Continuous T-wave alternans monitoring to predict impending life-threatening cardiac arrhythmias during emergent coronary reperfusion therapy in patients with acute coronary syndrome.

ABSTRACT

AIMS: T-wave alternans (TWA) can precede onset of ventricular tachyarrhythmia (VTA). We evaluated the usefulness of continuous TWA monitoring in ultra-short-term prediction of impending life-threatening VTA upon emergent reperfusion in acute coronary syndrome (ACS) patients. METHODS AND RESULTS: Twenty consecutive ACS patients undergoing emergent reperfusion therapy were studied. Continuous ambulatory electrocardiograms (ECGs) (leads V1 and V5) were recorded during emergency room visit and therapy. Peak TWA was determined before and after reperfusion by the modified moving average method. Coronary balloon angioplasty/stenting was successfully performed in 19 patients and intracoronary vasodilator was administered in 1 patient with coronary spasm. Three (15.0%) patients developed VTA requiring cardioversion soon after reperfusion. Peak TWA before reperfusion was higher in patients with VTA than in those without (33.0 ± 4.4 vs. 15.8 ± 4.0 µV, P < 0.001). Two patients with arrhythmia exhibited an upsurge in TWA to 75 and 105 µV before onset of VTA. In the third patient, macroscopic TWA appeared in leads V1-V4 in a 12-lead ECG prior to VTA upon pharmacological resolution of vasospasm, although the ambulatory ECG field of view could not detect the upsurge. CONCLUSION: Acute coronary syndrome patients at risk of developing VTA soon after reperfusion exhibit premonitory episodes of increased TWA. Thus, TWA monitoring may be useful for ultra-short-term prediction of life-threatening cardiac arrhythmia risk upon emergent reperfusion in ACS patients. Continuous 12-lead ECGs may be required to optimize detection of TWA, which is regionally specific.