Minimally invasive ventricular assist technology and method
The present invention is a cardiac-assist device and technique used to maintain a patient's cardiac output when normal cardiac output is insufficient. Blood is removed from a selected ventricle using an arterial or venous side approach. The use of a right side approach reduces the amount of work required and reduces the number of foreign objects present within the left side of the heart and associated blood transferring conduits. The device of the invention includes a flexible catheter positionable within the patient's body. An external assist mechanism connected to one end of the flexible catheter receives blood from the arterial circulation and includes a pumping membrane. A flexible cannula is connected for reinfusing blood. A control console is provided for alternately supplying vacuum and pressure to the pumping membrane. A synchronizing means varies inflation and deflation in synchrony with the cardiac cycle of a patient.
1. A minimally invasive technique for improving blood flow in a patient's body by removing blood directly or indirectly from a selected ventricle of the heart and then directly or indirectly infusing the blood back into the patient's circulatory system at a selected distant location, the technique comprising the steps of:
installing a flexible catheter having a length, an open interior, an exposed proximate end and a distal end within the patient's left ventricle by means of a transeptal puncture of the patient's right atrium, the catheter having at least one opening along the length of the said flexible tube for admitting blood into the open interior after the catheter has been installed;
providing an electrically active region having sensing, pacing and cardioversion electrodes integrated into the flexible catheter, the electrodes being positioned within the patient's right atrium;
achieving atrial pacing and/or cardioversion of atrial fibrillation or atrial tachycardia by electrical conduction between the electrodes on the flexible catheter or between a selected electrode on the flexible catheter and an external cutaneous pad on the patient's body;
providing a supplemental assist mechanism located externally of a patient's body and connected to the proximate end of the flexible catheter, the supplemental assist mechanism comprising a rigid housing with an inlet and an outlet and with a housing interior in communication with the flexible catheter for receiving blood from the arterial circulation, the rigid housing also having a pumping membrane located within the housing interior;
connecting a flexible cannula to the outlet of the rigid housing, the cannula having a distal end with an end opening which is located within the patient's body at a selected location distant from the ventricle for reinfusing blood at the selected distant location;
providing a control console having at least two independent control channels for alternately supplying vacuum and pressure to the pumping membrane, the application of vacuum to the membrane causing the membrane to collapse and causing blood to be drawn into the housing interior from the ventricle, the application of pressure to the membrane causing the membrane to inflate and act against blood in the housing interior to drive blood from the housing interior into the patient's body at the selected distant location.
2. The minimally invasive technique of claim 1 , further comprising the step of:
providing a synchronizing means as a part of the control console for varying the membrane inflation and deflation in synchrony with the cardiac cycle of a patient being treated with the device.
3. The minimally invasive technique of claim 1 , further comprising the steps of:
locating an additional electrically active catheter within the patient's cardiac vein such that a shock vector produced between the additional electrically active catheter in the cardiac vein and the electrically active region on the flexible catheter can be used to terminate ventricular tachycardia and/or ventricular flutter.
4. The minimally invasive technique of claim 3 , further comprising the use of external cutaneous pads to form a multi-directional shock field that can be characterized by shock vectors that form a three dimensional energy field within the patient's body to terminate difficult to terminate ventricular tachycardia or ventricular flutter.