How to read 12 lead ECG


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How to read 12 lead ECG

  1. 1. How to read ECG PG corner
  2. 2. Mr do not Miss  Lead reversal and ECG artefacts
  3. 3. Technology does not understood science of ECG  Do not believe in COMPUTERIZED ECG INTERPRETATIONS
  4. 4. At least 14 observations before answering
  5. 5. Standardizati on  Usual 1 mV = 10 mm  In special cases ECG may be intentionally recorded at one-half standardization (1 mV =5mm) or two times normal standardization (1 mV = 20 mm). However, overlooking this change in gain may lead to the mistaken diagnosis of low or high voltage.
  6. 6. Rhythm  Sinus rhythm  bradycardia or tachycardia  SR with APBs orVPBs  SR with AV block  Nonsinus:PSVT),Afib or flutter,VT and AV junctional escape
  7. 7. Sinus rhythm  Discrete P waves that are always positive (upright) in lead II (and negative in aVR
  8. 8. Heart Rate  Normally, the ventricular (QRS) rate and atrial (P) rates are the same (1:1 AV conduction)  Tachycardia >100  Bradycardia <60  Irregular  Regularly irregular :Wenchebach’s  Irregularly irregular :Fib
  9. 9. PR Interval  The normal PR interval (measured from the beginning of the P wave to the beginning of the QRS complex) is 0.12 to 0.2 sec  First-degree AV block  A short PR interval with sinus rhythm and with a wide QRS complex and a delta wave is seen in theWolff-Parkinson-White (WPW) pattern  A short PR interval with retrograde P waves (negative in lead II) generally indicates an ectopic (atrial or AV junctional) pacemaker.
  10. 10. P wave  Normal not exceed 2.5 mm in amplitude and is less than 3 mm (120 ms) wide in all leads  Tall, peaked P waves may be a sign of right atrial overload (P pulmonale)  Wide (and sometimes notched P) waves are seen with left atrial abnormality.
  11. 11. QRS Interval  0.1 sec (100 ms) or less, measured by eye  110 ms if measured by computer
  12. 12. QT/QTc Interval  Shortened :hyperkalaemia and digitalis effect  Prolonged:hypocalcemia or hypokalemia, drug effects (quinidine, procainamide, amiodarone, or sotalol), or myocardial ischemia
  13. 13. QRSVoltage  Stick to criteria for Normal /LVH/RVH
  14. 14. QRS Axis  Frontal plane  Normal: −30° to +100°
  15. 15. R wave progression  Inspect leadsV1 toV6  Normal increase in R/S ratio occurs as you move across the chest  Poor: (small or absent R waves in leadsV1 toV3)  AWMI  The term reversed R wave progression  Tall R waves in leadV1 that progressively decrease in amplitude:RVH, posterior (or posterolateral) infarction, and dextrocardia
  16. 16. Q,T,U Document changes
  17. 17. UWave  U Waves Look for prominent U waves.These waves, usually most apparent in chest leadsV2-V4, may be a sign of hypokalemia or drug effect or toxicity (e.g., ami-odarone ami-odarone, dofetilide, quinidine, or sotalol).
  18. 18. Normal frontal loop: 1.q in II/III/aVF 2.No q in I/AVL
  19. 19. Counter clock loop in frontal plane: 1.q inAVL 2.No q in II/III/AVF
  20. 20. (1) standardization—10 mm/mV; 25 mm/sec (2) rhythm—normal sinus (3) heart rate—75 beats/min (4) PR interval—0.16 sec (5) P waves—normal size (6) QRS width—0.08 sec (normal) (7) QT interval—0.4 sec (slightly prolonged for rate) (8) QRS voltage—normal (9) QRS axis—about 30° (biphasic QRS complex in lead II with positive QRS complex in lead I) (10) R wave progression:early precordial transition with relatively tall R wave in lead V2 (11) abnormal Q waves—leads II, III, and aVF (12) ST segments: elevated in leads II, III, aVF,V4,V5, andV6 slightly depressed in leads V1 and V2 (13)T waves—inverted in leads II, III, aVF, andV3 throughV6 (14) U waves—not prominent. Impression:This ECG is consistent with an inferolateral (or infero-posterolateral) wall myocardial infarction of indeterminate age, possibly recent or evolving. Comment:The relatively tall R wave in lead V2 could reflect loss of lateral potentials or actual posterior wall involvement EXAMPLE
  21. 21. Calcium and 12 Lead ECG
  22. 22. What ECG findings may be present in pulmonary embolus?  Sinus tachycardia (the most common ECG finding)  Right atrial enlargement (P pulmonale)—tall P waves in the inferior leads  Right axis deviation  T wave inversions in leadsV1-V2  Incomplete right bundle branch block (IRBBB)  S1Q3T3 pattern—an S wave in lead I, a Q wave in lead III, and an invertedT wave in lead III.Although this is only occasionally seen with pulmonary embolus, it is quite suggestive that a pulmonary embolus has occurred.
  23. 23. I can only give you hint because I know less