Ventricular arrhythmias and the ATc index in patients with ischemic heart disease

: In this multicenter study a group of 1,011 patients (233 females and 778 males, aged 23-68 years, mean 53) with ischaemic heart disease was included. Only nitrates, nifedipine and diuretics were administered during the investigation. Presence of other chronic disease excluded the patients from study group. In all patients a standard 12-lead electrocardiogram was obtained, from which the QT interval was measured, and its corrected value according to the Bazett's formula calculated [formula: see text] values greater than 440 ms were regarded to be abnormal. A 24-hour ecg ambulatory monitoring was also performed in each patient, and the detected ventricular ectopic activity was classified using the Lown's criteria. Mean QTc values were compared between each class of ventricular arrhythmia. No significant differences were disclosed. All the means were below 440 ms. Also the percentages of patients with a prolonged QTc were similar for all Lown classes of arrhythmia. The patients were then divided into two larger groups: Those with low grade (class 0-2) and high grade (class 3-5) arrhythmia. The portion of patients with the pathologic QTc was not significantly different (21% vs. 28%, NS). Such incidence of QTc prolongation was described for clinically healthy population. Since a 24-hour ecg fails to disclose the entire spectrum of arrhythmia in each individual, the fraction of patients with documented VT/VF in the past was analyzed separately. This subgroup was characterized by more frequent occurrence of QTc prolongation than other patients (35% vs. 20%, p = 0.043). Thus, no firm relationship was found between QTc prolongation and ventricular arrhythmias, but increased QTc favoured the occurrence of VT/VF.