Abstract: An implantable system for detecting electrical activity from a patient's heart comprises a first sensing electrode configured for positioning through the coronary sinus ostium and within a vein on the left surface of the left ventricle of the heart for sensing electrical activity from the heart, and a detector operatively associated with the first sensing electrode for determining (e.g., diagnosing or prognosing) a medical condition of the heart with the sensed electrical activity. Typically the system further comprises a second sensing electrode configured for positioning in the right ventricle of the heart, where the detector is operatively associated with both the first sensing electrode and the second sensing electrode. The second sensing electrode may be positioned in other locations as well, such as also within a vein on the left surface of the left ventricle of the heart (although spaced apart from the first sensing electrode), in the right atrium, in the superior vena cava, etc.

Abstract: A method and system for discriminating atrial and ventricular signal components from a single heart lead, and for using this information for identifying an arrhythmia condition as being atrial or ventricular in origin. The invention is effective in identifying P waves occurring in complex signal which includes relatively stronger R waves or other ventricular artifacts which mask the P waves. The contribution of the R wave signal to the complex signal is obtained by filtering, time windowing and transfer function estimation, then the R wave estimate is subtracted from the combined signal to leave the P wave. The ratio of P waves to R waves, P--P and R--R intervals, and their ratios to one another and to fixed values can be estimated, and used in a comparison to discriminate between atrial and ventricular arrhythmia, to thereby enable appropriate treatment.

Abstract: The device provides anti-tachyarrhythmia therapy, such as a countershock, to an atrium needing treatment, but delays its delivery for a programmable period of time following an indication of susceptibility to ventricular tachyarrhythmia (VT). This reduces the risk of reinducing VT during a period in which the heart is abnormally metabolically vulnerable to VT, including ventricular fibrillation (VF). The delay time may be independently programmed for different indications of VT, and may be synchronized to and delayed from the R-wave. The delay time may be adjusted, such as to exceed one second, or even to exceed several hours, in order to accommodate the metabolic abnormal susceptibility of the particular patient in the wide range of patients needing treatment of atrial tachyarrhythmias.

Abstract: A cardiac rhythm management system, such as an implantable cardioverter-defibrillator (ICD), provides atrial anti-tachyarrhythmia therapy, such as a bipolar or unipolar electrical cardioversion countershock, or provides both atrial and ventricular anti-tachyarrhythmia therapy. The atrial and ventricular anti-tachyarrhythmia therapies have independent cardioversion-defibrillation energy levels and other parameters. The system provides an endocardial lead that is convenient to implant for providing the anti-tachyarrhythmia therapy. The endocardial lead includes a first supraventricular electrode disposed in the atrium and superior vena cava, and optionally includes a first ventricular electrode and ICD housing electrode.

Abstract: A method and system for discriminating atrial and ventricular signal components from a single heart lead, and for using this information for identifying an arrhythmia condition as being atrial or ventricular in origin. The invention is effective in identifying P waves occurring in complex signal which includes relatively stronger R waves or other ventricular artifacts which mask the P waves. The contribution of the R wave signal to the complex signal is obtained by filtering, time windowing and transfer function estimation, then the R wave estimate is subtracted from the combined signal to leave the P wave. The ratio of P waves to R waves, P-P and R-R intervals, and their ratios to one another and to fixed values can be estimated, and used in a comparison to discriminate between atrial and ventricular arrhythmia, to thereby enable appropriate treatment.

Abstract: A method and system for discriminating atrial and ventricular signal components from a single heart lead, and for using this information for identifying an arrhythmia condition as being atrial or ventricular in origin. The invention is effective in identifying P waves occurring in complex signal which includes relatively stronger R waves or other ventricular artifacts which mask the P waves. The contribution of the R wave signal to the complex signal is obtained by filtering, time windowing and transfer function estimation, then the R wave estimate is subtracted from the combined signal to leave the P wave. The ratio of P waves to R waves, P--P and R--R intervals, and their ratios to one another and to fixed values can be estimated, and used in a comparison to discriminate between atrial and ventricular arrhythmia, to thereby enable appropriate treatment.

Abstract: A rate adaptive pacemaker of the type having a variable rate cardiac stimulating pulse generator and a sensor for monitoring some physiologic parameter whereby the pulse generator stimulating rate can be adjusted to meet physiologic demand is further provided with a hemodynamic sensor which is operative to provide an output signal representing the pumping performance of the heart in response to the pacing stimulation. The signal from the hemodynamic sensor is processed and then used in an algorithm to determine whether further rate increase should be permitted based upon whether the rate increase would be accompanied by a further increase in cardiac output, a plateau or a decrease in cardiac output. Hence, the adaptive rate pacemaker is provided with a real-time, hemodynamic maximum pacing rate instead of a preprogrammed, fixed, maximum rate.

Abstract: An implantable microprocessor-controlled dual chamber heart pacemaker is programmed to control the timing of the pacing of the ventricle in response to high rate atrial signals. The microprocessor operates in conjunction with an atrial timer to detect atrial signals which occur at a rate in excess of a predefined atrial rate limit. The microprocessor paces the ventricle at a predefined desirable demand rate and inhibits pacing of the atrium in response to the high rate atrial activity. The microprocessor also controls the timing of an atrial refractory interval which includes an absolute refractory portion during which atrial signals are not detected and a relative refractory portion during which atrial signals are detected but are not tracked. The combined absolute and relative atrial refractory portions insure that relatively high rate atrial signals are detected and spurious signals conducted from the ventricle are ignored.

Abstract: This invention is an apparatus for diffusing quench air at the exhaust of the air from a quench stack for cooling synthetic melt-spun fibers, comprising a series of slats arranged peripherally around the fibers in the quench stack.