Sudden cardiac death overview: Difference between revisions

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==Overview==
==Overview==
[[Sudden cardiac death]] is a natural, rapid, unexpected death secondary to [[cardiac]] causes other than conditions such as [[trauma]], [[drowning]]. [[Sudden cardiac arrest]] is defined as the unexpected cessation of pumping blood into vital organs due to electrical disturbance in the pathway of [[sinoatrial node]] ([[SA node]]), [[atrioventricular node]] ([[AV node]]), [[His Purkinje fibers]] or pumping failure in the setting of [[conditions]] such as [[cardiogenic shock]], massive [[pulmonary thromboembolism]],[[fulminant myocarditis]], and [[ruptured left ventricular free wall]]. Without any intervention for immediate restoration of the [[circulation]], biologic [[death]] will happen minutes to weeks after [[cardiac arrest]]. [[Sudden cardiac death]] is responsible for 50% of [[cardiac death]] annually in the United States. In-hospital [[cardiac arrest]] happened among 290,000 [[adults]] every year in the United States. The most common cause of [[sudden cardiac death]] is [[coronary artery disease]] and [[atherosclerosis]] process. The presence of underlying disorders such as [[malignancy]] or [[kidney disease]] at the time of [[cardiac arrest]] makes the [[condition]] worse. [[Patients]] with [[acute myocardial infarction]] and [[in-hospital cardiac arrest]] with [[shockable rhythm]] have a better [[prognosis]]. Post [[cardiopulmonary resuscitation]] state [[management]] should be focused on [[neurologic]] [[complications]], [[hemodynamic]] stability, and [[respiratory]] support. There are some definitions related to [[sudden death]] including [[Sudden cardiac death]] which is described as sudden and unexpected [[death]] due to [[arrhythmia]] or hemodynamic instability within one hour of having symptoms ( [[palpitation]], [[chest pain]], [[shortness of breath]]) or within 24 hours in an [[asymptomatic]] [[patient]].[[Sudden cardiac arrest]] is suddenly cessation of [[cardiac activity]], unresponsive [[patient]] with [[gasping respiration]] or no [[respiratory]] movement and unpalpable [[pulses]] due to [[cardiac]] [[etiology]] such as [[arrhythmia]], and [[pump failure]]. Aborted [[cardiac arrest]] is explained as unexpected [[circulatory collapse]] within one hour of being symptomatic, which is reversible after successful [[cardiopulmonary resuscitation]]. [[SIDS]] ([[sudden infant death syndrome]]) is [[sudden death]]  when there is normal structural [[heart]] without any specific findings in [[autopsy]] or [[toxicology]]. The [[pathogenesis]] of [[cardiac arrest]] is characterized by the [[ myocardial]] [[inflammatory]] process in the setting of [[atherosclerosis]], [[structural heart disease]], [[genetic disorders]], and environmental factors. The [[SCN5A]], [[KCNH2]], [[KCNQ1]], [[RYR2]], [[MYBPC3]], [[PKP2]], and [[DSP]] [[gene mutations]] are associated with the development of inherited causes of [[cardiac arrest]] and  [[sudden cardiac death]].[[Sudden cardiac arrest]] may be caused by underlying [[cardiac]] disorder including coronary [[atherosclerosis]], [[acute myocardial infarction]], [[coronary artery embolism]], [[coronary arteritis]], [[HCM]], [[hypertensive heart disease]], primary or secondary [[pulmonary hypertension]], [[ischemic cardiomyopathy]], [[non-ischemic cardiomyopathy]], [[myocarditis]], [[aortic stenosis]], [[aortic insufficiency]], [[mitral valve prolapse]], [[endocarditis]]
*[[Sudden cardiac death]] ([[SCD]]) is defined as the unexpected [[death]] within an hour of [[onset]] of [[symptoms]] that is attributed to [[cardiac]] problems and usually confirmed on [[post-mortem]] examination <ref name="pmid31992061">{{cite journal| author=Virani SS, Alonso A, Benjamin EJ, Bittencourt MS, Callaway CW, Carson AP | display-authors=etal| title=Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association. | journal=Circulation | year= 2020 | volume= 141 | issue= 9 | pages= e139-e596 | pmid=31992061 | doi=10.1161/CIR.0000000000000757 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=31992061 }} </ref> <ref name="pmid29097294">{{cite journal| author=Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB | display-authors=etal| title=2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. | journal=J Am Coll Cardiol | year= 2018 | volume= 72 | issue= 14 | pages= 1677-1749 | pmid=29097294 | doi=10.1016/j.jacc.2017.10.053 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=29097294 }} </ref>.
