JP2010500144A - Extracorporeal defibrillator for analysis of multiple arrhythmia conditions - Google Patents

Abstract

An external defibrillator and method that incorporates ECG rhythm analysis is described. ECG rhythm analysis can be used to advise defibrillator shocks based on that analysis. For certain conditions, the analysis algorithm (70) is in a rhythm where the heart is not a candidate for an unsynchronized defibrillation shock therapy (72), but is a candidate for a cardioversion therapy such as a synchronized electrocardioversion It may be determined (80) that there is a potentially serious condition. If such a condition is detected by the analysis algorithm, the defibrillator prompts the user to consider cardioversion therapy (84), alerts the clinician to alternative therapies that may be appropriate, and possibly Accelerating the application of the alternative therapy without adding the risks associated with the automatic application of the therapy.

Description

  The present invention relates to defibrillators, and more particularly to an external defibrillator that analyzes a patient's heart rhythm for both life-threatening and non-life-threatening conditions.

  Defibrillators have normal rhythm and contractile function in patients experiencing arrhythmias such as ventricular fibrillation (VF) or ventricular tachycardia (VT), also called sudden cardiac arrest Give the heart a high voltage impulse to recover. There are several classes of defibrillators, including manual defibrillators, implantable defibrillators and automatic external defibrillators (AEDs). Unlike manual defibrillators, AEDs are programmed in advance to determine whether defibrillation is necessary and automatically analyze the ECG (electrocardiogram) rhythm to provide administration measures. Has been. The delivery policy is a shock sequence of the appropriate energy level and the period during which subsequent or subsequent patients are given CPR. Thus, AED is suitable for use by rescuers without extensive medical training. A manual defibrillator reads a patient's ECG waveform, determines if a shock is appropriate, and is trained and able to configure the defibrillator to provide the proper shock sequence and energy level. Used by clinicians with experience in advanced cardiac life support (ACLS).

  The purpose of the AED is to enable people with little or no medical training to receive life-threatening defibrillation shocks for those who have undergone sudden cardiac arrest (SCA). Research has shown that it is usually crucial to shock the patient's survival in the first few minutes so that when possible, a trained rescuer can be treated before it can reach the scene. It is important to make it. However, improper application of defibrillation shocks can cause serious injury or death. In particular, AEDs have generally been conservatively designed to be very specific in terms of shock-tolerant conditions, because civilian rescuers lack advanced medical training to correct false results.

  The goal of defibrillation is to reduce blood flow by calming inappropriate electrical activity of the heart through the application of electric shock when the patient has ventricular fibrillation or non-perfusing tachycardia. It is to recover. Most AED algorithms distinguish ventricular fibrillation well, but it is impossible to determine whether a tachycardia is perfused from ECG signals alone. Ventricular tachycardia at high rates is believed not to give enough time for full filling of heart chambers, and the VT mechanism produces poor pumping. The American Heart Association has not given specific recommendations on when tachycardia should be shocked based on the ECG, and AHA can determine that the rhythm is of supraventricular origin Unless otherwise indicated, all tachycardia should be considered ventricular in origin. Even supraventricular tachycardia (SVT) can give insufficient cardiac output because the time between heartbeats is too short for ventricular filling.

  AED algorithms that shock ventricular tachycardia are generally “organized,” indicating a consistent and repetitive ECG, rather than for highly irregular “disorganized” (polymorphic) tachycardia. ) "(Monomorphic) with more stringent criteria for tachycardia. Some people can maintain a perfusion rhythm even at very high heart rates, so it can be assumed that the condition is perfusion while the monomorphic tachycardia rhythm remains stable. Non-perfusion tachycardia usually degenerates to an unstable rhythm, which is usually perceived as shockable by analysis algorithms. Setting very strict criteria to shock monomorphic tachycardia reduces the likelihood of improper and potentially dangerous shocks to perfused patients.

