Ultrasonic cardiac pacing in the porcine model.
Periodic pulses of intense ultrasound energy at 70 kHz with 5-ms duration at 3 MPa SPL applied to the exposed pig myocardium at physiologic rhythms were observed to produce cardiac pacing. Ten animals were successfully paced at pulse width and energy conditions above a certain threshold. Sigmoid strength-duration curves characterizing ultrasound's effectiveness in pacing were observed to resemble those of electrical stimulation. We suggest that bioelectrical stimulatory effects of ultrasound on the heart are a radiation pressure effect and a manifestation of the known myocyte sensitivity to stretch.
Towe
Bruce C
BC
Arizona State University, Bioengineering Department, Fulton College of Engineering, Tempe, AZ 85202-9709, USA. bruce.towe@asu.edu
Rho
Raymond
R
D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D023421:Models, Animal; D010138:Pacemaker, Artificial; D013552:Swine; D014464:Ultrasonic Therapy / Q000295:instrumentation* / Q000379:methods*