Asystole


Article Author:
Matthew Jordan


Article Editor:
Daphne Morrisonponce


Editors In Chief:
David Tauber


Managing Editors:
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Frank Smeeks
Kristina Soman-Faulkner
Benjamin Eovaldi
Radia Jamil
Sobhan Daneshfar
Pritesh Sheth
Hassam Zulfiqar
Steve Bhimji
John Shell
Matthew Varacallo
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Hajira Basit
Phillip Hynes
Kavin Sugumar


Updated:
3/8/2019 8:26:30 AM

Introduction

Asystole, colloquially referred to as flatline, represents the cessation of electrical and mechanical activity of the heart. Asystole typically occurs as a deterioration of the initial non-perfusing ventricular rhythms: ventricular fibrillation (V-fib) or pulseless ventricular tachycardia (V-tach). Additionally, pulseless electrical activity (PEA) can cease and become asystole. Victims of sudden cardiac arrest who present with asystole as the initial rhythm have an extremely poor prognosis (10% survive to admission, 0 % to 2% survival-to-hospital discharge rate).[1][2][3] Asystole represents the terminal rhythm of a cardiac arrest.

In out-of-hospital cardiac arrest, prolonged resuscitation efforts in a patient who presents in asystole is unlikely to provide a medical benefit. Termination of resuscitation efforts should be considered in these patients, in consultation with on-line medical direction, as allowed by local protocols. The American College of Emergency Physicians (ACEP) and National Association of Emergency Medical Services Physicians (NAEMSP) both recommend emergency medical services systems and have written protocols that allow for termination of resuscitation efforts by emergency medical services providers for a select group of patients in which further resuscitative measures and transport to the local emergency department would be considered futile.[4]

Etiology

Causes of asystole in cardiac arrest are wide and varied. Asystole typically results from decompensation of prolonged ventricular fibrillation arrest. Additionally, attempted defibrillation of ventricular tachycardia or ventricular fibrillation can precipitate asystole. However, any cause of cardiac arrest can eventually result in asystole if not promptly treated. When evaluating a patient with an initial cardiac rhythm of asystole, the reversible causes must be considered. A useful mnemonic taught in Advanced Cardiac Life Support (ACLS), for the reversible causes of cardiac arrest, involves the Hs and Ts. The Hs include Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, and Hypothermia. The Ts include Tension pneumothorax, Tamponade (cardiac), Toxins, and Thrombosis (both pulmonary and coronary). When identified, these cases should be immediately treated.[5][6]

Epidemiology

Each year, approximately 300,000 to 400,000 Americans experience a cardiac arrest outside of the hospital, with the mortality of these cases being extremely high. Data vary in different regions of the country and various studies. Differences range from 4.6% to 11% survival-to-hospital discharge rate.[2][3][7] An extensive surveillance study conducted by the Centers for Disease Control and Prevention (CDC) from 2005 through 2010 evaluated 40,274 out-of-hospital cardiac arrest cases entered into the Cardiac Arrest Registry to Enhance Survival (CARES) system. A total of 31,645 cases had a documented presenting initial rhythm. This is the largest number of cases (45.1%) presented in asystole. However, asystole had the lowest survival rate (2.3%).[8]

Fewer data are available with in-hospital cardiac arrest. This, in addition to a lack reporting consistency, makes the true number of in-hospital cardiac arrest cases largely unknown. Extrapolation of one large data set estimates approximately 200,000 in-hospital adult cardiac arrest cases per year. This estimate was confirmed in a second study using the Get With The Guidelines-Resuscitation registry. Neither of these studies investigated cardiac rhythms associated with cardiac arrest.[1][9]

Pathophysiology

Asystole results from failure of the heart’s intrinsic electrical system or an extracardiac cause. Extracardiac causes are varied. They include the Hs and Ts discussed above and their causes. Asystole typically occurs as a deterioration of the non-perfusing ventricular rhythms. If not rapidly corrected, electrical and mechanical cessation of cardiac activity will occur. This is manifested as asystole on the cardiac monitor.

History and Physical

The findings of cardiac arrest are straightforward. A patient who is in cardiac arrest is unresponsive to all stimuli and is without spontaneous breathing or a palpable pulse. The American Heart Association (AHA) has simplified their basic life support (BLS) cardiac arrest algorithm to encourage minimal compression interruption. The current algorithm has eliminated the “look, listen, and feel” step to check for breathing in an unresponsive patient. Instead, the rescuer should observe to see whether the patient is breathing normally. Emphasis is placed on “gasping” or agonal breathing being abnormal. If the patient is not breathing or only has agonal respirations, the rescuer should check for a carotid pulse for the unresponsive adult or the brachial pulse in the unresponsive infant for no more than 10 seconds. If a pulse is not felt or the rescuer is unsure if a pulse was felt, CPR should be initiated immediately.

Evaluation

Asystole is identified on cardiac monitoring. In asystole, there is no waveform present on the cardiac monitor, only an isoelectric “flat” line. This includes a lack of P-waves, QRS complexes, and T-waves.

Treatment / Management

Asystole should be treated following current American Heart Association BLS and ACLS guidelines. High-quality CPR is the mainstay of treatment and the most important predictor of favorable outcome. Asystole is a non-shockable rhythm. Therefore, if asystole is noted on the cardiac monitor, no attempt at defibrillation should be made. High-quality CPR should be continued with minimal (less than five seconds) interruption. CPR should not be stopped to allow for endotracheal intubation. Epinephrine (1 mg via intravenous or intraosseous line) should be delivered every three to five minutes and treatment of reversible causes addressed. Asystole is considered a terminal rhythm of cardiac arrest. Therefore, discussion of termination of resuscitation should be considered during an in-hospital cardiac arrest in the appropriate clinical picture. Out-of-hospital cardiac arrest patients in asystole should also be considered for the cessation of efforts according to local protocol.[4]

Pearls and Other Issues

Pitfalls

Providers should ensure that, if a patient appears to be in asystole on the cardiac monitor, that the patient is, in fact, in cardiac arrest. Disconnected cardiac monitoring leads can appear as asystole. Additionally, providers should differentiate between asystole and fine ventricular fibrillation, which may respond to defibrillation.

