Value of the aVR lead in differential diagnosis of atrioventricular nodal reentrant tachycardia

AimsDespite the several electrocardiographic (ECG) criteria, misclassification may still occur in differential diagnosis of the regular paroxysmal supraventricular tachycardia (PSVT). The aim of the present study was to evaluate the diagnostic accuracy of the aVR lead in ECG differentiation of atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT).Methods and resultsA 12-lead ECG was recorded in 150 consecutive patients (96 women, mean age, 45 ± 13.5 years) with drug-refractory regular 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 as well as our newly proposed criterion of pseudo-r� in the lead aVR. Mechanism of arrhythmia was confirmed by the electrophysiological study and the successful catheter ablation. Patients with AVNRT were older (50 ± 10 vs. 37 ± 15 years, P 0.001), predominantly female (71 vs. 53, P 0.03), and presented with slower tachycardia (175 ± 25 vs. 186 ± 26 b.p.m., P 0.01). Among the ECG criteria of the AVRT diagnosis, visible P-wave with RP interval <100 ms had highest diagnostic accuracy (sensitivity 79, specificity 87, and positive predictive value 79). For AVNRT diagnosis, pseudo-r� in aVR had a higher sensitivity, specificity, and predictive values compared with the conventional criteria of the pseudo-r� in V1 and pseudo-s in inferior leads (all P < 0.05).ConclusionsNew criterion of pseudo-r� in lead aVR appears to be more accurate than the standard ECG criteria for ECG diagnosis of AVNRT. © 2012 Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2012. For permissions please email: journals.permissionsoup.com

Misattribution of sensory input reflected in dysfunctional target: non-target ERPs in schizophrenia

Background. While numerous studies have found disturbances in the Event-Related Potentials (ERPs) of patients with schizophrenia linked to task relevant target stimuli (most notably a reduction in P300 amplitude), few have examined ERPs to task irrelevant non-targets. We hypothesize, from current models of dysfunction in information processing in schizophrenia, that there will be less difference between ERPs to targets and non-targets in patients with schizophrenia than in controls. Methods. EEGs were recorded for 40 subjects with schizophrenia and 40 age and sex matched controls during an auditory oddball reaction time task. ERPs to the targets and non-targets immediately preceding the targets were averaged separately. Results. There was a disturbance in ERPs to targets but also to non-targets (reduced N100 amplitude and earlier P200 latency) and the difference between target and non-target ERP components (N100 and P200 amplitude and P200 latency), was significantly reduced in the schizophrenic group compared with controls. Conclusions. These findings suggest a disturbance in processing task relevant and irrelevant stimuli, consistent with Gray\u27s (1998) hypothesis of misattributions in the ‘match[ratio]mismatch’ of novel (target) and familiar (non-target) sensory input compared with stored information