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- Title
QRS Complex Voltage Changes Associated with Supraventricular Tachycardia.
- Authors
Oreto, Giuseppe; Luzza, Francesco; Badessa, Francesco; Calabrò, Maria Pia; Mazzone, Patrizio; Carerj, Scipione; Saporito, Francesco; Pappone, Carlo
- Abstract
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 13 leads, the QRS complex voltage was measured, and the results of four heats were averaged both in SVT and in sinus rhythm (SR). The sum (Σ) of the QRS voltages measured in the 12 leads during SVT (ΣSVT) and SR (SSR) 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 V2 to V6. In addition, ΣSVT was significantly greater than ΣSR. Only lead V1 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.
- Subjects
VENTRICULAR tachycardia; CATHETER ablation; VOLTAGE-clamp techniques (Electrophysiology); ELECTROCARDIOGRAPHY; ELECTROTHERAPEUTICS
- Publication
Journal of Cardiovascular Electrophysiology, 2001, Vol 12, Issue 12, p1358
- ISSN
1045-3873
- Publication type
Article
- DOI
10.1046/j.1540-8167.2001.01358.x