Ablation of lesions of low-medium depths using ultrahigh radiofrequency (rf) power for ultrashort durations

Abstract

A method of body tissue ablation includes defining an ultrahigh-power ultrashort-duration (UPUD) ablation protocol that specifies an ablation signal having (i) a target ablation power of at least 400 Watts and (ii) a pulse duration that does not exceed three seconds, for creating a specified lesion in tissue in a body of a patient. Contact is made between an ablation probe and the tissue. Using the ablation probe, the ablation signal is applied to the tissue according to the UPUD protocol, which delivers the ablation signal having the specified target ablation power and duration.

1 . A system for body tissue ablation, the system comprising:
 (a) an ablation probe with one or more electrodes configured to make contact with tissue;   (b) a memory, which is configured to store values of an ultrahigh-power ultrashort-duration (UPUD) ablation protocol that specifies an ablation signal having (i) a target ablation power of at least 400 Watts per electrode and (ii) a pulse duration that does not exceed three seconds, for creating a specified lesion in tissue in a body of a patient;   (c) an ultrahigh-power ultrashort-duration (UPUD) generator, which is configured to generate the ablation signal; and   (d) a processor configured to control the generator and the ablation probe to apply the ablation signal to the tissue according to the UPUD protocol, which delivers the ablation power having the specified target ablation power and duration.   
     
     
         2 . The system of  claim 1 , wherein the pulse duration is (i) between 0.5 second and 0.9 second, (ii) not to exceed a patient's single heartbeat duration, or (iii) shorter than a global duration. 
     
     
         3 . The system of  claim 1 , wherein the pulse duration includes:
 (a) a first pulse duration between 0.5 seconds and 0.7 seconds for low-depth lesion; and   (b) a second pulse duration between 0.8 seconds and 0.9 seconds for medium-depth lesion.   
     
     
         4 . The system of  claim 1 , wherein the ablation signal and the pulse duration are configured to generate resistive heating of tissue. 
     
     
         5 . The system of  claim 4 , wherein the ablation signal and the pulse duration are configured to avoid conductive heating of tissue. 
     
     
         6 . The system of  claim 1 , wherein the processor is configured to control irrigation flow to tissue during ablation at a rate between 2 ml/min and 30 ml/min. 
     
     
         7 . The system of  claim 1 , wherein the patient's single heartbeat duration is pre-measured. 
     
     
         8 . A system for body tissue ablation, the system comprising:
 (a) a memory, which is configured to store values of an ultrahigh-power ultrashort-duration (UPUD) ablation protocol that specifies an ablation signal having (i) a maximum target ablation power of at least 400 Watts and an automatic minimum ablation power of zero Watts, and (ii) a pulse duration that does not exceed three seconds, for creating a specified lesion in tissue in a body of a patient;   (b) an ablation probe, which is configured to make contact with the issue;   (c) an ultrahigh-power ultrashort-duration (UPUD) generator, which Is configured to generate the ablation signal; and   (d) a processor, which is configured to control the generator and the ablation probe to apply the ablation signal to the tissue according to the UPUD protocol, which delivers the ablation power having the specified target ablation power and duration, the pulse duration being (i) between 0.5 second and 0.9 second, (ii) not to exceed a patient's single heartbeat duration, or (iii) shorter than a global duration.   
     
     
         9 . The system of  claim 8 , wherein the patient's single heartbeat duration is pre-measured. 
     
     
         10 . The system of  claim 8 , wherein the global duration is a sub-second duration. 
     
     
         11 . The system of  claim 8 , wherein the ablation probe includes a temperature sensor, and the processor is configured to halt ablation if temperature sensed by the temperature sensor exceeds a maximal value. 
     
     
         12 . The system of  claim 8 , wherein the ablation probe includes a contact force sensor, and the processor is configured to halt ablation if contact force sensed by the contact force sensor falls below a prespecified value. 
     
     
         13 . The system of  claim 12 , wherein contact force is sampled at a rate between Hz and 70 Hz. 
     
     
         14 . The system of  claim 11 , wherein contact force includes instantaneous contact force. 
     
     
         15 . A method of body tissue ablation, the method comprising:
 (a) defining an ultrahigh-power ultrashort-duration (UPUD) radiofrequency (RF) ablation protocol that specifies an ablation signal having (i) a target ablation power of at least 400 Watts per electrode and (ii) comprising setting a pulse duration for creating a specified lesion in tissue in a body of a patient, the tissue including cardiac tissue;   (b) making contact between one or more electrodes of an ablation probe and the tissue; and   (c) using the ablation probe, applying the ablation signal to the tissue according to the UPUD RF ablation protocol, which delivers the ablation signal having the specified target ablation power and duration.   
     
     
         16 . The method of  claim 15 , wherein the pulse duration is (i) between 0.5 second and 0.9 second, (ii) not to exceed a patient's single heartbeat duration, or (di) shorter than a global duration. 
     
     
         17 . The method of  claim 15 , wherein the pulse duration includes:
 (a) a first pulse duration between 0.5 seconds and 0.7 seconds for low-depth lesion; and   (b) a second pulse duration between 0.8 seconds and 0.9 seconds for medium-depth lesion.   
     
     
         18 . The method of  claim 15 , wherein the ablation signal and the pulse duration are configured to generate resistive heating of tissue. 
     
     
         19 . The method of  claim 18 , wherein the ablation signal and the pulse duration are configured to avoid conductive heating of tissue. 
     
     
         20 . The method of  claim 15 , wherein the processor is configured to control irrigation flow to tissue during ablation at a rate between 2 ml/min and 30 ml/min.