Basic Electrocardiography

Electrocardiogram ❖E❖ECG versus EKG ❖=❖= graphical recording of the electrical activity of the heart

Electrical Stimulation of the Heart ❖ SA node ❖ pacemaker ❖ AV junction (bridge) ❖ AV node ❖ bundle of His ❖ Bundle branches ❖ right ❖ left ❖ fasicles (small subdivisions) ❖ Purkinje fibers

Electrical Stimulation of the Heart ❖ Mayo Clinic Mayo Clinic ❖ Lifebeatonline Lifebeatonline

Electrical Stimulation of the Heart ❖N❖Normal conduction ❖s❖sinus rhythm ❖A❖Abnormal conduction ❖j❖junctional rhythm ❖e❖escape pacemaker

Cardiac Conductivity ❖ Conduction speed varies throughout the heart ❖ Slow - AV node ❖ Fast - Purkinje fibers

Example ❖ Sick Sinus Syndrome ❖ depressed SA node ❖ light-headedness ❖ syncope ❖ bradycardia

Cardiac Automaticity ❖ Automaticity ❖ SA node - primary pacemaker ❖ Other sites

Example ❖ Automaticity can increase outside the SA node ❖ ectopic (non-sinus) pacemaker ❖ a run of ectopic beats can lead to abnormal tachycardia

Abnormalities ❖ blockage of stimuli through AV junction = AV heart block ❖ disease of bundle branches = bundle branch block ❖ damage to ventricular muscle = abnormal ECG pattern

Class Organization 1. Understanding normal ECG and conditions that cause abnormal depolarization and repolarization 2. Recognizing abnormal rhythms and AV conduction disturbances