Abstract: For an infrared imaging catheter, means of achieving a spread of wavelengths or multiple wavelengths through a stacking arrangement of “monochromatic” laser diodes or LED's are disclosed. Since a stack of diodes or LED's have different temperatures, they produce a wavelength spread many times greater than a single laser diode or LED. The wavelength spread reduces speckle in the corresponding image. Adding wavelengths also improves the corresponding infrared image, since different wavelengths have different light penetration capabilities and can emphasize different biological entities.

Abstract: A novel transparent electrode that uses a conductive coating to allow delivery of current to the heart as well as outward imaging through the electrode is described. The embodiments disclose a catheter incorporating an endoscope, whose imaging tip is coated with a conductive coating that is transparent in the endoscopic image. However, a transparent electrode may be fashioned for any imaging modality, such as intracardiac echocardiography (ICE), that finds the electrode to be transparent to the energy used. This electrode coating may be a thin, optically transparent or translucent coating of platinum or gold or may be a pattern with enough open spaces to see the underlying tissue, such as looking through a screen. A wire is connected to the conductive coating and routed to a radiofrequency generator.

Abstract: An ablation catheter has an imager useful in connection with an ablation operation such as used in the treatment of a cardiac arrhythmia. The catheter has an ablation electrode positioned on a catheter tip, and the imager is located on a side of the catheter. Because the catheter tip is generally articulated when the lesion is formed, this position of the imager provides an image that corresponds with the position of the catheter when it is used to form a lesion. Rings for recording tissue electrograms are also positioned on the catheter tip. This arrangement allows the user to accurately place and contact the electrode and to monitor the ablation process such as by viewing bubbles and thrombi that may undesirably be formed.

Abstract: A device and method for imaging an object that is situated within a fluid environment having suspended particles uses infrared illumination. In a representative application, a catheter having fiber optics is inserted into the vasculature of a patient. The fiber optics transmits infrared light to an optical head at a distal end of the catheter, which transmits the light into a bloody environment to an object to be imaged. Light reflecting from the object is collected and transmitted throughout the fiber optic to an infrared camera, so that an image is formed. Proper selection of the wavelength of infrared illumination allows objects to be imaged through what would otherwise be an opaque liquid. The invention has particular utility in the field of medical imaging.

Abstract: A cardiac pacer which generates pacing pulses at a predetermined pacing rate, includes a device for generating an alternating signal which is unable to pace the heart. The pacing pulses and the alternating signal are transmitted together to the heart. The alternating signal after transmittal to the heart is measured and processed such that a respiratory signal is obtained. The predetermined pacing rate is then varied dependent on the respiratory signal.

Abstract: A cardiac pacer which generates pacing pulses at a predetermined pacing rate includes a device for making a body activity measurement. The measured body activity signal is non-linearly amplified such that signal portions having higher amplitudes are more amplified than signal portions having lower amplitudes. The non-linearly amplified body activity signal is integrated over a period of time. The predetermined pacing rate is varied dependent on the integrated signal.

Abstract: A pacemaker and physiological sensor for use therewith that allows the rate at which the pacemaker delivers electrical stimulation pulses to the heart, or the escape interval during which a natural heart event must occur before an electrical stimulation pulse is delivered, to be adjusted as needed in order to satisfy the body's physiological needs. The sensor measures the depolarization time interval between an atrial stimulation pulse, A, and the responsive atrial or ventricle depolarization, P or R respectively, as an indication of the physiological demands placed on the heart. The time interval between a ventricular stimulation pulse, V, and the responsive ventricular depolarization, R, may also be measured and used as an indication of physiological need, and hence as an alternative criteria for rate control. Atrial depolarization is sensed by detecting a P-wave, and ventricular depolarization is preferably sensed by detecting an R-wave.

Abstract: A cardiac pacer which generates pacing pulses at a predetermined pacing rate includes a device for processing the pacing pulses according to an impedance measurement such that a respiratory signal is obtained. The predetermined pacing rate is then varied dependent on the respiratory signal.

Abstract: An electrical pacer device which responds to cardiac demand so as to alter the cardiac output in a fashion to satisfy that demand. Changes in the fundamental period of the atrial electrical cycle are detected and averaged over a predetermined time interval and the resulting control signal is used to raise and lower the ventricular heart rate to increase and decrease the foresaid cardiac output. At the same time, means are provided for continuously driving the ventricular rate toward a predetermined lower rate (the at rest rate) on a time cycle which is significantly longer than the above-mentioned predetermined time interval.

Abstract: An improved implantable electrode for delivery of electrical stimulation pulses or signals to an organ such as the heart from an electrical pulse generator. The electrode is normally exposed to the organ to be stimulated and is, in turn, electrically coupled to a conductive lead extending from the pulse generator, with the electrode being a body which substantially completely envelopes the lead. The electrode comprises a plurality of electrically conductive metallic filaments compressed together to form a generally fibrous body which may in certain instances be pliant or flexible in nature. The filaments preferably have a mean, effective diameter less than about 100 microns and form from about 3% to 30% of the total volume of the fibrous member, and preferably from 5% to 20%. In one embodiment, the filaments are retained as a bundle within a metallic grid enclosure.