BMS 450 Lecture Notes - Ectopic Pacemaker, Cardiac Arrhythmia, Antiarrhythmic Agent
Document Summary
Electrical activity of the heart recorded through the skin. Result from disorders of impulse formation, conduction, or both. Excessive discharge of or sensitivity to autonomic transmitters. Either a change in the normal pacemaker (i. e. sa node) or the development of a new ectopic pacemaker (e. g. in the ventricles) Ectopic activity is possible because many cells of the conduction system are capable of rhythmic spontaneous activity. Dominant pacemaker will be the one with the highest frequency (normally the sa node) Under some conditions new pacemaker sites may become dominant. Abnormal acceleration of the ectopic (non-sa pacemaker) firing rate. Ectopic activity may result from injury due to ischemia or hypoxias which cause abnormal depolarization. Disorders of impulse conduction can cause either bradycardia ( hr) or tachycardia ( . Atrial fibrillation (too much depolarization going through the av node to the ventricles) Unidirectional block blocks spread in one direction, forms self-sustaining circuit/pacemaker.
