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[Supraventricular arrhythmia imitating ventricular ectopy due to simultaneous conduction in dual AV nodal pathways--a
1I Kliniki Chorób Wewnetrznych Slaskiej Akademii Medycznej w Katowicach.
Insights
In patients with premature ventricular complexes after myocardial infarction, transesophageal pacing revealed a dual pathway within the atrioventricular (AV) node as the likely cause. Verapamil effectively suppressed these wide QRS complex arrhythmias, suggesting a non-ventricular origin.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Premature ventricular complexes (PVCs) can complicate myocardial infarction (MI).
- The precise mechanism of some PVCs, particularly those with wide QRS complexes, remains incompletely understood.
- Programmed electrical stimulation is a valuable tool for elucidating arrhythmia mechanisms.
Observation:
- In three patients post-MI experiencing frequent PVCs, transesophageal pacing was used to induce the arrhythmia.
- ECG analysis of the induced PVCs suggested a potential mechanism involving simultaneous activation of two pathways within the atrioventricular (AV) node.
- The differing conduction times through these AV node pathways resulted in double ventricular activation, with the second activation being aberrantly conducted.
Findings:
- The study suggests a dual pathway mechanism within the AV node can cause PVCs with wide QRS complexes in post-MI patients.
- Verapamil demonstrated efficacy in suppressing these arrhythmias.
- The successful suppression by verapamil supports a non-ventricular origin for these specific wide QRS complex arrhythmias.
Implications:
- This finding offers a potential explanation for certain types of ventricular ectopy following myocardial infarction.
- Understanding the AV nodal role may guide therapeutic strategies for managing these arrhythmias.
- Further research into AV nodal reentry mechanisms could lead to more targeted treatments.
Abstract:
In 3 post-MI patients with multiple premature ventricular complexes, programmed transoesophageal pacing generated the arrhythmia and an ecg tracing was taken. Analysis of the ecg suggested that simultaneous activation of two pathways within the A-V node maybe the cause of the arrhythmia. The activation signal reaches the ventricle through both pathways but as the conduction time differs the ventricles can be twice activated. However the second activation is aberrantly conducted leading to an ecg picture of ventricular ectopy. Verapamil suppressed the arrhythmia which further indicates the non-ventricular origin of these wide QRS complexes.