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| {{Infobox Disease | | __NOTOC__ |
| | Name = Pulseless electrical activity
| | {| class="infobox" style="float:right;" |
| | Image =
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| | Caption =
| | | [[File:Siren.gif|30px|link= Pulseless electrical activity resident survival guide]]|| <br> || <br> |
| | DiseasesDB = 4166
| | | [[Pulseless electrical activity resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
| | ICD10 = {{ICD10|I|46|9|I|30}}
| | |} |
| | ICD9 = <!-- {{ICD9|xxx}} -->
| | {{Pulseless electrical activity}} |
| }}
| | {{CMG}},{{AE}} {{M.N}} |
| {{SI}} | |
| {{CMG}} | |
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| {{SK}} PEA; electromechanical dissociation; EMD; non-perfusing rhythm | | {{SK}} PEA; electromechanical dissociation; EMD; non-perfusing rhythm |
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| ==Overview== | | == [[Pulseless electrical activity overview|Overview]] == |
| Pulseless electrical activity is defined as the absence of a pulse or cardiac contractility despite the presence of electrocardiographic activity. The most common cause is [[hypovolemia]]. | |
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| ==Classification== | | == [[Pulseless electrical activity historical perspective|Historical Perspective]] == |
| ===True PEA===
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| There are no cardiac contractions despite electrical activity.
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| ===Pseudo PEA=== | | == [[Pulseless electrical activity classification|Classification]] == |
| There are very weak cardiac contractions present that fail to generate a blood pressure compatible with systemic perfusion and life despite electrical activity.
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| ===Post Defibrillation PEA=== | | == [[Pulseless electrical activity pathophysiology|Pathophysiology]] == |
| Following defibrillation, there can be a period of electromechanical dissociation where electrocardiographic complexes do not generate a pulse. As a result of post defibrillation PEA, it is often useful to continue CPR for up to one minute following restoration of a perfusing rhythm.
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| ==Pathophysiology== | | == [[Pulseless electrical activity causes|Causes]] == |
| There is often a downward spiral in the pathophysiology of PEA. A severe initial insult often reduces [[cardiac output]] which may in turn cause [[myocardial ischemia]], [[left ventricular failure]], [[hypoxia]] and [[metabolic acidosis]]. These pathophysiologic disturbances further reduce cardiac output further exacerbating the downward spiral. With loss of [[cardiac output]]; [[hypotension]], [[loss of consciousness]] and [[apnea]] rapidly ensue.
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| ===Reduced Preload and Inadequate Filling of the Left Ventricle or === | | == [[Pulseless electrical activity differential diagnosis|Differentiating Pulseless Electrical Activity from other Diseases]] == |
| PEA may be due to inadequate filling of the [[left ventricle]] with blood to stretch the cardiac sarcomeres adequately to result in a cardiac contraction (i.e. there is inadequate [[preload]]). Examples include rapid fluid or [[blood loss]] as occurs in major trauma. [[Cardiac tamponade]], [[pneumothorax]], and [[pulmonary embolism]] are other examples.
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| ===Elevated Afterload=== | | == [[Pulseless electrical activity epidemiology and demographics|Epidemiology and Demographics]] == |
| Elevated [[afterload]] is rarely a cause of PEA.
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| ===Electromechanical Dissociation=== | | == [[Pulseless electrical activity risk factors|Risk Factors]] == |
| In some cases, PEA may be caused by electromechanical dissociation. The normal condition when electrical activation of muscle cells precedes mechanical contraction is known as [[electromechanical coupling]]. This coupling is lost in some forms of PEA, and this is known as electromechanical dissociation.
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| ===Reduced Contractility=== | | == [[Pulseless electrical activity natural history, complications and prognosis|Natural History, Complications and Prognosis]] == |
| Contraction of the myocardium depends upon the integrity of the [[troponin]] subunits.
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| ====Reduced Calcium Influx====
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| Calcium binding to [[troponin]] is required for contractility. This binding can be reduced in [[calcium channel blocker]] overdoses.
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| ====Reduced Affinity of Troponin for Calcium==== | | == Diagnosis == |
| In the setting of [[hypoxia]], calcium binds less avidly to [[troponin]].
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| ==Causes==
| | [[Pulseless electrical activity history and symptoms|History and Symptoms]] | [[Pulseless electrical activity physical examination|Physical Examination]] | [[Pulseless electrical activity laboratory findings|Laboratory Findings]] | [[Pulseless electrical activity chest x ray|Chest X Ray]] | [[Pulseless electrical activity echocardiography|Echocardiography]] |
| Common causes of PEA include preceding [[respiratory failure]] in 40% to 50% of cases, and [[hypovolemia]].