, [[congenital septal defect]] with [[eisenmenger physiology]],  [[Wolf-Parkinson-White syndrome]], ([[CPVT]], [[LQTS]]). The diagnosis of [[sudden cardiac arrest]] is made when  the following diagnostic criteria are met: the absence of a [[palpable pulse]] of the [[heart]] due to abrupt cessation of pump function , the absence of [[carotid pulse]],[[gasping respiration]] or NO [[respiration]], loss of [[consciousness]] due to [[cerebral hypoperfusion]]. Following an initial diagnosis of [[cardiac arrest]], healthcare professionals further categorize the diagnosis based on the [[ECG]] [[rhythm]].
* [[SCD]] is one the leading causes of death in the western countries, accounting to 15-20% of all deaths <ref name="pmid30482683">{{cite journal| author=Wong CX, Brown A, Lau DH, Chugh SS, Albert CM, Kalman JM | display-authors=etal| title=Epidemiology of Sudden Cardiac Death: Global and Regional Perspectives. | journal=Heart Lung Circ | year= 2019 | volume= 28 | issue= 1 | pages= 6-14 | pmid=30482683 | doi=10.1016/j.hlc.2018.08.026 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=30482683  }} </ref>.
There are 4 [[rhythm]]s that result in a [[cardiac arrest]]. [[Ventricular fibrillation]] ([[VF]]) and Pulseless [[Ventricular tachycardia]] ([[VT]]) are both responsive to a [[defibrillator]] and so are colloquially referred to as [[Shockable]] [[rhythms]], whereas [[Asystole]] and [[Pulseless Electrical Activity]] ([[PEA]]) are [[non-shockable]].
* [[Coronary artery disease]] ([[CAD]]) is the most common [[pathology]] related to [[SCD]].
The nature of the presenting [[heart]] [[rhythm]] suggests different causes and treatment and is used to guide the rescuer as to what treatment may be appropriate.The [[prevalence]] of [[sudden cardiac death]] is approximately 1.40 per 100,000 individuals in [[women]] to 6.68 per 100.000 individuals in [[men]] worldwide. In 2015, the [[incidence]] of [[adult]] in-hospital [[cardiac arrests]] was estimated to be 970 cases per 100,000 individuals in the united states. [[Cardiac arrest]] is more commonly observed within the first year of life due to [[sudden infant death syndrome]] and also between 45-75 years old due to increased risk of [[coronary artery disease]]. There is a significant decrease in [[sudden cardiac death]] at age 75 and older due to decreasing risk of [[coronary artery disease]]. [[Men]] are more commonly affected with [[sudden cardiac death]] than [[women]] in all age groups. [[Black]] individuals are more likely to develop [[cardiac arrest]]. Common risk factors related to underlying [[coronary artery disease]] and inherited causes in the development of [[ sudden cardiac arrest]] are [[hypertension]], [[male]] gender, [[diabetes mellitus]], [[hyperlipidemia]], [[obesity]], [[smoking]], [[older age]], [[obstructive sleep apnea]] due to [[hypoxia]], early [[VF]] detection (within 48 hours of [[ACS]] increasing in-hospital mortality five times), [[early repolarization]] patten in early phase of [[MI]], family history of [[sudden death]].[[Sudden cardiac arrest]] occurs due to sudden disturbance in [[cardiac]] electrical propagation or failure of the [[heart]] to pumping the [[blood]] into vital [[organs]].
