Independent predictive accuracy of classical electrocardiographic criteria in the diagnosis of paroxysmal atrioventricular reciprocating tachycardias in patients without pre-excitation

Aims In patients without pre-excitation, the differential diagnosis of paroxysmal atrioventricular (AV) reciprocating tachycardias consists mainly of atrioventricular nodal re-entrant tachycardias (AVNRTs) and AV reciprocating tachycardias (AVRTs) through a concealed bypass. Our purpose was to validate the diagnostic accuracy of a predictive logistic model using classical electrocardiographic (ECG) criteria. Methods and results We included 470 patients who underwent an electrophysiological study for paroxysmal, regular, and narrow-QRS complex tachycardia without pre-excitation in sinus rhythm. The ECG recordings were reviewed for the presence of the following: (i) pseudo r' deflection (V1) and/or pseudo s-wave (inferior leads), (ii) identifiable P-wave after the QRS complex, (iii) QRS alternans, and (iv) repolarization abnormalities during tachycardia. We performed a cross-validation method using the first 300 patients to develop a logistic model to predict the tachycardia diagnosis. The model was validated through the remaining 170 patients. The invasive study demonstrated AVNRT in 314 patients and AVRT in 156 patients. The presence of pseudo r' deflection and/or pseudo s-wave, a visible P-wave after the QRS complex, and QRS alternans were selected by a stepwise multiple logistic regression analysis as predictors for the diagnosis of AVNRT. The application of the model in the validation group showed a shrinkage prediction factor of 3%. Diagnostic probabilities for both tachycardia mechanisms depending on every combination of selected ECG criteria were > 75% in 70% of the patients. Conclusion The presence of pseudo r' deflection and/or pseudo s-wave, an identifiable P-wave after the QRS, and QRS alternans during tachycardia permit us to derive a reliable logistic model to predict the mechanism of paroxysmal AVRT in patients without pre-excitation. Precise probabilities for a correct diagnosis associated with every combination of those classical ECG criteria are presented.