Continuous T-wave alternans monitoring and prediction of ventricular arrhythmias during coronary reperfusion therapy

The article by Takasugi et al., published online in the Journal on 12 February 2011, pertains to the innovative implementation of monitoring of T-wave alternans (TWA), starting in the emergency room and continuing during percutaneous coronary intervention (PCI) in 19 patients with an acute coronary syndrome, and the administration of intracoronary vasodilator in one patient with coronary spasm, for the prediction of the occurrence of ventricular tachyarrhythmia (VTA).1 The authors employed leads V1 and V5 and the modified moving average technique, and found higher values of TWA in patients with, than without, VTA. All in all, three patients had VTA, with two showing an increase in TWA prior to the onset of VT, and one showing macroscopic TWA, detected by a standard electrocardiogram (ECG) prior to VTA, but not by the TWA monitoring. This limited experience reveals a role for TWA in the prediction of VTA occurring in the peri-PCI period, and attests to the regionality of the TWA phenomenon (a previously noted characteristic), which may necessitate the use of the 12-lead ECG for its detection. Reperfusion is associated with major ST/T wave alterations and the phenomenon of ST/T reperfusion peak,2 which could be the reason for the upsurge of TWA, if there is a relationship between the magnitude of the TWA and the amplitude of the T-waves, used in the calculation of the TWA.3 This reader will be grateful to the authors if they provide him with a response to the following question: was there a relationship between the increase in the TWA and the possible increase in the T-wave amplitude in leads V1 and V5 in the patients who showed change in TWA prior to the occurrence of VTA? If there was such a relationship the upsurge of TWA was not due to increased arrhythmogenic risk, predicting the onset of VTA, but merely a consequence of an increased T-wave amplitude.3 Conflict of interest: none declared.