[Prognostic value and development of late potentials after aortocoronary bypass. A prospective study of 100 patients].

Ventricular late potentials are post-infarction markers of the risk of ventricular tachycardia and sudden death. In order to assess their prognostic value and evolution after coronary bypass surgery, 100 patients underwent signal-averaged electrocardiographic recordings 24 hours before and 9 days after surgery, and were then prospectively followed up for 40 +/- 8 months. Patients who displayed late ventricular potentials underwent an additional recording at 5 months with 24 hour Holter monitoring. The average age of the patients was 57.0 +/- 8.4 years; 55 had previous myocardial infarction; 32 had triple vessel disease; the mean left ventricular ejection fraction was 59.7 +/- 12.4%. Ventricular late potentials were recorded in 17 patients before surgery and their left ventricular ejection fraction was significantly lower (51.4 +/- 11.5% vs 61.4 +/- 11.9%: p less than 0.05). There was one operative death in a patient with late ventricular potentials. After surgery, late ventricular potentials were only recorded in 6 patients: at the 9th postoperative day in 3 cases and at the 5th postoperative day in 3 cases. Ventricular late potentials appeared postoperatively in 5 patients, 4 of whom had suffered perioperative myocardial infarction. The recordings became normal at the 5th month in 2 of these 5 patients. Holter monitoring at the 5th month compared with a control group, showed a significant correlation between left ventricular potentials and frequent repetitive or polymorphic ventricular extrasystoles. The 40 month survival rate was excellent: 2 patients were lost to follow-up; there were 3 cardiac deaths, one of which was sudden and 4 non-cardiac deaths. All patients with late ventricular potentials were still alive. These results show that late ventricular potentials persist after coronary bypass surgery in 2/3 of patients; their prognostic significance is not obvious. The low incidence of postoperative sudden death could be attributed to the favourable overall effects of revascularisation rather than on the arrhythmogenic substrate.