Abstract: A system for delivering an electrical stimulation pulse to tissue comprises a controller-transmitter and a receiver-stimulator. The controller-transmitter includes circuitry having an energy storage capacitor. The capacitance of the energy storage capacitor is adjusted to improve the efficiency of energy delivered from the receiver-stimulator to tissue by modifying the geometry of an acoustic drive burst from the controller-transmitter.

Abstract: Systems for pacing the heart include a vibrational transducer which directs energy at the heart, usually at at least a ventricle, to pace the heart and to promote synchronized contraction of the ventricles. Optionally, additional vibrational and/or electrical stimulation may be provided. The vibrational transducers are usually implantable at a location proximate the heart.

Abstract: Receiver-stimulators comprise a nearly isotropic transducer assembly, demodulator circuitry, and at least two tissue contacting electrodes. Use of near isotropic transducers allows the devices to be implanted with less concern regarding the orientation relative to an acoustic energy source. Transducers or transducer elements having relatively small sizes, typically less than ½ the wavelength of the acoustic source, enhance isotropy. The use of single crystal piezoelectric materials enhance sensitivity.

Abstract: Systems including an implantable receiver-stimulator and an implantable controller-transmitter are used for leadless electrical stimulation of body tissues. Cardiac pacing and arrhythmia control is accomplished with one or more implantable receiver-stimulators and an external or implantable controller-transmitter. Systems are implanted by testing external or implantable devices at different tissue sites, observing physiologic and device responses, and selecting sites with preferred performance for implanting the systems. In these systems, a controller-transmitter is activated at a remote tissue location to transmit/deliver acoustic energy through the body to a receiver-stimulator at a target tissue location. The receiver-stimulator converts the acoustic energy to electrical energy for electrical stimulation of the body tissue. The tissue locations(s) can be optimized by moving either or both of the controller-transmitter and the receiver-stimulator to determine the best patient and device responses.

Abstract: Systems for pacing the heart include a vibrational transducer which directs energy at the heart, usually at at least a ventricle, to pace the heart and to promote synchronized contraction of the ventricles. Optionally, additional vibrational and/or electrical stimulation may be provided. The vibrational transducers are usually implantable at a location proximate the heart.

Abstract: Methods and apparatus for cardiac pacing, cardioversion, and defibrillation rely on delivering ultrasonic and other vibrational energy to the heart, usually after the onset of an arrhythmia. A vibrational transducer assembly is implanted or applied externally so that vibrational energy can be directed toward at least a portion of the heart from an anterior or posterior aspect, typically being implanted over the ribs, over the sternum, between the ribs, beneath the ribs, or on the back.

Abstract: Methods and systems for pacing the heart include a vibrational transducer which directs energy at the heart, usually including at least a ventricle, to pace the heart to promote synchronized contraction of the ventricles. Optionally, additional vibrational and/or electrical stimulation may be provided.

Abstract: Methods and apparatus for treating heart failure rely on delivering ultrasonic or other vibrational energy to the heart. The energy may be delivered acutely or chronically, in response to detected cardiac events, in response to manual actuation and/or in response to operation of an implantable defibrillator. The vibrational transducer is implanted so that the vibrational energy can be directed toward at least a portion of the heart in order to increase contractility, vasodilation, tissue perfusion, and/or cardiac output.

Abstract: Methods and apparatus for cardiac pacing, cardioversion and defibrillation rely on delivering ultrasonic or other vibrational energy in combination with electrical energy to the heart, usually after the onset of an arrhythmia. A vibrational transducer and suitable electrical contacts may be combined in a single housing or distributed among various housings, and will usually be implantable so that the vibrational transducer can be directed at a target portion of the heart. Alternatively, external systems comprising the vibrational transducer and electrical contacts are also described.

Abstract: Methods and apparatus for cardiac pacing, cardioversion, and defibrillation rely on delivering ultrasonic and other vibrational energy to the heart, usually after the onset of an arrhythmia. A vibrational transducer assembly is implanted or applied externally so that vibrational energy can be directed toward at least a portion of the heart from an anterior or posterior aspect, typically being implanted over the ribs, over the sternum, between the ribs, beneath the ribs, or on the back.