Updated March 2006: D. Tucker, RPh, BCPS ECG Dysrhythmias Updated March 2006: D. Tucker, RPh, BCPS

Overview ECG waveforms Normal sinus rhythm Asystole Bradycardia Ventricular fibrillation Ventricular tachycardia

ECG Rhythm Strip Electrocardiogram or ECG is used to measure the activity of the heart ECG is used to represent the conduction of electrical impulses from the atria to the ventricles ECG is used to characterize rhythms and conduction abnormalities of the heart

ECG Waveforms P Wave PR Segment QRS Complex ST Segment T Wave U Wave Electrical activation (depolarization) of the right then left atrium due to discharge from the sinoatrial (SA) node PR Segment Passage of the impulse through the atrioventricular (AV) node and bundle of HIS QRS Complex Electrical depolarization of the ventricles ST Segment Plateau phase T Wave Repolarization of the ventricle U Wave Repolarization of the HIS-Purkinje system

ECG Waveforms healthcentral.org

Normal Sinus Rhythm Normal impulse conduction through the heart Normal sinus rhythm (NSR) is the standard against which all other rhythms are compared NRS contains no ectopic or aberrant beats

ECG Rhythms Normal sinus rhythm healthcentral.org

ECG Rhythms Asystole Bradycardia Ventricular fibrillation Ventricular tachycardia healthcentral.org

Asystole Asystole is a cardiac standstill, i.e., flatline Asystole is the absence of electrical activity in the venticles Asystole usually results from a prolonged period of cardiac arrest without resuscitation Asystole usually means the patient’s life has ended

ECG Rhythms Ventricular asystole healthcentral.org

Bradycardia Bradycardia is when the heart is < 60 beats/minute or when the heart rate is slower than expected Sinus bradycardia usually occurs as a response to a reduced demand for blood flow Signs and symptoms might include: Chest pain, shortness of breath Hypotension, pulmonary edema, congestive heart failure

ECG Rhythms Sinus bradycardia healthcentral.org

Ventricular Fibrillation Ventricular fibrillation (VF) occurs as a result of electrical impulses coming from multiple ectopic pacemaker in the ventricles VF results in no cardiac output as a result of producing no effective ventricular contractions With VF the ventricular muscle quivers instead of contracting

ECG Rhythms Ventricular fibrillation healthcentral.org

Ventricular Tachycardia Ventricular tachycardia (VT) is a result of 3 or more ventricular contractions occur earlier than expected resulting in a ventricular rate of >10 beats/minute VT usually preceeds VF Causes of VT include myocardial ischemia, heart failure, drug toxicity from procainamide, quinidine, or cocaine Pulseless VT refers to the fact that the heart has electrical activity but is not pumping blood to the extremities

ECG Rhythms Ventricular tachycardia healthcentral.org

Name These ECG Rhythms C A D E B healthcentral.org A: Ventricular Fibrillation B: Asystole C: Sinus Bradycardia D: Normal Sinus Rhythm E: Ventricular Tachycardia E B healthcentral.org