Use of a Mathematical Model to Identify Optimal Activation Pat- terns for Skeletal Muscle During Cardiomyoplasty

In cardiomyoplasty the latissimus dorsi muscle is electrical stimulated in synchrony with the heartbeat to enhance ventricular function. Current clinical stimulation protocols use 6-pulse trains with pulses within the train equally spaced by 33.3 ms (CFTs). Recent studies, however, have shown that variable-frequency trains (VFTs), which take advantage of the catchlike property of skeletal muscle, can produce more force than traditionally used CFTs. The purpose of this study was to systematically explore the effects of the number and dis-tribution of pulses within the train on muscle contractile output. With the aid of a mathe-matical model that we developed, a new stimulation pattern was identified that produced the greatest impulse per pulse for fatigued muscles. Experiments were conducted to com-pare muscle contractile performance by the new stimulation pattern (DFTs) with the tradi-tionally used CFTs and with previously studied VFTs. The 6-pulse DFTs produced a 49% augmentation over the traditionally used 6-pulse CFT and a 23 % augmentation over the 6-pulse VFT. DFTs thus show potential for improving muscle contractile performance in as-sisting cardiac function. This study illustrates the potential for using mathematical model