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Adenosine-sensitive ventricular tachycardia. Clinical characteristics and response to catheter ablation
D J Wilber1, J Baerman, B Olshansky
1Section of Cardiology, Loyola University Medical Center, Maywood, Ill 50153.
Background:
Sustained ventricular tachycardia in the absence of structural heart disease may have diverse mechanisms. Termination of the tachycardia by adenosine suggests triggered automaticity as the etiology in many of these patients. We examined the clinical characteristics, electrophysiological responses, and results of catheter ablation in this patient subgroup.
Methods And Results:
Intravenous adenosine terminated sustained ventricular tachycardia in seven of 14 consecutive patients without evidence of structural heart disease. In each of these patients, the tachycardia had a left bundle branch block, inferior-axis QRS configuration and occurred predominantly during stress or exertion. A morphologically similar sustained tachycardia was induced in six of seven patients during programmed ventricular stimulation, although day-to-day reproducibility was poor. Signal-averaged ECGs were normal in all patients. Imaging with 123I-metaiodobenzylguanidine did not reveal focal abnormalities in any of five patients. A discrete site of origin was identified in the free wall of the pulmonary infundibulum in all patients. Limited application of direct current shocks (two patients) or radiofrequency energy (five patients) resulted in long-term abolition of spontaneous and inducible ventricular tachycardia in all patients.
Conclusions:
Adenosine-sensitive ventricular tachycardia appears to arise from relatively discrete sites predominantly located in the free wall of the pulmonary infundibulum. The localized nature of this tachycardia renders it amenable to long-term cure by catheter ablation techniques.
Insights
Adenosine-sensitive ventricular tachycardia, often occurring during exertion, originates from the pulmonary infundibulum. Catheter ablation provides a long-term cure for this condition in patients without structural heart disease.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Sustained ventricular tachycardia (VT) without structural heart disease can stem from various mechanisms.
- Adenosine's ability to terminate VT suggests triggered automaticity as a common cause.
- This study investigates the characteristics and treatment of such VT patients.
Purpose of the Study:
- To examine the clinical features of adenosine-sensitive VT.
- To understand electrophysiological responses to programmed stimulation.
- To evaluate the efficacy of catheter ablation for this specific VT type.
Main Methods:
- Adenosine administration to terminate VT.
- Programmed ventricular stimulation to induce VT.
- Signal-averaged ECGs and myocardial scintigraphy (123I-metaiodobenzylguanidine) for diagnostics.
- Catheter ablation using direct current shocks or radiofrequency energy.
Main Results:
- Adenosine terminated VT in 7/14 patients lacking structural heart disease.
- VT presented with LBBB, inferior axis, and was linked to stress/exertion.
- A discrete origin in the pulmonary infundibulum free wall was identified in all cases.
- Catheter ablation achieved long-term VT abolition in all treated patients.
Conclusions:
- Adenosine-sensitive VT originates from discrete sites, primarily the pulmonary infundibulum free wall.
- The localized nature of this VT makes it highly curable with catheter ablation.
- Catheter ablation offers a definitive treatment option for this patient subgroup.