we will see so many ecgs in our daily lifrle..thid is a guide to decode any ecg to make easy diagnosis

1. ELECTROCARDIOGRAMs
(ECGs)
Dr. Renuka R
Asst Professor
General Medicine

2. LEAD PLACEMENT
• Limb Leads - 6 in all
- I, II, III, aVL, aVR, aVF
• Chest leads - 6 in all
-V1,V2,V3,V4,V5,V6
Standard 12-lead ECG:

5. PROCESS

6. PROCESS
SA Node - Heart pacemaker; located in the RA;
initiates next step

7. How to read the ECG
• Look at the whole tracing.
• Rhythm: Is there a P wave before each QRS complex?
− Yes: sinus rhythm No: AV junctional or heart block
• Rate: Count boxes; use caliper, ruler
• PR interval: Normal - 0.20 sec. or less
• QRS complex: Skinny (0.10 sec. or less) or broad (BBB or ventricular)
• ST segment: Isoelectric (normal), elevated or depressed
• T wave: Upright, flat or inverted
• Interpretation: Normal or abnormal.
− Is the rhythm dangerous?

8. “
”
NORMAL ECG
 Rhythm , Rate , Pwave
• PR interval , QRS complex
• ST segment ,T wave:

10. RHYTHM
Normal sinus rhythm:
• Each P wave is followed by a QRS
• Regular or irregular

11. RATE
• P wave rate 60 - 100 bpm with <10% variation - Normal
• Rate < 60 bpm = Sinus Bradycardia
- Results from:
- Excessive vagal stimulation
- SA nodal ischemia (Inferior MI)
• Rate > 100 bpm = Sinus Tachycardia
- Results from:
- Pain / anxiety
- CHF
- Volume depletion
- Pericarditis
- Chronotropic Drugs (Dopamine)

12. RATE
Methods:
• Method 1 = 1500/ # of small boxes between
RR
• Method 2

13. PWAVE
Normal:
• Height < 2.5 mm in lead II
• Width < 0.11 s in lead II

14. PWAVE ABNORMALITY

15. PWAVE ABNORMALITIES
Right atrial hypertrophy:
• A P wave in lead II taller then 2.5 mm
(2.5 small squares)
• The P wave is usually pointed

16. PR INTERVAL
Normal PR interval:
• 0.12 to 0.20 s (3 - 5 small squares)

17. QRS COMPLEX
• QRS Axis
• Normal duration of complex is < 0.12 s (3 small
squares)
• NO pathological Q waves
• NO left or right ventricular hypertrophy

18. AXIS
• Using leads I and aVF, the axis can be
assigned to one of the four quadrants at a
glance

19. AXIS - RIGHT AXIS DEVIATION
• Lead I -ve and aVF +ve = RIGHT AXIS DEVIATION
• Causes:
- Normal finding in children and tall thin adults
- Right ventricular hypertrophy
- Chronic lung disease even without pulmonary
hypertension
- Anterolateral myocardial infarction
- Left posterior hemiblock
- Pulmonary embolus
- Wolff-Parkinson-White syndrome - left sided
accessory pathway
- Atrial septal defect
- Ventricular septal defect

20. WIDE QRS COMPLEX
Right Bundle Branch Block:
• Wide QRS, more than 120 ms (3 small squares)
• Secondary R wave in lead V1 (RSR)
•Other features include slurred S wave in lateral leads
and T wave changes in the septal leads

21. WIDE QRS COMPLEX
Left Bundle Branch Block:
• Wide QRS, more than 120 ms (3 small squares)
• M shape QRS , R’R’

22. RIGHTVENTRICULAR
HYPERTROPHY (RVH)
• Right axis deviation
• Deep S waves in the lateral leads
• A dominant R wave in lead V1

23. LEFTVENTRICULAR
HYPERTROPHY (LVH)
∙ Sokolow + Lyon (Am Heart J, 1949;37:161)
∙ S in V1+ R in V5 or V6 > 35 mm
∙ Cornell criteria (Circulation, 1987;3: 565-72)
∙ S in V3 + R in aVL > 28 mm in men
∙ S in V3 + R in aVL > 20 mm in women
∙ Framingham criteria (Circulation,1990; 81:815-820)
∙ R in aVL > 11mm, R in V4-6 > 25mm
∙ S in V1-3 > 25 mm,
∙ S in V1 or V2 + R in V5 or V6 > 35 mm,
∙ R in I + S in III > 25 mm

24. LVH
• Increased amplitude in height and depth

25. QT INTERVAL
• Calculate the corrected QT interval
- QTc = QT / √RR = 0.42
- Normal = 0.42 s

26. LONG QT INTERVAL
Causes:
• Myocardial infarction, myocarditis, diffuse
myocardial disease
• Hypocalcemia, Hypercalcemia (Short QT),
hypothyrodism
• Subarachnoid hemorrhage, intracerebral
hemorrhage
• Drugs (e.g. Sotalol, Amiodarone)
• Heredity

27. ST SEGMENT
Normal ST segment:
• No elevation or depression

28. ST ELEVATION
Causes of elevation include:
• Acute MI (eg. Anterior, Inferior, Lateral).
• LBBB
• Acute pericarditis
• Normal variants (e.g. athletic heart, high-take off),

29. ACUTE MI
• ST elevation in leads where MI occurs
• Look for reciprocal changes
(e.g. Ant MI look for ST depression in inferior leads)

31. ST DEPRESSION
Causes of depression include:
• Myocardial ischemia
• Digoxin Effect
• Ventricular Hypertrophy
• Acute Posterior MI
• Pulmonary Embolus
• LBBB

32. ACUTE POSTERIOR MI
• The mirror image of acute injury in leads V1 - 3
• (Fully evolved) tall R wave, tall upright T wave in leads
V1 -V3
• Usually associated with inferior and/or lateral wall MI
Mirror Test: Once you have determined an inferior (or other) MI has
occurred, you begin looking for reciprocal changes. If there is ST
depression in V1, V2, and V3, flip the EKG over and hold it up to the
light. Now read those leads flipped over. Are there significant Q
waves? Is the ST segment elevated with a coved appearance? Are
the T waves inverted? Answering yes tells you, there is a posterior
infarct as well.

