Basic Electrocardiography

History of Electrocardiography, Einthoven law, Einthoven triangle, additional leads,vectorcardiography

1. BASIC ELECTROCARDIOGRAPHY Dr. N.PRAVEEN MD,DM Dr. N. Praveen M.D.,D.M.

2. Wilson invented central terminal Precordial leads were born Carlo Matteucci Electrical activity from the heart of a frog 1842 1887 1901 1934-38 Goldberg used the central terminal with augmentation 1942 AHA Standardized 12 lead ECG 1954 EVOLUTION OF ELECTROCARDIOGRAPHY

3. Einthoven’s law Helpful rule to remember to detect instances in which the technician has attached the electrodes to the wrong limbs.

4. For unipolar leads , multiple electrodes are connected together to represent the negative end of the bipolar pair - reference electrode . The single electrode serving as the positive input - exploring electrode, The concerned lead records the potential difference between the two.

5. Unipolar limb leads With the exploring electrode on one limb, the potential at the root of the explored limb is recorded exclusively .

6. Additional Leads

7. Ventricular depolarization Occurs in three successive steps -- generation of three vectors ( the expression of three dipoles) Ventricular depolarization starts at three different sites in the LV – the areas of the anterior and posterior papillary muscles and midseptal area. 1 – rightward, anterior, inferior 2 - leftward, posterior, inferior 3 - rightward , anterior, superior

8. RIGHT LEFT ANTERIOR POSTERIOR

9. Take home message The two electrodes to be misplaced frequently are the RA (Red) and LA (Yellow). Einthoven law states Lead II = Lead I + Lead III. Right sided leads are useful for detection of RVMI. Posterior leads are useful for detection of posterior wall STEMI. Vectorcardiography is depiction of the vectors in loops rather than waves and complexes. Scalar ECG gives almost every information obtained by vectorcardiography .

10. Thank you