This ECG is from a 42 yr old male with known pre-excitation who presented with a 3 day history of episodic palpitations, dizziness and GI illness.
Click to enlarge
NOTE the rhythm strip on this ECG has not been recorded concurrently with the 12 lead ECG
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
What is cardiac T-wave memory ?
‘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.
Vakil K, Gandhi S, Abidi KS, et al. Deep T-Wave Inversions: Cardiac Ischemia or Memory? JCvD 2014;2(2):116-118. Full text here.
We’ve had some cases on the blog before with Cardiac T-wave memory:
Thanks to Adrian and Jason for sharing more resources and further reading on T-wave memory, links below:
What happened ?
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
He was referred for out-patient electrophysiology follow-up for discussion of management options related to his pre-excitation
References / Further Reading
Life in the Fast Lane
- Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
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