The American frontier comprises the geography, history, folklore, and cultural expression of life in the forward wave of American westward expansion that began with English colonial settlements in the early 17th century and ended with the admission of the last mainland territories as states in 1912.
Atrial Flutter Causes. Atrial flutter may be caused by abnormalities or diseases of the heart, by a disease elsewhere in the body that affects the heart, or by consumption of substances that change the way electrical impulses are transmitted through the heart. In some people, no underlying cause is ever found.
Atrial Flutter & Atrial Tachycardia. Typical atrial flutter results from a single short-circuit in the right atrium. This short-circuit causes the atria to beat at about 300 beats per minute while the lower chamber of the heart (the ventricles) beat at a slower rate (often 75 to 150 beats per minute). Like atrial fibrillation, atrial flutter occurs most commonly in elderly patients and those with other types of heart disease.