VT vs SVT

Differentials of WCT
SHIT (usually these are slower <100-120/min)
STEMI with massive ST
Hyperkalemia
Idioventricular, accelerated
Tox TLCDD (TCA, Lithium, Cocaine, Dig, Diphenhydramine]
Pacemaker-Mediated Tachycardia

VT vs SVT with abberancy

Clinical
- unstable = sync CV
- the older the age, the more it's VT
- Hx ACS/CHF/CMP/ICD
- young patients, if not sure, treat as VT

Seven Things = only look here if patient is stable
1. old ECG: (eg if known RBBB, likely SVT)
2. check P waves before QRS = don't miss sinus
3. RBBB and LBBB is clearly identified = SVT
4. FACC: Fusion beats, AV dissociation, Capture beats, Concordance
5. QRS duration: VT >140ms/3.5small sq (except fascicular VT or RBBB + leftward axis), the longer the more it's VT
6. check R wave of V1, look for subtle notching = could be P wave = AV dissociation
7. Algorithms: Brugada, Vereckei, aVR (Vereckei 2), Sasaki

Sasaki
1. initial R in aVR
2. longest RS ≥100 ms (2.5 small squares) in any precordial leads
3. initial r or q ≥40ms (1 small square) in "any" lead

Others:
- R or qR pattern on V1 = VT
- frontal QRS axis between 180 and 270 degrees = VT (ERAD)
- LBBB + Right axis deviation = VT
- RBBB pattern when present in the native sinus rhythm = SVT
- varying BBB = SVT
- rsR' pattern in V1 = SVT
- ectopic P wave preceding the dysrhythmia = SVT

- If there is a transition from narrow to wide, is the rate the same? then it must be SVT.

Algorithms:

1. Brugada
2. Vereckei
3. aVR (Vereckei 2)
4. Sasaki = simplest, and most superior (?)

Step 1: Initial R in aVR?
If yes, then rhythm is VT. If no, step 2.

Step 2: Interval from onset of R wave to the nadir of the S ≥ 100 msec (0.10 sec) in any precordial leads?
If yes, then rhythm is VT. If no, step 3.

Step 3: Initial r or q ≥ 40 ms in any lead?
If yes, then it is VT.
If no, then it is SVT

If still uncertain and patient is stable, handover to next shift

Links:

http://lifeinthefastlane.com/ecg-library/basics/vt_vs_svt/