Brugada Criteria for Ventricular Tachycardia

Brugada Criteria for Wide QRS-complex Tachycardias

Beyond wide complex tachycardias (WCTs) lies a complex differential diagnosis between ventricular tachycardia (VT) versus supraventricular tachycardia (SVT) with aberration.

Clinicians tasked with interpreting an electrocardiogram (ECG) may be able to mitigate risk of misdiagnosis and treatment in these potentially lethal conditions by employing the stepwise approach proposed in the Brugada criteria.

Where VT is diagnosed by the Brugada criteria, ACLS protocol recommends amiodarone and preparing for synchronized cardioversion.

If all four of the above are absent, then specificity for supraventricular tachycardia (SVT) is 98.7%.

In 1991, Brudaga et al. checked the value of four new criteria incorporated in a stepwise approach was prospectively analyzed in a total of 554 tachycardias with a widened QRS complex (384 ventricular and 170 supraventricular). The sensitivity of the four consecutive steps was 0.987, and the specificity was 0.965.

The criteria have been criticised for only showing limited agreement between physicians and whilst the original study showed an accuracy of 98%, subsequent validation studies only found accuracies ranging from 77 to 85%.

For example, in a study by Isenhour et al. cardiologists and emergency physicians were unable to reproduce the high sensitivity and specificity seen in the original study, on a database of 157 electrocardiograms with WCT findings.

Interobserver agreement for the emergency physicians and the cardiologists in determining VT was 82% and 81%, respectively.

Risk factors for VT are age over 35, structural or ischaemic heart disease, previous myocardial infarction, congestive heart failure or cardiomyopathy.

Some of the electrocardiographic features that may increase likelihood of a VT diagnosis include:

• Absence of typical RBBB or LBBB morphology;
• Brugada sign – the distance from the onset of the QRS complex to the nadir of the S-wave is > 100ms;
• Josephson sign– notching near the nadir of the S-wave;
• AV dissociation(P and QRS complexes at different rates);
• Positive or negative concordancethroughout the precordial (chest) leads;
• Capture beats— occur when the sinoatrial node transiently ‘captures’ the ventricles, in the midst of AV dissociation, to produce a QRS complex of normal duration;
• Fusion beats— when a sinus and ventricular beat coincides to produce a hybrid complex.

References

Original reference

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):1649-1659.

Validation

Isenhour JL, Craig S, Gibbs M, Littmann L, Rose G, Risch R. Wide-complex tachycardia: continued evaluation of diagnostic criteria. Acad Emerg Med. 2000; 7(7):769-773.

Other references

B Garner J, M Miller J. Wide Complex Tachycardia - Ventricular Tachycardia or Not Ventricular Tachycardia, That Remains the Question. Arrhythm Electrophysiol Rev. 2013; 2(1):23-9.

Brugada P, Brugada J. Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a multicenter report. J Am Coll Cardiol 1992; 20:1391–6.