Abstract: Devices, systems and methods are provided to modulate portions of neural tissue of the nervous system, such as portions of the central nervous system or portions of the peripheral nervous system. In some embodiments, the systems and devices of the present invention are used to stimulate one or more dorsal root ganglia, dorsal roots, dorsal root entry zones, or portions thereof, while minimizing or excluding undesired stimulation of other tissues, such as surrounding or nearby tissues, ventral root and portions of the anatomy associated with body regions which are not targeted for treatment. In other embodiments, the systems and devices are used to stimulate portions of the peripheral nervous system. In some embodiments, the modulation generates a massaging sensation, particularly when stimulating neural tissue on particular spinal levels, such as L2 or L3.

Abstract: A system and method which employs atrial discrimination algorithms to distinguish between different atrial arrhythmias occurring in a patient for selecting an optimal pacing therapy corresponding to the type of arrhythmia identified. In response to the detection of an atrial rate above the atrial tracking rate, discrimination criteria are applied to a detected atrial activity signal to distinguish between different types of supraventricular tachycardia, such as fast atrial flutter and other atrial flutter at a relatively slower rate, which may be occurring in the patient. The pacer is controlled to provide pacing therapy to a heart in a manner corresponding to the type of supraventricular tachycardia identified. The output of an atrial discrimination algorithm may be tracked and the trend thereof used to improve therapy timing. Various embodiments are disclosed herein.

Abstract: A system and method which employs atrial discrimination algorithms to distinguish between different atrial arrhythmias occurring in a patient for selecting an optimal pacing therapy corresponding to the type of arrhythmia identified. In response to the detection of an atrial rate above the atrial tracking rate, discrimination criteria are applied to a detected atrial activity signal to distinguish between different types of supraventricular tachycardia, such as fast atrial flutter and other atrial flutter at a relatively slower rate, which may be occurring in the patient. The pacer is controlled to provide pacing therapy to a heart in a manner corresponding to the type of supraventricular tachycardia identified. The output of an atrial discrimination algorithm may be tracked and the trend thereof used to improve therapy timing. Various embodiments are disclosed herein.

Abstract: An apparatus and method for treating atrial fibrillation is described that uses a vascular stent deployed within the pulmonary veins of the left atrium. The stent may be used alone or in combination with chemical, thermal, electrical, or radioactive energy sources to ablate myocardial tissue residing in the pulmonary veins. The targeted myocardial tissue in the pulmonary veins will have been identified as the source of initiation and/or sustenance of atrial fibrillation. Ablation therapy using the pulmonary venous stent stops discharges from ectopic foci in the vein or alternatively stops impulses from reaching the left atrium. The deployed stent can then be left in place to prevent stenosis of the vein.

Abstract: An apparatus and method for treating atrial fibrillation with ablation therapy in which a stent is deployed within a pulmonary vein and tissue surrounding the stent is ablated with radiofrequency energy to stop discharges from ectopic foci in the vein from reaching the left atrium. The deployed stent can then be left in place to prevent stenosis of the vein as well as allowing repeat ablation procedures as needed.

Abstract: A system and method which employs atrial discrimination algorithms to distinguish between different atrial arrhythmias occurring in a patient for selecting an optimal pacing therapy corresponding to the type of arrhythmia identified. The invention may be implemented in a bradycardia pacemaker or other implantable cardiac device. In response to the detection of an atrial rate above the atrial tracking rate, discrimination criteria are applied to a detected atrial activity signal to distinguish between different types of supraventricular tachycardia, such as fast atrial flutter and other atrial flutter at a relatively slower rate, which may be occurring in the patient. The discrimination criteria may be, for example, rate-based or morphology based. The pacer is controlled to provide pacing therapy to a heart in a manner corresponding to the type of supraventricular tachycardia identified.

Abstract: An apparatus and method for brachytherapy. One method includes locating a region of cardiac tissue having a relatively large probability of originating or transmitting electrical signals which result in arrhythmic activity and irradiating the region of cardiac tissue to reduce the amount of arrhythmic activity. Irradiating can include regulating protein expression of myocardial cells, killing myocardial cells, ablating myocardial cells, irradiating sleeves of atrial muscle that extend from a left atrial wall around the pulmonary veins, and/or creating lesions that block electrical conduction through myocardial tissue. Locating the region can include locating a foci of an atrial arrhythmia or locating the foci adjacent a pulmonary vein.