  However, some cardiologists recommend more aggressive treatment protocols. Such doctors argue that even if the type of tachycardia is questionable, if it is perfusable, it is less likely to induce a non-perfusion rhythm by shock. And even though the applied shock induces a non-perfusion rhythm, the most common rhythm is fibrillation, which is easily converted in the recently perfused heart. Since the probability of successful non-perfusion rhythm conversion decreases with increasing non-perfusion length, it is desirable to restore normal rhythm before reaching the non-perfusion state. In situations where more severe conditions are induced in a hospital or EMS setting, trained rescuers have already been dispatched. Thus, some cardiologists conclude that delaying a shock to a non-perfusion rhythm is at higher risk than shocking a questionable rhythm.

  In these cases, this philosophy argues that it may be more appropriate to deliver a synchronized shock, which is the therapy recommended by AHA for some classes of tachycardia. Synchronized cardioversion, however, is a procedure for ACLS-trained medical professionals that exceeds the expected level for AED users. Synchronous cardioversion is and is often applied to patients who are responsive and breathing. This is contraindicated for (asynchronous) defibrillation. Defibrillation is for life-threatening conditions where treatment protocols should be initiated immediately, but synchronous cardioversion treatment is usually as soon as practical as soon as practical ) Should be started.

American Heart Association, 2005 Guidelines for Cardiopulmonary Resuscitation and Cardiovascular Care (2005 Guidelines for Cardiopulmonary Resuscitation and Cardiovascular Care)

Previous methods have approached the uncertainty of whether to treat monomorphic tachycardia in one of four ways:
1. By setting a very high rate threshold, it becomes very specific to avoid shocking the perfusion rhythm,
2. Relying on the low risk of complications due to unnecessary shocks, it becomes very sensitive to provide the earliest treatment,
3. Pick any point that balances sensitivity versus specificity,
4). If ventricular fibrillation is suspected, it automatically switches from defibrillation to synchronous cardioversion.

  Each of these approaches is problematic. Overly specific can delay electrotherapy for conditions that can benefit from intervention. While waiting for a surely shockable rhythm, the patient's condition can deteriorate to the point where the probability of recovery decreases. Oversensitivity can be unnecessarily shocked and can cause side effects that may be unacceptable to less trained first responders. An intermediate defibrillation threshold is simply a trade-off between the risk of one error and the other. For example, automatic mode change from (asynchronous) defibrillation to synchronous cardioversion as described in US Pat. No. 6,246,907 (Lin et al.) Is a risk to patients involved in applying unsynchronized shocks. It does not reduce the possibility of applying inappropriate shocks. In other words, changing the mode does not change the possibility of making a wrong decision to apply a shock, but even if an improper shock is given, the application to the non-perfusion rhythm by applying the wrong shock The possibility of conversion is reduced by switching to a synchronized shock delivery instead of an unsynchronized shock. The treatment protocol described in Lin et. Al is such that if a QRS waveform is not available to synchronize therapy pulses within a given time frame, an unsynchronized defibrillation therapy can be applied instead. Use a suitable starting energy for defibrillation. In general, the energy threshold for synchronous cardioversion is much lower than for rhythms that require defibrillation, and for monophasic shocks, AHA is half the starting energy for defibrillation for synchronous cardioversion The starting energy is recommended. See Non-Patent Document 1.

  There are several other reasons why the synchronized cardio version is not immediately applied if it can be delayed. First, shock is painful and pre-administering anesthesia helps the patient's comfort. Second, the starting energy level for the cardioversion should be selected by experienced clinical personnel based on cardiac rhythm, and rhythm discrimination by the defibrillator is confirmed before applying electrotherapy It should be. Third, the preferred therapy electrode placement often differs between the atrial cardioversion and the ventricular cardioversion. Fourth, long-term atrial fibrillation tends to cause thrombosis, and cardioversion without echocardiograms to confirm the absence of prophylactic thrombolytics and thrombosis can eliminate clots and seizures Can be caused. Finally, selecting an ECG lead for analysis without a dominant QRS will cause the defibrillator to select the wrong sync point and potentially trigger a shock to a high T wave It is possible. Such a shock can cause the very situation that a synchronous cardio version tries to avoid. Most treatment protocols, including AHA guidelines, indicate that ACLS-trained rescuers should verify that the defibrillator correctly identifies the QRS as a sync point before shocking. ing.

