Abstract: Method and device for catheterizaton within human ducts so as remove concretions, plaques or sclerotic clots, including generating exteriorally of the human body a series of high voltage pulses of sufficiently low amperage to avoid harm to human tissues, directing said pulses within an insulating medium into the human ducts to the situs of said concretions and selectively discharging sid pulses radially outwardly in order to impact across the surface of said concretions. A liquid may be flowed peripherally of discharging and against the concretion so as to achieve a hydroelectric cavitation. A suggested apparatus includes a pair of flexible electrodes insulated one from the other and co-terminating at the situs of the concretion. The positive electrode is positioned coaxially of the encircling negative electrode, such that the electrical discharging is radially outwardly from the positive electrode to the encircling surface of the negative electrode.