Practical Electrocardiography - Rate and Rhythm -

1. Practical Electrocardiography- Rate and Rhythm - Scott E. Ewing, D.O. Cardiology Fellow Lecture #2

2. Review • Electrophysiology • Anatomy • Depolarization • ECG Paper • Lead Placement • Normal ECG • Waves / Intervals / Segments

4. Depolarization

6. ECG Frontal Plane

7. Normal ECG

8. QRS Complex

9. Waveform Review

10. 8-Step Method ECG Interpretation • Rate • Rhythm • Axis • P wave • PR interval • QRS complex • QT interval • ST segment and T wave

11. Rate

12. Rate Determination

14. Rate

15. Rate?

16. Rate?

17. Rate?

18. Rate?

19. Rate?

20. Rhythm • Atrial • Junctional • Ventricular • Pacemaker • Last but not least

21. Normal Sinus Rhythm

22. Normal Sinus Rhythm

23. Sinus Bradycardia

24. Sinus Bradycardia • Pathophysiology • Increased vagal tone in athletes • Inferior wall myocardial infarction • Digitalis glycosides, beta-blockers, calcium channel-blocking agents, class I antiarrhythmic agents, amiodarone • Other drugs, toxins, environmental exposure (lithium, paclitaxel, toluene, dimethyl sulfoxide, topical ophthalmic acetylcholine, fentanyl, reserpine, clonidine) • Electrolyte disorders • Infection (diphtheria, rheumatic fever, viral myocarditis) • Sleep apnea • Hypoglycemia • Hypothyroidism • Hypothermia • Increased intracranial pressure

25. Sinus Bradycardia

26. Sinus Tachycardia

27. Sinus Tachycardia • Pathophysiology • Hypoxia • Hypovolemia / Sepsis • Pain • Fever • Anxiety • Hyperthyroidism • PE • Exercise • Drugs (nicotine, caffeine, atropine, pseudoephedrine, cocaine, methamphetamines, ecstasy)

28. Sinus Tachycardia

29. Sinus Arrhythmia

30. Sinus Pause

31. Wandering Atrial Pacemaker

32. Atrial Tachycardia

33. PAC’s

34. Nonconducted PAC

35. Atrial Bigeminy

36. 1st Degree AV Block

37. 1st Degree AV Block • Pathophysiology • PR interval represents time needed for electrical impulse from sinoatrial node to conduct through the atria, AV node, bundle of His, bundle branches, and Purkinje fibers • PR interval prolongation due to conduction delay within the right atrium, the AV node, or the His-Purkinje system • AV nodal dysfunction accounts for the majority of cases • First-degree AV block caused by conduction delay in the His-Purkinje system often is associated with bundle-branch block

38. 1st Degree AV Block

39. 2nd Degree AV BlockMobitz Type I (Wenckebach)

40. Karel Frederik Wenckebach(1864 – 1940) • 1988 – Doctorate University of Utrecht, Netherlands • 1901-1910 – professor of IM at Groningen, Netherlands • 1911-1914 – professor of IM Strasbourg , France • 1915-1929 – professor of IM Vienna, Austria, retired from his chair 1929 • Early work concerned embryology, later pathology and clinics of heart and circulatory diseases • 1903-1904 – first description of the beneficial effects of quinine alkaloids on arrhythmias and mainly in patients with auricular fibrillation or recent onset • 1905-1906 – second degree AV block independently discovered by English physician John Hay and Wenckebach • 1934 – monograph on beriberi

41. 2nd Degree AV BlockMobitz Type I (Wenckebach) • Pathophysiology • Conduction disturbance in the AV node • Rarely secondary to AV nodal structural abnormalities when the QRS complex is narrow in width and no underlying cardiac disease is present • May be vagally mediated (well-trained athletes, digoxin excess, neurally mediated syncopal syndromes) • Vagally mediated AV block improves with exercise and may occur more commonly during sleep when parasympathetic tone dominates • Cardioactive drugs (digoxin, beta-blockers, calcium channel blockers, and certain antiarrhythmic drugs) • Various inflammatory, infiltrative, metabolic, endocrine, and collagen vascular disorders

42. 2nd Degree AV Block Mobitz Type I

43. 2nd Degree AV Block Mobitz Type I

44. 2nd Degree AV BlockMobitz Type II (Hay) • Intermittent failure of conduction of P waves • PR interval is constant (may be normal or prolonged) • May include wide QRS • May progress to complete third degree AV block

45. 2nd Degree AV Block Mobitz Type II

46. Woldemar Mobitz(1889 – 1951) • Born May 31, 1889 St. Petersburg, Russia, the son of a prominent surgeon • 1908 – gymnasium Meiningen, Saxony • 1914 – doctorate University of Munich • Internship, hospital service, and assistant years in the surgical clinics in Berlin and Halle, and medical clinics Munich and Freiburg • 1924 – first classified second degree AV block into Type I and II • 1928-1943 – professor extraordinary at University of Freiburg in Breisgau • Remained in Magdeburg until it was occupied by the Russian army in 1945 • Suffered from laryngeal tuberculosis until his death April 11, 1951 • Primary interest in cardiovascular circulation and arrhythmias

47. 3rd Degree Heart Block

48. 3rd Degree Heart Block • Pathophysiology • Class Ia antiarrhythmics (eg, quinidine, procainamide, disopyramide) • Class Ic antiarrhythmics (eg, flecainide, encainide, propafenone) • Class II antiarrhythmics (beta-blockers) • Class III antiarrhythmics (eg, amiodarone, sotalol, dofetilide, ibutilide) • Class IV antiarrhythmics (calcium channel blockers) • Digoxin or other cardiac glycosides • Infection • Profound hypervagotonicity • Anterior wall MI • Cardiomyopathy, eg, Lyme carditis and acute rheumatic fever • Metabolic disturbances, eg, severe hyperkalemia

49. 3rd Degree Heart Block

50. 3rd Degree Heart Block