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| The goal of treatment of PEA is to treat the underlying cause. These possible causes are remembered as the Hs and Ts.<ref name=ACLS_2003_H_T>''ACLS: Principles and Practice''. p. 71-87. Dallas: American Heart Association, 2003. ISBN 0-87493-341-2.</ref><ref name=ACLS_2003_EP_HT>''ACLS for Experienced Providers''. p. 3-5. Dallas: American Heart Association, 2003. ISBN 0-87493-424-9.</ref><ref name="ECC_2005_7.2">"2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care - Part 7.2: Management of Cardiac Arrest." ''Circulation'' 2005; '''112''': IV-58 - IV-66.</ref>
| | == Treatment == |
| * [[Hypovolemia|'''H'''ypovolemia]]
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| * [[Hypoxia|'''H'''ypoxia]]
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| * [[Hydrogen|'''H'''ydrogen]] ions ([[Acidosis]])
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| * [[Hypothermia|'''H'''ypothermia]]
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| * [[Hyperkalemia|'''H'''yperkalemia]] or [[Hypokalemia|'''H'''ypokalemia]]
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| * [[Hypoglycemia|'''H'''ypoglycemia]]
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| * [[Tablets|'''T'''ablets]] or [[Toxins|'''T'''oxins]] ([[Drug overdose]]) such as [[beta blocker]]s, [[tricyclic antidepressant]]s, or [[calcium channel blockers]]
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| * [[Cardiac tamponade|Cardiac '''T'''amponade]]
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| * [[Tension pneumothorax|'''T'''ension pneumothorax]]
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| * [[Thrombosis|'''T'''hrombosis]] ([[Myocardial infarction]])
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| * [[Thrombosis|'''T'''hrombosis]] ([[Pulmonary embolism]])
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| * [[Physical trauma|'''T'''rauma]] ([[Hypovolemia]] from [[blood loss]])
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| As noted by repeated balloon inflations in the cardiac catheterization laboratory, transient occlusion of the coronary artery does not cause PEA.
| | [[Pulseless electrical activity medical therapy|Medical Therapy]] | [[Pulseless electrical activity surgery|Surgery]] | [[Pulseless electrical activity primary prevention|Primary Prevention]] | [[Pulseless electrical activity secondary prevention|Secondary Prevention]] | [[Pulseless electrical activity cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Pulseless electrical activity future or investigational therapies|Future or Investigational Therapies]] |
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| ==Risk Factors== | | == Case Studies == |
| The administration of [[beta blockers]] and [[calcium channel blockers]] is associated with an increased risk of PEA. This may be due to their effect on Ca / troponin interactions, and their inhibition of myocardial contractility.
| | [[Pulseless electrical activity case study one|Case #1]] |
| | | ==Related Chapters== |
| ==Differentiating PEA From Other Disorders Causing Cardiac Arrest==
| | *[[Ventricular fibrillation]] |
| *[[Asystole]]: In [[asystole]], there is cessation of any cardiac activity and lack of cardiac output on this basis. In PEA, electrical activity is present.
| | *[[Ventricular tachycardia]] |
| *[[Ventricular fibrillation]]: There is no organized electrical activity present. There are only fine fibrillatory waves present in ventricular fibrillation. In PEA, there is organized electrical activity.
| | *[[Asystole]] |
| *[[Peripheral arterial disease]]: The inability to feel a peripheral pulse may be due to severe [[peripheral arterial disease]].
| | * [[Cardiac arrest]] |
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| ==Epidemiology and Demographics==
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| PEA accounts for approximately 20% of out of hospital cardiac arrests, and accounts for about a third of inhospital cardiac arrests. <ref name="pmid16391216">{{cite journal | author = Nadkarni VM, Larkin GL, Peberdy MA, Carey SM, Kaye W, Mancini ME, Nichol G, Lane-Truitt T, Potts J, Ornato JP, Berg RA | title = First documented rhythm and clinical outcome from in-hospital cardiac arrest among children and adults | journal = JAMA : the Journal of the American Medical Association | volume = 295 | issue = 1 | pages = 50–7 | year = 2006 | month = January | pmid = 16391216 | doi = 10.1001/jama.295.1.50 | url = http://jama.jamanetwork.com/article.aspx?doi=10.1001/jama.295.1.50 | issn = | accessdate = 2012-09-16}}</ref> PEA is responsible for 10% of in-hospital deaths.<ref name="pmid831417">{{cite journal | author = Raizes G, Wagner GS, Hackel DB | title = Instantaneous nonarrhythmic cardiac death in acute myocardial infarction | journal = The American Journal of Cardiology | volume = 39 | issue = 1 | pages = 1–6 | year = 1977 | month = January | pmid = 831417 | doi = | url = http://linkinghub.elsevier.com/retrieve/pii/S0002-9149(77)80002-7 | issn = | accessdate = 2012-09-16}}</ref>
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| ===Gender===
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| There is a slight female preponderance of PEA. It is unclear if this is mediated by a direct influence of gender on the pathophysiology, or if female gender is a confounder.
