ECG Tutorial: Rhythm Recognition

1. ECG Tutorial: Rhythm Recognition • Review – the systematic approach • Rhythm – the hardest part! • Again – be systematic • Mind your p’s & q’s & follow the rules! • The Approach – Tachy –vs- Brady • Examples • Quiz

2. ECG Tutorial: Rhythm Recognition • My systematic approach: • Rate • Rhythm • Axis • Intervals (PR, QRS, QTc) • Blocks / Hypertrophy / Enlargement • Segments (PR, ST) • Waves (Q-waves, T-waves) • Ectopy • Compare to old ECG

3. Rhythm Recognition • Golden rule: mind your ‘p’s (& ‘q’s’) • Step I – Is it fast or slow? • Tachycardia = >100 • Bradycardia = < 60 • Step II – Is it sinus rhythm or not? • 2 questions (rules): • ‘p’ with every QRS complex? • Upright ‘p’ in I, II & aVF? • Yes to BOTH = sinus origin (nice job!)

4. Rhythm : Is there a p wave? = Sinus Is it followed by a QRS?

5. PR QRS AH HV How does the heart work

6. Is the rhythm regular or irregular?

7. Tachycardias: The ‘Down & Dirty’ • Common • Need to recognize the ‘bad boys’! • ACLS, etc… • 2 questions • Is the QRS narrow (<=0.12 second or 2.5 small boxes) or wide? • “Wide complex Tachycardia”-vs-“Narrow Complex Tachycardia” • Is the rhythm regular or irregular?

8. Normal Sinus Rhythm; Rate = 75

9. Sinus Arrythmia • Typically a normal finding – esp. in younger, fit individuals • Due to changes in autonomic tone during inspiration

10. Tachycardias: DDx(Rule of 3’s!) • Narrow Complex & Regular: • Sinus Tachycardia • Atrial Flutter • Other supraventricular Tachycardia (SVT) • AVNRT (A-V nodal reentrant tachycardias) • Atrial reciprocating tachycardia (from pre-excitation, ex: WPW) • Ectopic atrial tachycardia • Other uncommon causes

12. Physiologic (#1) Response to exercise Stress, anger, etc.. (‘fight or flight’) Other causes: Fever Hyperthyroidism Effective volume depletion, hypotension Sepsis, Shock Anemia PE CHF Drugs (stimulants) Drug withdrawal (ETOH) Pheochromocytoma Sinus Tachycardia…but why?

13. Atrial Flutter – characteristics?

14. Atrial Flutter – characteristics?

15. Suspect A-flutter: • Narrow complex tachycardia • ‘F’ (flutter waves) = rate of 300 (“sawtooth”) • Ventricular rate = 150 bpm

16. Atrial Flutter – what is happening in the heart!

18. Other Narrow Complex Tachycardiaa - AVNRT Premature Atrial Complex (PAC) NSR • Regular, Narrow-complex tachycardia w/rate: 120-220 • ‘p’ buried or after QRS (usually) & inverted (retrograde) in leads I, II & aVF • Most common non-fib/flutter SVT

19. AVNRT

20. Ectopic Atrial Tachycardia • Regular narrow complex tachycardia • Originates outside of the AV node • Constant ‘p’ wave morphology • Constant P-R intervals • Use the “rule of sinus rhythm” & mind your ‘p’s’

21. Ectopic atrial tachycardia

22. Ectopic atrial tachycardia:Can occur with block (ie-digoxin toxicity)

23. Tachycardias: DDx • Narrow Complex &IR-regular: • Atrial Fibrillation (“irregularly irregular”) • Atrial Flutter with variable A-V block • MAT (Multifocal Atrial Tachycardia) • Other Supraventricular tachycardias with variable AV block

26. Atrial Fibrillation • The most common arrythmia in older patients • ECG: • Absent ‘p’-waves • “fibrillatory waves” – vary in appearance • Irregularly irregular R-R intervals • Typically narrow complex QRS (unless aberrant conduction) • Bundle Branch Blocks / other blocks • Re-entry (WPW) • Rate > 100 = “rapid ventricular response” (RVR)

