ACLS Megacode 3: Narrow Complex Tachycardia

The rhythm demonstrates a narrow complex, irregularly irregular rhythm, most likely atrial fibrillation. For stable patients, attempt vagal maneuvers first, which included Valsalva maneuvers, carotid massage, ice-water immersion.

Both metoprolol (beta-blocker) and diltiazem (calcium channel blocker) can be used for rate control. The remaining choices are pressors that would actually potentially increase the heart rate.

This patient is unstable with narrow complex, irregular tachycardia (in this case atrial fibrillation). The appropriate management is synchronized cardioversion. Defibrillation is not indicated for a patient with a pulse. Metoprolol would further drop blood pressure and would likely worsen the clinical scenario. IVFs may transiently help raise the blood pressure, but ultimately would unlikely help control the rate, which is the source of the hypotension.

This rhythm demonstrates sinus tachycardia. The treatment for tachycardia is to treat the underlying cause. Patient does not need to be cardioverted as she is in sinus rhythm. Metoprolol or diltiazem would potentially slow the rate, however, the heart rate may be required to maintain cardiac output and blunting this response could precipitate hypotension.

The rhythm strip demonstrates SVT. Patient is hemodynamically stable with normal blood pressure, and mentating appropriately. For treatment of stable, narrow complex tachycardia, adenosine can be given for diagnostic and therapeutic purposes. If patient does not respond to 6mg, an additional dose of 12mg can be given.