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Generation of action potential PowerPoint Presentation
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Generation of action potential

Generation of action potential

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Generation of action potential

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  1. Generation of action potential

  2. ECG Graph paper

  3. Unipolar precordial leads

  4. Normal ECG

  5. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  6. Standardization Heart rate 60 - 100 beats/min bradycardia < 60 tachycardia > 100 PR interval 0.12 – 0.20 sec QRS < 0.12 sec QRS axis - 30º to + 110º QTc < 0.47 sec males < 0.48 sec females

  7. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  8. Rhythm SA node – sinus AV node – junctional Ventricular rhythm

  9. Rhythm Are there p waves?  sinus, atrial fibrillation Do they look similar?  MFAT, wandering pacemaker Are they regular?  AF Does a QRS complex follow each p wave?  SVT, junctional rhythm, ventricular rhythm

  10. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  11. Determination of Heart Rate Heart rate assessment by “rule of 300”

  12. Measurement of Rate Formula 1: 300 # big squares between R-R Formula 2: 1500 # small squares between R-R

  13. Determination of Heart Rate Is the atrial rate same as ventricular rate? PVC’s, PAC’s, 3rd degree AV block Is there normal-looking QRS complex after each p wave? What if there are no p waves? Six second strip heart rate

  14. RATE • Sinus Bradycardia • Sinus Tachycardia • AV junctional rhythm • Inherent rate of 40-60/min • No p waves • Normal looking QRS complex • Ventricular rhythm • Inherent rate of 20-40/min • No p waves • Bizaare-looking QRS complex

  15. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  16. Determination of Axis Hexaxial System

  17. QRS axis

  18. Vectorial Analysis

  19. Determination of Axis Axis = 90 x QRS in AVF QRS in [ I] + QRS in [AVF] Special cases: negative QRS deflection in I Add 90 to result

  20. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  21. P wave morphology and duration No p waves Atrial fibrillation Multiple p waves Multifocal atrial tachycardia Wandering pacemaker Notched p wave Left atrial enlargement Peaked p wave Right atrial enlargement

  22. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  23. P-R Interval

  24. P-R interval Prolongation Hypokalemia 1st degree AV block Shortening Wolff-Parkinson White

  25. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  26. QRS morphology and duration Normal looking Supraventricular origin Bizarre looking Ventricular in origin Paced rhythm

  27. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  28. ST segment Elevation Infarction >1mm in limb leads >2 mm in chest leads depression Ischemia >1 mm in all leads from the J point

  29. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  30. T and U waves T wave Hypokalemia 1st degree AV block Shortening Wolff-Parkinson White

  31. Guide in Reading ECG Standardization & technique Rhythm Rate: atrial & ventricular Axis P wave morphology & duration P-R interval QRS complex morphology & duration ST segment T-wave U wave Q-T interval Hypertrophy and enlargement arrhythmias

  32. Determination of QT interval Corrected QT interval = QT (actual) R-R

  33. QT interval prolongation hypocalcemia shortening hypercalcemia

  34. Chamber Enlargement

  35. Atrial Enlargement (due to chronic lung disease or pulmonay embolus

  36. Atrial Enlargement (commonly seen in mitral valve disease) B V1 II V1

  37. Ventricular Enlargement

  38. Ventricular Enlargement Right Ventricular Hypertrophy R in V1 + S in V5-V6 >11 mm R in V1 >7mm R:S in V1 >1 RAD > +90 degrees

  39. Ischemic Heart Disease

  40. Anatomy of Myocardial Infarction *LAD = left anterior descending aretery; LCX = left circumflex artery LM = left main artery; PDA = posterior descending artery; PL = posterolateral branches

  41. Evolution of Infarct ST segment elevation Progressive decrease in ST segment elevation Q wave formation T wave flattening/inversion Q wave with upright T wave

  42. Significant Q wave

  43. RULES on Q waves • Not significant in aVR • Ignored in V1 unless with abnormalities in other precordial leads • Ignored in III unless with abnormalities in II, AVFmore reliable if with St-T segment changes • Not significant if located in V1-V3 in LBBB • Significant in V1-V2 in the presence of RBBB • Pathologic if >= 0.04 sec and >25% of R wave amplitude

  44. RHYTHM DISORDERS