Ventricular Late Potentials Immediately Post ST-Elevation Myocardial Infarction, and Very Long-Term Mortality.

BACKGROUND: The very long-term prognostic significance of ventricular late potentials (VLP) in patients post ST-elevation myocardial infarction (STEMI) is unclear.

OBJECTIVES: To evaluate the long-term predictive value of VLP for mortality post-STEMI.

METHODS: We conducted serial signal-averaged electrocardiography (SAECG) measurements in 63 patients on the 1st, 2nd and 3rd day pre-discharge, and 30 days after STEMI in patients admitted in 2001. We followed the patients for 10 years and correlated the presence of VLP with all-cause and cardiovascular mortality.

RESULTS: The mean age was 59.9 ± 12.3 years. Thrombolysis was performed in 41 patients (65%). Percutaneous coronary intervention was performed pre-discharge in 40 patients (63%) and coronary artery bypass grafting in 7 (11%). Five consecutive measurements to define the presence of VLP were obtained in 52 patients (21 with VLP and 31 without). We found a higher prevalence of VLP in males compared to females (QRS segment > 114 msec, 51% vs. 12%, P = 0.02, duration of the low amplitude signal < 40 mV) in the terminal portion of the averaged QRS complex > 38 msec, 47% vs. 25%, P = 0.05). Over 10 years of follow-up, 14 (22%) patients died, 10 (70%) due to cardiovascular non-arrhythmic complications, 6 with VLP compared to only 3 without (28.6% vs. 9.7%, P = 0.125, hazard ratio = 2.96, confidence intervals = 0.74-11.84) (are these numbers meant to total 10?).

CONCLUSIONS: Over 10 years of follow-up, the presence of VLP in early post-STEMI is not predictive of arrhythmic or non-arrhythmic cardiovascular mortality.