In using the Sequential Method, what do you need to mark on the ECG strip?

Using the Sequential Method in ECG analysis involves focusing on specific components of the heart's electrical activity that align with the grid on the ECG strip. The correct choice emphasizes marking both the R waves and P waves that fall on the dark lines, which represent the major time intervals in the ECG.

The rationale behind this is that the dark lines on the ECG strip usually denote significant time segments, typically every 0.2 seconds (i.e., 5 small boxes). Marking the R waves, which indicate the peak of the QRS complex, is crucial for determining the heart rate and rhythm. Additionally, marking the P waves assists in analyzing atrial activity and helps in assessing the relationship between atrial (P waves) and ventricular (R waves) events.

By marking both R and P waves that fall on these dark lines, one can achieve a clear visual reference that aligns with intervals critical for determining various measurements such as the PR interval, the QRS duration, and the overall rhythm of the heart. This method allows for better qualitative and quantitative analysis of the ECG tracing.