Aim: To assess whether 24-h ambulatory ECG (AECG) recording underestimates arrhythmic risk in subjects with both ventricular ectopy and cardiovascular risk factors or history of coronary heart disease (CHD).
Methods: 29 consecutive patients with both ECG evidence of premature ventricular contractions (PVCs) and cardiovascular risk factors (n=14) or history of CHD (n=15) underwent 6 days prolonged AECG with an apposite device. Patients were divided according to number of PVCs, Lown's classification and evidence of non-sustained ventricular tachycardia (NSVT). Day by day data were compared with final findings at 6th day.
Results: Significant differences between findings at 24 h and those at 6th day were observed for all considered parameters. Differences became statistically not significant only at 4th day for number of PVCs and Lown's classes, at 5th day for NSVT. Results were significant both among patients with only risk factors and those with history of CHD. Sensitivity for NSVT significantly and progressively increased from 18% at 24 h, up to 82% only at 120 h.
Conclusions: Twenty-four-hour AECG underestimates the risk of ventricular arrhythmias in patients with cardiovascular risk factors or history of CHD. Prolonged AECG might reduce this underestimation, particularly among patients at low risk. A careful cost-benefit assessment needs to be held in order to identify the most convenient AECG duration and subsets of patients most benefiting from prolonged AECG.