1. Chapters 11, 12, 13 Electrocardiogram Dr. Marko Ljubković Department of Physiology

2. Normal EKG

3. EKG – Principle of Detection

4. AP vs. EKG

5. EKG Leads Standard leads Precordial (chest) leads

6. Current Flows during Ventricular Depolarization

7. Cardiac Current Vectors Axes of the leads Average cardiac electrical axis (mean of all instantaneous vectors) Resultant (instantaneous) vector

8. Vectorial Analyses Determination of projected vectors with standard leads

9. Vectorial Analysis of the Normal EKG Instantaneous vectors during atrial depolarization (similar to average vector)

10. Instantaneous vectors during ventricular depolarization Q wave – left part of the septum depolarizes first Vectorial Analysis of the Normal EKG

11. Ventricular repolarization Vectorial Analysis of the Normal EKG

12. Average Cardiac Electrical Axis Constructed from QRS complexes of standard leads Indicates the mean direction of depolarization spreading through the ventricle Normally around 59º May be pathologically altered (axis deviation)

13. Ventricular Hypertrophy Left ventricular hypertrophyRight ventricular hypertrophy

14. Bundle Branch Block Blok lijeve grane snopa Vector directed to the side of the block QRS prolonged

15. Arrhythmias Abnormal sinus rythms: Tachycadia (fever, sympathetic stimulation) Bradycardia (athletes, carotid sinus syndrome)

16. Atrioventricular Block Possible causes: AV node ischemia AV node or bundle compression Myocarditis Excessive vagal stimulation First degree block Second degree block Complete AV block

17. Premature Contractions (Extrasystolae) Atrial extrasystole AV nodal extrasystole Ventricular extrasystolae

18. Paroxysmal Tachycardia Supraventricular (atrial and AV nodal)  Common in young, healthy individuals Ventricular  Often caused by ischemia  May precede ventricular fibrilation

19. Ventricular Fibrillation Electric shock to the heart (alternating current ~ 60 Hz) Pathological cardiac alterations Dilatation Reduced velocity of conduction

20. Atrial Fibrillation Common in dilated atria Lack of P waves QRS-T complexes preserved Irregular rhythm