Related Experiment Videos
Intra-His bundle blocks (102 cases)
Insights
Accurate His bundle exploration is crucial for detecting intra-His bundle blocks, often missed on standard ECGs. This study highlights the prevalence and varied presentation of these blocks, emphasizing the need for advanced diagnostic methods.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Intra-His bundle (intra-HB) blocks are frequently misdiagnosed as supra- or infrahisian blocks.
- Routine His bundle exploration may miss concealed or paroxysmal intra-HB blocks.
Purpose of the Study:
- To investigate the diagnostic challenges and characteristics of intra-His bundle blocks.
- To emphasize the necessity of advanced His bundle exploration techniques for accurate diagnosis.
Main Methods:
- Analysis of 102 cases with intra-HB blocks.
- Detailed His bundle activity recording (proximal and distal ends).
- Inclusion of dynamic tests and drug injections for concealed block detection.
Main Results:
- 20% of cases showed no surface electrocardiogram criteria for AV block.
- Only 4% exhibited a completely normal conduction pattern (normal PR interval and QRS).
- Prevalence of block degrees: 35% first-degree, 23% second-degree, 42% third-degree intra-HB blocks.
Conclusions:
- Advanced His bundle exploration is vital for identifying intra-HB blocks, especially paroxysmal types.
- Intra-HB blocks present diverse ECG findings, often without overt AV block criteria.
- Isolated intra-HB blocks were common in elderly women with chronic third-degree AV block.
Abstract:
Some intra-His bundle (intra-HB) blocks escape the routine exploration of the His bundle and are confused with supra- or infrahisian blocks. We believe that a more accurate exploration (recording of His bundle activity successively at the proximal end and the distal end of the His bundle, dynamic tests and drug injection) is needed to detect some concealed cases, mostly paroxysmal intra-HB blocks. In this series of 102 cases of intra-HB blocks, 20% had no criteria of AV block on the surface electrocardiogram, and only 4% had an intact conduction pattern (normal PR interval and normal QRS complexes.) A first degree intra-HB block was found in 35% (15 cases with a normal PR interval), a second degree intra-HB block in 23% and a thired degree intra-HB block in 42% of the cases (unidirectional in 4 cases). Of the 43% having an isolated intra-HB block, most were elderly women with a chronic third degree AV block.