Ecg

Fundamentals of ECG interpretation

Part IDr. Anil Barkul

MD(MED) DTCD

E.C.G BASICS

1

PART II

Electrocardiogram (ECG)

Provides representation of the electrical activity of the heart

Extremely important diagnostic tool for various cardiac dysfunctions

Used extensively in healthcare systems

3

2

WILLIAM ENTHOVAN.

2

3

Dr. Nagel developed the first telemetry unit for transmitting E.C.G.recordings via radio waves from the field to the hospital.

4

4

ECG in heart disease

v1 v2v3

v4v5

v6

5

5

Summary of events of cardiac cycle

10

10

12

12

ECG Reported as:

1.Standardisation 9.QRS Complex

2.Voltage 10.QRS Duration

3.Rate 11.ST Segment

4.Rhythm 12.T Wave

5.Axis 13.QT Interval

6.Position 14.U Waves

7.P Waves 15. Conclusion

8.PR Interval

14

13

Step - Rate

Method

Count the number of R waves for a six second interval and multiply by ten

3 sec 3 sec

6 sec

(can be used for regular & irregular)

15

14

Step - Rate

Method :

Count the number of 5mm squares in R-R interval and divide into 300

300150

10075

6050

4337

3330 … slow

16

15

Step 1 - Rate

RATE:

Tachycardia exists if the rate is greater than 100 beats/min.

Bradycardia exists if the rate is less than 60 beats/min.

17

16

Step : Rhythm

RHYTHM:

Determine if the ventricular rhythm is regular or irregular (pattern to irreg.?)

R-R intervals should measure the same

P-P intervals should also measure the same

18

17

STEP - Rhythm

IRREGULAR

REGULAR

1918

STEP - Rhythm Example

• Irregularly Irregular

20

19

STEP 3 – Is the P Wave Normal?

21

20

23

22

STEP 3 - Is the P Wave Normal ?

Normal P wave with no QRS complex

NormalSame Shape

Associated with a QRS Complex?

2423

STEP 4 –PR Interval/Relationship

Consistent PRI of <0.20 secs is normal, lengthened or variant

PRIs could indicate an AV block

25

24

STEP 5 –QRS DURATION

• A narrow QRS complex (< 0.12), indicates the impulse has

followed the normal conduction pathway

• A widened QRS complex (> 0.12), may indicate the impulse was generated

somewhere in the ventricles

25

27BARKUL HOSPITAL

STEP 6 – ST segment & T wave

• Ventricular repolarization characterized on ECG as ST

segment and T wave

• Changes in ST segment and T wave often seen in

ischemic heart disease

ST depression T wave inversion ST elevation

29

Identifying ST segment changes30

Regional association with ECG

Area of infarction

Leads associated Vessels involved

Inferior Leads II, III, and aVF; ST elevations Right coronary artery, left circumflex

Posterior Leads V1, V2, V3 ST depression; large R wave

Proximal right coronary artery, left circumflex

Anterior Leads V1, V2, V3, V4; ST elevation Left anterior descending

Lateral Leads V1, AVL, V5, V6; ST elevation Left circumflex

Rightventricular

Elevations in leads II, III, aVF, andV1; elevation greater in III thanII; large R wave V4

Proximal right coronary artery

31

ST elevation myocardial infarction (STEMI)

ST elevation 1 mm or more in 2 contiguous leads

ST elevation in II, III & aVF

32

Evolving infarction:

ECG progression

A. Normal ECG prior to MI

B. Ischemia from coronary artery occlusion results in ST depression (not shown) and peaked T-waves

C. Infarction from ongoing ischemia results in marked ST elevation

D/E. Ongoing infarction with appearance of pathologic Q-waves and T-wave inversion

F. Fibrosis (months later) with persistent Q- waves, but normal ST segment and T- waves

33

Sequence of changes seen during evolution of MI

34

Clinical implications of ECG changes…

Peaked T waves◦Present only for 5-30

mins after onset of MI

◦Intervention at this stage may prevent infarction; improved outcomes than initiating therapy at later stages

35

Clinical implications of ECG changes …

ST segment elevation◦Injury to myocardium ◦Patients with largest ST

deviation benefit most from fibrinolysis

36

Clinical implications of ECG changes …

Pathological Q waves ◦May develop within 1-2 hrs of onset

of symptoms of acute MI, though often they take 12 hrs to appear

◦ If ST segment elevation and Q waves evident on ECG and chest pain is of recent onset, patient may benefit from thrombolysis or direct intervention

◦Absence of Q waves post fibrinolysis may serve as favorable prognostic indicator

37

Clinical implications of ECG changes…

T wave inversion ◦Late sign of evolving MI; occurs in

3/4th patients with completed MI ◦May persist for months and

occasionally remains a permanent sign of infarction

38

Clinical implications of ECG changes

Normalization of ST segment◦Last ECG change during MI; occurs when

transmural MI progresses to completed infarction

◦ST elevation with an inferior MI may take up to two weeks to resolve, may persist even longer with anterior MI and may persist indefinitely if left ventricular aneurysm develops

◦Role of reperfusion therapy limited

39

Evolving ECG in STEMI

Middle-aged male presents to emergency medical service with chest pain; initial ECG demonstrates nonspecific abnormalities; within 15 minutes during transport, ECG demonstrates significant inferior ST segment elevation, consistent with inferior wall STEMI

40

Inferior Wall STEMI

ST elevation in II, III & aVF

41

Anterior Wall STEMI

ST elevation in V1-V5

42

Anterolateral MI

This person’s MI involves both the anterior wall (V2-V4) and the lateral wall (V5-V6, I, and aVL)!

43

Unstable angina/NSTEMI

ECG ST-segment depression or prominent T-wave inversion and/or positive biomarkers of necrosis in absence of ST-segment elevation and appropriate clinical setting (chest discomfort or anginal equivalent)

NSTEMI if elevated biomarkers present (Troponin T, Troponin I or Creatine Kinase- MB [CK-MB])

44

UA vs. NSTEMI

T wave inversion in II, III, aVF, V1-V6

If biomarkers normal, Unstable angina

If biomarkers elevated, NSTEMI45

Angina

Patient complained of chest pain

A.ST depression

B.5 minutes later, after nitroglycerin, ST segments revert to normal with relief of angina

46

Prinzmetal’s angina with transient ST elevationPatient with history ofexertional and restangina

A. Baseline resting ECG shows non-specific inferior ST-T changes

B. With chest pain, ST elevations in II, III, aVF and reciprocal ST depression in I and aVL

C. Return of ST segments to baseline after nitroglycerin

47

Summary

ECG an essential adjunct to clinical history & physical examination in patients with chest pain

ECG adds considerable information for risk stratification and clinical decision support for treatment strategies in ACS

48

ECG.exe

Ecg.exe

49

Dr.Anil BarkulMD(Med.)DTCD

Consulting Physician,Beed

50

Ecg

Health & Medicine

Transcript of Ecg