The potential and limitations of standard electrocardiography for the differential diagnosis of wide QRS complex tachycardias

The possibility to identify potentially life-threatening ventricular arrhythmias by analysis of standard electrocardiography (ECG) parameters without the use of sophisticated and expensive diagnostic techniques, such as electrophysiological heart studies, has been an important achievement of the last decades. Current differential diagnostic methods for wide QRS complex tachycardias can be categorized into 4 groups: 1) identification the ECG signs diagnostic of ventricular tachycardia, such as atrioventricular dissociation and/or sinus captures and/or fusion QRS complexes; 2) analysis of the distinct morphological features of QRS complexes during wide QRS complex tachycardias; 3) analysis of the ECG characteristics in between wide QRS complex tachycardia attacks; 4) comparison of the morphological QRS features during wide QRS complex tachycardia and during sinus rhythm periods. The list of ECG algorithms for differential diagnosis of wide QRS complex tachycardias has been growing and updated year after year; however, all of them have their limitations. Most frequently, the differential diagnosis between ventricular and aberrant supraventricular tachycardias is based on the morphological criteria of wide QRS complexes developed by H.J. Wellens et al., P. Brugada et al., M. Griffith et al., K.E. Kindwal et al., A. Vereckei et al. At the same time, there is a continuous search for new algorithms or criteria that could be easily used without decreased specificity and/or sensitivity of the diagnosis of ventricular tachycardia. The aim of this review is to comprehensively analyze the literature data and results of our own studies on the potential and limitation of standard ECG for the differential diagnosis of ventricular and various aberrant supraventricular tachycardias.