  In accordance with the principles of the present invention, an external defibrillator can improve the ECG analysis for rhythms that cannot respond to shock therapy, and can provide alternatives such as cardioversions to complement defibrillation measures. This is accomplished by adding an alert for electrotherapy while not automatically applying the alternative electrotherapy in situations that may be inappropriate. The method of the present invention improves the general ECG-based shock decision analysis algorithm for external defibrillators, and the analyzed rhythm meets certain inclusion criteria, but for defibrillation. We suggest that rescuers consider cardioversion as a treatment option if they are not confirmed candidates. This improvement is for a defibrillator for a medical system with a user trained to deliver cardioversion therapy, an electrically synchronous cardioversion using a defibrillation device or alternatively a drug therapy that induces cardioversion. Can be enhanced to allow cardioversion to be applied. During analysis of rhythms suitable for defibrillation, the defibrillator of the present invention indicates the appropriateness of cardioversion therapy when defibrillation is not indicated and when the proper personnel and conditions are present Can be used to Although inadequately trained personnel should not carelessly give the therapy, prompts from the device can speed up therapy by trained rescuers. The present invention overcomes the problem that defibrillators do not direct the clinician's attention to the treatments that can be identified and delivered, while additional conditions are unknown or for therapies When other interventions required for the treatment can be directed to delay such therapy, the therapy is not automatically applied.

1 is a diagram of a defibrillator operable in manual mode or automatic (AED) mode in accordance with the principles of the present invention. FIG. FIG. 2 is a diagram of a defibrillation electrode connected to the defibrillator of FIG. 1. FIG. 2 is a diagram of monitoring electrodes connected to the defibrillator of FIG. 2 is a diagram of the defibrillator of FIG. 1 with the access door for manual mode in the open position. FIG. FIG. 2 is a simplified block diagram of the defibrillator of FIG. 1 in accordance with the present invention. 2 is a flowchart illustrating a method of operating an external defibrillator according to the present invention. FIG. 2 is a diagram of the user interface of the defibrillator of FIG. 1 in AED mode using a graphic display device in accordance with the principles of the present invention. FIG. 2 is a diagram of the user interface of the defibrillator of FIG. 1 in manual mode using a graphic display device in accordance with the principles of the present invention.

  FIG. 1 is an illustration of an external defibrillator 10 constructed in accordance with the principles of the present invention. The defibrillator 10 has an access door 20 shown in a closed position on the housing 19. Located on the top surface of the defibrillator 10 is a power-on button 22 labeled “1”. This initiates the process of energizing the defibrillator 10 and urging the first responder 12 to connect the defibrillation electrode 16 to the patient 14. Next to the power on button 22 is an analysis button 24 labeled “2”. This initiates an automatic analysis of the ECG signal obtained from the patient 24. Automatic analysis generates a shock advisory message. ECG analysis may also be initiated automatically upon detection of patient contact via defibrillation electrode 16. Next to the analysis button 24 is a shock button 26 labeled “3”. This initiates the delivery of a defibrillation shock to the patient 14 via the defibrillation electrode 16 when a shock is recommended by ECG analysis. The power-on button 22, the analysis button 24, and the shock button 26 labeled “1”, “2”, and “3” are collectively an AED button 34. This is used when the defibrillator 10 is operated in AED mode. Various buttons 34 may be operable in manual mode. As long as the logical order of the AED user interface is maintained and confusion is minimized, the precise labeling of the AED button 34 is not important.

