ACLS — Advanced Cardiovascular Life Support — All Questions

Which pair of rhythms is treated with defibrillation (i.e., is 'shockable')?

• a.Asystole and pulseless electrical activity (PEA)
• b.Ventricular fibrillation and pulseless ventricular tachycardia✓
• c.Sinus bradycardia and first-degree AV block
• d.Normal sinus rhythm and atrial flutter with a pulse

Only ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) are shockable — defibrillation can reset the chaotic ventricular activity so an organized rhythm can resume. Asystole and PEA are non-shockable; they are treated with CPR, epinephrine, and correction of reversible causes. Delivering a shock to asystole or PEA provides no benefit.

The monitor shows a flat line, confirmed in two leads, in a pulseless patient. The correct action is to:

• a.Defibrillate immediately
• b.Perform synchronized cardioversion
• c.Continue high-quality CPR, give epinephrine, and treat reversible causes — do not shock✓
• d.Give adenosine 6 mg rapid IV push

A confirmed flat line is asystole, a non-shockable rhythm. Management is high-quality CPR, epinephrine 1 mg every 3-5 minutes, and an active search for the H's and T's (reversible causes). Confirming asystole in more than one lead rules out 'fine VF' or a lead/equipment problem masquerading as a flat line. Defibrillation and cardioversion have no role in asystole.

A stable patient has a regular narrow-complex tachycardia at 180 bpm; vagal maneuvers have not worked. The next appropriate step is:

• a.Defibrillate the patient
• b.Give adenosine 6 mg by rapid IV push✓
• c.Give atropine 1 mg IV
• d.Give epinephrine 1 mg IV push

A regular narrow-complex tachycardia that persists after vagal maneuvers in a stable patient is treated with adenosine 6 mg rapid IV push (then 12 mg if needed). This most likely represents a re-entrant SVT, and adenosine's transient AV nodal block can break the circuit. Defibrillation, atropine, and arrest-dose epinephrine are all inappropriate for a stable, perfusing SVT.