Overview
This lecture covers essential methods for calculating heart rate from an ECG strip, which is vital for nursing exams and practice.
ECG Basics
- The ECG strip displays electrical activity of the heart, represented by P, Q, R, S, and T waves.
- The R-wave (the upward peak) is especially important for heart rate calculation.
300 Rule (Big Square Method)
- Use for regular rhythms.
- Count the number of big squares between two consecutive R-waves.
- Divide 300 by this number to get beats per minute (bpm).
- Example: 5 big squares between R-waves → 300/5 = 60 bpm.
6-Second Method
- Use for irregular rhythms like atrial fibrillation.
- 30 big squares on the ECG = 6 seconds.
- Count the number of R-waves in 30 big squares and multiply by 10.
- Example: 6 R-waves in 30 big squares → 6 × 10 = 60 bpm.
- For atrial rate, count P-waves instead of R-waves.
Small Square Method (1500 Rule)
- Use for fast rhythms.
- Count the number of small squares between two R-waves.
- Divide 1500 by this number for bpm.
- Example: 25 small squares between R-waves → 1500/25 = 60 bpm.
Practice & Quiz
- Regular practice with ECG strips builds confidence and accuracy.
- Example quiz: Using the 6-second method, the answer was 80 bpm.
Key Terms & Definitions
- ECG (Electrocardiogram) — A recording of the heart’s electrical activity.
- R-wave — The prominent upward wave in the QRS complex; used for rate calculation.
- Big square — Five small squares on ECG paper, representing 0.2 seconds.
- Small square — The smallest division on ECG paper, representing 0.04 seconds.
- Atrial Fibrillation — An irregular heart rhythm.
Action Items / Next Steps
- Practice each heart rate calculation method on various ECG strips.
- Review the video or accompanying blog for a summary of these methods.
- Prepare for upcoming exams by mastering ECG interpretation skills.