Ventricular dysrhythmias

djorgenmorris

1. Dysrhythmias Originating in the Ventricles Ventricular escape complexes and rhythms Accelerated idioventricular rhythm Premature ventricular contraction Ventricular tachycardia Torsades de pointes Ventricular fibrillation Asystole Artificial pacemaker rhythm

2. Dysrhythmias Originating in the Ventricles >0.12 seconds, bizarre QRS None PRI None P Waves Ventricle Pacemaker Site Escape complex, irregular; escape rhythm, Regular Rhythm 15–40 Rate Ventricular Escape Complexes and Rhythms Rules of Interpretation

3. Dysrhythmias Originating in the Ventricles Ventricular Escape Complexes and Rhythms Etiology Safety mechanism to prevent cardiac standstill Results from failure of other foci or high-degree AV block Clinical Significance Decreased cardiac output, possibly to life-threatening levels Treatment For perfusing rhythms, administer atropine and/or TCP For nonperfusing rhythms, follow pulseless electrical activity (PEA) protocols

4. Dysrhythmias Originating in the Ventricles >0.12 seconds, bizarre QRS None PRI None P Waves Ventricle Pacemaker Site Escape complex, irregular; escape rhythm, Regular Rhythm 60-100 Rate Accelerated Idioventricular Rhythm Rules of Interpretation

5. Dysrhythmias Originating in the Ventricles Accelerated Idioventricular Rhythm Etiology A subtype of ventricular escape rhythm that frequently occurs with MI Ventricular escape rhythm with a rate of 60–110 Clinical Significance May cause decreased cardiac output if the rate slows Treatment Does not usually require treatment unless the patient becomes hemodynamically unstable Primary goal is to treat the underlying MI

6. Dysrhythmias Originating in the Ventricles >0.12 seconds, bizarre QRS None PRI None P Waves Ventricle Pacemaker Site Interrupts regular underlying rhythm Rhythm Underlying rhythm Rate Premature Ventricular Contractions Rules of Interpretation

7. Dysrhythmias Originating in the Ventricles Premature Ventricular Contractions Etiology Single ectopic impulse resulting from an irritable focus in either ventricle Myocardial ischemia, increased sympathetic tone, hypoxia, idiopathic causes, acid-base disturbances, electrolyte imbalances, or as a normal variation of the ECG May occur in patterns Bigeminy, trigeminy, or quadrigeminy Couplets and triplets

8. Dysrhythmias Originating in the Ventricles Premature Ventricular Contractions Clinical Significance Malignant PVCs More than 6/minute, R on T phenomenon, couplets or runs of ventricular tachycardia, multifocal PVCs, or PVCs associated with chest pain Ventricles do not adequately fill, causing decreased cardiac output

9. Dysrhythmias Originating in the Ventricles Premature Ventricular Contractions Treatment Nonmalignant PVCs do not usually require treatment in patients without a cardiac history Cardiac patient with nonmalignant PVCs Administer oxygen and establish IV access Malignant PVCs: Lidocaine 1.0 –1.5 mg/kg IV bolus Repeat doses of 0.5-0.75 mg/kg to max dose of 3.0 mg/kg If PVCs are suppressed, administer lidocaine drip 2–4 mg/min Reduce the dose in patients with decreased output or decreased hepatic function and patients >70 years old

10. Dysrhythmias Originating in the Ventricles >0.12 seconds, bizarre QRS None PRI If present, not associated with QRS P Waves Ventricle Pacemaker Site Usually regular Rhythm 100–250 Rate Ventricular Tachycardia Rules of Interpretation

11. Dysrhythmias Originating in the Ventricles Ventricular Tachycardia Etiology 3 or more ventricular complexes in succession at a rate of >100 Causes include myocardial ischemia, increased sympathetic tone, hypoxia, idiopathic causes, acid-base disturbances, or electrolyte imbalances VT may appear monomorphic or polymorphic Torsade’s De Pointes Clinical Significance Decreased cardiac output, possibly to life-threatening levels May deteriorate into ventricular fibrillation

12. Dysrhythmias Originating in the Ventricles Torsades de pointes Polymorphic VT

13. Dysrhythmias Originating in the Ventricles Torsades de pointes Typically occurs in nonsustained bursts Prolonged QT interval during “breaks” QRS rates from 166–300 RR interval highly variable Treatment Do not treat as standard VT Administer magnesium sulfate 1–2 g diluted in 100 ml D5W over 1–2 minutes Overdrive pacing

14. Dysrhythmias Originating in the Ventricles None QRS None PRI Usually absent P Waves Numerous ventricular foci Pacemaker Site No organized rhythm Rhythm No organized rhythm Rate Ventricular Fibrillation Rules of Interpretation

15. Dysrhythmias Originating in the Ventricles Ventricular Fibrillation Etiology Wide variety of causes, often resulting from advanced coronary artery disease Clinical Significance Lethal dysrhythmia with no cardiac output and no organized electrical pattern

16. Dysrhythmias Originating in the Ventricles Ventricular Fibrillation Treatment Initiate CPR Defibrillate with 200, 300 and 360 J (or biphasic equivalent) Control the airway and establish IV access Administer epinephrine 1:10,000 every 3–5 minutes Consider 40 IU Vasopressin IV (one time only) Consider second-line drugs Amiodarone Lidocaine Provide continuous compressions

17. Dysrhythmias Originating in the Ventricles Absent QRS Absent PRI Absent P Waves No Electrical Activity Pacemaker Site No Electrical Activity Rhythm No Electrical Activity Rate Asystole Rules of Interpretation

18. Dysrhythmias Originating in the Ventricles Asystole Etiology Primary event in cardiac arrest, resulting from massive myocardial infarction, ischemia, and necrosis Final outcome of ventricular fibrillation Clinical Significance Asystole results in cardiac arrest Poor prognosis for resuscitation

19. Dysrhythmias Originating in the Ventricles Asystole Treatment Administer CPR and manage the airway Treat for ventricular fibrillation if there is any doubt about the underlying rhythm Administer medications: Epinephrine

20. Dysrhythmias Originating in the Ventricles >0.12 seconds, bizarre QRS If present, varies PRI None produced by ventricular pacemakers; pacemaker spike P Waves Depends upon electrode placement Pacemaker Site May be regular or irregular Rhythm Varies with pacemaker Rate Artificial Pacemaker Rules of Interpretation

21. Dysrhythmias Originating in the Ventricles Artificial Pacemaker Rhythm Etiology Single vs. dual chamber pacemakers Fixed-rate vs. demand pacemakers Clinical Significance Used in patients with a chronic high-grade heart block, sick sinus syndrome, or severe symptomatic bradycardia

22. Dysrhythmias Originating in the Ventricles Artificial Pacemaker Rhythm Problems with Pacemakers Battery failure “Runaway” pacers Displaced leads Management Considerations Identify patients with pacemakers Treat the patient Use of a Magnet