27. Remember this? A-flutter with variable AV-block

28. MAT – Multifocal Atrial Tachycardia • Narrow complex, irregularly irregular • You’re thinking A-fib, but… • You see clearly conducted ‘p’-waves • ‘p’-waves are not all the same • You see 3 different ‘p’-wave morphologies • “Multifocal” • Varying P-P & R-R intervals • Associated with lung disease (COPD), theophylline, hypertension, etc…

29. MAT

30. Regular: Sinus Tachycardia Atrial Flutter Other “SVT” AVNRT (A-V nodal reentrant tachycardias) Atrial reciprocating tachycardia (from pre-excitation, ex: WPW) Ectopic atrial tachycardia Others (uncommon) IR-regular: Atrial Fibrillation (“irregularly irregular”) Atrial Flutter with variable A-V block MAT (Multifocal Atrial Tachycardia) Others Narrow Complex Tachycardias - Review

31. Doctor…come quick!

32. Wide Complex Tachycardias (WCT) • A Big Deal…may require emergent treatment! • A limited Differential Diagnosis • Ventricular Tachycardia (VT) • NOT Ventricular Tachycardia: • SVT w/aberrant conduction (Aberrancy) • SVT w/pre-excitation (ie-WPW) • What is “aberrancy”? • Assume Ventricular Tachycardia until proven otherwise • Esp. in a patient over 40 years old

33. Doctor, hurry up & read that EKG…

34. Wide Complex Tachycardia • Rate > 100 bpm • QRS duration > 0.12 seconds • Again • Regular –vs- Irregular

35. Wide Complex Tachycardia • Regular • Ventricular Tachycardia • A REGULAR SVT w/Aberrant conduction • Sinus tachycardia • A-flutter • AVNRT • Atrial Tachycardia

36. Wide Complex Tachycardia • IR-Regular • Ventricular Fibrillation • An IR-Regular SVT w/Aberrant conduction • Atrial fibrillation • Aflutter with variable AV block • MAT • Special Case: WPW & A-fib

39. V-Tach –vs- SVT w/Aberrancy • Assume V-T until proven otherwise • Treatment for SVT can kill a patient in VT • Treatment for VT usually won’t kill a patient in SVT • Criteria – Brugada, others (beyond our scope) • AV dissociation, increased age, CV risk factors = VT • Fusion / Dresler beats = VT

41. Wide, Fast & Irregularly, Irregular = WPW (usually) Special Treatment

42. This patients resting EKG after you cardiovert him…

43. Bradyarrythmias • I. Pauses • #1 cause of a pause is a non-conducted PAC • II. Early, weird-looking beats: PVC –vs- PAC • PVC • Wide complex • Compensatory pause • PAC • Narrow, no compensatory pause

44. Bradyarrythmias • I. Problem is sinus or at the AV node • Sinus: • Sinus bradycardia • Sinus Arrest • AV Node: • 1st Degree AV block • 2nd Degree • Mobitz I (Wenkebach) • Mobitz II • 3rd Degree AVB

45. 2nd degree Mobitz I (Wenkebach) • lengthening PR interval…then…dropped beat • “Group Beating” = Wenkeback until proven otherwise • Block at AV node • Normal in young patients (high vagal tone) • Think Meds (B-blockers, CCBs)

46. 2nd degree Mobitz II • Constant PR interval…then dropped beat • Block always BELOW AV node (more serious) • Never normal • Likely needs a pacemaker

47. 3rd degree (complete) heart block • A-V dissociation is present • ‘p’ waves “march” out • Atrial rate > ventricular rate** • “Escape” rhythm • Clinical settings • Likely needs a pacemaker

48. Summary • Follow the rules – be systematic • Tachycardia • Narrow or Wide • Regular or Irregular • Bradycardia • Mind your ‘p’s’ • Know the basics • Questions • Now, let’s do some examples