischemia means that the amount of blood supplied to the tissue is inadequate to supply the needs of the tissue.
    • If the blood flow to the tissue is improved, myocardial ischemia can be reversed.

  • Electrocardiogram and Correlation of ECG Waves with Systole

    • Abnormalities in the QRS complex may indicate cardiac hypertrophy or myocardial infarctions.
    • An elevated ST segment is the classic indicator for myocardial infarctions, though missing or downward sloping sloping ST segments may indicate myocardial ischemia.
    • It generally occurs with myocardial infarcations and heart failure, and is thought to be caused by action potentials that re-enter the AV nodes from the muscle tissue and induce rapid, irregular, weak contractions of the heart that fail to pump blood.

  • Heart Circulation

    • This could result in angina and ultimately a myocardial infarction.
    • A myocardial infarction (heart attack) may be caused by prolonged ischemia (oxygen deprivation) in the heart, which occurs due to blockage of any of the coronary arteries.
    • When these vessels become blocked, the myocardium becomes oxygen-deprived, a condition called ischemia.
    • As the time period of ischemia increases, the hypoxic conditions cause muscle tissue to die, causing a myocardial infarction (heart attack).
    • Myocardial infarction is one of the most common causes of death worldwide.

  • Localization of Pain

    • Visceral structures are highly sensitive to stretch, ischemia, and inflammation, but relatively insensitive to other stimuli that normally evoke pain in other structures, such as burning and cutting.
    • An example is the case of ischemia brought on by a myocardial infarction (heart attack), where pain is often felt in the neck, shoulders, and back rather than in the chest, the site of the injury.
    • The pain related to a myocardial infarction could either be referred pain or pain radiating from the chest.
    • Classically, the pain associated with a myocardial infarction is located in the middle or left side of the chest, where the heart is actually located.

  • Cerebrovascular Accident

    • This can be due to ischemia (lack of blood flow) caused by blockage (thrombosis, arterial embolism), or a hemorrhage (leakage of blood).
    • It is most commonly due to cardiac pump failure from cardiac arrest or arrhythmias, or from reduced cardiac output as a result of myocardial infarction, pulmonary embolism, pericardial effusion, or bleeding.
    • Conversely, aspirin confers some protection against first stroke in patients who have suffered a myocardial infarction or patients with a high cardiovascular risk.

  • Myocardial Thickness and Function

    • A flabby heart is typically the result of myocardial infections, in which the heart muscle becomes so weak that it cannot efficiently pump blood, which also leads to heart failure.

  • Layers of the Heart Walls

    • During ventricular contraction, the wave of depolarization from the SA and AV nodes moves from within the endocardial wall through the myocardial layer to the epicardial surface of the heart.
    • The Purkinje fibers are located just beneath the endocardium and send nervous impulses from the SA and AV nodes outside of the heart into the myocardial tissues.
    • The dark area on the heart wall is scarring from a previous myocardial infarction (heart attack).

  • Pericarditis

    • Acute pericarditis is more common than chronic pericarditis, and can occur as a complication of infections, immunologic conditions, or even as a result of a heart attack (myocardial infarction).
    • Due to similarity to myocardial infarction (heart attack) pain, pericarditis can be misdiagnosed as an acute myocardial infarction (a heart attack) solely based on the clinical data and so extreme suspicion on the part of the diagnostician is required.
    • Ironically an acute myocardial infarction (heart attack) can also cause pericarditis, but often the presenting symptoms vary enough to warrant a diagnosis.

  • Blood Flow in the Brain

    • Too little blood flow (ischemia) results in tissue death.