The display 36 located next to the AED button is preferably a liquid crystal display (LCD) capable of displaying text such as labels and messages and graphics such as ECG traces. A printer 38 installed on the top surface of the defibrillator 10 provides a hard copy printout of the event markers collected during the ECG signal and patient treatment. A set of softkey controls 40 located next to the display 36 allow selection of functions according to softkey labels on the display 36 (shown in FIG. 7). Speaker 42 provides an audio prompt to the user, particularly when defibrillator 10 is in the AED mode. Connector 44 allows for coupling with other sensors that collect patient parameters such as pulse oximetry (SpO ₂ ).

  An AED usage label 46 is placed on the top surface of the defibrillator 10. The AED usage label 46 provides an initial indication to the first responder who must use the defibrillator 10 in AED mode.

  A manual mode warning label 48 is located on the upper side of the access door 20. The manual mode warning label 48 includes text or graphics that are intended to warn a general public first visitor not to open the access door 20. For example, the text “manual mode” may be used if the label “manual mode” has sufficient meaning for the first responder to prevent confusion in an emergency situation. Software access code for manual mode implementation that must be entered using a mechanical key lock (not shown) on the access door 20 or by a combination of button presses. Further protection can be achieved using.

  FIG. 2 is an illustration of a defibrillation electrode 16 having a connector 18 for insertion into a patient connector socket (not shown) on the defibrillator 10. The defibrillation electrode 16 is used both to acquire an ECG signal from the patient and to couple a defibrillation shock from the defibrillator 10 through the patient. The defibrillator electrode 16 may be automatically selected by the defibrillator 10 in the AED mode, or manually selected by the defibrillator 10 set to operate in the manual mode.

  FIG. 3 is an illustration of a set of monitoring electrodes 28 having a connector 30 for connection to a monitoring port 32 on the defibrillator 10. Three monitoring electrodes 28 are shown for illustration. More or fewer monitoring electrodes 28 are selected for various applications and may implement, for example, 3, 5 or 12 lead ECG monitoring.

  FIG. 4 is an illustration of a defibrillator 10 according to the present invention shown with the access door 20 in an open position. Manual access button 50 controls access to manual mode. In the manual mode, various manual functions can be selected using the manual function selection control 51, including defibrillation, synchronized cardioversion or pacing. Behind the access door 20 is a manual mode usage label 52 that gives ACLS users instructions on manual mode operation. Manual access button 50, manual function selection control 51 and manual mode usage label 52 are only visible to the user when access door 20 is in the open position.

  In an alternative embodiment of the present invention, switching between AED mode and manual mode may be done simply by opening the access door 20. This eliminates the need to press manual access button 50 to place defibrillator 10 in manual mode. Access door 20 includes a switch or sensor (not shown) to detect whether access door 20 is in the open or closed position and place defibrillator 10 in manual mode or AED mode, respectively. ) May be combined. Nevertheless, the manual function selection 51 located under the access door 20 is used to select between various manual functions when the defibrillator 10 is in manual mode.

  FIG. 5 is a simplified block diagram of a defibrillator 10 according to the present invention. The ECG front end 100 is connected to the defibrillation electrode 16, which in turn is connected across the patient's chest. The ECG front end 100 operates to amplify, buffer, filter and digitize the electrical ECG signal generated by the patient's heart to generate a stream of digitized ECG sample values. The digitized ECG sample values are provided to controller 102, which performs ECG analysis to detect VF, VT or other shockable rhythms. If a shockable rhythm is detected, the controller 102 sends a signal to the HV delivery unit 104 to charge in preparation for defibrillation shock delivery. Pressing the shock button 26 (shown in FIG. 1) triggers the HV delivery 104 to deliver a defibrillation shock to the patient through the electrode 16 via the controller 102.

  Further, there is a set of monitoring electrodes 28 connected to the ECG front end 100. The ECG front 100 can make a selection between the defibrillation electrode 16 and the monitoring electrode 28, preferably under the control of the controller 102.

