What is the rhythm strip in an ECG described as lead II recording that shows the heart's rhythm?

• A. Rhythm Strip
• B. Purkinje Fibers
• C. SA Node
• D. QRS Complex

Answer: (A)

The key idea is the rhythm strip: a long, continuous tracing from a single ECG lead (usually Lead II) used specifically to observe the heart’s rhythm over time. This type of tracing makes it easy to see the sequence and regularity of beats, as well as the timing between P waves and QRS complexes, which is essential for evaluating rate and rhythm.

Lead II is often chosen for rhythm assessment because its orientation tends to make atrial activity (P waves) and overall rhythm appear clearly, helping you track the heart’s pacing patterns across many beats.

The other terms describe parts or components of the heart’s electrical system or a single waveform, not the continuous rhythm recording itself: Purkinje fibers are part of the conduction pathway; the SA node is the natural pacemaker; the QRS complex represents ventricular depolarization.