Method and apparatus for treating hemodynamic disfunction

Abstract

A method of treating hemodynamic disfunction by simultaneously pacing both ventricles of a heart. At least one ECG amplifier is arranged to separately detect contraction of each ventricle and a stimulator is then activated for issuing stimulating pulses to both ventricles in a manner to assure simultaneous contraction of both ventricles, thereby to assure hemodynamic efficiency. A first ventricle is stimulated simultaneously with contraction of a second ventricle when the first fails to properly contract. Further, both ventricles are stimulated after lapse of a predetermined A-V escape interval. One of a pair of electrodes, connected in series, is placed through the superior vena cava into the right ventricle and a second is placed in the coronary sinus about the left ventricle. Each electrode performs both pacing and sensing functions. The pacer is particularly suitable for treating bundle branch blocks or slow conduction in a portion of the ventricles.

What is claimed is:  
     
       1. A method for improving the hemodynamic efficiency of a sick heart comprising the steps of: 
       (a) detecting respective cardiac signals originating in the left and right ventricles of the heart;  
       (b) analyzing said cardiac signals and the absence thereof in an electronic control circuit; and  
       (c) providing electrical pulses from a stimulating circuit controlled by said control circuit to one, the other or both ventricles as required for effecting substantially simultaneous contraction of both ventricles, said step of analyzing including providing a control signal from said control circuit to said stimulating circuit for producing an electrical stimulating pulse to one or both ventricles in response to the absence of a detected cardiac signal from one or both ventricles within a time interval which is a small fraction of the pulse width of a detected cardiac signal.  
     
     
       2. The method of  claim 1  wherein said step of detecting respective cardiac signals comprises deposing electrodes in or on the left and right ventricles for separately detecting the respective cardiac signals of the left and right ventricles, and applying said cardiac signals to separate ECG amplifier means connected to each of said electrodes to amplify the cardiac signal for analysis. 
     
     
       3. The method of  claim 2  wherein said step of providing electrical pulses includes delivering an electrical pulse from said stimulating circuit to said electrodes in or on both the left and right ventricles. 
     
     
       4. The method of  claim 1  wherein said step of analyzing further includes providing a control signal from said control circuit to the stimulating circuit to produce an electrical stimulating pulse to the left ventricle in the absence of a detected cardiac signal from the left ventricle, or to the right ventricle in the absence of a detected cardiac signal from the right ventricle, or to both ventricles in the absence of detected cardiac signals from both ventricles. 
     
     
       5. A method for effecting simultaneous contraction of both left and right ventricles of a heart for improving hemodynamic efficiency comprising the steps of: 
       separately sensing for the presence of cardiac depolarization signals from both left and right ventricles;  
       determining whether said cardiac depolarization signals are simultaneously present in both the left and right ventricles; and  
       stimulating at least one ventricle substantially simultaneously with the contraction of a least one other ventricle in the event that said cardiac depolarization signals are determined not to be simultaneously present in both ventricles.  
     
     
       6. A method of effecting simultaneous contraction of both left and right ventricles of a heart for improving hemodynamic efficiency comprising the steps of: 
       sensing the cardiac signals of the atria and separately sensing the cardiac depolarization signals of both the left and right ventricles;  
       determining whether said cardiac depolarization signals are simultaneously present in both the left and right ventricles;  
       stimulating at least one ventricle simultaneously with the contraction of at least one other ventricle after a predetermined A-V period in the event that said cardiac depolarization signals are determined not to be simultaneously present in both ventricles.  
     
     
       7. A method of increasing the cardiac output of a sick heart comprising the steps of: 
       (a) implanting a pacing lead having at least two sensing/pacing electrodes in the body such that one of said sensing/pacing electrodes is in or on the right ventricle and the other of said sensing/pacing electrodes is in or on the left ventricle;  
       (b) sensing depolarization signals picked up by said sensing/pacing electrodes upon their occurrence;  
       (c) determining whether the depolarization signals sensed in step (b) fail to occur within a predetermined time interval of one another and, if so;  
       (d) applying an electrical stimulating pulse to the sensing/pacing electrode associated with the ventricle not producing a depolarization signal within said time interval at the conclusion of said time interval.  
     
     
       8. The method as in  claim 7  wherein said predetermined time interval is in the range of from about 5 ms. to 10 ms. 
     
     
       9. A bi-ventricular pacemaker, comprising: 
       (a) sense means for sensing ventricular depolarization signals originating in or on the right and left ventricles;  
       (b) means coupled to said sense means for initiating a time delay of a predetermined length which is short compared to the period of a QRS complex upon detection of a ventricular depolarization signal in one of said right or left ventricles; and  
       (c) pulse generator means operative upon the termination of said time delay for producing a ventricular simulating pulse and applying same to the other of said right or left ventricles unless a ventricular depolarization signal occurs in said other of said right or left ventricle prior to the expiration of said time delay.  
     
     
       10. The bi-ventricular pacemaker as in  claim 9  wherein said sense means comprises a bi-ventricular lead having a first electrode for contacting the left ventricle and sense amplifier means electrically coupled to said first and second electrodes. 
     
