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U wave manifesting in alternating beats: The bigeminal U wave
Francesco Luzza1, Francesco Catanzariti1, Michela Navarra1
1Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.
Journal of Electrocardiology
|August 8, 2025
Summary
This study details a unique "bigeminal U wave" pattern on electrocardiograms, appearing in alternating heartbeats. The U wave
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Physiology
Background:
- The U wave on an electrocardiogram (ECG) is a poorly understood phenomenon.
- Its origin and clinical importance remain subjects of ongoing research.
- U waves typically manifest after the ventricular complex in specific ECG leads.
Purpose of the Study:
- To report a distinctive case of U wave presentation.
- To investigate the relationship between U wave occurrence and preceding cardiac cycle length.
- To explore potential mechanisms underlying this unique U wave pattern.
Main Methods:
- Case report of a patient exhibiting an unusual U wave pattern.
- Analysis of electrocardiogram (ECG) recordings to identify the U wave characteristics.
- Correlation of U wave presence with preceding cardiac cycle durations.
Main Results:
- A unique electrocardiogram (ECG) pattern of "bigeminal U wave" was observed.
- The U wave appeared exclusively in alternating cardiac cycles.
- U wave occurrence was associated with preceding cardiac cycle lengthening, but not shortening.
Conclusions:
- The observed "bigeminal U wave" phenomenon is rare and requires further investigation.
- Prolonged ventricular action potentials in M cells are hypothesized as a potential contributing factor.
- This case highlights the complex and not fully understood nature of U wave generation.
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