Implantable defibrillators with programmable cross-chamber blanking

Abstract

Miniature defibrillators and cardioverters detect abnormal heart rhythms and automatically apply electrical therapy to restore normal heart function. Therapy decisions are typically based on the time between successive beats of various chambers of the heart, such as the left atrium and left ventricle. To prevent confusing a left ventricle beat for a left atrium beat, some devices use cross-chamber blanking, a technique which disables sensing of atrial beats for a certain time period after sensing. Conventionally, these devices lack any mechanism for adjusting length of this period. Accordingly, the inventor devised a implantable device including a mechanism for adjusting this time period. This mechanism ultimately allows tailoring of the cross-chamber blanking period to fit the needs of individual patients.

1 . An implantable dual-chamber defibrillation or cardioversion device, comprising: 
 at least first and second input leads for sensing atrial and ventricular electrical signals from a heart;    a therapy circuit for delivering electrical energy through one or more of the leads; and    a monitoring circuit for monitoring the electrical signals through one or more of the leads, the monitoring circuit comprising: 
 a programmable memory device for storing one or more cross-chamber blanking settings; and  
 circuitry for blanking an effect of atrial electrical signals in the monitoring circuitry for a period of time based on at least one of the cross-chamber blanking settings.  
   
     
     
         2 . A dual-chamber defibrillation or cardioversion system comprising: 
 a dual-chamber defibrillator or cardioverter including first and second leads for sensing signals from respective first and second chambers of a heart and a monitoring circuit for monitoring signals sensed at the first and second leads, the monitoring circuit having: 
 preset time period based on at least one of the settings; and  
   means for changing one or more of the cross-chamber blanking settings after implantation of the defibrillator or cardioverter.    
     
     
         3 - 5 . (Canceled)  
     
     
         6 . The device of  claim 1 , wherein the circuitry for blanking includes means for computing a noise window width based on a refractory period and one of the cross-chamber blanking settings.  
     
     
         7 . The system of  claim 2 , wherein the cross-chamber blanking module includes means for computing a noise window width based on at least the one of the cross-chamber blanking settings.  
     
     
         8 . An implantable dual-chamber cardioversion or defibrillation device, comprising: 
 first and second leads for sensing signals from respective first and second chambers of a heart;    a monitoring module for monitoring signals sensed at the first and second leads, the monitoring means including: 
 a memory module for storing one or more cross-chamber-blanking settings; and  
 cross-chamber-blanking module responsive to at least one of the settings for disabling sensing signals at the first or second lead or for ignoring signals at the first or second lead for a time period based on at least one of the stored cross-chamber blanking settings;  
   means, coupled to the memory module, for wirelessly receiving at least one cross-chamber blanking settings after implantation of the device and for programming the memory module based on the one received cross-chamber blanking setting; and    a therapy module, responsive to the monitoring module, for delivering a therapeutic agent to the heart.    
     
     
         9 . The device of  claim 7 , wherein the therapeutic agent is a non-electrical agent.  
     
     
         10 . The device of  claim 7 , wherein the cross-chamber-blanking module comprises means for computing a noise window duration based at least on the one cross-chamber blanking setting.