Prevalence of late potentials in patients undergoing Holter monitoring

High-frequency, low-amplitude signals detected in the terminal portion of the surface QRS, called late potentials (LP), have been shown to correlate with inducibie sustained ventricular tachycardia and to be absent in normal subjects. We studied LP in 152 patients without a history of sustained ventricular tachycardia who underwent 24-hour Holter monitoring for varying clinical indications (chest pain 21%, syncope 17%, palpitations 32%, dizziness 20%, other 10%). Twenty-one patients (14%) had a positive test. Of the 152 patients, 84 (55%) had complex ventricular arrhythmias and 68 (45%) had simple or no ventricular arrhythmias. Complex ventricular arrhythmias were present in 71% of patients with and in 52% of those without LP. In conclusion: (1) patients without history of sustained ventricular tachycardia who demonstrate complex nonsustained ventricular arrhythmias on Holter monitoring have a low prevalence of LP; (2) the presence of LP on signal-averaged ECG indicates an electrical property of the heart, which is distinct from complex ventricular arrhythmias detected on Holter monitoring.