Abstract: An ablation catheter stores a platelet inhibitor substance within a plurality of pockets or recesses of its shaft. The substance is adapted to elute upon contact with biological fluid. In the pocket configuration, the platelet inhibitor substance is in a capsule positioned within the pocket. In the recess configuration, the platelet inhibitor substance is in a hydrogel or silicone-based porous/semi-porous matrix positioned within the recess. Elution of the platelet inhibitor substance prevents or at least substantially minimizes the adhesion of blood platelets on the catheter surface during ablation. In another configuration, the catheter includes an internal lumen network having apertures terminating at the surface of the shaft. The lumen communicates with a source of platelet inhibitor fluid that is forced through the lumen by a variable pump.

Abstract: A catheter carries a plurality of electrodes, each with multiple thermal sensors attached and is used to position the electrodes proximal biological tissue. A processor responsive to each of the thermal sensors determines the temperature at the thermal-sensor/electrode junction. A display provides a graphic representation of the temperatures of the thermal-sensor/electrode junctions. An exemplary representation is a bar graph having the temperature of one thermal sensor at one end and the temperature of another thermal sensor at the other end. The length of the bar graph combined with the position of the bar graph relative to a temperature range region provides an indication of the position of the thermal-sensor/electrode junctions relative to the biological tissue. The processor also monitors the spread between the sensor temperatures and compares it to a threshold value. Base on the result of the comparison, the processor controls the power applied to the electrode.

Abstract: A first power output with a first frequency is provided to a first set of electrodes while a second power output with a second frequency, different then the first frequency, is provided to a second set of electrodes. Power outputs are provided to electrodes so adjacent electrodes receive power outputs with different frequencies, thereby establishing a voltage potential between adjacent electrodes and bipolar current flow. The frequencies of the power outputs are selected such that the resultant waveform indicative of the magnitude of the amplitude difference between the outputs has a period short enough to avoid stimulation of excitable muscular and cardiac tissue. Periodic frequency switching between the first and second power output provides uniform current flow between the electrodes over a given period of time. The addition of a backplate establishes unipolar current flow.

Abstract: A first power output with a first frequency is provided to a first set of electrodes while a second power output with a second frequency, different then the first frequency, is provided to a second set of electrodes. Power outputs are provided to electrodes so adjacent electrodes receive power outputs with different frequencies, thereby establishing a voltage potential between adjacent electrodes and bipolar current flow. The frequencies of the power outputs are selected such that the resultant waveform indicative of the magnitude of the amplitude difference between the outputs has a period short enough to avoid stimulation of excitable muscular and cardiac tissue. Periodic frequency switching between the first and second power output provides uniform current flow between the electrodes over a given period of time. The addition of a backplate establishes unipolar current flow.

Abstract: Power signals having controllable peak-to-peak amplitudes are provided to electrode sets so that during a first period of time, a first amplitude signal is provided to a first electrode set and a second amplitude signal is provided to a second electrode set. The first amplitude is greater than the second amplitude and bipolar current flows from the first electrode set to the second electrode set. During a second period of time, a third amplitude signal is provided to the first electrode set and a fourth amplitude signal is provided to the second electrode set. The third amplitude is less than the fourth amplitude and the current flows from the second electrode set to the first electrode set. Alternating first and second periods of time establish repetitive bipolar current flow between electrode sets. The addition of a backplate establishes unipolar current flow.

Abstract: An ablation catheter stores a platelet inhibitor substance within a plurality of pockets or recesses of its shaft. The substance is adapted to elute upon contact with biological fluid. In the pocket configuration, the platelet inhibitor substance is in a capsule positioned within the pocket. In the recess configuration, the platelet inhibitor substance is in a hydrogel or silicone-based porous/semi-porous matrix positioned within the recess. Elution of the platelet inhibitor substance prevents or at least substantially minimizes the adhesion of blood platelets on the catheter surface during ablation. In another configuration, the catheter includes an internal lumen network having apertures terminating at the surface of the shaft. The lumen communicates with a source of platelet inhibitor fluid that is forced through the lumen by a variable pump.

