Overview
This lecture provides an introduction to identifying common cardiac arrhythmias on ECG/EKG strips, including sinus arrhythmia, premature beats, bradycardia, and tachycardia, with key features and examples discussed.
Major Types of Arrhythmias
- Arrhythmias are grouped into sinus, premature beats, bradycardic, tachycardic, atrial, junctional, ventricular rhythms, and heart blocks.
- Focus is on causes, defining ECG features, and clinical significance of each type.
Sinus Arrhythmias
- Originate in the SA node, identified by upright P waves and narrow QRS complexes.
- Heart rate varies (increases and decreases), but P waves remain present and QRS is narrow.
- Usually benign and reflect normal fluctuation in heart rate.
Premature Beats
- Premature Atrial Complex (PAC): Early beat with upright P wave, narrow QRS, and sometimes a different P wave shape; originates in the atria.
- Premature Junctional Complex (PJC): Early beat with narrow QRS and absent or inverted P wave; arises from the AV junction (rare).
- Premature Ventricular Complex (PVC): Early, wide QRS beat with no preceding P wave; originates in the ventricle, T wave often opposite in direction to QRS; usually benign.
Bradycardic and Tachycardic Rhythms
- Sinus Bradycardia: Regular rhythm from SA node, but with heart rate <60 bpm, narrow QRS, upright P waves; may be normal in athletes or due to medication, disease, or aging.
- Sinus Tachycardia: Regular rhythm from SA node, heart rate >100 bpm, narrow QRS, upright P waves; often due to increased sympathetic activity (pain, fever, hypovolemia).
- Supraventricular Tachycardia (SVT): Heart rate >150 bpm, regular rhythm, narrow QRS, P waves indistinguishable; originates above the ventricles.
Key Terms & Definitions
- Sinus Arrhythmia — Heart rhythm originating from the SA node with variable rate but preserved P waves and QRS.
- PAC (Premature Atrial Complex) — Early beat from the atria with altered P wave morphology.
- PJC (Premature Junctional Complex) — Early beat from AV junction, absent or inverted P wave.
- PVC (Premature Ventricular Complex) — Early, wide QRS beat from the ventricles, no preceding P wave.
- Bradycardia — Heart rate less than 60 bpm.
- Tachycardia — Heart rate greater than 100 bpm.
- SVT (Supraventricular Tachycardia) — Rapid rhythm (>150 bpm) originating above the ventricles.
Action Items / Next Steps
- Review next lesson covering atrial, junctional, and ventricular rhythms.
- Practice identifying sinus arrhythmia, PAC, PJC, PVC, bradycardia, tachycardia, and SVT on ECG strips.