562 The Effect of Gender on R-Wave Amplitudes in the ConfirmRx Cardiac Monitor

The effects of body mass index on R-wave amplitude in insertable cardiac monitors have been reported however, there is limited information on R-wave amplitude in males vs females. To investigate the influence of gender on R-wave amplitudes in the ConfirmRxTM cardiac monitor. The ConfirmRxTM device was inserted in seventy-nine patients (43 females, 36 males) clinically indicated for cardiac monitoring and, R-wave amplitudes were measured at defined postures and physical activities. Assessments were performed at device implant and at 30 days post procedure. Measurements immediately post-insertion showed that females experienced reduction in R-wave amplitude when lying on right-side, lying on left-side, sitting and standing compared to the supine position (0.39±0.03, p<0.000; 0.45±0.04, p=0.001; 0.50±0.04, p<0.01 and 0.53±0.03mV, p<0.05 respectively vs 0.64±0.04mV). This effect was no longer significant at 30-days post-procedure and was not observed at all in males. Interestingly, males lying on the right-side (0.62±0.07 vs 0.53±0.06mV, p<0.05), left-side (0.57±0.07 vs 0.50±0.05mV, p<0.05), sitting (0.55±0.06 vs 0.47±0.05mV, p<0.01) and standing (0.58±0.07 vs 0.52±0.06mV, p<0.01) positions had higher amplitudes at 30-days compared to the same postures at insertion. In females, increase at 30-days was only observed in the lying on the right-side posture (0.48±0.04 vs 0.39±0.03mV, p=0.003). There was no correlation between the changes in R-wave amplitude and body mass index. Males had less dependence of R-wave amplitude on posture than females at both timepoints and had higher R-wave amplitudes than females at 30-days post-procedure.View Large Image Figure ViewerDownload Hi-res image Download (PPT)