1. ECG monitoring

2. Introduction to the E.C.G.
Noble prize – Einthoven for discovery of EKG
It can provide evidence to support a diagnosis, but remember…..LOOK AT THE PATIENT NOT JUST THE PAPER or Monitor
Is essential in the diagnosis of chest pain and abnormal heart rhythms
Is helpful in diagnosing breathlessness
Italian realized , irish analysed , william credited for

3. Principles of Electrocardiograph
MAKING ECGS EASY - CDOCKX
Principles of Electrocardiograph
Electrocardiograph – is the instrument that records the electrical activity of the heart
Electrocardiogram (ECG) is the record of that activity
It works on the principle of Galvanometer

4. In the perioperative setting, electrocardiography serves two main functions: diagnosis and monitoring.
In the preoperative period, the standard 12-lead ECG is performed mainly for risk assessment. It is used to provide information on the patient's baseline (chronic) cardiac status with regard to myocardial ischemia and conduction or rhythm abnormalities as part of the whole preoperative clinical assessment.
During and after surgery the ECG is used mainly for monitoring to detect changes in rate and rhythm or myocardial ischemia

6. Waveforms & Intervals

7. Segments and Intervals
Segment – Straight line b/w waves
Interval – wave + segment
ST segment – end of ventricular depolarization to start of vent. repolarization
QT interval – QRS complex + ST segment + T wave ventricular cycle, 40% of each cardiac cycle

8. ECG Graph Paper Runs at a paper speed of 25 mm/sec
Each small block of ECG paper is 1 mm2
At speed of 25 mm/s, 1 small block = 0.04 s
5 small blocks make up 1 large block = 0.20 s
Hence, there are 5 large blocks/sec
Voltage: 1 mm = 0.1 mV between each individual block vertically

10. ECG MONITORING SYSTEMS
Three electrode monitoring system
Five electrode monitoring system
Ten electrode,twelve lead monitoring system.

11. The three-electrode system :simplest and most common mode .
Monitoring of three bipolar leads by recording the potential difference between each of three pairs of electrodes: lead I , lead II, lead III, or other modified chest leads.
ADVANTAGE: -good enough to track the heart rate,
- detect R waves for synchronized direct-current (DC)
shock in cardioversion
-and detect ventricular fibrillation.
DISADVANTAGE: Inadequate for diagnosing more complex arrhythmias, such as distinguishing between RBBB and left bundle-branch block (LBBB) or between ventricular tachycardia (VT) and supraventricular tachycardia (SVT).
Inadequate for ST-segment monitoring thus NOT sensitive for detecting ischemia.

12. Five-electrode monitoring system, the four limb electrodes, LA, RA, LL, and RL placed at their corresponding monitoring locations, allow any of the six limb leads to be obtained (leads I, II, III, aVR, aVL, and aVF), and a fifth chest electrode can be placed in any of the standard V1 through V6 locations .
V1 is the preferred lead for special arrhythmia monitoring,
The other precordial leads, especially V3 to V5, are the preferred leads for ischemia monitoring. The five-electrode monitoring system is currently the standard for monitoring patients with suspected perioperative myocardial ischemia.

13. TWELVE LEAD ECG MONITORING:
The RA and LA electrodes were attached to the right and left infraclavicular fossae, and the LL electrode was attached to the left iliac fossa. The RL electrode usually placed on the right iliac fossa along with 6 precordial leads.
ADVANTAGE:
ST-segment monitoring software has been developed to analyze all 12 leads and to sound an alarm for ST-segment changes. Therefore, if lead II is being displayed but the patient has a transient ischemic event involving lead V5, an ST alarm would be triggered.

14. ECG interpretation :step-by-step
Rate
Rhythm
Cardiac Axis
P – wave
PR - interval
QRS Complex
ST Segment
QT interval (T & U wave)
Other ECG signs

15. RATE

16. lead II - rhythm strip. Look at # (squares) b/w one R-R interval.
CALCULATING RATE
lead II - rhythm strip. Look at # (squares) b/w one R-R interval.
300
Rate =
number of BIG SQUARE b/w R-R OR
1500
Rate =
number of SMALL SQUARE b/w R-R

17. CALCULATING RATE Eg 300 1500 Rate = Rate = 3 15or
Rate = 3 15
Rate = 100 beats/minute

18. Rhythm

19. RHYTHM
P -QRS relationships- Lead II is commonly used Regular or irregular? Ventricular rhythm –measured by R-R interval &
Atrial rhythm - measured P-P interval.

