MyMichigan Telemetry Monitoring And Management Practice Test

Sinus rhythm hinges on atrial activation starting in the sinoatrial node, which produces one P wave before every QRS complex, with the P waves upright and similar in shape and size, and the rhythm usually regular. If the P waves are not one per QRS, or they don’t precede each QRS in a consistent, uniform way (or are absent/inverted), the rhythm cannot be sinus because the atrial activation is not linked cleanly to each ventricular contraction. In this item, the statement that P waves are not 1 per QRS, upright, and similar in shape and size violates that essential 1:1, orderly P-to-QRS relationship, so it cannot be sinus rhythm. The other statements describe features compatible with sinus rhythm: a single, upright, uniform P wave before each QRS, a regular rhythm, and a narrow QRS.