Do we HAVE to take a 12 lead to diagnose SVT?
YES. In order to differentiate tachycardia mechanism (via your diagnostic pathway taught in this years CME), you need to assess for Atrial activity (P-waves) in ALL leads. Therefore, a 12-lead ECG is required (2015 ACC/AHA/HRS Guidelines for Management of Adult Patients with Supraventricular Tachycardia)
Recall: Focused Approach to SVT (from Mandatory CME in-class)
1. Rate (HR ï‚³150 bpm)
2. QRS Normal (narrow vs wide)
3. Rhythm (Regular vs Irregular)
4. Atrial activity (P waves?) and relationship with QRS*
If yes, or the underline option, and Patient characteristics in keeping with your conclusion, you may consider the Valsalva Maneuver.
*With regards to Atrial activity and the diagnosis of SVT:
|Signs of SVT include:
||Signs of non-SVT rhythm include:
- cannot identify P-waves (buried in QRS)
- retrograde P-waves (inverted)
- P waves found after the QRS
- upright P waves present before every QRS (sinus rhythm)
- signs of impulse from sinus node: P wave upright in II, negative in aVR (sinus)
- saw tooth P waves (consider Atrial Flutter)
- fibrillating baseline (consider Atrial Fibrillation)
Page RL et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2016. Apr 5;67(13):1575-1623.