* With the advancement in [[medical]] [[treatment]] and [[prevention]] of [[CAD]], the [[incidence]] of [[CAD]] and [[SCD]] have declined <ref name="pmid30516758">{{cite journal| author=Hindricks G, Lenarczyk R, Kalarus Z, Döring M, Shamloo AS, Dagres N| title=Prevention of sudden cardiac death by the implantable cardioverter-defibrillator. | journal=Pol Arch Intern Med | year= 2018 | volume= 128 | issue= 12 | pages= 764-770 | pmid=30516758 | doi=10.20452/pamw.4386 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=30516758 }} </ref> <ref name="pmid22371442">{{cite journal| author=Myerburg RJ, Junttila MJ| title=Sudden cardiac death caused by coronary heart disease. | journal=Circulation | year= 2012 | volume= 125 | issue= 8 | pages= 1043-52 | pmid=22371442 | doi=10.1161/CIRCULATIONAHA.111.023846 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22371442  }} </ref>.
Early clinical features include abrupt [[palpitation]], [[presyncope]], [[syncope]], [[chest pain]], [[dyspnea]], [[hypotension]] within one hour before terminal event.
* Further investigation is needed to improve understanding of the underlying mechanisms involved in this condition.
Patients  may progress to develop [[cardiac arrest ]], [[sudden collapse]], [[loss of effective circulation]], [[loss of consciousness]].
If left untreated or failed resuscitation, biological [[death]] may occur within minutes to weeks. Common complications in survivors of [[cardiac arrest]] include [[pneumonia]], [[gastrointestinal bleeding]], [[injuries]] related to [[resuscitation]], [[liver function test disturbance]], [[acure renal failure]], [[electrolytes disturbances]], [[seizure]].Two-thirds of patients with out-of-hospital cardiac arrest admitted in intensive care unit die of [[neurological]] complications.Most of the in-hospital [[cardiac death]] occur due to [[multiorgans dysfunction]] and one forth death is due to [[neurological complications]]. Factors associated poor prognosis after in-hospital [[cardiac arrest]] include age > 70 years old, concomitant underlying disorders such as [[pneumonia]], [[hypotension]], [[renal dysfunction]], [[hepatic dysfunction]],non shockable [[rhythm]] such as [[asystole]] or [[pulseless electrical activity]]. Factors associated with better prognosis after in-hospital cardiac arrest include early detection of [[cardiac arrest]] or being witnessed during [[arrest]],shockable [[rhythm]] such as [[VF]], [[VT]], [[women]] between 15-45 years old. Prognosis of in-hospital [[cardiac arrest]] is generally better than out-of- hospital [[cardiac arrest]] and the 1-year survival rate of patients who survived to [[hospital]] discharge was approximately 25% in the GWTG-R registry. Survival after out-of-hospital [[cardiac arrest]] and in-hospital [[cardiac arrest]] has continued to improve over time according to the guideline. Symptoms related to [[arrhythmia]] or underlying [[heart]] disease within one hour before [[cardiac arrest]] may include
, [[palpitation]]
, [[lightheadedness]]
, [[syncope]]
, [[Dyspnea]] at rest or on exertion
, [[orthopnea]]
, [[paroxysmal nocturnal dyspnea]]
, [[chest pain]], [[edema]].[[Patients]] with [[cardiac arrest]] usually appear [[cyanotic]]. [[Physical examination]] maybe remarkable for [[heart rate]] and [[regularity]], [[blood pressure]], [[ Jugular venous pressure]], [[Murmurs]]
, [[ Pulses]], [[bruits]]
, [[Edema]]
