In anterior myocardial infarction, frequency domain is better than time domain analysis of the signal-averaged ECG for identifying patients at risk for sustained ventricular tachycardia.

Low amplitude signals at the end of the QRS in patients with prior myocardial infarction (MI) are related to fragmentation of the electrical impulse in ventricular myocardium and are known to correlate with an increased risk of sustained ventricular tachycardia (VT). We hypothesized that in patients with anterior MI (AMI), earlier activation of the damaged anterior wall would cause an earlier fragmentation of the signal-averaged ECG (SAECG) signal, making conventional time domain analysis of late potentials difficult. We performed SAECG in 213 patients (62 with AMI and 58 with inferior MI [IMI]).