Wearable cardioverter defibrillator (wcd) with power-saving function

Abstract

A Wearable Cardioverter Defibrillator (WCD) system has a processor that performs two different analyses to an ECG of the patient. A first-level analysis can be computationally economical, while a fuller second-level analysis can give shock/no-shock advice with more certainty. In some of these embodiments the second-level analysis of the ECG is performed only if the first-level analysis of the ECG detects a possible shockable condition. As such, the first-level analysis may operate as a gatekeeping function, often preventing the more computationally intensive second-level analysis from being performed. An advantage can be that the WCD system needs to store less charge, for powering the processor. In turn, this permits portions of the WCD system to be less bulky and weigh less.

1 . A wearable cardioverter defibrillator (WCD) system, comprising:
 a support structure configured to be worn by a patient;   an energy storage module;   a discharge circuit coupled to the energy storage module;   a transducer configured to render, from a sensed Electrocardiogram (ECG) of the patient, a physiological input that includes ECG data of the patient; and   a processor configured to:
 perform a first-level analysis of the physiological input to detect whether a shockable condition exists, 
 perform, responsive to an outcome of the first-level analysis being that a shockable condition does not exist, a second-level analysis of the physiological input to detect whether the shockable condition exists, and 
 control, responsive to detecting that the shockable condition exists, the discharge circuit to discharge a stored electrical charge through the patient to deliver a shock to the patient while the support structure is worn by the patient. 
   
     
     
         2 . The WCD system of  claim 1 , wherein the first-level analysis is performed on a first portion of the physiological input. 
     
     
         3 . The WCD system of  claim 2 , wherein the first-level analysis is performed on the first ECG data as the first ECG data is streaming only in a single direction. 
     
     
         4 . The WCD system of  claim 2 , wherein the second-level analysis is performed on a second portion of the physiological input wherein the first portion includes second ECG data from a second time segment. 
     
     
         5 . The WCD system of  claim 4 , wherein the first portion includes first ECG data from a first time segment. 
     
     
         6 . The WCD system of  claim 5 , wherein the second portion includes second ECG data from a second time segment. 
     
     
         7 . The WCD system of  claim 6 , wherein the second time segment has a different time duration than the first time segment. 
     
     
         8 . The WCD system of  claim 6 , wherein the second time segment overlaps with the first time segment at least in part. 
     
     
         9 . The WCD system of  claim 1 , wherein the second-level analysis is performed responsive to a checking input being received. 
     
     
         10 . The WCD system of  claim 9 , further comprising:
 a timer configured to generate the checking input at a preset time.   
     
     
         11 . The WCD system of  claim 9 , further comprising:
 a motion detector configured to generate the checking input responsive to a motion of the patient that is detected by the motion detector.   
     
     
         12 . The WCD system of  claim 1 , wherein the first-level analysis is configured to detect a possible shockable condition. 
     
     
         13 . The WCD system of  claim 12 , wherein the second-level analysis is configured to detect an actual shockable condition. 
     
     
         14 . The WCD system of  claim 13 , wherein the possible shockable condition and the actual shockable condition are different. 
     
     
         15 . The WCD system of  claim 1 , in wherein when shocking condition is not detected, the first-level analysis is repeated. 
     
     
         16 . The WCD system of  claim 1 , wherein when the shocking condition is not detected, neither the first- level analysis nor the second-level analysis is then performed for a preset pause time. 
     
     
         17 . The WCD system of  claim 1 , wherein:
 the ECG data is acquired from a plurality of ECG channels,   the first-level analysis includes analyzing the ECG data of a first number of the ECG channels, and   the second-level analysis includes analyzing the ECG data of a second number of the ECG channels that is larger than the first number.   
     
     
         18 . The WCD system of  claim 1 , wherein:
 the ECG data is acquired from at least a first ECG channel and a second ECG channel, wherein the first ECG channel is designated as a selected ECG channel,   the first-level analysis includes analyzing the ECG data of only the selected ECG channel,   the second ECG channel becomes designated as a selected ECG channel responsive to the second-level analysis, and   after the second-level analysis is performed, the first-level analysis is performed again and analyzes the ECG data of only the second ECG channel that has been designated as the selected ECG channel.   
     
     
         19 . The WCD system of  claim 1 , wherein the processor includes:
 a first computational module configured to perform the first-level analysis, and a second computational module distinct from the first computational module,   wherein the second computational module configured to perform the second-level analysis.   
     
     
         20 . The WCD system of  claim 1 , wherein the processor has a clock speed, and wherein the clock speed is faster when the second-level analysis is being performed than when the first-level analysis is being performed.