Abstract: A surface covering including a primary layer of a porous polymer structure and a secondary surface covering one or both of a metallic element layer and a hydrophilic layer is positioned over the surface of an ablation electrode. The pores of the surface covering are sized such that blood platelets are prevented from contacting the surface of the electrode while physiological fluid is allowed to pass through and contact the electrode surface to hereby provide a conduction path for current from the electrodes. The surface covering may further include an electrically non-conductive and thermally conductive portion positioned over another portion of the electrode to prevent alternate or non-intended site ablations.

Abstract: An apparatus and method for treating atrial fibrillation is described that uses a vascular stent deployed within the pulmonary veins of the left atrium. The stent may be used alone or in combination with chemical, thermal, electrical, or radioactive energy sources to ablate myocardial tissue residing in the pulmonary veins. The targeted myocardial tissue in the pulmonary veins will have been identified as the source of initiation and/or sustenance of atrial fibrillation. Ablation therapy using the pulmonary venous stent stops discharges from ectopic foci in the vein or alternatively stops impulses from reaching the left atrium. The deployed stent can then be left in place to prevent stenosis of the vein.

Abstract: Power signals having controllable peak-to-peak amplitudes are provided to electrode sets so that during a first period of time, a first amplitude signal is provided to a first electrode set and a second amplitude signal is provided to a second electrode set. The first amplitude is greater than the second amplitude and bipolar current flows from the first electrode set to the second electrode set. During a second period of time, a third amplitude signal is provided to the first electrode set and a fourth amplitude signal is provided to the second electrode set. The third amplitude is less than the fourth amplitude and the current flows from the second electrode set to the first electrode set. Alternating first and second periods of time establish repetitive bipolar current flow between electrode sets. The addition of a backplate establishes unipolar current flow.

Abstract: An apparatus and method for brachytherapy. One method includes locating a region of cardiac tissue having a relatively large probability of originating or transmitting electrical signals which result in arrhythmic activity and irradiating the region of cardiac tissue to reduce the amount of arrhythmic activity. Irradiating can include regulating protein expression of myocardial cells, killing myocardial cells, ablating myocardial cells, irradiating sleeves of atrial muscle that extend from a left atrial wall around the pulmonary veins, and/or creating lesions that block electrical conduction through myocardial tissue. Locating the region can include locating a foci of an atrial arrhythmia or locating the foci adjacent a pulmonary vein.

Abstract: The efficacy of a lesion produced between a pair of ablation electrodes is assessed by analyzing the time it takes for a pulse of energy to travel from one electrode to the other. During a first time period, a first pulse of energy is applied to a first electrode. The time it takes for the pulse to conduct through the tissue to a second electrode is determined. During a time period subsequent to the first time, a subsequent pulse of energy is applied to the first electrode and the time it takes for the subsequent pulse to conduct through the tissue to the second electrode is determined. Changes in the conduction times are monitored by calculating the difference between consecutive conduction times and comparing the difference to a preset value. If the difference is below the preset value the lesion is considered adequate.

Abstract: An apparatus and method for treating atrial fibrillation with ablation therapy in which a stent is deployed within a pulmonary vein and tissue surrounding the stent is ablated with radiofrequency energy to stop discharges from ectopic foci in the vein from reaching the left atrium. The deployed stent can then be left in place to prevent stenosis of the vein as well as allowing repeat ablation procedures as needed.

Abstract: A surface covering including a primary layer of a porous polymer structure and a secondary surface covering one or both of a metallic element layer and a hydrophilic layer is positioned over the surface of an ablation electrode. The pores of the surface covering are sized such that blood platelets are prevented from contacting the surface of the electrode while physiological fluid is allowed to pass through and contact the electrode surface to hereby provide a conduction path for current from the electrodes. The surface covering may further include an electrically non-conductive and thermally conductive portion positioned over another portion of the electrode to prevent alternate or non-intended site ablations.