Which heart rate defines sinus tachycardia?

Which heart rate defines sinus tachycardia?

• A. 60-100
• B. 120-140
• C. >100
• D. <60

Answer: (C)

Sinus tachycardia means the heart is beating faster than normal, but the rhythm originates from the SA node and remains regular with normal P waves before each QRS. The defining threshold for tachycardia in adults is a resting heart rate exceeding 100 beats per minute. That’s why the statement of “greater than 100” best fits sinus tachycardia. Normal resting heart rates are 60–100, and bradycardia is under 60. A rate like 120–140 can occur, but the key criterion for tachycardia is the >100 bpm threshold, combined with a sinus (regular) rhythm.

Sinus tachycardia means the heart is beating faster than normal, but the rhythm originates from the SA node and remains regular with normal P waves before each QRS. The defining threshold for tachycardia in adults is a resting heart rate exceeding 100 beats per minute. That’s why the statement of “greater than 100” best fits sinus tachycardia. Normal resting heart rates are 60–100, and bradycardia is under 60. A rate like 120–140 can occur, but the key criterion for tachycardia is the >100 bpm threshold, combined with a sinus (regular) rhythm.