Pacing induced electrical activation grading

Abstract

In one embodiment, a medical procedure system includes a probe for insertion into a chamber of a heart of a living subject, and including a first electrode to apply a sequence of pacing pulses at a position in the chamber, a second electrode to sense an electrical activation signal responsively to electrical activations induced by capture of the pacing pulses in a myocardium of the chamber, a display, and processing circuitry to evaluate a successful acquisition by the second electrode of the induced electrical activations responsively to the electrical activation signal, the successful acquisition being indicative of a successful capture of the pacing pulses by the myocardium, compute a capture grade responsively to the evaluation of the successful acquisition of the induced electrical activations, the capture grade being indicative of a count of the induced electrical activations evaluated as being successfully acquired, and render the capture grade to the display.

What is claimed is: 
     
         1 . A medical procedure system comprising:
 a probe configured for insertion into a chamber of a heart of a living subject, and comprising a first electrode configured to apply a sequence of pacing pulses at a position in the chamber;   a second electrode configured to sense an electrical activation signal responsively to electrical activations induced by capture of the pacing pulses in a myocardium of the chamber over time;   a display; and   processing circuitry configured to:
 evaluate a successful acquisition by the second electrode of the induced electrical activations responsively to the electrical activation signal, the successful acquisition being indicative of a successful capture of the pacing pulses by the myocardium; 
 compute a capture grade responsively to the evaluation of the successful acquisition of the induced electrical activations, the capture grade being indicative of a count of the induced electrical activations which were evaluated as being successfully acquired; and 
 render the capture grade to the display. 
   
     
     
         2 . The system according to  claim 1 , wherein the processing circuitry is configured to evaluate the successful acquisition by the second electrode of respective ones of the electrical activations induced by respective ones of the pacing pulses responsively to the electrical activation signal exceeding a threshold signal amplitude within a given time window after the respective pacing pulses. 
     
     
         3 . The system according to  claim 1 , wherein the processing circuitry is configured to compute the capture grade responsively to a count of the induced electrical activations evaluated as being successfully acquired by the second electrode. 
     
     
         4 . The system according to  claim 3 , wherein the processing circuitry is configured to compute the capture grade also responsively to a count of unacquired electrical activations. 
     
     
         5 . The system according to  claim 3 , wherein the processing circuitry is configured to compute the capture grade also responsively to a total count of the pacing pulses. 
     
     
         6 . The system according to  claim 1 , wherein the processing circuitry is configured to compute the capture grade responsively to a count of unacquired electrical activations and a total count of the pacing pulses. 
     
     
         7 . The system according to  claim 1 , further comprising a pacing unit configured to generate the pacing pulses for application by the first electrode. 
     
     
         8 . The system according to  claim 1 , wherein the processing circuitry is configured to render to the display the capture grade with a representation of the electrical activation signal. 
     
     
         9 . The system according to  claim 1 , wherein the processing circuitry is configured to track a location of the second electrode. 
     
     
         10 . The system according to  claim 9 , wherein the processing circuitry is configured to render to the display a representation of another probe responsively to the tracked location. 
     
     
         11 . A medical procedure method comprising:
 inserting a first probe into a chamber of a heart of a living subject;   applying with a first electrode of the first probe a sequence of pacing pulses at a position in the chamber;   sensing with a second electrode an electrical activation signal responsively to electrical activations induced by capture of the pacing pulses in a myocardium of the chamber over time;   evaluating a successful acquisition by the second electrode of the induced electrical activations responsively to the electrical activation signal, the successful acquisition being indicative of a successful capture of the pacing pulses by the myocardium;   computing a capture grade responsively to the evaluation of the successful acquisition of the induced electrical activations, the capture grade being indicative of a count of the induced electrical activations which were evaluated as being successfully acquired; and   rendering the capture grade to a display.   
     
     
         12 . The method according to  claim 11 , wherein the evaluating includes evaluating the successful acquisition by the second electrode of respective ones of the electrical activations induced by respective ones of the pacing pulses responsively to the electrical activation signal exceeding a threshold signal amplitude within a given time window after the respective pacing pulses. 
     
     
         13 . The method according to  claim 11 , wherein the computing includes computing the capture grade responsively to a count of the induced electrical activations evaluated as being successfully acquired by the second electrode. 
     
     
         14 . The method according to  claim 13 , wherein the computing also includes computing the capture grade also responsively to a count of unacquired electrical activations. 
     
     
         15 . The method according to  claim 13 , wherein the computing also includes computing the capture grade also responsively to a total count of the pacing pulses. 
     
     
         16 . The method according to  claim 11 , wherein the computing includes computing the capture grade responsively to a count of unacquired electrical activations and a total count of the pacing pulses. 
     
     
         17 . The method according to  claim 11 , further comprising generating the pacing pulses for application by the first electrode. 
     
     
         18 . The method according to  claim 11 , wherein the rendering includes rendering to the display the capture grade with a representation of the electrical activation signal. 
     
     
         19 . The method according to  claim 11 , further comprising tracking a location of the second electrode. 
     
     
         20 . The method according to  claim 19 , wherein the rendering including rendering to the display a representation of another probe responsively to the tracked location.