Defibrillation/cardioversion system with multiple evaluation of heart condition prior to shock delivery
First Claim
1. A method for defibrillating/cardioverting the heart comprising the steps of:
- (a) sensing the electrical activity of the heart including the interval between successive R-waves of the ECG;
(b) comparing the interval between successive R-waves with a preset value corresponding to an interval indicative of a heart arrhythmia, to detect heart arrhythmias;
(c) charging a defibrillation capacitor to a predetermined voltage level upon detecting an arrhythmia of the heart;
(d) storing the interval between successive R-waves during the step of charging the defibrillation capacitor;
(e) providing a first delay of a first predetermined period of time subsequent to said capacitor being charged to said predetermined level;
(f) comparing the stored interval between successive R-waves detected during the charging step with said preset value after said first delay;
(g) providing a second delay of a second predetermined period of time if said stored interval between successive R-waves is greater than said preset value as determined in step (f);
(h) comparing intervals between successive R-waves detected during the second delay with said preset value; and
(i) discharging said defibrillation capacitor through the heart if any interval between successive R-waves detected during the second delay is less than said preset value as determined in step (h).
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Accused Products
Abstract
An automatic implantable defibrillator/cardioverter having a non-committed defibrillation/cardioversion algorithm. The defibrillator/cardioverter includes an ECG amplifier with automatic gain control (AGC) which detects the electrical activity of the heart for analysis by a cardiac condition detector. Logic is provided which receives input from the ECG amplifier and the cardiac condition detector for analyzing the heart activity. The non-committed defibrillation algorithm sensing begins upon the determination of an arrhythmia. The capacitor is charged while the heart activity is simultaneously monitored. After the capacitor is charged, a check is made on the duration of the last detected R-R interval while so charging the capacitor, and a comparison is made between this R-R interval and a preset value. If the last R-R interval is greater than the preset value, a non-committing period is entered which lasts approximately 2 seconds. The purpose of the non-committing period is to allow detection to monitor the arrhythmia further before making the decision to discharge the capacitor or dump the charge internally. If any R-R interval detected during this interval is less than PCLL, this indicates that the arrhythmia has not reverted and the capacitor charge is delivered to the patients, synchronously with the second R-wave of the fast R-R interval. If no rapid interval is detected during this time, a post intervention (PI) monitoring routine is entered at the end of the non-committing period to further monitor cardiac activity and shock if necessary.
357 Citations
27 Claims
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1. A method for defibrillating/cardioverting the heart comprising the steps of:
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(a) sensing the electrical activity of the heart including the interval between successive R-waves of the ECG; (b) comparing the interval between successive R-waves with a preset value corresponding to an interval indicative of a heart arrhythmia, to detect heart arrhythmias; (c) charging a defibrillation capacitor to a predetermined voltage level upon detecting an arrhythmia of the heart; (d) storing the interval between successive R-waves during the step of charging the defibrillation capacitor; (e) providing a first delay of a first predetermined period of time subsequent to said capacitor being charged to said predetermined level; (f) comparing the stored interval between successive R-waves detected during the charging step with said preset value after said first delay; (g) providing a second delay of a second predetermined period of time if said stored interval between successive R-waves is greater than said preset value as determined in step (f); (h) comparing intervals between successive R-waves detected during the second delay with said preset value; and (i) discharging said defibrillation capacitor through the heart if any interval between successive R-waves detected during the second delay is less than said preset value as determined in step (h). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for defibrillating/cardioverting the heart comprising:
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means for sensing the electrical activity of the heart including the interval between successive R-waves of the ECG; means for detecting an arrhythmia of the heart; means for storing the interval between successive R-waves; defibrillation capacitor means; means for charging said defibrillation capacitor means to a predetermined voltage level upon detecting an arrhythmia of the heart using said means for detecting; means for triggering the discharge of said defibrillation capacitor means; and logic means including means for providing a first delay of a first predetermined period of time subsequent to said capacitor being charged to said predetermined level means for providing a second delay of a second predetermined period of time subsequent to said first delay;
means for comparing the stored interval between successive R-waves detected during charging of the defibrillation capacitor means with a preset value during said first delay;
means for entering said second delay of said second predetermined period of time if said stored interval between successive R-waves is greater than said preset value; and
means for discharging said defibrillation capacitor to the heart if any interval between successive R-waves is less than said preset value during said second delay. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of non-committed defibrillation/cardioversion of the heart comprising the steps of:
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(a) sensing the electrical activity of the heart including the interval between successive R-waves of the ECG; (b) comparing the interval between successive R-waves with a first preset value and a second preset value, each of said first and second preset values corresponding to an interval indicative of a heart arrhythmia, to detect heart arrhythmias; (c) charging a defibrillation capacitor to a predetermined voltage level upon detecting an arrhythmia of the heart; (d) storing the interval between successive R-waves during the step of charging the defibrillation capacitor; (e) comparing the stored interval between successive R-waves detected during the charging step with said first preset value; (f) providing a non-committing period of a first predetermined period of time if said stored interval between successive R-waves is greater than said first preset value as determined in step (e); (g) comparing intervals between successive R-waves detected during the non-committing period with the second preset value; and (h) discharging said defibrillation capacitor through the heart if any interval between successive R-waves detected during the non-committing period is less than said second preset value as determined in step (g). - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A method for defibrillating/cardioverting the heart, according to the existence of first and second predetermined conditions of the heart, said method comprising the steps of:
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(a) sensing a physiological indicator of an arrhythmia; (b) detecting an arrhythmia of the heart based on the physiological indicator; (c) charging a defibrillation capacitor to a predetermined voltage level upon detecting an arrhythmia of the heart; (d) storing data related to the cardiac function of the heart during the step of charging; (e) detecting whether the first predetermined condition of the heart occurs during the step of charging; (f) providing a non-committing period of a first predetermined period of time if the first predetermined condition of the heart does not occur during the step of charging as determined in step (e); (g) detecting whether the second predetermined condition of the heart occurs during said non-committing period based on the physiological indicator; and (h) discharging said defibrillation capacitor through the heart if said second predetermined condition of the heart is detected during said non-committing period as determined in step (g). - View Dependent Claims (24, 25, 26, 27)
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Specification