WCT

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Ibtisam Al-Hoqani

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WCT

  1. 1. Ibtisam Al Hoqani EM – R2 31/8/2010 Approach to Wide Complex Tachycardia
  2. 2. Outline : <ul><li>Basic ECG </li></ul><ul><li>What is WCT </li></ul><ul><li>Mechanisms of WCT </li></ul><ul><li>Diagnostic criteria </li></ul><ul><li>Management </li></ul><ul><li>Take home message </li></ul>
  3. 3. The Normal Conduction System
  4. 4. what is this rhythm ?
  5. 5. Normal Intervals <ul><li>PR </li></ul><ul><ul><li>0.20 sec (less than one large box) </li></ul></ul><ul><li>QRS </li></ul><ul><ul><li>0.08 – 0.10 sec (1-2 small boxes) </li></ul></ul><ul><li>QT </li></ul><ul><ul><li>450 ms in men, 460 ms in women </li></ul></ul><ul><ul><li>Based on sex / heart rate </li></ul></ul><ul><ul><li>Half the R-R interval with normal HR </li></ul></ul>
  6. 6. Differential Diagnosis of Tachycardia Tachycardia Narrow Complex Wide Complex Regular ST SVT Atrial flutter ST with aberrancy VT Irregular A-fib A-flutter with variable conduction MAT A-fib with aberrancy A-fib with WPW PVT
  7. 7. What is this rhythm?
  8. 8. What is WCT? <ul><li>It is refers to dysrhythmias with rate greater than 100 beats/min associated with QRS complex duration of more than 0.12 sec </li></ul><ul><li>It is divided to: </li></ul><ul><li>=Regular </li></ul><ul><li>=Irregular </li></ul>
  9. 10. Causes of WCT : <ul><ul><li>Irregular WCT: </li></ul></ul><ul><ul><li>Afib with BBB or IVCD (pre-existent or rate related) </li></ul></ul><ul><ul><li>Afib with anterograde conduction over accessory pathway in WPW </li></ul></ul><ul><ul><li>Polymorphic VT ex: Torsades de pointes or due to Digitalis intoxication </li></ul></ul><ul><ul><li>Other causes of an irregular rhythm ( A flutter with variable conduction, MAT etc) with BBB, WPW, IVCD </li></ul></ul>
  10. 12. Causes of WCT: <ul><li>Regular rhythm: </li></ul><ul><li>Ventricular driven rhythm: </li></ul><ul><ul><li>VT : worst case scenario </li></ul></ul><ul><li>Supraventricular rhythm with aberrant conduction: </li></ul><ul><ul><li>SVT with BBB </li></ul></ul><ul><ul><li>SVT with accessory pathway Ex: WPW </li></ul></ul>
  11. 13. How to distinguish SVT from VT <ul><li>Focus History </li></ul><ul><li>Physical examination </li></ul><ul><li>ECG tracing </li></ul><ul><li>Using specific Criteria : </li></ul><ul><li>Wellens criteria </li></ul><ul><li>Brugada criteria </li></ul>
  12. 14. Preceding P waves with QRS QRS <0.14 Normal axis Slow or terminate with vagal maneuvers Fusion beats AV dissociation QRS >0.14 Extreme LAD No response to vagal maneuvers ECG Absence of variability Cannon A wave Variation in arterial pulse Variation in S1 Physical examination Mitral valve prolapse (WPW) Previous Hx of SVT Age>50 Hx of MI, CHD, CABG, ASHD Mitral valve prolapse Previous Hx of VT History SVT with aberrancy VT
  13. 17. Management of WCT Any new onset symptomatic WCT is VT until proven otherwise
  14. 18. Management of WCT <ul><li>If the patient is hemodynamically unstable, the first - choice therapy for ventricular tachycardia (VT) is synchronized direct-current (DC) cardioversion with 50 – 100 J </li></ul><ul><li>If the patient is suffering from monomorphic VT and has a preserved heart function, the first-line treatment is lidocaine . Alternatives include either amiodarone or procainamide . </li></ul>
  15. 19. <ul><li>If the patient has polymorphic VT with a normal baseline QT interval, AHA guidelines state that the first steps are to treat ischemia and correct any electrolyte imbalance . </li></ul><ul><li>If cardiac function is impaired, use amiodarone or lidocaine, followed by synchronized DC cardioversion </li></ul>
  16. 20. <ul><li>If the patient has polymorphic VT with a prolonged baseline QT interval, ACLS guidelines state that any electrolyte imbalance should be corrected . Following this, any one of these treatments can be administered : magnesium sulfate , overdrive pacing, or lidocaine </li></ul>
  17. 21. <ul><li>Long - term treatment of sustained ventricular arrhythmias includes placement of an implantable cardioverter -defibrillator (ICD) and possible adjunctive therapy with amiodarone or sotalol in certain subsets of patients. Patients should be under the care of a cardiologist or electrophysiologist </li></ul>
  18. 23. Take home message <ul><li>Any new onset symptomatic WCT is VT until proven otherwise </li></ul><ul><li>About 80% of all WCT are ventricular tachycardia </li></ul><ul><li>In patients with known structural heart disease almost all WCT are ventricular tachycardia </li></ul>

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