A patient reports sudden palpitations. The strip shows a perfectly regular narrow-complex rhythm at 180 beats per minute with P waves that cannot be identified. What is the most likely rhythm?

Explanation

Supraventricular tachycardia is a regular narrow-complex rhythm, usually 150 to 250 beats per minute, in which the P waves are buried in the preceding T waves and cannot be seen. Sinus tachycardia usually stays under 160 and has visible P waves that speed up gradually. Ventricular tachycardia has wide QRS complexes, and an accelerated junctional rhythm runs about 60 to 100.