Abstract: Apparatus and associated methods relate to cell culture systems having controlled gas concentration boundary conditions around cell culture. In an illustrative example, a programmable cell culture system (PCCS) may include one or more manifolds, each releasably coupled to multiple cell culture modules. The cell culture modules, for example, may include a nutrient capacitive medium (NCM) in fluid communication with a concentration-controlled gas source through at least two gas transfer interfaces. The gas transfer interfaces (GTIs) may, for example, be spatially distributed in relation to a cell growth surface in the NCM. Each GTI, for example, may include a gas permeable membrane (GPM) and a plenum. The GPM may be disposed between the plenum and the NCM. Various embodiments may advantageously selectively control a concentration of at least one target gas in the NCM by maintaining predetermined boundary conditions of the cell growth surface via the GTIs.

Abstract: An apparatus and method to discriminate cardiac events by sensing atrial and ventricular depolarizations having associated refractory periods thereafter. A fast ventricular rate is detected in response to the sensed ventricular depolarizations. Responsive to detecting the fast ventricular rate, at least one stimulus pulse is delivered to atrial tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial tissue. A ventricular response to the atrial tissue stimulus pulse is determined, and the cardiac event is discriminated based on the ventricular response to the atrial tissue stimulus pulse.

Abstract: Various techniques for delivering atrial pacing and supraventricular stimulation to achieve a desired ventricular rate and/or cardiac output are described. One example method described includes delivering a pacing signal configured to cause an atrial depolarization to a heart of a patient, wherein the atrial depolarization results in an associated refractory period during the cardiac cycle, and delivering a signal to a supraventricular portion of the heart of the patient subsequent to the atrial refractory period and during a ventricular refractory period of the cardiac cycle.

Abstract: An apparatus and method to discriminate cardiac events by sensing atrial and ventricular depolarizations having associated refractory periods thereafter. A fast ventricular rate is detected in response to the sensed ventricular depolarizations. Responsive to detecting the fast ventricular rate, at least one stimulus pulse is delivered to atrial tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial tissue. A ventricular response to the atrial tissue stimulus pulse is determined, and the cardiac event is discriminated based on the ventricular response to the atrial tissue stimulus pulse.

Abstract: An apparatus and method to discriminate cardiac events by sensing atrial and ventricular depolarizations having associated refractory periods thereafter. A fast ventricular rate is detected in response to the sensed ventricular depolarizations. Responsive to detecting the fast ventricular rate, at least one stimulus pulse is delivered to atrial tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial tissue. A ventricular response to the atrial tissue stimulus pulse is determined, and the cardiac event is discriminated based on the ventricular response to the atrial tissue stimulus pulse.

Abstract: Various techniques for delivering atrial pacing and supraventricular stimulation to achieve a desired ventricular rate and/or cardiac output are described. One example method described includes delivering a pacing signal configured to cause an atrial depolarization to a heart of a patient, wherein the atrial depolarization results in an associated refractory period during the cardiac cycle, and delivering a signal to a supraventricular portion of the heart of the patient subsequent to the atrial refractory period and during a ventricular refractory period of the cardiac cycle.

Abstract: A system and associated method measure monophasic action potential signals for identifying a targeted tissue location and delivering a therapy to the targeted tissue location. The system includes a hollow needle having a sharpened distal tip, a first electrode at the distal tip and a fluid delivery lumen extending through the needle from a proximal needle end to an opening in the sharpened distal tip.