basics of ecg

PRESENTED BY: Raghwender Singh (D-

754)

THE BASICS OF EKG

INRODUCTIONECG or EKG

ECG is essential for diagnosis

Essential in management of cardiac rhythm

Helps in diagnosis of chest pain

Proper use of thrombolysis in treatment of MI depend upon it

HISTORY

1842- Italian scientist Carlo Matteucci realizes that electricity is associated with the heart beat

1872- French scientist Gabriel Lippmann , invented the capillary electrometer which can measure electricity by utilizing mercury

1876- Irish scientist Marey analyzes the electric pattern of frog’s heart

CONTD…

1895 - William Einthoven , credited for the invention of EKG

1906 - using the string electrometer EKG, William Einthoven diagnoses some heart

problems

1924 - the noble prize for physiology or medicine is given to William Einthoven for his work on EKG

MODERN ECG INSTRUMENT

ELECTRICITY OF HEART

Contraction of any muscle is associated with electrical charges called depolarization

These changes can be detected by electrodes attached to the surface of the body

Although the heart has 4 chambers, from the electrical point it is having only 2

THE WIRING DIAGRAM OF THE HEART

• SA

• AV node

• Bundle of His

• Bundle branches (left and right)

THE SHAPE OF ECG

• Contraction of atria - P wave

Ventricular depolarization - QRS complex

Ventricular repolarization - T wave

NORMAL ECG

ECG INTERPRETATION

RELATIONSHIP BETWEEN THE NUMBER OF LARGE SQUARES COVERED BY R-R INTERVAL AND THE

HEART RATE

R-R INTERVAL(large squares)

HEART RATE (beats/min)

1 300

2 150

3 100

4 75

5 60

6 50

ECG RHYTHM

NORMAL SINUS RHYTHM Looking at the ECG you'll see that:-

• RHYTHM - Regular • RATE - (60-100 bpm) • QRS DURATION - Normal • P WAVE - Visible before each QRS

complex • P-R INTERVAL - Normal (<5 small Squares.

Anything above and this would be 1st degree block)

• Indicates that the electrical signal is generated by the sinus node and travelling in a normal fashion in the heart.

NORMAL SINUS RHYTHM

SINUS BRADYCARDIALooking at the ECG you'll see that:-

• RHYTHM - Regular • RATE - Less than 60 beats per

minute • QRS DURATION - Normal • P WAVE - Visible before each QRS complex• P-R INTERVAL - Normal

• Usually benign and often caused by patients on beta blockers

SINUS BRADYCARDIA

SINUS TACHYCARDIA

Looking at the ECG you'll see that:-

• RHYTHM - Regular • RATE - More than 100 beats per

minute • QRS DURATION - Normal • P WAVE - Visible before each QRS

complex • P-R INTERVAL - Normal

• The impulse generating the heart beats are normal, but they are occurring at a faster pace than normal. Seen during exercise

SINUS TACHYCARDIA

ECG RULESIf you follow Professor Chamberlains 10

rules they'll give you an understanding of what is normal:-

RULE 1

PR interval should be 120 to 200 milliseconds or 3 to 5 little squares

RULE 2

The width of the QRS complex should not exceed 110 ms, less than 3 little squares

RULE 3

The QRS complex should be dominantly upright in leads I and II

RULE 4

QRS and T waves tend to have the same general direction in the limb leads

RULE 5

All waves are negative in lead aVR

RULE 6

The R wave must grow from V1 to at least V4The S wave must grow from V1 to at least V3 and disappear in V6

RULE 7

The ST segment should start isoelectric except in V1 and V2 where it may be elevated

RULE 8

The P waves should be upright in I, II, and V2 to V6

RULE 9

There should be no Q wave or only a small q less than 0.04 seconds in width in I, II, V2 to V6

RULE 10

The T wave must be upright in I, II, V2 to V6

REFERENCES:-The EKG made easy-John R. Hamptonwww.ambulancetechnicianstudy.co.ukwww.learntheheart.com