B-IN02-10 USING HOLTER MONITOR TO RECORD SKIN SYMPATHETIC NERVE ACTIVITY

Abstract

neuECG is a new method to simultaneously record ECG and skin sympathetic nerve activity (SKNA). The available equipment for neuECG recording is expensive and not fully portable. To test the hypothesis that Bittium Faros 180, a small (4.8 x 2.9 x 1.2 cm) Holter monitor, can be used to record neuECG in ambulatory outpatients. We placed conventional ECG patch electrodes on the chest of 5 female outpatients (39±17 years old). The electrodes were connected to Biomation ME6000 (sampling rate 10,000 Hz) and Faros (sampling rate 1,000 Hz) during orthostatic testing (from supine to 3-min standing, then sitting). The ME6000 signals were bandpass filtered 500-1000 Hz while the Faros signals were high pass filtered at 300 Hz to display the SKNA. The same original signals were bandpass filtered 0.05-150 Hz to display ECG. The total recording time was 18.8±19.7 minutes/patient. As shown in Panel A, these two devices recorded similar patterns of nerve activities. While the amplitude of the SKNA was lower in Faros than in ME6000, they track each other over time (Panel B) with good correlations (Panel C, each dot is 1-min). For all 5 patients studied, the average SKNA (aSKNA) at supine, 1, 2 and 3 min after standing up and after sitting down were 1.02±0.34, 1.43±0.37, 1.18±0.12, 1.19±0.28 and 1.20±0.18 μV for ME6000 and were 0.94±0.05,1.05±0.10, 1.01±0.09, 0.99±0.08, 0.98±0.09 μV for Faros 180, respectively. The r values averaged 0.774 (N=5, P<0.001 for all). Holter monitors with sampling rate of 1000 Hz can be used to record neuECG. It will enable the direct measurements of SKNA in ambulatory outpatients to study the neural mechanisms of cardiac arrhythmias.