Reliability of sampling during long-term ECG recordings in the detection of ventricular ectopy and abnormal ST...

Two ambulatory ECG recording-analysis methods were each compared in 10 subjects with a careful hand counted analysis of 16 continuously recorded hr and examined for total VEB count, complex VEB and ST-depression. The sampling method made a 28-sec tape recording every 15 min and was visually coded. The other method (conventional Holter) continuously recorded ECG data and used a dedicated computer with technician editing. Both recorders were simultaneously worn by study participants for 16 hr. Neither method showed a statistically significant difference from the hand counted data or systematic over- or under-estimation of clinically important ECG detections. A probability model is presented which provides a theoretical basis for the success of ECG sampling. Findings from this pilot study indicate electrocardiographic sampling may provide event detection comparable with the more conventional analyses, with considerably less data acquisition. The choice of ambulatory ECG recording mode should be governed by the level of quantification required, specific events to be detected and cost.