Physiologically responsive VAD

A ventricular assist device comprising:

• a rotary pump configured to be implantable in fluid communication with a ventricle and an artery of a subject to assist blood flow from the ventricle to the artery;
• a pump drive circuit for applying power to the pump;
• one or more sensors for sensing one or more electrogram signals in a patient;
• a signal processing circuit in communication with the sensors and the pump drive circuit, the signal processing circuit being operative to receive the electrogram signals,
• wherein the signal processing circuit is operative to determine the presence or absence of an arrhythmia based on the electrogram signals from the sensors and to control power supplied to the pump from the pump drive circuit so as to operate the pump in a normal pulsatile mode in the absence of an arrhythmia and to operate the pump in at least one modified mode of operation in the presence of an arrhythmia.

A ventricular assist device comprising:

• a rotary pump configured to be implantable in fluid communication with a ventricle and an artery of a subject to assist blood flow from the ventricle to the artery;
• a pump drive circuit for applying power to the pump;
• one or more sensors for sensing one or more electrogram signals in a patient;
• a signal processing circuit in communication with the sensors and the pump drive circuit, the signal processing circuit being operative to receive the electrogram signals from the sensors, and control power supplied to the pump from the pump drive circuit so that in a normal pulsatile mode the pump drive circuit varies the power applied to the pump in synchronism with the cardiac cycle and such variation causes the pump to run with a varying speed synchronized with the cardiac cycle of the subject so that the pump speeds up and slows down during each cardiac cycle,
• wherein the pump drive circuit is operative to apply AC power to the pump and to vary the power applied to the pump by varying a frequency of the AC power in synchronism with the cardiac cycle so that the frequency of the AC power increases and decreases during each cardiac cycle.