Which description defines sinus rhythm on ECG?

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Multiple Choice

Which description defines sinus rhythm on ECG?

Sinus rhythm means the heartbeat is driven by the sinoatrial node and shows a normal sequence: a P wave before each QRS complex, with a regular rhythm and a normal PR interval. The P waves are typically upright in a standard view and precede every heartbeat, and the interval from the start of the P wave to the start of the QRS complex stays within about 0.12 to 0.20 seconds. This combination—regular rhythm plus visible P waves before each QRS and a normal PR interval—best fits the description given. If you see an irregularly irregular rhythm with no P waves, that’s atrial fibrillation, not sinus rhythm. A regular narrow complex tachycardia with concealed P waves implies a tachyarrhythmia where P waves aren’t visible, again not sinus rhythm. A wide complex tachycardia points to a ventricular origin or a supraventricular tachycardia with aberrant conduction, also not sinus rhythm.

Sinus rhythm means the heartbeat is driven by the sinoatrial node and shows a normal sequence: a P wave before each QRS complex, with a regular rhythm and a normal PR interval. The P waves are typically upright in a standard view and precede every heartbeat, and the interval from the start of the P wave to the start of the QRS complex stays within about 0.12 to 0.20 seconds. This combination—regular rhythm plus visible P waves before each QRS and a normal PR interval—best fits the description given.

If you see an irregularly irregular rhythm with no P waves, that’s atrial fibrillation, not sinus rhythm. A regular narrow complex tachycardia with concealed P waves implies a tachyarrhythmia where P waves aren’t visible, again not sinus rhythm. A wide complex tachycardia points to a ventricular origin or a supraventricular tachycardia with aberrant conduction, also not sinus rhythm.

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