When considering terminating care of a patient in asystole, the rhythm should be confirmed in two separate leads.

Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government.

I am a military service member. This work was prepared as part of my official duties. Title 17 U.S.C. 105 provides that “Copyright protection under this title is not available for any work of the United States Government.” Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person’s official duties.

Enhancing Healthcare Team Outcomes

All healthcare workers including the nurse practitioner should be familiar with asystole and its management. Asystole should be treated according to current American Heart Association BLS and ACLS guidelines. High-quality CPR is the mainstay of treatment and the most important predictor of favorable outcome. Asystole is a non-shockable rhythm. Therefore, if asystole is noted on the cardiac monitor, no attempt at defibrillation should be made. In many hospitals, it is mandatory for all healthcare workers who look after patients to be certified in BLS and ACLS.

 

 


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Asystole - Questions

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Which of the following is the appropriate first step in treating a patient presenting with asystole?



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Which of the following rhythms carries the worst long-term prognosis for survival?



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You are the code team leader and respond to a "code blue" on the inpatient medical-surgical unit with the rest of the code team. Upon arrival, you note nursing staff performing high-quality CPR on an elderly male patient. You confirm he is a "full code," and the charge nurse states he was admitted with failure to thrive. CPR has been in progress for 2 minutes so far. You ask to hold CPR to assess the cardiac rhythm and have another team member check for a pulse. There is no pulse and you see no activity on the cardiac monitor except for a few agonal beats then a progression to asystole. What is the next step in management?

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    Contributed by Tammy J. Toney-Butler, AS, RN, CEN, TCRN, CPEN
Attributed To: Contributed by Tammy J. Toney-Butler, AS, RN, CEN, TCRN, CPEN



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You are the team leader in a cardiac arrest patient. High-quality CPR is in progress. As the next 2-minute cycle of CPR finishes, you call for a pulse and rhythm check. No pulses are felt, and there is no cardiac activity on the monitor. In what rhythm is this patient?



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A 74-year-old male arrives by emergency medical services (EMS) in cardiac arrest. High-quality compressions were in progress by the EMS crew upon patient arrival to the emergency department (ED). The ED team takes over, confirms no pulse, and continues with high-quality CPR. After 2 minutes, a pulse and rhythm check is performed. No pulses are felt, and the rhythm is determined to be asystole. Which medication and dose are indicated at this time?



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Asystole - References

References

Rapid Response Teams: A Systematic Review and Meta-analysis., Chan PS,Jain R,Nallmothu BK,Berg RA,Sasson C,, Archives of internal medicine, 2010 Jan 11     [PubMed]
Survival rates in out-of-hospital cardiac arrest patients transported without prehospital return of spontaneous circulation: an observational cohort study., Drennan IR,Lin S,Sidalak DE,Morrison LJ,, Resuscitation, 2014 Nov     [PubMed]
Incidence of treated cardiac arrest in hospitalized patients in the United States., Merchant RM,Yang L,Becker LB,Berg RA,Nadkarni V,Nichol G,Carr BG,Mitra N,Bradley SM,Abella BS,Groeneveld PW,, Critical care medicine, 2011 Nov     [PubMed]
Termination of resuscitation of nontraumatic cardiopulmonary arrest: resource document for the National Association of EMS Physicians position statement., Millin MG,Khandker SR,Malki A,, Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors, 2011 Oct-Dec     [PubMed]
Implementation trial of the basic life support termination of resuscitation rule: reducing the transport of futile out-of-hospital cardiac arrests., Morrison LJ,Eby D,Veigas PV,Zhan C,Kiss A,Arcieri V,Hoogeveen P,Loreto C,Welsford M,Dodd T,Mooney E,Pilkington M,Prowd C,Reichl E,Scott J,Verdon JM,Waite T,Buick JE,Verbeek PR,, Resuscitation, 2014 Apr     [PubMed]
Duration of resuscitation efforts and functional outcome after out-of-hospital cardiac arrest: when should we change to novel therapies?, Reynolds JC,Frisch A,Rittenberger JC,Callaway CW,, Circulation, 2013 Dec 3     [PubMed]
Kleinman ME,Goldberger ZD,Rea T,Swor RA,Bobrow BJ,Brennan EE,Terry M,Hemphill R,Gazmuri RJ,Hazinski MF,Travers AH, 2017 American Heart Association Focused Update on Adult Basic Life Support and Cardiopulmonary Resuscitation Quality: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2018 Jan 2;     [PubMed]
Panchal AR,Berg KM,Kudenchuk PJ,Del Rios M,Hirsch KG,Link MS,Kurz MC,Chan PS,Cabañas JG,Morley PT,Hazinski MF,Donnino MW, 2018 American Heart Association Focused Update on Advanced Cardiovascular Life Support Use of Antiarrhythmic Drugs During and Immediately After Cardiac Arrest: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2018 Dec 4;     [PubMed]
McNally B,Robb R,Mehta M,Vellano K,Valderrama AL,Yoon PW,Sasson C,Crouch A,Perez AB,Merritt R,Kellermann A, Out-of-hospital cardiac arrest surveillance --- Cardiac Arrest Registry to Enhance Survival (CARES), United States, October 1, 2005--December 31, 2010. Morbidity and mortality weekly report. Surveillance summaries (Washington, D.C. : 2002). 2011 Jul 29;     [PubMed]

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