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- 72 bpm
- Sinus rhythm
On the 12 lead ECG (non-rhythm strip recording)
- PR - Normal (~200ms)
- QRS - Normal (100ms)
- rSr' pattern lead V1
- T wave inversion leads II, III, aVF
- Prominent T waves leads aVL, V2-4
On the lead II rhythm strip
- Variable conduction
- Complexes #1-3, 8-10 normal PR with same morphology as 12 lead complexes
- Complexes #4-7, 11-13 pr shortening with QRS prolongation and distinctly different QRS morphology
- Rhythm strip likely reflects intermittent pre-excitation conduction down accessory pathway (AP)
- T wave changes seen on the 12 lead ECG may reflect:
- Electrolyte abnormality
- Most likely cardiac T-wave memory secondary to intermittent AP conduction
'Cardiac T-wave memory' this occurs after a period of abnormal ventricular depolarisation e.g. paced rhythm, VT, SVT with aberrancy and pre-excitation. There is a recent paper by Vakil that is freely available (linked to below) that contains a nice overview of T-wave memory, proposed mechanisms, and a case example. Deep T wave inversion corresponds to the leads in which a negative QRS was seen in the patients pre-excited ECG. Patient's often require work-up to exclude underlying ischaemia or structural disease but cardiac T-wave memory is a benign and self-resolving condition in itself.
Thanks to Adrian and Jason for sharing more resources and further reading on T-wave memory, links below:
- Lead researches on the topic Chiale PA & Elizari MV.
- "Cardiac Memory" A Struggle Against Forgetting. Folco EJ et al.
- Cardiac Memory Variations in Surface ECG Precordial Mapping. Sadiq Ali F. Baranchuk A.
- ECG Challenge from Jason's Blog.
- Wolff-Parkinson-White Syndrome: Could a Normal PJ Interval Exclude Bundle Branch Block? Chen Y, Xu Z.
- Successful Ablation of Antero-septal Accessory Pathway in the Non-Coronary Cusp in a Child. Kobayashi D, Arya SO, Singh HR.
The patient had normal electrolytes and cardiac biomarkers. Extended telemetry revealed no episodes of arrhythmia. His echo showed:
- Abnormal septal wall motion secondary to intraventricular conduction delay
- Low normal LV systolic function
- Moderate left atrium dilation
- Normal RV size and function
- Normal valvular function
References / Further Reading
Life in the Fast LaneTextbook
- Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.