Cardiac Memory: A Case Report and Review of the Literature

Memory T-Waves: An Uncharted Territory in T-Wave Inversions

T-wave inversions on electrocardiograms (ECGs) can present a diagnostic challenge due to their association with various underlying causes. One less-explored cause is memory T-waves, a phenomenon characterized by T-wave inversions, often seen in chest and inferior leads, following a period of abnormal ventricular conduction. In this case report, we discuss the intriguing case of an 80-year-old woman who recently underwent percutaneous coronary intervention (PCI) for a myocardial infarction and subsequently developed memory T-waves. We are also discussing how important it can be to understand and recognize memory T-waves, as it will avoid further unnecessary tests and longer hospital stays.

Pediatric T-wave memory after accessory pathway ablation in Wolff-Parkinson-White syndrome

BACKGROUND

Altered ventricular depolarization due to manifest accessory pathway conduction (ie, Wolff-Parkinson-White syndrome) leads to repolarization abnormalities that persist after pathway ablation. The term T-wave memory (TWM) has been applied to these changes, as the postablation T-wave vector "remembers" the pre-excited QRS vector. In adults, these abnormalities can be misinterpreted as ischemia leading to unnecessary interventions. To date, no comprehensive studies have evaluated this phenomenon in the pediatric population.

OBJECTIVE

The purpose of this study was to define TWM in the pediatric population, identify preablation risk factors, and delineate the timeline of recovery.

METHODS

Pre- and postablation electrocardiograms (ECGs) in patients ≤25 years were analyzed over a 5-year period. Frontal plane QTc interval, T-wave axis, QRST angle, and T-wave inversions were used to identify patients with TWM. Univariate analysis was performed to determine the association of preablation ECG features with the outcome of TWM.

RESULTS

TWM was present in 42% of pediatric patients, with resolution occurring within 3 months of ablation. Preablation QRS axis <0° was a strong predictor of TWM (odds ratio [OR] 15.2; 95% confidence interval [CI] 5.7-40), followed by posteroseptal pathway location (right posteroseptal-OR 8.9; 95% CI 4.2-18.8; left posteroseptal-OR 6.1; 95% CI 1.7-22.3). The degree of pre-excitation had a modest association with the development of TWM. No adverse events were observed.

CONCLUSION

TWM is less common in children compared to adults, and normalization occurred within 3 months postablation. The most predictive features for the development of TWM include a leftward pre-excited QRS axis and posteroseptal pathway location.

Cardiac Memory-induced T-wave Inversions

Introduction

Cardiac memory refers to T-wave inversions that result when normal ventricular activation resumes following a period of abnormal ventricular activation.

Case Report

We present a case of a 29-year-old man with a pacemaker who presented with new, deep symmetric T-wave inversions caused by cardiac memory.

Discussion

Abnormal ventricular activation is most commonly induced by ventricular pacing but can also occur in the setting of transient left bundle branch blocks, ventricular tachycardia, and intermittent ventricular pre-excitation.

Conclusion

Recognition of this phenomenon may help to reduce unnecessary admissions, cardiac testing, and cardiac catheterizations.