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Ecg 2

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Ecg 2

  1. 2. Normal ECG
  2. 3. Normal ECG
  3. 4. Mechanisms of Rhythm Disorders Underlying Mechanisms Impulse Formation Impulse Conduction <ul><li>Abnormal Automaticity </li></ul><ul><li>Slow or Blocked </li></ul><ul><li>Conduction </li></ul><ul><li>Triggered Activity </li></ul><ul><li>Reentry </li></ul>
  4. 6. Mechanisms of Rhythm Disorders Triggered Activity <ul><li>Afterpotentials occurring in </li></ul><ul><li>Phase 3 (early) or 4 (late) of </li></ul><ul><li>action potential </li></ul><ul><li>Can trigger arrhythmias </li></ul>
  5. 7. <ul><li>Early Afterdepolarization </li></ul><ul><li>Potential Causes: </li></ul><ul><li>- Low potassium blood levels </li></ul><ul><li>- Slow heart rate </li></ul><ul><li>- Drug toxicity (ex. Quinidine </li></ul><ul><li> causing Torsades de Pointes) </li></ul><ul><li>Late Afterdepolarization </li></ul><ul><li>Potential Causes: </li></ul><ul><ul><li>Premature beats </li></ul></ul><ul><ul><li>Increased calcium blood levels </li></ul></ul><ul><ul><li>Increased adrenaline levels </li></ul></ul><ul><ul><li>Digitalis toxicity </li></ul></ul>Mechanisms of Rhythm Disorders Triggered Activity
  6. 8. <ul><li>ERP - Effective Refractory Period </li></ul><ul><ul><li>Phases 0, 1, 2 and early Phase 3 </li></ul></ul><ul><ul><li>A depolarization cannot be initiated by an impulse of any strength </li></ul></ul>Action Potential of a Cardiac Cell Refractory Periods
  7. 9. <ul><li>RRP - Relative Refractory Period </li></ul><ul><ul><li>Late Phase 3 and early Phase 4 </li></ul></ul><ul><ul><li>A strong impulse can cause depolarization, possibly with aberrancy </li></ul></ul>Action Potential of a Cardiac Cell Refractory Periods
  8. 10. Mechanisms of Rhythm Disorders Conditions of Reentry
  9. 11. Mechanisms of Rhythm Disorders Reentry Substrate + Trigger = Reentry
  10. 12. Mechanisms of Rhythm Disorders Reentry
  11. 13. Causes of Rhythm Disorders <ul><li>Congenital </li></ul><ul><li>Present at birth due to genetics, environment </li></ul><ul><li>Heart Disease </li></ul><ul><li>Myocardial Infarction, Cardiomyopathy, High Blood Pressure </li></ul><ul><li>Chemically Induced </li></ul><ul><li>Diet Pills, Cold Medicine, Illegal Drugs, Caffeine, Tobacco, Alcohol </li></ul>
  12. 14. Causes of Rhythm Disorders <ul><li>Secondary to other conditions </li></ul><ul><li>Hyper-Thyroid </li></ul><ul><li>Neurocardiogenic Syncope </li></ul><ul><li>- Hypersensitive Carotid Sinus Syndrome (CSS) </li></ul><ul><li>- Vasovagal Syncope (VS) </li></ul>
  13. 15. RBBB
  14. 16. RBBB Diagnostic criteria 1 QRS ≥ 0.12 s with slurring in the mid-final portion of the QRS. 2 V1: rsR′ pattern with a slurred R wave and a negativeT wave. 3 V6: qRs pattern with S-wave slurring and a positive T wave. 4 aVR: QR with evident R-wave slurring and a negative T wave. 5 T wave with polarity opposite to that of the slurred component of the QRS.
  15. 17. Partial or first-degree RBBB In this case, activation delay of the ventricle is less delayed. The QRS complex is 0.1–0.12 s in duration, but V1 morphology is rsR′ or rsr′.
  16. 18. LBBB
  17. 19. Diagnostic criteria 1 QRS ≥ 0.12 s, sometimes over 0.16 s, especially with slurring in the mid-portion of the QRS. 2 V1: QS or rS pattern with a small r wave and a positive T wave. 3 I and V6: a single R wave with its peak after the initial 0.06 s (delayed intrinsicoid deflection). 4 aVR: a QS pattern with a positive T wave. 5 T waves with their polarity usually opposite to the slurred component of the QRS complex. LBBB
