Extrasystole

Extrasystole (premature contraction, premature depolarization, premature contraction) is an excitation arising prematurely outside the SA node. Such an excitation occurs before the excitation in the SA node, it precedes the excitation from the SA node and thus prematurely depolarizes the cardiac myocardium. The excitation from the SA node is not applied because it comes at a time when the myocardium is already in the refractory phase after the previous depolarization by the premature excitation.

Etiopathogenesis
Pathogenetically, extrasystoles arise on the basis of "ectopy" or "reentry mechanism", the basis of which can be:
 * hypoxia;
 * ischemia;
 * ion breakdown;
 * acidosis;
 * some types of drugs;
 * drugs.

Types
According to the place where the premature excitation occurs, we distinguish 3 types of extrasystoles:
 * 1) atrial extrasystoles;
 * 2) junctional extrasystoles;
 * 3) ventricular extrasystoles.

Related Articles

 * Atrial extrasystoles • Junctional extrasystoles • Ventricular extrasystoles
 * Flutter halls
 * Ventricular fibrillation
 * Antiarrhythmics