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| ===Age===
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| Patients with PEA tend to be older.
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| ==Natural History, Complications, Prognosis==
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| PEA is associated with a poor prognosis, particularly if the underlying cause is not readily identifiable and treated. The presence of a [[QRS interval]] > 0.20 seconds is associated with a poorer prognosis.
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| ==Diagnosis==
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| ===Symptoms=== | |
| *[[Loss of consciousness]] | |
| *[[Apnea]] | |
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| ===Electrocardiogram===
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| The appearance of the [[electrocardiogram]] varies, but several common patterns exist. There may be a normal [[sinus rhythm]] or [[sinus tachycardia]], with discernible [[P waves]] and [[QRS complexes]]. Sometimes there is a [[bradycardia]], with or without [[P waves]], and often there is a [[wide QRS complex]].<ref>Foster B, Twelve Lead Electrocardiography, 2nd edition, 2007</ref> The presence of a [[QRS interval]] > 0.20 seconds is associated with a poorer prognosis.
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| ==Treatment==
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| ===Reverse The Underlying Cause===
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| The mainstay of treatment is to reverse the underlying cause of PEA.
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| ====Hypovolemic Shock====
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| The most common reversible cause is [[hypovolemia]] (i.e. [[hypovolemic shock]]) which should be treated with [[IV fluids]] or [[packed red blood cell transfusion]].
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| ====Tension Pneumothorax====
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| Another readily identifiable and immediately treatable causes include [[tension pneumothorax]] (not uncommon in the ICU setting). Often in the ICU, this may occur in a ventilated patient, but conscious patients may complain of the sudden onset of [[chest pain]], there may be the sudden appearance of [[cyanosis]], [[tracheal deviation]], and [[absent breath sounds]] on the involved side of the chest. A thin needle can be inserted in the upper intercostal space to relieve the pressure and allow the lung to reinflate.
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| ====Cardiac Tamponade====
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| ===Treatment in the Absence of an Identifiable Underlying Cause===
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| If an underlying cause for PEA cannot be determined and/or reversed, the treatment of pulseless electrical activity is similar to that for [[asystole]].<ref name="2010AHA" />
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| ===Epinephrine===
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| The mainstay of drug therapy for PEA is [[epinephrine]] 1 mg every 3–5 minutes.
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| ===Atropine===
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| Although [[atropine]] was previously recommended in the treatment of PEA/asystole, this recommendation was withdrawn in 2010 by the American Heart Association due to lack of evidence for therapeutic benefit.<ref name="2010AHA">{{cite journal |author=2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care |title=Part 8: Adult Advanced Cardiovascular Life Support|journal=Circulation |year=2010 |month=November |volume=122 |issue=18 Suppl |pages=S729–S767 | doi=10.1161/CIRCULATIONAHA.110.970988|url=http://circ.ahajournals.org/cgi/content/full/122/18_suppl_3/S729 |pmid=20956224}}</ref>
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| ===Na Bicorbonate===
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| Sodium bicarbonate at a dose of 1 meq per kilogram may be considered in this rhythm as well, although there is little evidence to support this practice. Its routine use is not recommended for patients in this context, except in special situations (e.g. preexisting [[metabolic acidosis]], [[hyperkalemia]], [[tricyclic antidepressant overdose]]).<ref name="2010AHA" />
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| ===CPR===
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| All of these drugs should be administered along with appropriate [[CPR]] techniques.
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| ===Defibrillation===
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| [[Defibrillation]] is '''''not''''' used to treat this rhythm, as the problem lies in the response of the myocardial tissue to electrical impulses.
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| ==References==
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| {{Reflist|2}}
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| [[de:Elektromechanische Entkoppelung]] | | [[de:Elektromechanische Entkoppelung]] |
| [[pl:PEA]] | | [[pl:PEA]] |
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| | [[Category:Electrophysiology]] |
| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| [[Category:Emergency medicine]] | | [[Category:Emergency medicine]] |
| | [[Category:Intensive care medicine]] |
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