  18. 21. Diagnostic criteria 1 QRS complex duration < 0.12 s. 2 ÂQRS deviated to the left (mainly between –45° and –75°). 3 I and aVL: qR, in advanced cases with slurring especially of the descending part of R wave. 4 II, III and aVF: rS with SIII > SII and RII > RIII. 5 S wave seen up to V6. LAHB
  19. 22. Diagnostic criteria 1 QRS complex duration < 0.12 s. 2 ÂQRS shifted to the right (between +90° and +140°). 3 I and aVL: RS or rS pattern. 4 II, III and aVF: qR morphology. 5 Precordial leads: S waves up to V6. Must first exclude (on clinical or other grounds) other causes of right axis deviation such as cor pulmonale, pulmonary heart disease, pulmonary hypertension, etc., because these conditions can result in the identical ECG picture! (A) An example of left posterior hemiblock. (B) The ECG of same patient some days before. The sudden appearance of ÂQRS shifted to the right confirms the diagnosis of LPH LPHB
  20. 23. (A) Right bundle branch block plus left anterior hemiblock and, the following day, (B) right bundle branch block plus left posterior hemiblock
  21. 24. Nonspecific Intraventricular Conduction Defects (IVCD) <ul><li>QRS duration >0.10s indicating slowed conduction in the ventricles </li></ul><ul><li>Criteria for specific bundle branch or fascicular blocks not met </li></ul><ul><li>Causes of nonspecific IVCD's include: </li></ul><ul><li>Ventricular hypertrophy (especially LVH) </li></ul><ul><li>Myocardial infarction (so called periinfarction blocks ) </li></ul><ul><li>Drugs, especially class IA and IC antiarrhythmics (e.g., quinidine, flecainide) </li></ul><ul><li>Hyperkalemia </li></ul>
  22. 26. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders Bradycardias Impulse Conduction Disorders Impulse Formation Disorders
  23. 27. Bradyarrhythmia Classifications Classification Based on Disorder Impulse Formation Disorders Impulse Conduction Disorders <ul><li>Sinus Arrest </li></ul>
  24. 28. <ul><li>Sinus Node emits energy very slowly </li></ul>Sinus Bradycardia
  25. 30. Bradyarrhythmia Classifications Classification Based on Disorder <ul><li>Sinus Arrest </li></ul><ul><li>Exit Block </li></ul><ul><li>Sinus Bradycardia </li></ul><ul><li>Brady/Tachy Syndrome </li></ul><ul><li>1 st Degree AV Block </li></ul><ul><li>2 nd Degree AV Block </li></ul><ul><li>3 rd Degree AV Block </li></ul>Impulse Formation Disorders Impulse Conduction Disorders
  26. 31. <ul><li>Failure of sinus node discharge </li></ul><ul><li>Absence of atrial depolarization </li></ul><ul><li>Periods of asystole </li></ul>Sinus Arrest * Animation
  27. 33. <ul><li>Transient block of impulses from the SA node </li></ul><ul><li>Identified by P-P interval relationship </li></ul>Exit Block
  28. 36. Bradyarrhythmia Classifications <ul><li>S-A Block </li></ul>Classification Based on Disorder <ul><li>Sinus Arrest </li></ul><ul><li>Sinus Bradycardia </li></ul>Impulse Formation Disorders Impulse Conduction Disorders
  29. 38. Bradyarrhythmia Classifications <ul><li>S-A Block </li></ul><ul><li>A-V Block </li></ul><ul><ul><li>1 degree </li></ul></ul><ul><ul><li>2 degree </li></ul></ul><ul><ul><ul><li>Type1 </li></ul></ul></ul><ul><ul><ul><li>Type2 </li></ul></ul></ul><ul><ul><ul><li>2:1 A-V Block </li></ul></ul></ul><ul><ul><ul><li>High degree </li></ul></ul></ul><ul><ul><li>3 degree (complete) </li></ul></ul>Classification Based on Disorder <ul><li>Sinus Arrest </li></ul><ul><li>Sinus Bradycardia </li></ul>Impulse Formation Disorders Impulse Conduction Disorders
  30. 39. Normal or
  31. 40. Or>.12
  32. 54. (A) An example of left anterior hemiblock. (B) SI SII SIII pattern. See in this case SII > SIII and there is S in lead I.

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