Ventricular Arrhythmias

Ventricular Arrhythmias Terry White, RN, EMT-P

Analyze the Rhythm

Premature Ventricular Complexes (PVCs) • Definitions • Early depolarization of the ventricles • Occur as a result of automaticity or reentry • A PVC is a characteristic of an underlying ECG rhythm • PVC is not the name of a dysrhythmia

Premature Ventricular Complexes • Causes • Hypoxia • Myocardial Ischemia • Electrolyte Imbalance • Digitalis Toxicity • Stimulants • Chronic Heart Disease (CHF, COPD)

Premature Ventricular Complexes (PVCs) • Characteristics • Complex is earlier than expected • Wide QRS (wide is not always ventricular) • OFTEN has a compensatory pause • Usually irregular • Not preceded by a P wave • T wave opposite deflection • May or may not result in perfused beat

Premature Ventricular Complexes (PVCs) • More Terms to Know • Unifocal, Multifocal • R on T Phenomenon • Bigeminy, Trigeminy, Quadrigeminy, Couplet

Premature Ventricular Complexes (PVCs) • PVCs are not always dangerous • Common for some people • Consider treating PVCs if: • >6/minute associated with: • Severe Chest pain • Hypotension, Decreased Perfusion • Shortness of Breath

Premature Ventricular Complexes (PVCs) • Treat PVCs if consistently see any of the following with other symptoms: • Multifocal • Ventricular Couplets • Runs of Ventricular Tachycardia • R on T Phenomenon (Malignant PVCs)

Premature Ventricular Complexes (PVCs) • Management (Rate <60) • Oxygen & Ventilation are initial treatments for ALL ectopic beats • ECG Monitor, IV NS TKO • assess the underlying rhythm • Treat like bradycardia • Atropine • TCP • Dopamine

Premature Ventricular Complexes (PVCs) • Management (Rate >60) • Oxygen & Ventilation are initial treatments for ALL ectopic beats • ECG Monitor, IV NS TKO • assess the underlying rhythm • If symptomatic (see previous):

Premature Ventricular Complexes (PVCs) • Management (Rate >60) • Lidocaine • IV Bolus, 1 - 1.5 mg/kg • Infusion, 1 - 4mg/min • Repeat IV push 0.5 - 0.75 mg/kg every 5 minutes to 3 mg/kg max • Increase Infusion 1mg/min for every 1mg/kg IV bolus given

Premature Ventricular Complexes (PVCs) • Management (Rate >60) • Procainamide • 20 mg/min IV until: • PVCs suppressed • 17 mg/kg given • Hypotension occurs • QRS widens by 50% or more • Continuous infusion at 1 - 4 mg/min

Premature Ventricular Complexes (PVCs) • Management (Rate >60) • Bretylium • IV push, 5 mg/kg slowly • Infusion, 1 - 2 mg/min • Used less frequently today due to supply shortage

Idioventricular Rhythm • Causes • Myocardial ischemia • Hypoxia • High vagal tone • Drug effects

Idioventricular Rhythm • Characteristics • A ventricular focus takes over as an escape pacemaker site • Rate 20 - 40 bpm • Wide QRS complexes • No P waves

Idioventricular Rhythm • Management • Slow rate will probably decrease cardiac output • Usually a later and often pre-terminal rhythm • If symptomatic, treat as unstable bradycardia • Do NOT give Lidocaine or other ventricular antidysrhythmics!!!!!!!

Accelerated Idioventricular Rhythm • Characteristics • Like Idioventricular rhythm except for rate • Rate, greater than 40 bpm but less than 100 bpm

Accelerated Idioventricular Rhythm • Management • Patient may maintain adequate cardiac output • Identify underlying cause and treat!!! • Monitor cardiac output and perfusion • Often a late and pre-terminal rhythm • Do NOT give Lidocaine or other antidysrhythmics!!!!!!!

Ventricular Tachycardia (VT) • Causes • Myocardial ischemia • Hypoxia • Electrolyte imbalance • Digitalis toxicity • Myocardial trauma

Ventricular Tachycardia (VT) • Characteristics • Pacemaker site • Irritable ventricular focus takes over as pacemaker site, OR • May result from multiple ventricular foci attempting to become pacemaker site • Complexes look similar to PVCs • May see P waves before complexes but uncommon • Rate, usually between 100 and 250 bpm

Ventricular Tachycardia (VT) • Complications • Can decrease cardiac output • Increases cardiac workload • Decreases coronary perfusion • Can quickly deteriorate into V-fib

Ventricular Tachycardia (VT) • Types • Monomorphic • QRS complexes all have same morphology • Polymorphic • QRS complexes have more than one morphology • “Torsades de Pointes” • “Twisting of the points” • Usually > 200 bpm • Susceptible if slow repolarization (long QT)

Ventricular Tachycardia (VT) • Treatment of Stable and Unstable • Oxygen, Ventilations, Assess Pulse • ECG Monitor • If unstable, proceed to synchronized cardioversion • IV NS TKO • Determine monomorphic vs polymorphic • If wide complex of unknown origin, attempt 12 lead ECG to determine

Ventricular Tachycardia Treatment: Monomorphic • Treatment of Stable (limit to one antidysrhythmic) • procainamide 20 mg/min IV • avoid if poor cardiac function • amiodarone 150 mg slow IV (15 mg/min) • lidocaine 1.0 mg/kg IV (max 3.0 mg/kg) • Begin with 0.5 - 0.75 mg/kg poor cardiac function • Follow with lidocaine infusion, 1 - 4 mg/min • synchronized cardioversion

Tachycardia: Wide Complex (VT) Polymorphic (Torsades) • Treatment (limit to one antidysrhythmic) • Normal QT • Lidocaine, 1 - 1.5 mg/kg IV (max 3.0 mg/kg), repeat @ 0.5-0.75 mg/kg q 5 min to max 3 mg/kg • Amiodarone, 150 mg slow IV (15 mg/min) • Procainamide, 20 mg/min until • PVCs suppressed • 17 mg/kg given • Hypotension occurs • QRS widens by 50% or more • Then, infusion at 1 - 4 mg/min

Tachycardia: Wide Complex (VT) Polymorphic (Torsades) • Treatment (limit to one antidysrhythmic) • Long QT (including Torsades w/o arrest) • Magnesium sulfate 10%, 1-2 g slow IV over 5 mins or greater • Lidocaine, 1 - 1.5 mg/kg IV (max 3.0 mg/kg), repeat @ 0.5-0.75 mg/kg q 5 min to max 3 mg/kg • Other considerations • phenytoin, isoproterenol, or overdrive pacing

Interesting Questions What is a capture beat? What is a fusion beat? How do they help or hurt you in your ECG interpretation?

Ventricular Arrhythmias