  Memory 106 may be implemented as on-board RAM or ROM, a removable memory card, or a combination of various memory technologies. The memory 106 includes an AED personality program 108 and a manual personality program 110. The AED personality program 108 defines the operation of the defibrillator 10 in the AED mode, such as the operation of the AED button 34 and the information content displayed on the display 36. The manual personality program 110 defines the operation of the defibrillator 10 in manual mode, such as the operation of the buttons 34, softkey controls 40, manual function selection control 51 and the information content displayed on the display 36.

  The AED button 34, soft key 40, display 36, speaker 42, printer 38, manual access button 50, and manual function selection 51 collectively form the user interface of the defibrillator 10 and receive input from the user to the user. It is connected to the controller 102 to provide audible or visual feedback to it. Dedicated buttons such as controlling printer operation or adjusting ECG size, display contrast and speaker volume may be included to control general functions of defibrillator 10 in both AED and manual modes. Good.

  FIG. 6 is a flowchart of the operation sequence of the defibrillator 10 according to the present invention. When the controller 102 begins to receive ECG sample values from the ECG front end 100, at 70, the controller begins to execute its ECG analysis routine. This is at 72 to determine if there is a shockable rhythm. When the ECG analysis routine indicates that there is a life-threatening arrhythmia such as VF or polymorphic tachycardia, the user is notified at 74 that a shock is advised. An “advise shock” message may be audibly emitted through the speaker 42 and additionally or alternatively displayed on the display 36. This message is followed by other messages, such as warning the user not to touch the patient during the shock. The HV delivery unit 104 then charges the capacitor of the high voltage circuit and delivers a shock at 76, preferably a biphasic defibrillation pulse.

  Alternatively, the ECG analysis routine may be 72 and it may be concluded that there are no life threatening arrhythmias. In accordance with the present invention, the ECG analysis routine is 80 and evaluates the ECG data to determine if the cardioversion is appropriate. In the illustrated embodiment, ECG analysis analyzes whether a synchronized or chemical cardioversion has adequate cardiac conditions if it is determined that defibrillation is inappropriate. For example, ventricular tachycardia exceeding 150 beats per minute may not meet all defibrillation shock instructions from the AED algorithm, but AHA may consider that an ACLS-trained provider is appropriate For example, it allows this rhythm to be treated with a synchronized electrical cardioversion. If the result of this analysis is that no other therapy is properly identified, a message “shock is not advised” is issued at 82 and the defibrillator continues with an ECG analysis at 70. When the result of the analysis is that the cardioversion may be appropriate, the user is advised to consider the cardioversion at 84. This may be done by notifying the clinician about suggested alternative treatments for cardiac rhythms that may respond to cardioversion therapy through the visual display and / or sound generation capabilities of the device. For example, ECG analysis determines that defibrillation is not indicated, but after determining that the analysis is synchronized or a chemical cardioversion may be appropriate, the defibrillator will display the word "Consider cardioversion" A voice prompt such as “Defibrillation is not advised. Consider cardioversion” is announced on the speaker 42. The exact representation, both visual and auditory, will be determined by the user's wishes and may be translated into the appropriate language for where the defibrillator is used. If the visual display or audio speaker is not part of the defibrillator, the corresponding announcement may be omitted. Other forms of announcements such as tones, lights or other non-verbal or linguistic alerts can also be used. The defibrillator then resumes ECG analysis at 70 unless an ACLS qualified operator begins using the defibrillator to apply an alternative therapy as illustrated below.

  7A and 7B are illustrations of portions of the user interface of the defibrillator 10 in AED mode and manual mode, respectively. In FIG. 7A, where the defibrillator 10 is in AED mode, the AED button 34 for operating the defibrillator 10 defines a function according to the AED character 108, including “ON”, “Analysis”, “Shock” display. Labeled by the set of soft labels 54 above. A graphic trace 56 of the ECG signal may be displayed in the central portion of the display 36. A message block 58 containing a selected user prompt such as “Shock is not advised. Check patient” may be located at the bottom of display 36. In this example, the defibrillator has concluded an analysis of whether alternative therapies can be advised and has concluded that the cardioversion may be appropriate for the patient. In that case, message block 58 advises the user to “review the cardio version”. Softkey control 40 may be set on or off for defibrillator 10 depending on the particular version of AED personality program 108 that is selected. In some EMS systems, none of the softkey controls 40 may be enabled. In other EMS systems, a selected set of functions may be made available for AED mode defibrillators.

