Heart, Section Through the Middle

The interior of the heart is composed of valves, chambers, and associated vessels.

Heart, Front View

The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.

Acute MI

A heart attack or acute myocardial infarction (MI) occurs when one of the arteries that supplies the heart muscle becomes blocked. Blockage may be caused by spasm of the artery or by atherosclerosis with acute clot formation. The blockage results in damaged tissue and a permanent loss of contraction of this portion of the heart muscle.

Post Myocardial Infarction ECG Wave Tracings

Various phases can be seen through ECG wave tracings following a heart attack:

• Hyperacute phase begins immediately after a heart attack
• Fully evolved phase starts a few hours to days after a heart attack
• Resolution phase appears a few weeks after a heart attack
• Stabilized chronic phase is the last phase and typically has permanent pathological changes compared to a normal ECG tracing

Progressive Build-Up of Plaque in Coronary Artery

Plaque may build-up in a coronary artery at the site of a tear in the lining of the vessel.

Posterior Heart Arteries

The coronary arteries supply blood to the heart muscle. The right coronary artery supplies both the left and the right heart; the left coronary artery supplies the left heart.

Anterior Heart Arteries

The coronary arteries supply blood to the heart muscle. The right coronary artery supplies both the left and the right heart; the left coronary artery supplies the left heart.

Heart Attack Symptoms

Symptoms of a possible heart attack include chest pain and pain that radiates down the shoulder and arm.