     
       11. The bi-ventricular pacemaker as in  claim 10  wherein said means coupled to said sense means includes: 
       (a) first and second set-reset flip-flop connected to be set by an output from said sense amplifier means;  
       (b) presetable counter means for initially containing a digital value representative of said time delay;  
       (c) means for incrementing or decrementing said digital value in said presettable couter means at regular intervals until a predetermined count is reached;  
       (d) means responsive to the value in said counter means reaching said predetermined count for producing a control signal;  
       (e) logic means coupled to said first and second flip-flops and to said presettable counter means for receiving said control signals; and wherein  
       (f) said pulse generator means is enabled by said logic means.  
     
     
       12. The bi-ventricular pacemaker as in  claim 11  wherein said pulse generator means is coupled to said first and second electrodes. 
     
     
       13. An atrial-coupled, bi-ventricular pacemaker for implantation or external use comprising atrial and ventricular sensing means for detecting cardiac signals, said sensing means including first and second ventricular electrodes connected in series for sensing and stimulating the right and left ventricles, respectively, and an atrial electrode adapted to be disposed in an atrial chamber for detecting cardiac signals of the atria, all of said electrodes being connected to separate ECG amplifier means for amplifying the sensed signals; a control circuit coupled to said ECG amplifier means for analyzing the cardiac signals picked up by said sensing means and providing a control signal; and a stimulating circuit means for producing an electrical stimulating pulse to the left ventricle in the absence of a detected cardiac signal from the left ventricle, and to the right ventricle in the absence of a detected cardiac signal from the right ventricle, and to both ventricles in the absence of detected cardiac signals from both ventricles to effect substantially simultaneous contraction of both ventricles after a predetermined A-V delay period. 
     
     
       14. The pacemaker of  claim 13  wherein said first electrode is adapted to be placed in the right ventricle and the second electrode is adapted to be placed in the coronary sinus extending about the left ventricle. 
     
     
       15. A method for improving the hemodynamic efficiency of a heart comprising the steps of: 
       
         detecting a cardiac depolarization signal originating from a first ventricle;  
       
       
         immediately and unconditionally stimulating both ventricles for effecting a coordinated contraction of both ventricles when a cardiac depolarization signal originating from the first ventricle is detected. 
       
     
     
       16. The method of  claim 15  wherein the step of immediately and unconditionally stimulating both ventricles further comprises providing electrical pulses from a stimulating circuit to both ventricles. 
     
     
       17. The method of  claim 16  wherein said step of detecting a cardiac depolarization signal further comprises positioning electrodes in or about both ventricles for detecting cardiac depolarization signals and for conducting a signal to an electronic control circuit for controlling the stimulating circuit. 
     
     
       18. The method of  claim 17  wherein said step of detecting a cardiac depolarization signal further comprises conducting the signal to an amplifier means to amplify the detected signal, and applying the amplified signal to the control circuit. 
     
     
       19. A method for improving the hemodynamic efficiency of a heart comprising the steps of: 
       
         sensing a contraction of the atria; and  
       
         stimulating both ventricles for effecting a coordinated contraction of both ventricles when a contraction of the atria is sensed and following a predetermined A - V delay period.   
     
     
       20. The method according to  claim 19 , further comprising, before said sensing step: 
       
         placing a first electrode into the right ventricle through the superior vena cava and placing a second electrode into the left ventricle through the coronary sinus;  
       
       
         wherein said stimulation of both ventricles is an electrical discharge through said first and second electrode. 
       
     
     
       21. The method according to  claim 19 , further comprising, before said sensing step: 
       
         placing a pair of sensing and pacing tip electrodes into each of the right and left ventricles;  
       
       
         wherein said sensing is detected through said pair of sensing tip electrodes. 
       
     
     
       22. A bi- ventricular pacemaker, comprising:    
       
         sense means for sensing ventricular depolarization signals originating from one of left and right ventricles; and  
       
       
         pulse generator means operative upon sensing a depolarization signal from the one of the ventricles for producing a stimulating pulse and immediately and unconditionally applying the stimulating pulse to both ventricles. 
       
     
     
       23. A bi- ventricular pacemaker according to    claim 22   , wherein the sense means includes a lead having a first electrode for placement in or about the left ventricle and a second electrode for placement in or about the right ventricle.   
     
     
       24. A bi- ventricular pacemaker according to    claim 22   , wherein the pulse generator means includes a sense amplifier means electrically coupled to the first and second electrodes for amplifying a sensed depolarization signal, a stimulating circuit for producing the stimulating pulse, and a control circuit operative to control the stimulating circuit in response to the amplified sensed depolarization signal.   
     
     
       25. A bi- ventricular pacemaker comprising:    
       
         detecting means for detecting a cardiac signal resulting from a contraction of a first ventricle;  
       
       
         stimulating means for effecting immediate and unconditional contraction of a second ventricle in response to the detected cardiac signal, thereby effecting simultaneous contraction of both ventricles. 
       
     
     
       26. A bi- ventricular pacemaker according to    claim 25    further comprising stimulating means for providing a stimulating pulse to the first ventricle simultaneous with the effecting of the immediate and unconditional contraction of the second ventricle.