Comparison of digitized ECGs simultaneously recorded with CR and V leads

Evidence is presented that electrocardiograms recorded with bipolar chest-right arm (CR) leads are diagnostically similar to electrocardiograms recorded with unipolar V leads. Electrocardiograms were simultaneously recorded with CR and V leads on six chest sites in 45 cardiac patients and submitted, unmarked, for evaluation, by four cardiologists. In spite of relatively small differences in the amplitudes of P, Q, R, S, and T waveforms, the diagnosis based on tracings recorded with CR leads was similar to the diagnosis based on tracings recorded with V leads in nearly 90% of patients. Because CR leads are set up with only two electrodes, one on the right arm and one on the chest, their use in cardiac emergencies saves time and simplifies the recording technique. This investigation is part of a project aimed at developing a portable electrocardiograph for use outside the hospital or clinic.