In FIG. 7B, the manual access button 50 exposed by opening the access door 20 may be pressed to place the defibrillator 10 in manual mode. In manual mode, functions that can be controlled by more advanced ACLS users are added to the manual mode menu structure based on the manual personality program 110, thus changing the set of soft labels 54. As shown, the set of soft labels 54 on the display, which defines the function of the button 34 in the operation of the button 34 with the defibrillator in manual mode, is now "energy selection""charge""shock". It has become. Various manual functions, such as synchronized cardioversion or pacing, can be selected using a manual function selection 51 that is also located under the access door 20. In addition, a softkey control 40 is added to label each function of the softkey control 40 for additional user control of manual functions based on the manual personality program 110, eg, “Alarm Settings”. It may be actuated to expose a set of soft labels 60 including “lead selection” “SpO ₂ ”. A menu tree may be implemented and logically configured to provide easy access to the desired manual functions available based on the manual personality program 110.

  In hospital settings in non-critical wards, highly trained clinical personnel arrive at the heart event site when AED is applied to the patient and the rhythm is analyzed. Most hospitals may not be fully trained in advanced cardiac lifesaving skills by nurses who are first responders, so in these non-critical wards, this advanced defibrillator can be used. Use in AED mode. In doing so, the AED mode immediately provides the initial care needed during this initial response period. Subsequent ACLS eligible rescuers can be prompted to consider a cardio version as a treatment option and respond accordingly. Alternatively, a more basic level of AED can be improved to optionally deliver a synchronized cardioversion by a person with proper training. In another embodiment, independent of analysis for shockable rhythms, an algorithm that advises the cardioversion can be used as an additional monitoring alert for the heart monitor.

  For advanced defibrillators, the application of alternative therapies can be accomplished as is known for the application of synchronous cardioversion pulses, which is device independent. One such defibrillator accomplishes this by exiting AED mode and entering manual mode operation. The button is pressed to initiate “synchronous cardioversion mode”, the appropriate energy for the pulse is selected, and the “charge” button is pressed. After the device is charged, the “shock” button is pressed to give a cardioversion shock. Determining that patient is properly prepared for electrical cardioversion, eg resting / unconscious; thrombolytics if recommended, and ECG instructions are appropriate for the therapy Is responsible for clinical personnel.

  As a further example, advanced defibrillators can more easily apply a synchronized cardioversion from within AED mode without leaving the AED application, for example by pressing a button that initiates a “synchronous cardioversion” . The defibrillator is automatically charged to a predetermined cardioversion level and the application of the pulse is triggered by pressing the “shock” button. Alternative protocol protocols can be determined by the clinical service that deployed the defibrillator, depending on the training level of the staff. Defibrillators can be configured for various therapy protocols.

  For basic AED, it is generally desirable to prevent anyone who is not ACLS-trained for cardioversion therapy from using it for cardioversion. For example, the application of a synchronized cardio version can be performed only after the operator presses a button on the defibrillator in a pattern that only a trained user knows, or by some other method. It can be implemented by inputting a code that enables a correct operation. The constrained use of cardioversion mode prevents ordinary users from giving therapy that should only be performed by properly trained professionals.

