Abstract: A catheter terminates at a tip that includes an array of pressure sensors. The sensors are responsive to detect and alert the user to variations of pressure that indicate the tip is either encountering an obstruction or constriction of smaller diameter than the catheter, as well as to guide the catheter through the conduit into which it is being inserted.

Abstract: A catheter terminates at a tip that includes an array of pressure sensors. The sensors are responsive to detect and alert the user to variations of pressure that indicate the tip is either encountering an obstruction or constriction of smaller diameter than the catheter, as well as to guide the catheter through the conduit into which it is being inserted.

Abstract: A method for treating a patient's heart which comprising delivering a gene therapy agent into the pericardial sac around the patient's heart. The agent is introduced surgically or by transvascular means such as a catheter which has been introduced percutaneously or otherwise. Introducing the gene therapy agent into the pericardial sac contains the agent, allowing high concentration of the agent adjacent large regions of the epicardium and pericardium without spillage or systemic distribution to other organs or tissues. The gene therapy agents of this invention comprise vectors for transferring genetic information to the epicardial cells in vivo or harvested cells which have been genetically engineered in vitro. In a preferred embodiment, a catheter is percutaneously introduced, such as through the femoral artery, and guided upstream into the left ventricle. The distal end of the catheter advanced until it penetrates through the epicardium so that agent can be introduced into the pericardial space.

Abstract: Inhibition of cardiac arrhythmias such as tachycardia and fibrillation is achieved by determining a refractory period after a selected heartbeat during which a stimulus applied to the heart will not propagate a heart response, determining a time within the refractory period after the selected heartbeat for the application of one or more electrical pulses to the heart to inhibit arrhythmic beats, determining a voltage of the electrical pulse as a function of the time which will inhibit the arrhythmic beats, and applying the electrical pulse to an area of the heart at the determined time to inhibit the arrhythmic beats. A plurality of electrical pulses may be employed having various voltage levels related to the times at which they are applied during the refractory period. One or more electrical pulses may be applied after the refractory period, each having a voltage providing a current less than a threshold current which would propagate a heart response.

Abstract: An implantable medical device to deliver cardioverting energy to cardiac tissue in synchrony with detected ventricular depolarizations. The energy renders refractory, areas of the heart associated with a reciprocating or automatic tachycardia, thus reverting these tachyarrhythmias to normal sinus rhythm without the risk of stimulating the heart during the vulnerable portion of repolarization.