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[Unmasking an exclusively retrograde accessory pathway by catecholamines]
P Weismüller1, S Thamasett, G Grossmann
1Abteilung Innere Medizin II (Kardiologie, Angiologie, Pneumologie, Nephrologie) Universitt Ulm.
Zeitschrift Fur Kardiologie
|December 1, 1996
Summary
Electrophysiological testing can reveal hidden accessory pathways causing tachycardia, especially after administering catecholamines like orciprenaline. This improves diagnosis and guides successful radiofrequency ablation for narrow QRS complex tachycardias.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Narrow QRS complex tachycardias require precise diagnosis for effective treatment.
- Electrophysiological (EP) testing is crucial for evaluating cardiac arrhythmias.
- Accessory pathways can cause reentrant tachycardias, but their detection can be challenging.
Observation:
- A 52-year-old male presented with frequent narrow QRS complex tachycardias.
- Standard EP testing, including atrial and ventricular stimulation, failed to induce tachycardia or reveal accessory pathway conduction.
- Administration of orciprenaline unmasked a ventriculoatrial (VA) accessory pathway, enabling induction of atrioventricular (AV) macro-reentrant tachycardia.
Findings:
- The accessory pathway exhibited unidirectional VA conduction, only active during adrenergic stimulation.
- Retrograde atrial activation localized the earliest signal to the left anterolateral region.
- Radiofrequency catheter ablation successfully eliminated the accessory pathway, confirmed by repeat orciprenaline challenge.
Implications:
- Catecholamine administration during EP testing is essential for uncovering latent accessory pathways.
- This diagnostic approach is vital for identifying the mechanism of undiagnosed tachycardias.
- Successful ablation of the identified accessory pathway resolved the patient's recurrent tachycardias.