Claims (19)

An external defibrillator:
A pair of electrodes operable to deliver a defibrillation shock and operable to receive an ECG signal;
In response to the ECG signal, the ECG signal is analyzed to determine whether a defibrillation shock is desirable, and if the analysis determines that the defibrillation shock is not desirable, the ECG signal In response to the controller determining whether alternative cardiac electrotherapy should be considered;
A user interface operable to provide a user message that an alternative cardiac electrotherapy should be considered in response to a determination that the alternative cardiac electrotherapy should be considered And having
An external defibrillator.   The external defibrillator of claim 1, wherein the alternative cardiac therapy includes a cardioversion.   The external defibrillator of claim 2, wherein the user interface includes a display operable to display a message that cardioversion should be considered.   The external defibrillator of claim 2, wherein the user interface includes a speaker operable to emit an audio message that cardioversion should be considered.   The external defibrillation of claim 1, further comprising a high voltage delivery circuit coupled to the electrode responsive to the controller operable to deliver a defibrillation shock when a defibrillation shock is desired. vessel.   6. The high voltage delivery circuit is further operable to administer cardioversion therapy subsequent to providing the user message that an alternative cardiac therapy should be considered. An external defibrillator. 7. An external defibrillator as claimed in claim 6 intended for use by rescuers who are not ACLS qualified,
An external defibrillator configured to allow cardioversion therapy to be administered only by an ACLS-qualified rescuer.   8. The external defibrillator of claim 7, operable in AED mode by a rescuer without ACLS qualification and operable in manual mode by a rescuer with ACLS qualification. The controller is programmed to advise a defibrillation shock when analysis of the ECG signal indicates the presence of ventricular fibrillation or polymorphic tachycardia;
The controller is further programmed to advise a cardioversion review when analysis of the ECG signal indicates the presence of monomorphic tachycardia;
The external defibrillator according to claim 1. The method of operation of the external defibrillator is:
Applying an electrode to the subject;
Receiving an ECG signal;
Analyzing the ECG signal to determine if a defibrillation shock is desired;
Analyzing the ECG signal to determine whether alternative cardiac electrotherapy should be considered when defibrillation shock is undesirable;
Notifying the user to consider alternative cardiac electrotherapy,
Method.   The method of claim 10, wherein notifying the user further comprises advising the user to consider a cardio version. Analyzing the ECG signal by an ACLS qualified rescuer after the user has been advised to consider cardioversion;
Providing the cardioversion therapy synchronized by the ACLS qualified rescuer when the ACLS qualified rescuer determines that cardioversion is desirable;
The method of claim 11.   11. The method of claim 10, further comprising providing an unsynchronized defibrillation shock if the analyzing the ECG signal determines that a defibrillation shock is desired. Informing the user further comprises notifying an unsupported rescuer of ACLS that alternative cardiac therapy should be considered;
Further comprising preventing said ACLS unqualified rescuer from taking said alternative cardiac therapy using said external defibrillator;
The method of claim 10.   15. The method of claim 14, further comprising allowing an ACLS qualified rescuer to administer the alternative cardiac therapy using the external defibrillator.   The method of claim 15, wherein the allowing further comprises recognizing user input identifying the rescuer as being an ACLS qualified rescuer. The external defibrillator is operable in AED mode or manual mode;
The steps prior to allowing an ACLS-qualified rescuer to administer the alternative cardiac therapy are performed using the defibrillator operating in AED mode;
The step of allowing an ACLS qualified rescuer to administer the alternative cardiac therapy using the external defibrillator is performed using the defibrillator operating in a manual mode;
The method of claim 15. Determine that defibrillation shock is desirable when analysis of the ECG signal indicates the presence of ventricular fibrillation or polymorphic tachycardia;
Informing the user to consider alternative cardiac electrotherapy is done when the analysis of the ECG signal indicates the presence of monomorphic tachycardia,
The method of claim 10. An external defibrillator:
A pair of electrodes operable to deliver a defibrillation shock and receive an ECG signal;
In response to the ECG signal, the ECG signal is analyzed to determine whether a defibrillation shock is desirable, and if the analysis determines that the defibrillation shock is not desirable, the ECG signal In response to the controller determining whether a cardio version should be considered;
A user interface operable to provide a user message that the cardioversion should be considered in response to determining that the cardioversion should be considered;
An external defibrillator.

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