Increased occurrence of arrhythmias in men with ischaemic type ST-segment depression during long-term ECG recording. Prognostic impact on ischaemic heart disease: results from the prospective population study 'Men born in 1914', Malmö, Sweden.
The objective of this long-term ECG (LTER) study in 394 68-year-old men, selected at random from the general population of Malmö, Sweden, was to determine the prevalence and occurrence of cardiac arrhythmias and their impact on morbidity and mortality from IHD. According to Lown classification, 29.4% (116 men) had ventricular arrhythmia (VA) group 4-5. Serious ventricular arrhythmia (Lown group 4-5) was more common in men with asymptomatic ischaemic type ST-segment depression (STD) than in those without it (37.8% vs. 26.7%: P less than 0.05). During the mean follow-up period of 53.1 months there were seven IHD deaths (6%) among the 116 patients with VA, Lown 4-5, and nine IHD deaths (3.2%) among the 278 patients without serious VA, Lown 0-3, (P = 0.26). Six and three of these deaths, respectively, were considered to be sudden (P = 0.022). The increased cardiac event rate (fatal or non-fatal MI or deaths due to chronic IHD) associated with a serious ventricular arrhythmia disappeared when history of IHD at baseline and occurrence of STD during LTER were taken into account. The study did not provide any evidence to suggest that ventricular arrhythmia was triggered by myocardial ischaemia. Five of 9 (56%) deaths due to IHD in men with STD occurred among the 38% (37/98) of patients who belonged to Lown class 4-5. It is concluded that the prognostic information derived from LTER can be improved by combined monitoring of STD and ventricular arrhythmias.