Postinfarction risk assessment for sudden cardiac death using late potential analysis of the digital Holter...

Noninvasive postinfarction risk assessment for sudden cardiac death is limited. Standard analysis of the signal-averaged QRS complex can identify patients at risk for monomorphic ventricular tachycardia, but its value for discriminating patients at risk for sudden death is low.

The aim of this study was to prospectively investigate repeated late potential analysis of digital Holter ECG and compare it with standard analysis of the signal-averaged QRS complex within a short ECG period and with common clinical risk factors for sudden cardiac death in 756 consecutive patients after acute myocardial infarction. Digital Holter ECG were subdivided into 5-minute segments, and late potential analysis was performed on each 5-minute segment. During follow-up of 32 +/- 15 months, 35 patients died of sudden cardiac death and 50 patients died of nonsudden cardiac death. Sudden cardiac death was associated with ejection fraction < 40%, nonsustained ventricular tachycardia, creatine kinase > 1,000 IU/L, and late potentials in > 75% of analyzed Holter ECGs (abnormal LP75), but not with late potentials determined by only a short ECG period. According to multivariate analysis, the best independent significant predictor of sudden cardiac death was abnormal LP75 (P = 0.002, sensitivity 29%, specificity 96%, positive predictive value 40%, negative predictive value 97%). Nonsudden cardiac death was associated with ejection fraction < 40% (P = 0.001).

Late potential analysis of digital Holter ECG is a powerful tool that can be used to determine postinfarction patients at risk for sudden cardiac death and is optimized when combined with determination of ejection fraction.