Differential diagnosis of wide QRS tachycardia: A review

Abstract

Differential diagnosis of wide QRS tachycardia (WQRST) on the electrocardiogram remains a challenging exercise. Correct diagnosis is important for prescribing appropriate therapy and determining prognosis. Differential diagnosis of wide QRS tachycardia revolves around differentiation between supraventricular tachycardia with aberrant conduction and ventricular tachycardia. Observations such as clinical history, findings of physical examination during tachycardia, AV dissociation, QRS morphology in lead V1 and lead V6, precordial concordance, RS complexes in precordial leads, contralateral bundle branch block during wide QRS tachycardia, R wave morphologies in lead aVR, and ventricular initial/terminal velocity of conduction ratio can help arrive at the correct diagnosis with reasonable accuracy. The observations described here can help arrive at the correct diagnosis of WQRST with both reasonable accuracy and confidence.

Taquicardia supraventricular aberrante con vía accesoria

“…Electrocardiograma de 12 derivaciones que muestra taquicardia supraventricular con evidencia de onda p seguida de complejo QRS ancho por conducción aberrante por vía accesoria. como resultado una conducción aberrante 6 . También pueden ocurrir por reentrada, cuando las regiones del miocardio activadas más tarde preexcitan zonas que ya han recuperado la excitabilidad, lo que tiene como resultado una propagación anormal del impulso eléctrico y de la refractariedad de los tejidos 7 .…”

“…Respecto al origen, un patrón de BRD con un QRS ancho orienta hacia un origen en la pared lateral, mientras que un patrón de BRI con un QRS menos ancho apunta a un origen más septal; un eje superior (onda Q y QRS predominantemente negativo en derivaciones inferiores) indica un origen en la cara inferior, mientras que un eje inferior (QRS predominantemente positivo en derivaciones inferiores) apunta a un origen en la región superior del ventrículo 6 .…”

“…En los ventrículos, la conducción del sistema de His-Purkinje es varias veces más rápida que en el miocardio contráctil (2.5 vs. 0.4-0.9 m/s, respectivamente) 5 . El fenómeno de Ashman es la conducción aberrante debida a precocidad, con combinaciones idénticas de ciclos largos y cortos 6 .…”

Electrocardiographic Differential Diagnosis of Narrow QRS and Wide QRS Complex Tachycardias

“…Although such tachycardias often occur in patients with a normal heart, they may cause bothersome symptoms and rarely represent life-threatening conditions. Among these tachycardias with a heart rate greater than 100 beats per minute (bpm), the narrow QRS complex tachycardias (NCTs) are defined by the presence in a 12-lead electrocardiogram (ECG) of a QRS complex duration less than 120 ms and the wide QRS complex tachycardias (WCTs) are defined by the presence in a 12-lead ECG of a QRS complex duration more than 120 ms (Figure 1) [1][2][3][4][5][6][7][8][9][10]. The NCTs are typically of supraventricular origin above or within the His bundle, although rarely narrow complex ventricular tachycardias (VT) have been reported in the literature in which early activation of the His bundle can also occur in high septal VT, resulting in relatively narrow QRS complexes of 110-140 ms (Table 1, [1][2][3][4][5]].…”

“…The NCTs are typically of supraventricular origin above or within the His bundle, although rarely narrow complex ventricular tachycardias (VT) have been reported in the literature in which early activation of the His bundle can also occur in high septal VT, resulting in relatively narrow QRS complexes of 110-140 ms (Table 1, [1][2][3][4][5]]. The WCTs can be VT or supraventricular tachycardia (SVT) with right or left bundle branch block (BBB) or right or left accessory pathway (Table 1, [6][7][8][9][10]]. Because administration of medications based on misdiagnosis of these tachycardias can be harmful and sometimes fatal, diagnosis…”