Which statement best describes the clinical picture of sinus tachycardia?

• A. Rapid, regular pulse
• B. Slow, irregular pulse
• C. No symptoms
• D. Chest pain always

Answer: (A)

Sinus tachycardia happens when the sinus node speeds up but still keeps the normal pathway of electrical conduction, so each beat follows the same sequence with a P wave before every QRS and the rhythm remains steady. The key clinical clue is a pulse that is rapid yet regular, typically with a heart rate over 100 beats per minute in adults. This regular rhythm comes from the SA node firing more quickly but not losing the orderly conduction pattern.

Understanding helps: a rapidly beating heart can also feel like palpitations, and in some situations you’ll notice lightheadedness or shortness of breath, but the defining feature is the consistent, regular rhythm with a faster rate. If the rhythm were irregular or if the rate were slow, that would point to other conditions such as atrial fibrillation, flutter, or bradycardia, rather than sinus tachycardia. Chest pain is not a necessary or universal component of sinus tachycardia.