Western Maricopa Education Center (West-MEC) Medical Assisting ADE Practice Exam

Normal sinus rhythm means the heart’s rhythm is paced by the SA node and follows the usual conduction pathway, giving a steady, regular heartbeat. In this pattern, each beat has a P wave before every QRS complex, with normal timing and a rate typically 60–100 beats per minute in adults. The SA node acts as the natural pacemaker, so when the rhythm starts from it and stays regular, that’s characteristic of a normal sinus rhythm.

The other terms aren’t the rhythm you’d expect from the SA node’s normal pacing: a P wave is just the waveform for atrial depolarization, not a rhythm name; paroxysmal atrial tachycardia describes a sudden, rapid atrial rhythm; ischemia refers to reduced blood flow to heart tissue, not a rhythm.