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QRS complex voltage changes associated with supraventricular tachycardia.
1Cattedra di Cardiologia and tCattedra di Cardiologia Pediatrica, Università di Messina, Milano, Italy. oretogmp@tin.it
Journal of Cardiovascular Electrophysiology
|January 19, 2002
Summary
Supraventricular tachycardia (SVT) significantly increases QRS complex voltage, regardless of the reentrant circuit. This voltage increase in SVT may be due to reduced ventricular filling or proximity effects.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Supraventricular tachycardia (SVT) is a common arrhythmia.
- Understanding voltage changes during SVT is crucial for diagnosis and management.
Purpose of the Study:
- To evaluate changes in ventricular complex voltage during narrow QRS SVT.
- To determine if these voltage changes differ between AV nodal reentrant tachycardia (AVNRT) and AV reentrant tachycardia (AVRT).
Main Methods:
- Studied 145 patients undergoing catheter ablation for SVT (85 AVNRT, 60 AVRT).
- Measured QRS complex voltage in 12 leads during SVT and sinus rhythm (SR), averaging four beats.
- Calculated the sum of QRS voltages (sigmaSVT, sigmaSR) and QRS axis in both rhythms.
Main Results:
- QRS complex voltage significantly increased during SVT compared to SR in multiple leads (II, III, aVF, V2-V6).
- Total QRS voltage (sigmaSVT) was significantly greater than sigmaSR.
- Voltage changes were similar in AVNRT and AVRT patients; no correlation with tachycardia rate was found.
- Significant shift in QRS axis observed during SVT.
Conclusions:
- QRS voltage increase is a consistent finding in reentrant SVT, irrespective of the circuit.
- This phenomenon may be attributed to reduced ventricular filling, leading to proximity effects or altered potential transmission.
- Findings suggest a potential mechanism for altered ECG morphology during SVT.