Differential Procedure Of Narrow Qrs Complex Tachycardia Basing On Lead V₁and Avl In Electrocardiograms

ObjectiveTo observe the differential algorithms of slow-fast atrioventricular node reentrant tachycardia(AVNRT) and overt atrioventricular reciprocating tachycardia(O-AVRT), so to propose a set of differential procedure and evaluate the clinical significance.MethodsWe randomly selected277patients who were in hospital for "proximal supraventricular tachycardia" and received radiofrequency ablation. We collected the electrocardiograms of both sinus rhythm and tachycardia. In the first part, we observed the clinical significance and differential algorithms in165patients (90in group AVNRT,75in group O-AVRT). According to the sensitivity, specifity, PPV and NPV of every algorithm, we proposed a set of differential procedure basing on pseudo r wave in lead V1and terminal notching of QRS complex in lead avL. In the second part, we carried on an prospective research on the other112patients" electrocardiograms, compared the diagnostic results with the electrophysiological examination, and evaluated the accuracy of the procedure.Results1. Age of the first onset of palpitation and the heart rate while tachycardia were not significantly different in AVNRT and O-AVRT groups (P>0.1)2. Electrical axis deviation of p wave and the alteration of QRS complex were seldomly seen in both groups, and were of no significant differences (P>0.75).3. Pseudo r’wave in lead V1combined with terminal notching of QRS complex in lead avL was more frequently seen in AVNRT (38.89%vs2.67%, P<0.005). The PPV and NPV of diagnosing AVNRT were94.59%and57.03%. 4. Pseudo q wave, pseudo s wave or the disappearance of original s wave in the inferior leads were more frequently seen in AVNRT (35.56%vs8.00%,p<0.005, PPV84.21%, NPV54.33%).5. RP interval longer than70ms (4.44%vs73.33%. P<0.005). ST segment elevation in lead avR (30.00%vs62.67%,p<0.005) or depression over0.2mV in precordial leads (21.11%vs66.67%,p<0.005) were more frequently seen in O-AVRT.6. The differential procedure basing on lead V1and avL correctly diagnose91.38%of AVNRT and88.89%of O-AVRT.Conclusions1. Age of the first onset of palpitation and the heart rate while tachycardia were of no accurate significance in the diagnosis of reciprocating mechanisms of tachycardia.2. Pseudo r’ wave in lead V1combined with terminal notching of QRS complex in lead avL was an accurate algorithm in the diagnosis of AVNRT.3. Pseudo q wave, pseudo s wave or the disappearance of original s wave in the inferior leads were more frequently seen in AVNRT.4. RP interval longer than70ms, ST segment elevation in lead avR or depression over0.2mV in precordial leads indicated O-AVRT.6. The differential procedure basing on lead V1and avL can improve the accuracy of differential diagnosis between slow-fast AVNRT and overt O-AVRT.