The reliability and accuracy of a noncontact electrocardiograph system for screening purposes.

Abstract

Electrocardiography (ECG) requires the application of electrodes to the skin and often necessitates undressing. Capacitively coupled electrodes embedded in a normal chair would be a rational alternative for ECG screening. We evaluated the reliability and accuracy of ECG electrodes imbedded in a chair cushion. Two independent clinicians compared ECG recordings obtained using skin electrodes with recordings obtained using capacitively coupled electrodes that were embedded in a chair cushion in an anesthesiology premedication room, a cardiology outpatient ward, and a cardiology day ward. We analyzed the data to compare the sensitivity and specificity for the diagnosis of cardiac arrhythmias. ECG recordings were obtained from 107 patients. Heart rate was accurately measured using the capacitively coupled electrodes, but motion artifacts made the identification of P and T waves unreliable. Signal quality was poor for patients with low body weight, patients wearing clothing containing mixed fibers, and patients wearing sweaty shirts. Heart rate was accurately measured, and some cardiac arrhythmias were correctly diagnosed using capacitive ECG electrodes. Capacitive electrodes embedded into an examination chair are a promising tool for preoperative screening. Improved artifact reduction algorithms are needed before capacitive electrodes will replace skin electrodes.