ECG of Supraventricular tachycardia

A 36-year-old white female nurse comes to the ER due to a sensation of fast heart rate, slight dizziness, and vague chest fullness. Blood pressure is 110/70. The following rhythm strip is obtained, which shows which of the following?

• a.Atrial fibrillation
• b.Atrial flutter
• c.Supraventricular tachycardia
• d.Ventricular tachycardia

The answer is (c).

Paroxysmal supraventricular tachycardia due to AV nodal reentry typically displays a narrow QRS complex without clearly discernible P waves, with a rate in the 160 to 190 range. The atrial rate is faster in atrial flutter, typically with a classic sawtooth pattern of P waves, with AV conduction ratios most commonly 2:1 or 4:1, leading to ventricular rates of 150 or 75 per min.

Atrial fibrillation would show an irregularly irregular rhythm without discrete P waves. Wide QRS complexes with rate greater than 100 would be expected in ventricular tachycardia.