Basic Ecg

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Basic Ecg

  1. 1. BASIC ECG WORKSHOP FOR PARAMEDIC Dr. Rashidi Ahmad MD USM, MMED USM, FADUSM Lecturer/Emergentist Dept. of Emergency Medicine School of Medical Sciences USM Health Campus Kelantan, Peninsular of Malaysia
  2. 2. What is an ECG? • An ECG is a method of measuring, displaying and recording the electrical activity of a heart • Electrical stimuli is amplified to create a “rhythm strip” by a machine that consistently produces representations of the heart’s electrical activity
  3. 3. 1st ECG machine - 1920
  4. 4. Indications • ECG is used as a baseline and screening test for CAD, cardiomyopathies, or left ventricular hypertrophy • Preoperatively, TRO silent coronary artery disease. • To detect metabolic alterations • To evaluate patients with chest pain and in the management of patients with suspected or known ACS. • To demonstrate ECG abnormalities in patients with myocardial, valvular, and congenital heart disease will eventually demonstrate. • To evaluate rhythm disorders
  5. 5. EKG Precordial Leads
  6. 6. Vertical and horizontal perspective of the ECG Leads Leads Anatomical II, III, aVF Inferior surface of heart V1 to V4 Anterior surface of heart I, aVL, V5, and V6 Lateral surface of heart V1 and aVR Right atrium
  7. 7. • Electrical impulse traveling directly towards the electrode produces an upright (“positive”) deflection relative to the isoelectric baseline
  8. 8. Components of a NSR
  9. 9. How to Read an EKG Strip
  10. 10. Electrocardiographic diagnosis • Rate of waves • Rhythm of waves • Sequence of the waves in one cardiac cycle • Presence or absence of waves within each cardiac cycle • Duration of the waves • Distance between waves in one cardiac cycle • Configuration of waves
  11. 11. Sequence of reading ECG • Identify P, QRS and T • Rate • Rhythm • P wave • PR interval • QRS complex • ST segment • T wave • QT interval • U wave • Morphological changes
  12. 12. Identify P, QRS and T
  13. 13. Rate determination • Method I - Times Ten - Simplest, quickest, most commonly used technique that is particularly useful if the rhythm is irregular. • Method II – 1500 or 300 Method - Use only if cardiac rhythm is regular. • If P & QRS are independent – calculate atrial rate & ventricular rate separately
  14. 14. Determine the rate
  15. 15. Rhythm Regular, irregular, irregularly irregular
  16. 16. P wave • P waves usually precede each QRS complex • < 3 small squares in duration • < 2.5 small squares in amplitude • Commonly biphasic in lead V1 • Best seen in leads II
  17. 17. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 The P waves should be upright in I, II, and V2 to V6 & negative in lead aVR
  18. 18. More P waves than QRS complex P waves entirely absent
  19. 19. QRS complex without P wave in front of them Abnormal P wave configuration
  20. 20. PR interval
  21. 21. 1.0 R PR interval 0.5 T PR interval should be Millivolts P 0.12-0.20s or 3 to 5 little Q 0 squares -0.5 S 0 200 400 600 Milliseconds
  22. 22. QRS Complex
  23. 23. 1.0 R 0.5 The width of the QRS Millivolts T P complex should not exceed 0 Q 0.12s or less than 3 little squares -0.5 S QRS 0 200 400 600 Milliseconds
  24. 24. I II III aVR aVL aVF The QRS complex should be dominantly upright in leads I and II
  25. 25. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 Non-pathological Q waves: < 2 small squares deep, < 1 small square wide, < 25% of the amplitude of the corresponding R wave There should be no Q wave or only a small q in I, II, V2 to V6
  26. 26. V6 V5 V4 V3 V2 V1 The height of the R wave: variable & increases progressively across the precordial leads; < 27 mm in leads V5 and V6 The R wave in lead V6,is often smaller than the R wave in V5
  27. 27. S wave • S wave - Deepest in the right precordial leads • Decreases in amplitude across the precordium, and is often absent in leads V5 and V6 • The depth of the S wave should not exceed 30 mm in a normal individual
  28. 28. Which one are normal, RBB, LBB?
  29. 29. ST Segment • Normal ST Segment is flat (isoelectric) • Elevation or depression of ST segment by 1 mm or more, measured 0.08 s (or 2 small squares) past the J point is ABNORMAL
  30. 30. J point or a point up to 40 msec (one small square) beyond the J point were the favoured points of measurement.
  31. 31. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 The ST segment should start isoelectric except in V1 and V2 where it may be elevated
  32. 32. “Non-specific T and ST changes” • T-wave flattening: • T-wave inversion: • ST-segment scooping: •ST-segment depression
  33. 33. T wave • Asymmetrical: first half has a more gradual slope than second half • < than 2/3 of R amplitude • T wave amplitude rarely exceeds 10 mm
  34. 34. I II III aVR aVL aVF T and QRS tend to have the same general direction in the limb leads
  35. 35. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 The T wave must be upright in I, II, V2 to V6
  36. 36. Hyperacute T wave - Earliest change of AMI - Lasting only 5- 30 minutes from onset of pain
  37. 37. QT interval • QT interval decreases when heart rate increases • QT interval should be 0.35- 0.45 s, and should not be more than half of the interval between adjacent R waves (R-R interval).
  38. 38. U wave • Normal U waves are small, round, symmetrical and positive in lead II, with amplitude < 2 mm (amplitude is usually < 1/3 T wave amplitude in same lead) • U wave direction is the same as T wave direction in that lead • More prominent at slow heart rates and usually best seen in the right precordial leads.
  39. 39. Summary
  40. 40. Sequence of reading ECG • Identify P, QRS and T • Rate • Rhythm • P wave • PR interval • QRS complex • ST segment • T wave • QT interval • U wave • Morphological changes
  41. 41. Electrocardiographic diagnosis • Rate of waves • Rhythm of waves • Sequence of the waves in one cardiac cycle • Presence or absence of waves within each cardiac cycle • Duration of the waves • Distance between waves in one cardiac cycle • Configuration of waves
  42. 42. Dr. Rashidi Ahmad MD USM, MMED USM, FADUSM Pensyarah/Pakar Perubatan kecemasan Pusat Pengajian Sains Perubatan USM Kampus Kesihatan, Malaysia shidee_ahmad@yahoo.com +609 7663244

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