Giant Negative T-Waves as Cardiac Memory Phenomenon Following Ablation of Right-Sided Posteroseptal Accessory Pathway.

We present a paradigmatic example of "cardiac memory," characterized by deep, giant, and negative T-waves in the inferior leads, after a successful ablation of a right-sided posteroseptal accessory pathway. Copyright:

INTRODUCTION

The “cardiac memory” is a phenomenon originally described after ventricular pacing[1] and also after ventricular tachycardia,[2] intermittent bundle branch block,[3] and following periods of preexcitation in patients with Wolff–Parkinson–White (WPW) syndrome.[4] This phenomenon is characterized by T-wave inversions occurring after a period of altered ventricular depolarization where the T-vector has the same direction as the vector of the previous altered QRS complex.[5] Previous studies showed that these repolarization abnormalities may occur after successful ablation of overt accessory pathways, mostly posteroseptal, remaining some weeks after the ablation procedure.

CASE PRESENTATION

Figure 1a shows the electrocardiogram (ECG) of a 24-year-old boy with an overt preexcitation due to a right-sided posteroseptal accessory pathway (delta wave positive in I, II, and aVL, V2–V6 and negative in III, aVR, and V1). The patient was referred to our center because of recurrent episodes of palpitations. The accessory pathway was identified in the right posteroseptal portion of the right atrium, near the ostium of the coronary sinus, and a radiofrequency application successfully resulted in disappearance of the preexcitation and dissociation of ventriculo-atrial retroconduction. The ECG performed 20 h later still showed the absence of the prexcitation and also deep, giant, negative T-waves in II, III, and aVF [Figure 1b], secondary to “cardiac memory.”

Figure 1

(a) The picture shows a manifest preexcitation due to a right-sided posteroseptal accessory pathway (delta wave positive in I, II, aVL, and V2–V6 and negative in III, aVR, and V1). (b) The electrocardiogram after the ablation shows the absence of the prexcitation and also deep, negative T-wave in II, III, and aVF (b), due to “cardiac memory

DISCUSSION

Previous studies reported that cardiac memory developed in 47%–100% of cases following ablation of overt WPW;[5] these postablation abnormalities are predominantly reflected in the horizontal plane in those patients with overt left-sided accessory pathways and in the frontal plane in those with right-sided accessory pathways, as in our case. The resumption of this phenomenon after ablation commonly occurs within 3 months, but 10% of available ECG shows the persistence of cardiac memory beyond this period.[5]

As radiofrequency ablation has become a cornerstone for the treatment of WPW syndrome, it is crucial for physicians to be aware of these ECG changes which can persist for several months. As in our case, T-wave inversions following radiofrequency ablation of posterospeptal accessory pathways are located in the inferior leads and might be misinterpreted as a sign of inferior wall ischemia. When these patients come to the emergency room for a chest pain, it might be difficult to differentiate between cardiac memory and myocardial ischemia. As shown in our case, when the repolarization abnormalities of cardiac memory are represented by deep, giant, negative T-waves, this might resemble ischemia. Although the majority of patients with WPW syndrome are young and mostly in a clinical health status and therefore unlikely to suffer from ischemic heart disease, Aunes-Jansson[5] reported that 20 of 125 (16%) patients in their study were more than 50 years old and the oldest 76 years.

CONCLUSION

Our case represents a paradigmatic example of cardiac memory with unexpectedly giant negative T-waves following catheter ablation of a right-sided posteroseptal accessory pathway.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.