20. P wave is upright in leads I and II
RHYTHM
Normal Sinus Rhythm
ECG rhythm -usual rate b/w bpm, every P wave must be followed by a QRS & every QRS is preceded by P wave.
P wave is upright in leads I and II

21. Axis

22. AXIS
Axis refers to general direction of heart's depolarization wave front (or mean electrical vector) in the frontal plane.
In healthy conducting system - axis is related to where the major muscle bulk of heart lies.
Electrical impulse that travels towards the electrode produces an upright (positive) deflection (of the QRS complex) relative to the isoelectric baseline. One that travels away produces negative deflection. And one that travels at a right angle to the lead, produces a biphasic wave.

23. Leads were based on Einthoven triangle and associated with limb leads.
AXIS
Leads were based on Einthoven triangle and associated with limb leads.
Leads put heart in middle of this triangle.
Lead I, II and III are bipolar leads. Lead aVR, aVL and aVF are augmented leads, V1-V6 are chest leads

24. Einthoven triangle

26. AXIS
Electrical impulse that travels towards the electrode produces an upright (positive) deflection (of the QRS complex) relative to the isoelectric baseline. One that travels away produces negative deflection. And one that travels at a right angle to the lead, produces a biphasic wave.

27. Basics of 12 Lead ECG's Determining AXIS
Technique : Two Lead Method Uses just 2 leads of the 6 limb leads Look at Lead I & aVF

28. AXIS
1. Lead I & aVF divide thorax into quadrants, (Lt, N , Rt, No Man's) 2. If Lead I & aVF are both upright- Axis is normal. 3. If lead I is upright & lead aVF is downward - Axis is Left.

29. AXIS
4. If lead aVF is upright & lead I is downward - Axis is Rt 5. If both leads are downward - Axis is extreme Right Shoulder & most often is Vent. Tachy
. If both leads are downward - Axis is extreme Right Shoulder & most often is Vent. Tachy

30. CARDIAC AXIS

31. CARDIAC AXIS
Positive
Positive
N Axis

32. CARDIAC AXIS

33. CARDIAC AXIS
Positive
Negative
LAD

34. CARDIAC AXIS

35. CARDIAC AXIS
Negative
Positive
RAD

36. P Wave

37. Depolarization of both atria
P Wave
Depolarization of both atria
Relationship b/w P & QRS - distinguish various arrhythmias
Shape & duration of P - indicate atrial enlargement
May indicate atrial

42. <3 small sqs - duration <2.5 small sqs - amplitude
P Wave
Always +ve in lead I & II
Always -ve in lead aVR
<3 small sqs - duration
<2.5 small sqs - amplitude
Best seen in lead II
Atrial depolarisation
Electrically both atria act almost as one.
They have relatively little muscle and generate a single, small P wave.
P wave amplitude rarely exceeds two and a half small squares (0.25 mV).
The duration of the P wave should not exceed three small squares (0.12 s).
The wave of depolarisation is directed inferiorly and towards the left, and thus the P wave tends to be upright in leads I and II and inverted in lead aVR.
Sinus P waves are usually most prominently seen in leads II and V1.
A negative P wave in lead I may be due to incorrect recording of the electrocardiogram (that is, with transposition of the left and right arm electrodes), dextrocardia, or abnormal atrial rhythms.
Normal P waves may have a slight notch, particularly in the precordial (chest) leads. Bifid P waves result from slight asynchrony between right and left atrial depolarisation.
A pronounced notch with a peak­to­peak interval of > 1 mm (0.04 s) is usually pathological, and is seen in association with a left atrial abnormality—for example, in mitral stenosis. 42

43. P Pulmonale
P MITRALE

44. PR Interval

45. Onset of P wave to onset of QRS Normal = 0.12 - 2.0 sec
PR INTERVAL
Onset of P wave to onset of QRS
Normal = sec
Represents A to V conduction time (via bundle of hiss)
Prolonged PR interval indicate AV block
A long PR interval- first degree heart block, hypokalemia, acute rheumatic fever, or carditis associated with Lyme disease.

47. QRS Complex

48. Ventricular depolarization Is d/t contraction of Ventricular mass
QRS COMPLEX
Ventricular depolarization
Is d/t contraction of Ventricular mass
Normal duration = secs
Q wave >25% the height of R wave or >0.04 sec is abnormal; may represent MI
Its duration, amplitude, & morphology – indicates arrhythmias, LVH/RVH, MI, electrolyte derangement.

