Differential diagnosis of wide QRS tachycardia. Assess each criterion in order: any Yes answer ends at VT.
Step 1
Absence of an RS complex in all precordial leads (V1–V6)?
Answer Yes if V1 through V6 show only QS, QR, monophasic R, rSR′ or other forms without RS (QR, QRS, QS, monophasic R and rSR′ do not count as RS). Includes positive and negative concordance.
A tool to support learning and decision-making. The result does not replace clinical evaluation of the patient.
About: Brugada algorithm
Published in 1991, the Brugada algorithm is the classic flowchart for differentiating ventricular tachycardia (VT) from supraventricular tachycardia with aberrancy in regular wide QRS tachycardias.
It asks four questions in sequence, based on the precordial leads and atrioventricular dissociation. Any Yes answer ends the algorithm at VT.
How to use
Check whether an RS complex is present in any lead from V1 to V6.
If so, measure the longest RS interval (onset of R to nadir of S): more than 100 ms favors VT.
Look for atrioventricular dissociation, capture beats or fusion beats.
Finally, apply the morphology criteria in V1–V2 and V6; answer Yes only if both regions meet VT criteria.
How to interpret
Any positive criterion: ventricular tachycardia.
All four negative: SVT with aberrancy, by exclusion.
Limitations
Wide QRS tachycardia algorithms were derived in selected populations and lose accuracy in the hands of infrequent users. No result safely rules out ventricular tachycardia: when in doubt, or if the patient is unstable, manage as VT. The algorithm does not distinguish VT from pre-excited SVT; if you suspect it, use the Steurer algorithm or the modified Vereckei algorithm.
References
Brugada P, Brugada J, Mont L, Smeets J, Andries EW. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex. Circulation. 1991;83(5):1649–59.
Jastrzebski M, Kukla P, Czarnecka D, Kawecka-Jaszcz K. Comparison of five electrocardiographic methods for differentiation of wide QRS-complex tachycardias. Europace. 2012;14(8):1165–71.
Kaiser E, Darrieux FCC, Barbosa SA, Grinberg R, Assis-Carmo A, Sousa JC, et al. Differential diagnosis of wide QRS tachycardias: comparison of two electrocardiographic algorithms. Europace. 2015;17(9):1422–7.
