A new method for multi-site cardiac pacing using leadless electrodes and high frequency transthoracic currents.

Cardiac pacing using long leads has inherent complications of adhesions, fractures and infection. Current leadless pacemakers include battery-operated devices that are relatively large in size. We present here the initial design and animal experiments with a new ultrathin leadless device, activated by subcutaneous application of short trains of high frequency (250 kHz) alternating electrical fields (HFAF). The myocardial 40 × 0.5 mm rectifying device, implanted in the right ventricle and in epicardial veins, converts the HFAF sinusoidal transients to unidirectional current pulses which stimulate the myocardium. The method was tested in a swine model under open and closed chest conditions for both endocardial and cardiac venous approaches. We demonstrated pacing under all these conditions and measured the thresholds of current, voltage and pulse duration. This method allows for leadless stimulation at multiple points. It may be applied to various pacing needs and has an interesting appeal for CRT Therapy, where multiple electrodes can be implanted, overcoming the limitations of current long pacing leads.