49. QRS complex
Poor R Wave Progression in V1 to V6: suggests prior anterior MI Pathologic Q wave: previous MI. Q wave amplitude 25% or more of the subsequent R wave, OR > 0.04 s in width + > 2 mm in amplitude in more than one lead
Is there good R wave progression?
Normal R wave progression: around V3 or V4, QRS transitions from predominately negative to predominately positive and R/S ratio becomes>1.
Poor R wave progression suggests anterior MI, but not diagnostic
Are Q waves present, suggestive of infarction?

51. ST Segment

52. Connects QRS complex & T wave Duration = 0.08 - 0.12 sec
ST Segment
Connects QRS complex & T wave
Duration = sec
Interval from beginning of QRS to apex of T is referred to as the Absolute Refractory Period

54. T Wave
“small to moderate” size +ve deflection wave after QRS complex,( s)
It is 1/3rd - 2/3rd that of corresponding R wave
Septal repolarization (not always seen on ECG)
U Wave

56. Beginning of QRS to end of T wave Normal QT is usually about 0.40 sec
QT Interval
Beginning of QRS to end of T wave
Normal QT is usually about 0.40 sec
QT variations are based on HR- faster HR ,shorter QT .
Hence QTc.
  QTC = QT / √ RR interval
The normal male is < or = to 430. female is < or = 450.The borderline QTC for a male is and borderline QTC for a female is The abnormal QTC range for a male is > 450 and for a female is > 470.

57. Hypertrophy RVH: V1 R/S ratio >1 or V6 S/R ratio >1.
LVH: S in V1 or V2 + R in V5 or V6 ≥ 35 mm.
Hypertrophy – LVH: S wave in V1 or V2 + R wave in V5 or V6 ≥ 35 mm. RVH: V1 R/S ratio >1 or V6 S/R ratio >1. There are many other different criteria that can be used. These are the simplest.
RVH: V1 R/S ratio >1 or V6 S/R ratio >1.

58. The electrocardiographic manifestation of RBBB consists of prominent and notched R waves with rsr′, rsR′, or rSR′ on the right-sided leads and wide S waves on the left-sided leads, along with QRS prolongation (≥120 msec).
LBBB prolonged QRS duration(>120ms), abnormal QRS complex, and ST-T wave abnormalities. There is also a broad, sometimes notched R wave in the left-sided leads (I, aVL, V5, V6) with deep S waves in the right precordial leads and absent septal Q waves.

59. ACUTE ST SEGMENT DEPRESSION

60. Acute ST Elevation Inferior MI

61. Atrial Flutter

62. Atrial Fibrillation

63. HEART BLOCKS

65. VENTRICULAR FIBRILLATION
Ventricular fibrillation - irregular rhythm due to rapid discharge of impulses from one or more ventricular foci or from multiple wandering reentrant circuits in the ventricles. The ventricular contractions are erratic and are represented on the ECG by bizarre patterns of various size and configuration. P waves are not seen.

66. VENTRICULAR PREMATURE BEATS
VPBs result from ectopic pacemaker activity arising below the AV junction resulting in a wide (>0.12-second), bizarre QRS complex.
There is no P wave associated with a VPB.
VPBs are common during anesthesia- 15% of observed arrhythmias.
Results in a fully compensatory pause consisting of the interval from the VPB to the expected normal QRS, which is blocked at the AV node, plus a normal sinus interval.

67. VENTRICULAR TACHYCARDIA
Heart rate: 100 to 200 /min.
Rhythm: Generally regular, but may be irregular if the VT is paroxysmal.
P/QRS: Usually no fixed relationship because VT is a form of AV dissociation in which the P waves can be seen marching through the QRS complex.
QRS complex: Wide, more than 0.12 second.
Significance: Acute onset is life threatening and requires immediate treatment.
The presence of three or more sequential VPBs defines VT. Diagnostic criteria include the presence of fusion beats, capture beats, and AV dissociation.
By duration, non sustained VT lasts three beats and up to 30 seconds, and sustained VT lasts 30 seconds or longer

69. HYPERKALEMIA

70. HYPOKALEMIA ST segment depression,
Decreased t wave amplitude f/b T wave inversion
Increased U wave height.
Increased PR interval and features of heart block

71. Thank you