Abstract: ObjectiveTo evaluate the diagnostic accuracy of the combining V1 and aVL or aVR lead in electrocardiographic(ECG) differentiation of atrioventricular nodal reentrant tachycardia (AVNRT) from atrioventricular reciprocating tachycardia (AVRT).MethodsA 12lead ECG was recorded in 143 consecutive patients with regular paroxysmal supraventricular tachycardia(PSVT) during both sinus rhythm and tachycardia. All ECGs were reviewed by two experienced electrophysiologists who had no knowledge of the tachycardia mechanism. The ECG recordings were evaluated for standard criteria including pseudor′wave in lead V1， notch in lead aVL， pseudor′ wave in lead aVR， RP  interval ≥100 ms， STsegment elevation ≥1.5 mm at the Jpoint lasting 80 ms in lead aVR during tachycardia， and so on. Mechanism of arrhythmia was confirmed by the electrophysiological study. ResultsPatients with AVNRT were older (P<0.01)， predominantly female (72.4% vs 50.0%，P<0.01). Among the ECG criteria of the AVRT diagnosis， visible Pwave with RP  interval ≥100 ms had the highest diagnostic accuracy (sensitivity 69.6%， specificity 87.4%， and positive predictive value 78.0%). The combination of  visible Pwave with RP  interval ≥100 ms and STsegment elevation≥1.5 mm at the Jpoint lasting 80 ms in lead aVR obviously improved the sensitivity of the AVRT diagnosis. For AVNRT diagnosis， notch in lead aVL had a higher sensitivity（60.9%）， specificity（89.3%）， and positive predictive value(89.8%) compared with the conventional criteria of the pseudor′ in V1 and pseudos in inferior leads (all P<0.05). The combination of V1 and aVL or aVR lead obviously improved the sensitivity of the AVNRT diagnosis to 78.2% and 74.7%， respectively.But the positive predictive value did not decrease obviously.ConclusionThe combination of V1 and aVL or aVR lead is helpful to improve the accuracy of AVNRT diagnosis in ECG.

Key words: tachycardia, electrocardiography, electrocardiography lead