1 / 59

Roger A. Freedman, M.D.

Roger A. Freedman, M.D. Anatomy of the cardiac conduction system Relationship between intracardiac events and ECG Bradyarrhythmias Pacemakers. THE CONDUCTION SYSTEM. Heart Beat Anatomy. The Heart’s ‘Natural Pacemaker’ - 60-100 BPM at rest. SINUS NODE. Sinus Node (SA Node).

gaerwn
Download Presentation

Roger A. Freedman, M.D.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Roger A. Freedman, M.D. • Anatomy of the cardiac conduction system • Relationship between intracardiac events and ECG • Bradyarrhythmias • Pacemakers

  2. THE CONDUCTION SYSTEM

  3. Heart Beat Anatomy • The Heart’s ‘Natural Pacemaker’ • - 60-100 BPM at rest SINUS NODE Sinus Node (SA Node)

  4. Heart Beat Anatomy • Receives impulse from • SA Node • Delivers impulse to the His- • Purkinje System • 40-60 BPM if SA Node fails to • deliver an impulse AV NODE Sinus Node (SA Node) Atrioventricular Node (AV Node)

  5. Heart Beat Anatomy • Begins conduction to • the Ventricles • AV Junctional Tissue: • 40-60 BPM BUNDLE OF HIS Sinus Node (SA Node) Atrioventricular Node (AV Node) Bundle of His

  6. Heart Beat Anatomy THE PURKINJE NETWORK • Bundle Branches • Purkinje Fibers • Moves the impulse through • the ventricles for contraction • Provides ‘Escape Rhythm’: • 20-40 BPM Sinus Node (SA Node) Atrioventricular Node (AV Node) Bundle of His Bundle Branches Purkinje Fibers

  7. Impulse Formation In SA Node

  8. Atrial Depolarization

  9. Delay At AV Node

  10. Conduction Through Bundle Branches

  11. Conduction Through Purkinje Fibers

  12. Ventricular Depolarization

  13. Plateau Phase of Repolarization

  14. Final Rapid (Phase 3) Repolarization

  15. Normal EKG Activation

  16. Reading EKGs Intervals and Timing • Normal Ranges • in Milliseconds: • PR Interval 120 – 200 ms • QRS Complex 60 – 100 ms • QT Interval 360 – 440 ms

  17. Each square = 40 ms Each interval = 200 ms Reading EKG Squares Intervals and Timing

  18. Ca2+ in K+ out Na+ in K+ out Calcium channel blockers (verapamil, diltiazem) slow sinus rate and slow or block conduction through AV node Sodium channel blockers (flecainide, propafenone, amiodarone) widen the QRS Potassium channel blockers (dofetilide, sotalol, amiodarone) prolong the QT interval

  19. Prolonged QT interval

  20. RHYTHM DISORDERS Bradyarrhythmias

  21. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders Bradycardias Impulse Conduction Disorders

  22. Bradyarrhythmia Classifications Classification Based on Disorder • Sinus Bradycardia Impulse Formation Disorders Impulse Conduction Disorders

  23. Sinus Bradycardia

  24. Bradyarrhythmia Classifications Classification Based on Disorder • Sinus Bradycardia Impulse Formation Disorders • Sinus Arrest Impulse Conduction Disorders

  25. * Animation Sinus Arrest • Failure of sinus node discharge • Absence of atrial depolarization • Periods of asystole

  26. Bradyarrhythmia Classifications Classification Based on Disorder • Sinus Bradycardia Impulse Formation Disorders • Sinus Arrest • Brady/Tachy Syndrome Impulse Conduction Disorders

  27. Brady/Tachy Syndrome • Intermittent episodes of slow and fast rates from the SA node or atria • Brady <60 BPM • Tachy >100 BPM

  28. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders • Sinus Arrest • Sinus Bradycardia • Brady/Tachy Syndrome Impulse Conduction Disorders • Sino-atrial Exit Block

  29. Sino-atrial Exit Block • Transient block of impulses from the SA node • Identified by P-P interval relationship

  30. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders • Sinus Arrest • Sinus Bradycardia • Brady/Tachy Syndrome Impulse Conduction Disorders • Sino-atrial Exit Block • AV block

  31. First-Degree AV Block • PR interval > 200 ms • Delayed conduction through the AV Node - Example shows PR Interval = 320 ms

  32. Second degree AV block

  33. * Animation Second-Degree AV Block - Mobitz I Known as Wenckebach Block • Progressive prolongation of the PR interval until there is failure to conduct and a ventricular beat is dropped

  34. * Animation Third-Degree AV Block • No impulse conduction from the atria to the ventricles • Ventricular rate = 37 BPM • Atrial rate = 130 BPM • PR interval = variable

  35. Third degree AV block

  36. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders • Sinus Arrest • Sinus Bradycardia • Brady/Tachy Syndrome Impulse Conduction Disorders • Exit Block • 1st Degree AV Block • 2nd Degree AV Block • 3rd Degree AV Block

  37. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders • Sinus Arrest • Sinus Bradycardia • Brady/Tachy Syndrome Impulse Conduction Disorders • Exit Block • 1st Degree AV Block • 2nd Degree AV Block • 3rd Degree AV Block • Bundle Branch Block

  38. Bundle Branch Block Left bundle branch block

  39. Left bundle branch block

  40. Right bundle branch block

  41. Causes of Bradyarrhythmias • Congenital Heart Disease • Present at birth due to genetics, environment • Acquired Heart Disease • Acute Myocardial Infarction, Ischemic Heart Disease, Dilated or Hypertrophic Cardiomyopathy, Hypertension, Valvular Heart Diease, Post-operative Drug-induced Neurocardiogenic • Hypersensitive Carotid Sinus Syndrome • Vasovagal Syncope

More Related