SIGNAL-AVERAGED ECG VARIABLES IN PRONE POSITION: COMPARISON WITH THOSE IN SUPINE POSITION

摘要

We hypothesized that 1) signal-averaged ECG (S AECG) with acceptable level of noise is possible in prone position and 2) variables of SAECG taken in prone position may differ from that taken in supine position in normal controls and patients with arrhythmogenic right ventricular dysplasia (ARVD). The purpose of this study was to compare SAECG parameters between those taken in supine and prone position in normal controls and patients with ARVD.The subjects consisted of 9 ARVD patients (42+9 years old, 5 males) and 35 normal controls (23+-2 years old, all males). A high resolution ECG was performed using a MAC 15 system with high gain amplification and bi-directional Butterworth filters (40-250 Hz). Noise level was significantly higher in prone than supine position (p<0.01). However, SAECG taken in prone position with acceptable level of noise was achived in 80% of all study subjects. Two ARVD patients and 7 normal controls were excluded from further analysis due to high noise level (>=0.3(mu)V). SAECG parameters including the duration of the filtered QRS complex, the duration of the late potentials <40 (mu)V and the root-mean-square voltage of the last 40 ms were analyzed.LAS40 and RMS40 were different between supine and prone positions in normal controls. Variables of SAECG taken in prone position may different from those taken in supine position in normal controls. However, it was not in patients with ARVD. Clinical significance of these differences is not clear. Further studies are needed.