Basic Dysrhythmias & Ekg Interpretation Study Guide Rated A+

Premature Atrial Contractions (PACs) {Ans: These ectopic cells origionate in the atria (but not the SA node), therefore the contour of the P wave, the PR interval, and the timing are DIFFERENT than normally generated pulse from the SA node Etiology--Excitation of an atrial cell forms an impulse that is then conducted normally through the AV node and the ventricles --One cell randomly firing (anywhere in atria)}AV Junction {Ans: AV Node Arrhythmias The AV Junction can: --Fire continuously due to a looping re-entrant circuit (Paroxysmal Supraventricular Tachycardia [PSVT or SVT]) --Block impulses coming from the SA node (AV Junctional Blocks)}Normal Sinus Rhythm {Ans: NSR Rate: 60-100 bpm Regularity: Regular P Waves: Normal PR Interval: 0.12-0.20 s QRS Duration: 0.04-0.12 s QT Duration: 0.36-0.44 s}Ventricular Fibrillation (VFib) {Ans: Completely abnormal --Course vs. Fine Etiology--the ventricular cells are excitable and depolarizing randomly. Not contracting, just quivering; no CO, considered "dead" (no breathing or pulse)}Sinus Tachycardia (ST) {Ans: May be appropriate response to stress Rate >100 bpm Etiology--SA node is depolarizing faster than normal, impulse is conducted normally Remember: it is a response to physical or psychological stress, not primary arrhythmia}Premature Ventricular Contractions [PVCs]) {Ans: Ectopic beats