The document summarizes the basics of electrocardiography (ECG). It describes that anatomically the heart has four chambers but electrically it functions as two chambers, with the atria stimulating together and ventricles together. The conducting system is responsible for transmitting electrical signals through the heart and includes the sinoatrial node, atrioventricular node, bundle of His, and Purkinje fibers. The ECG records and displays the electrical activity of the heart through electrodes placed on the skin.

1. Basic ECG Mazen Tawfik, md

2. Although Anatomically the heart is composed of 4 Chambers (2 atria and 2 ventricles) Yet, Electrically it is composed of 2 Chambers . The two atria stimulated together and the two ventricles also stimulated together. There is complete separation between the atria and ventricles by central fibrous body . The only connection between atria and ventricles is through the A-V node . Anatomy of the Heart

3. Anatomy of the Heart

4. The conducting tissue is composed of SA node , situated in the top of right atrium at the junction of superior vena cava and the right atrium. It is the pacemaker of the entire heart. The AV node is situated at the base of the right atrium, anterior to the ostium of the coronary sinus. The Bundle of His extends from the end of AV node and branching to the right and left branches. The Purkinje fibers are terminal network of fibers that spreads the impulses directly to the ventricular walls. The specialized conducting tissue receives its innervation from sympathetic and parasympathetic nervous system. The Conducting System

5. The Conducting System

6. The Conducting System

8. Cardiac Action Potential

15. The E.C.G. Paper

16. The Paper and the Graph

19. P - QRST

21. The ideal ECG comment Heart rate. Rhythm. P wave. PR interval. QRS : Axis Morphology Voltage Duration ST segment. T wave. QT interval.

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27. Normal ECG

28. Objectives ECG leads. ECG recording. ECG waves & intervals. Calculation of Heart rate.