Automatic strength duration plot to optimize pacing amplitude and pulse width

Pacemaker longevity is highly affected by the programmed pacing amplitude and pulse width. The purpose of this study was to investigate an automatic optimization of pacemaker pacing amplitude and pulse width by determining the pacing threshold strength-duration curve. Data from 4 animals showed that the strength-duration plot could be obtained correctly by measuring pacing thresholds at two data points. This study found that both the exponential and hyperbolic equations could describe the strength-duration relationship accurately (R²=0.989 for the hyperbolic equation vs. 0.987 for the exponential equation). The results also indicated that a strength-duration curve could be accurately plotted by measuring the pacing thresholds at two pulse widths and using the hyperbolic equation. It appeared that the best fit between the calculated strength-duration curve and the experimental data were obtained from the pair of pulse widths of 0.125 ms and 0.625 ms