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A new ECG sign of an accessory pathway in sinus rhythm: pseudo partial right bundle branch block
E W Lau1, G A Ng, M J Griffith
1Department of Cardiology, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK. e.w.lau@bham.ac.uk
Insights
Detecting accessory pathways is crucial for preventing sudden cardiac death. A pseudo right bundle branch block pattern on an electrocardiogram (ECG) may indicate a left-sided accessory pathway, aiding diagnosis.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Accessory pathways can cause life-threatening arrhythmias like pre-excited atrial fibrillation.
- Early detection of accessory pathways is vital for timely intervention, such as radiofrequency ablation.
- Classic electrocardiogram (ECG) signs like short PR intervals or delta waves are not always present.
Observation:
- A pseudo partial right bundle branch block pattern (rSr' complex in lead V1) can be the only sign of a left-sided accessory pathway.
- This ECG pattern may be observed in patients without other typical indicators.
- An electrophysiological mechanism is proposed to explain this association.
Findings:
- The study proposes a novel ECG sign for diagnosing accessory pathways during sinus rhythm.
- The pseudo partial right bundle branch block pattern in lead V1 is identified as a potential sole indicator of a left-sided accessory pathway.
- This finding expands the diagnostic criteria for accessory pathways.
Implications:
- This research offers a new, potentially simpler ECG-based method for identifying individuals with accessory pathways.
- Improved detection can lead to earlier treatment and reduced risk of sudden cardiac death.
- Further validation of this ECG sign could enhance diagnostic accuracy in clinical practice.
Abstract:
It is clinically important to be able to detect the presence of an accessory pathway, as pre-excited atrial fibrillation is a well recognised cause of sudden cardiac death, for which there is a potential "cure" in the form of radiofrequency ablation of the pathway. The classic manifestations such as a shortened PR interval or delta waves may not always be present. In certain patients a pseudo partial right bundle block pattern-that is, an rSr' complex in lead V1- may be the sole manifestation of a left sided accessory pathway. An electrophysiological mechanism is proposed for this pattern and it is suggested that this pattern may be used as a new ECG sign for diagnosing an accessory pathway in sinus rhythm.