Diagnostic clues that favor VT
(assume until proven o/w)
- Prior MI, CHF, or LV dysfunction best predictors that WCT is VT (Am J Med 1998;84:53)
- Hemodynamics and rate do not reliably distinguish VT from SVT
- MMVT is regular, but initially it may be slightly irregular, mimicking AF w/ aberrancy; grossly irregularly irregular rhythm suggests AF w/ aberrancy or pre-excitation
- ECG features that favor VT (Circ 2016;133:e506)
-Brugada Criteria
- AV dissociation (independent P waves, capture or fusion beats) proves VT
- Very wide QRS (>140 ms in RBBB-type or >160 in LBBB-type);
- extreme axis deviation
- QRS morphology atypical for BBB (longest precordial RS >100 ms and R wider than S)
- RBBB-type:
- absence of tall R′ (or presence of monophasic R) in V1,
- r/S ratio <1 in V6
- LBBB-type:
- onset to nadir >60 ms in V1,
- q wave in V6
- Initial R wave in aVR; concordance (QRS in all precordial leads w/ same pattern/direction)