Unit 2 ekg module 3-1
- 1. ECG Rhythm Interpretation Module III Normal Sinus Rhythm
- 2. Course Objectives • To recognize the normal rhythm of the heart - “Normal Sinus Rhythm.” • To recognize the 13 most common rhythm disturbances. • To recognize an acute myocardial infarction on a 12-lead ECG.
- 3. Learning Modules • ECG Basics • How to Analyze a Rhythm • Normal Sinus Rhythm • Heart Arrhythmias • Diagnosing a Myocardial Infarction • Advanced 12-Lead Interpretation
- 4. Normal Sinus Rhythm (NSR) • Etiology: the electrical impulse is formed in the SA node and conducted normally. • This is the normal rhythm of the heart; other rhythms that do not conduct via the typical pathway are called arrhythmias.
- 5. NSR Parameters •Rate 60 - 100 bpm •Regularity regular •P waves normal •PR interval 0.12 - 0.20 s •QRS duration 0.04 - 0.12 s Any deviation from above is sinus tachycardia, sinus bradycardia or an arrhythmia
- 6. Arrhythmia Formation Arrhythmias can arise from problems in the: • Sinus node • Atrial cells • AV junction • Ventricular cells
- 7. SA Node Problems The SA Node can: • fire too slow Sinus Bradycardia • fire too fast Sinus Tachycardia Sinus Tachycardia may be an appropriate response to stress.
- 8. Atrial Cell Problems Atrial cells can: • fire occasionally Premature Atrial from a focus Contractions (PACs) • fire continuously Atrial Flutter due to a looping re-entrant circuit
- 9. Teaching Moment • A re-entrant pathway occurs when an impulse loops and results in self- perpetuating impulse formation.
- 10. Atrial Cell Problems Atrial cells can also: • fire continuously Atrial Fibrillation from multiple foci or fire continuously Atrial Fibrillation due to multiple micro re-entrant “wavelets”
- 11. Teaching Moment Atrial tissue Multiple micro re- entrant “wavelets” refers to wandering small areas of activation which generate fine chaotic impulses. Colliding wavelets can, in turn, generate new foci of activation.
- 12. AV Junctional Problems The AV junction can: • fire continuously Paroxysmal due to a looping Supraventricular re-entrant circuit Tachycardia • block impulses AV Junctional Blocks coming from the SA Node
- 13. Ventricular Cell Problems Ventricular cells can: • fire occasionally Premature Ventricular from 1 or more foci Contractions (PVCs) • fire continuously Ventricular Fibrillation from multiple foci • fire continuously Ventricular Tachycardia due to a looping re-entrant circuit