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[A-V conduction block at His bundle level; as the cause of syncopal crisis in patients with normal ECG (author's
Insights
Syncopal crisis can stem from His bundle disturbances, often missed by standard ECGs. Continuous monitoring and electrophysiologic studies are crucial for diagnosing these intermittent conduction issues.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Syncopal crisis diagnosis can be challenging.
- Intermittent atrioventricular (A-V) conduction disturbances may present with normal surface electrocardiograms (ECGs).
Observation:
- A series of 5 patients with syncopal crisis due to His bundle A-V conduction disturbances were studied.
- The His bundle disturbances were intermittent, with normal surface ECGs and no visible A-V block or QRS broadening.
Findings:
- Standard ECGs are insufficient for diagnosing His bundle conduction disturbances causing syncope.
- Continuous cardiac monitoring (Holter system, Intensive Care Unit) and electrophysiologic studies are essential for diagnosis.
Implications:
- Early and accurate diagnosis of His bundle conduction disturbances is vital for managing syncopal crisis.
- These findings highlight the need for advanced diagnostic tools beyond surface ECGs in specific patient populations.
- Understanding intermittent conduction abnormalities is key to preventing syncope and related complications.
Abstract:
The history, clinical evolution and complementary studies used to identify the diagnostic etiology of syncopal crisis in a series of 5 patients are presented. The crisis consisted of advanced disturbances of the A-V conduction at the level of the His bundle. It is pointed out that although the evolution of the disturbance was intermittent, the surface ECG was normal and neither A-V block nor broadening of the QRS complex were seen. The importance of continued monitorization, whether as out-patients (Holter system) or, in some cases in an Intensive Care Unit, as well as the need to practice electrophysiologic studies in all these cases as the only way of establishing a firm diagnosis, are underlined. The fact that these disturbances do not always lead to an advanced blockage of A-V conduction is discussed as being reminiscent of the prospective and retrospective studies in the similar case of bi-fascicle block.