Learning Center

Heart Attack (Myocardial Infartction – MI)
Scarring, or death, of the heart muscle due to lack of oxygen. Oxygen-rich blood is blocked by a blood clot in a coronary artery, usually due to plaque-related narrowing of the artery.

Heart Block
An interference with the normal conduction of electric impulses that control activity of the heart muscle. Heart block usually is defined as to the location of the block and the type.

Heart Sound
A normal noise produced within the heart during the cardiac cycle that can be heard over the pericardium and may reveal abnormalities in cardiac structure or function.

Hemodynamic Instability
Instability of the blood pressure.

Hemodynamics
The study of the movements of the blood and of the forces concerned therein.

Hemoglobin
The red pigmented complex protein found in the red blood cells that functions to carry oxygen and carbon dioxide.

Hemostasis
The cessation of bleeding through normal coagulation or by surgical procedure.

Heparin
A negatively charged polysaccharide normally found in lung or gut mucosa that naturally prolongs the time it takes blood to clot by catalyzing anti-thrombin III.

Hypertension
Characterized by increased or excessive blood pressure. Hypertension is the most powerful and potent risk factor for stroke.

Hyperthermia
Temperature above normal.

Hypoperfusion
Decreased blood flow to an organ or tissue such as in shock.

Hypotension
Characeterized by decreased or lower than normal blood pressure. Excessive and prolonged blood pressure reductions may lead to watershed cerebral infarction.

Hypothermia
A body temperature significantly below 98.6°F (37°C).



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