Module 06
Tachycardia
Determine stability first, then select the correct algorithm — vagal maneuvers, adenosine, or synchronized cardioversion.
First Determine: Stable or Unstable
- Signs of instability:
- — Hypotension
- — Shock
- — Chest pain
- — Altered mental status
- — Heart failure
Stable SVT Algorithm
1
Vagal maneuvers
Attempt vagal stimulation first for stable regular narrow-complex tachycardia.
2
Adenosine 6 mg IV push
Rapid bolus with flush, followed by rhythm assessment.
3
Adenosine 12 mg IV push
If 6 mg ineffective, escalate to 12 mg. May repeat once.
Unstable Tachycardia
1
Immediate synchronized cardioversion
Do not delay for pharmacologic management when the patient is unstable.
Defibrillation vs. Cardioversion — Critical Distinction
| Defibrillation | Cardioversion |
|---|---|
| Patient has NO pulse | Patient HAS a pulse |
| Ventricular Fibrillation (VF) | Unstable tachycardia |
| Pulseless VT | Deliver a synchronized shock |
| Unsynchronized shock | Synchronized to the R wave |
Clinical Pearl
If the patient has a pulse, think cardioversion. If the patient is pulseless, think defibrillation. This distinction drives the entire algorithm.
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