33. ST DEPRESSION
In diagnosis with ischemia:
• Looking for at least 1mm (1 square)
• This can be
1. Upsloping
2. Horizontal (can be combined w/ 1 or 3)
3. Downsloping

34. TWAVES
• Repolarization of the ventricles is signaled by
the T wave

35. COMMON ARRHYTHMIAS

36. SINUS BRADYCARDIA
• Less than 60 bpm
• If profound, could have decreased cardiac output
• Treatment:
- None if uncomplicated
- Atropine
- Pacing

37. SINUSTACHYCARDIA
• Greater than 100 bpm
• 🡩 Myocardial oxygen demand and may 🡩 coronary
artery perfusion resulting in angina in CAD
• Decreased cardiac output could be exhibited

38. ATRIAL FLUTTER
• Saw toothed pattern; 200-350bpm atrial rate
• Can convert to atrial fibrillation

39. ATRIAL FLUTTER (CONT’D)
• People can feel flutter sensation… if short lived then no
complication; however, with an increased ventricular rate,
people can experience decreased cardiac output.
• Treatment:
- Veramapril, vagal stimulation
- Digoxin (perhaps in combo with other drugs)
- Cardioversion or pacing

40. ATRIAL FIBRILLATION
• Chaotic atrial dysrhythmia; atrial rate can be 350+ bpm
• Higher ventricular response = cardiac output
• Treatment:
- Drugs (Digitalis, Verapamil, Beta blocker)
- Anticoagulation therapy
- Cardioversion

41. PAROXYSMAL ATRIALTACHYCARDIA
OR SUPRAVENTRICULARTACHYCARDIA
• High ventricular rate
• Inadequate ventricular filling time, decreased cardiac output, and
inadequate myocardial perfusion time
• Treatment:
- Prevent CHF
- Carotid sinus massage to stimulate vagal response
- Cardioversion
- Drugs (Verapamil, Propranolol, and Digoxin)

42. MULTIFOCAL ATRIALTACHYCARDIA
• Irregular rhythm with multiple (at least 3) P wave
morphologies in same lead with an irregular and
usually rapid ventricular response.
• Pulmonary disease, hypoxia.
• Rate is greater than 100 bpm.
• Treatment:
- Verapamil
- Resolve causative disorder

43. 1ST DEGREE AV BLOCK
• PR greater than 120 msec
• No hemodynamic complications
• Could progress to higher AV blocks

44. 2ND DEGREE AV BLOCK MOBITZ
TYPE 1 (WENCKEBACH)
• PR interval progressively lengthens with each beat until it is
completely blocked
• If bradycardic, could have decreased cardiac output
• Treatment:
- Only if brady (Atropine)
- Rare pacemaker

45. 2ND DEGREE AV BLOCK MOBITZ
TYPE 2
• Rare, occurs with large ant MI
• PR interval fixed and p waves occur in a regular ratio to QRS
(atrial rate is regular) until conduction is blocked

46. • Symptoms of decreased cardiac output occur with
slowing ventricular rate
- Could progress to complete block
• Treatment:
- Atropine initially
- Permanent pacemaker
2ND DEGREE AV BLOCK MOBITZ
TYPE 2 (CONT’D)

47. 3RD DEGREE AV BLOCK
(COMPLETE)
• Atria and ventricles are independent of each other;
no relationship present
• Symptoms could include lightheadedness or syncope from
decreased rate

48. 3RD DEGREE AV BLOCK
(COMPLETE) (CONT’D)
• Decreased cardiac output, compromised
coronary perfusion
• Treatment:
- Emergency
- Atropine
- Pacemaker

49. PREMATUREVENTRICULAR
CONTRACTION (PVC)
• Occasional PVC’s have minimal consequences
• Increased frequency or multifocal PVCs can lead to
ventricular tachycardia
• Make sure it does not progress to more PVCs
• Couplet is 2 PVCs in a row
• Triplet is 3 PVCs in a row

50. VENTRICULAR BIGEMINY
• Premature Ventricular contraction (PVC) in a bigeminal pattern
• Can be trigeminy (every third is a PVC), quadrigeminy
• Can be multifocal - increased irritability of the ventricle could
lead to more severe dysrhythmia

51. VENTRICULARTACHYCARDIA (VT)
•More than 3 PVC’s in a row > 100bpm
• Wide QRS, AV dissociation, QRS complex does not
resemble typical bundle branch block
• Irritable ventricle
• Sustained VT is an emergency rhythm and could
convert to ventricular fibrillation

52. VT
• Decreased cardiac output , irritable ventricle
• Treatment:
- Cardioversion
- Lidocaine or Procainamide to get NSR
- Emergent care
- Long term care: ICD (implantable
cardioverter defibrillator)

53. TORSADES DE POINTES
• Form of VT – “twisting of the points”
• People with prolonged QT interval are susceptible

54. VENTRICULAR FIBRILLATION
• Chaotic activity of the ventricles
• No effective cardiac output or coronary perfusion
• Associated with severe myocardial ischemia.
• Life-threatening - death occurs within 4 min.
• Treatment:
- Immediate defibrillation
- CPR
- Lidocaine, bretylium. epinephrine

59. THANKYOU