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QRS Complex Voltage Changes Associated with Supraventricular Tachycardia
Author(s) -
ORETO GIUSEPPE,
LUZZA FRANCESCO,
BADESSA FRANCESCO,
CALABRÒ MARIA PIA,
MAZZONE PATRIZIO,
CARERJ SCIPIONE,
SAPORITO FRANCESCO,
PAPPONE CARLO
Publication year - 2001
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2001.01358.x
Subject(s) - medicine , cardiology , qrs complex , sinus rhythm , tachycardia , supraventricular tachycardia , ventricle , catheter ablation , electrocardiography , atrioventricular reentrant tachycardia , ventricular tachycardia , ablation , anesthesia , accessory pathway , atrial fibrillation
QRS Voltage Changes in SVT.
Introduction: The aim of this study was to evaluate the changes in ventricular complex voltage associated with narrow QRS supraventricular tachycardia (SVT). Methods and Results: One hundred forty‐five patients undergoing catheter ablation for SVT, 85 with AV nodal reentrant tachycardia (AVNRT) and 60 with AV reentrant tachycardia (AVRT) due to a concealed accessory pathway, were studied. Four consecutive tachycardia beats and four consecutive sinus beats were analyzed, excluding the last tachycardia complex and the first sinus one. For each of the 12 leads, the QRS complex voltage was measured, and the results of four beats were averaged both in SVT and in sinus rhythm (SR). The sum (∑) of the QRS voltages measured in the 12 leads during SVT (∑SVT) and SR (∑SR) were calculated, as well as the QRS axis during SVT and SR. QRS complex voltage was significantly increased during SVT, with respect to SR, in leads II, III, aVR, aVF, and V 2 to V 6 . In addition, ∑SVT was significantly greater than ∑SR. Only lead V 1 showed a significant voltage decrease during SVT. These voltage changes were almost identical in patients with AVNRT and patients with AVRT. No relationship was found between tachycardia rate and QRS voltage variation. The QRS axis showed a significant shift during SVT, from 55.8° to 64.5°. Conclusion: QRS voltage increase occurs in reentrant SVT, independent of the underlying reentrant circuit. The phenomenon likely depends on tachycardia‐related reduced ventricular filling. This could result in displacement of the heart in such a way that the left ventricle becomes closer to the precordial electrodes (proximity effect). Alternatively, decreased intracavitary blood mass could diminish the intracardiac short‐circuiting of potentials, resulting in augmented transmission of cardiac vectors to the body surface.