Critical Care Exam II Chapter 35 Dysrhythmias/ Arrhythmias

+ Autonomic Nervous System - Parasympathetic . Nervous System (Decreases rate of SA node/Slows impulse conduction of AV node) - Sympathetic Nervous System + Increases rate of SA node + Increases impulse conduction of AV node + Increases cardiac contractility Causes of Heart Failure + HTN, Drugs (Recreational and Prescription), Electrolyte imbalances (K+, Mg+, Ca+), CAD, Heart Attack (MI), Valvular heart disease, Hypoxia, Hyperthyroid (Endocrine), - SA node is the normal pacemaker of heart (SA node (atrial side) = Switch of Heart) + HR 60-100 BPM (if SA node if functioning properly) - Secondary Pacemakers + AV node (atrial septum) takes charge if SA node is not functioning properly - HR 40-60 BPM + His-Purkinje Fibers/"Tertiary Pacemaker" takes charge if SA & AV node not working - HR 20-40 BPM = NEEDS PACEMAKER! (ECG/EKG) STANDARD DIAGNOSTIC FOR HEART - ER with angina (chest pain)  12 lead EKG 1. The P-Wave-depolarization (contraction) + P-Wave should be round, smooth, small, upright above isoelectric line - Like a hill 2. The PR Interval is measured from the beginning of the P Wave to the beginning of the QRS complex.  Time it takes impulse to travel from SA node to AV node 4. The ST Segment-time between ventricular depolarization and repolarization (diastole). + The ST Segment should be isoelectric (flat). - ST elevation  MI!! - ST depression  Cardiac ischemia 5. The T Wave represents the time for ventricular repolarization + T Wave should be upright [peaked T wave=hyperkalemia] + Inverted T wave=abnormality 6. The QT Interval-time taken for entire electrical depolarization and repolarization of the ventricles [prolonged=dysrhythmias] 1