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Narrow-Complex Tachycardia With Intermittent Irregularity and Variable QRS Morphology.
Juan Mundisugih1, Rajiv Mahajan2
1Department of Cardiology, Westmead Hospital, Westmead, New South Wales, Australia; Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
JACC. Case Reports
|May 21, 2026
Summary
Serial electrocardiogram analysis, focusing on QRS morphology changes, is crucial for diagnosing complex arrhythmias. This method aids in understanding underlying mechanisms beyond simple pattern recognition for accurate patient management.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Arrhythmias pose diagnostic challenges, often requiring advanced interpretation of electrocardiogram (ECG) data.
- Complex tachyarrhythmias can present with variable regularity and QRS morphology, complicating diagnosis.
Purpose of the Study:
- To highlight the diagnostic utility of serial ECG analysis in complex tachyarrhythmia cases.
- To emphasize the importance of detailed QRS morphology assessment for elucidating arrhythmia mechanisms.
Main Methods:
- Case presentation of an 83-year-old patient with palpitations.
- Serial electrocardiogram (ECG) monitoring and analysis.
- Detailed assessment of QRS morphology variations during tachycardia.
Main Results:
- Serial ECGs revealed narrow-complex tachycardia with changing QRS morphology and regularity.
- Morphological analysis provided insights into the underlying mechanisms of the complex arrhythmia.
Conclusions:
- Serial ECG analysis, especially tracking QRS morphology, offers critical diagnostic information.
- Detailed morphological evaluation aids in precise identification and management of complex arrhythmias.
- This approach moves beyond basic pattern recognition to uncover specific arrhythmia mechanisms.
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