Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway.

OBJECTIVE

The present study aimed to evaluate the diagnostic value of specific ECG markers in the differentiation of common type atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) via a concealed accessory pathway.

METHODS

One hundred and ten ECGs with paroxysmal narrow QRS complex, short RP tachycardia were evaluated. Subjects with overt ventricular pre-excitation during sinus rhythm were excluded from the study. The mechanism of arrhythmia was established during the electrophysiological study and confirmed by the efficacy of radiofrequency ablation.

RESULTS

Of the 110 patients, 74 displayed common type AVNRT and 36 AVRT. Predictors of AVNRT were the presence of pseudo r'-waves in lead V1 [sensitivity 39.19%; specificity 97.14%; positive predictive value (PPV) 96.67%; negative predictive value (NPV) 43.04%] and pseudo S-waves in inferior leads (sensitivity 28.38%; specificity 94.29%; PPV 91.30%; NPV 38.37%). In the setting of visible P-waves, an RP interval < or =90 ms favoured the diagnosis of AVNRT (sensitivity 57.14%; specificity 80.65%). Predictors of AVRT were QRS alternans (sensitivity 50%; specificity 89.19%; PPV 69.23%; NPV 78.57%) as well as ST-segment alterations during tachycardia. The overall sensitivity, specificity, PPV and NPV of ST-segment depression for discriminating AVRT from AVNRT were 97.22%, 58.11%, 53.03%, 97.73%, respectively. Similarly, the sensitivity, specificity, PPV and NPV of ST-segment elevation in lead aVR were 94.44%, 58.11%, 52.31%, and 95.56%, respectively. Multiple logistic regression analysis showed that ST-segment depression [(odds ratio (OR): 12.67, 95% confidence interval (CI): 1.77-90.81, P = 0.011)] and QRS alternans (OR: 9.43, 95% CI: 1.38-64.37, P = 0.022) displayed the highest predictive ability favouring the diagnosis of AVRT.

CONCLUSIONS

Twelve-lead ECG parameters may help to differentiate the mechanism of supraventricular tachycardia prior to the ablation procedure.