RESUMO
OBJECTIVE: Applying shock waves to the heart has been reported to stimulate the heart and alter cardiac function. We hypothesized that shock waves could be used to diagnose regional viability. METHOD: We used a Langendorff model to investigate the acute effects of shock waves at different energy levels and times related to systole, cycle duration and myocardial function. RESULTS: We found only a small time window to use shock waves. Myocardial fibrillation or extrasystolic beats will occur if the shock wave is placed more than 15 ms before or 30 ms after the onset of systole. Increased contractility and augmented relaxation were observed after the second beat, and these effects decreased after prolonging the shock wave delay from 15 ms before to 30 ms after the onset of systole. An energy dependency could be found only after short delays (-15 ms). The involved processes might include post-extrasystolic potentiation and simultaneous pacing. CONCLUSION: In summary, we found that low-energy shock waves can be a useful tool to stimulate the myocardium at a distance and influence function.