, [[Sternotomy scars]]. An elevated concentration of  [[brain natriuretic peptide]] ([[BNP]]) has been shown as the predictor of [[ventricular arrhythmia]] and [[sudden cardiac death]].An [[ECG]] may be helpful in the diagnosis of [[Sudden cardiac death]]. Findings on [[ECG]] associated with [[ sudden cardiac arrest]] include [[Sinus tachycardia]] (39%), abnormal [[T-wave inversions]] (30%), prolonged [[QT]] interval (26%), left/[[right atrial]] abnormality (22%), [[left ventricular hypertrophy]] (17%), abnormal frontal [[QRS axis]] (17%), delayed [[QRS]]-transition zone in precordial leads (13%), pathological [[Q waves]] (13%), [[intraventricular conduction delays]] (9%), multiple [[premature ventricular contractions]] (9%), normal [[ECG]] (9%). A [[chest x-ray]] may be helpful in the diagnosis of the underlying cause of [[cardiac arrest]] such as [[cardiomegaly]], [[pulmonary  edema]], massive [[pericardial effusion]], widening [[aorta]] silhouette. [[Echocardiography]] may be helpful in the diagnosis the cause of [[lethal]] [[arrhythmia]] and [[sudden cardiac arrest]] by assessment of ,[[regional wall motion abnormality]],[[systolic function ]] of [[left ventricle]], evidence of [[ myocardial infarction]], [[valvular heart disease]] such as [[aortic stenosis]],[[right ventricular cardiomyopathy]]
,[[pericardial effusion]], [[ tamponade]], [[ aorta dissection]]. [[Cardiac CT scan]] may be helpful in the diagnosis of the causes of [[cardiac arrest]] by evaluation of
[[left ventricular]] volumes, [[Ejection fraction]],[[Cardiac mass]]
, anomalous origin of [[coronary arteries]]
, [[coronary arteries]] [[calcification]]
, [[pulmonary embolism]]
,[[aorta dissection]]. [[Cardiac MRI]] is an accurate modality for diagnosis of structural and functional causes of [[cardiac arrest]] by the evaluation of
[[chamber volumes]], [[left ventricular]] mass
, [[left ventricular]] size and function
, [[ right ventricular]] size and [[function]]
, [[regional wall motion abnormality]]. For survivors of [[sudden cardiac death]] due to lethal [[arrhythmia]] from [[ischemic heart disease]], [[coronary angiography]] and probable [[revascularization]] is recommended. [[Electrophysiology study]] is recommended for induction of [[bradyarrhythmia]] , [[ventricular tachyarrhythmia]], determination the indication for [[ICD]] implantation  in [[dilated cardiomyopathy]],[[ARVC]], [[HCM]]. [[Electrophysiology study]] is not recommended in [[long QT syndrome]] ([[LQTS]]), [[cathecolaminergic polymorphic ventricular tachycardia]] ([[CPVT]]), [[short QT syndrome]] ([[SQTS]]). The mainstay of therapy for [[patients]] with [[cardiac arrest]]  is starting [[cardiopulmonary resuscitation]] with minimizing interruption in [[chest compression]].The [[rhythm]] should be reassessed. If the [[rhythm ]]is [[VF]] or [[pulseless VT]], the [[shock]] should be delivered immediately. If the [[rhythm]] is [[asystole]] or [[pulseless electrical activity]] ([[PEA]]), [[CPR]] should be resumed. [[Advanced life support]] ([[ALS]]) includes
[[advanced airway]], continuous [[chest compressions]], [[capnography]], IV/IO access, [[vasopressors]], [[antiarrhythmics]] therapy, correcting reversible causes including [[hypoxia]], [[hypovolemia]],[[hypothermia]], [[hyperkalemia]], [[hypokalemia]],[[acidosis]], [[tension pneumothorax]], [[tamponade]], toxins ([[benzodiazepines]], [[alcohol]], [[opiates]], [[tricyclics]], [[barbiturates]], [[betablocker]]s, [[calcium channel blocker]]s). The followings should be considered immediately in [[post cardiac arrest]] patients: 12–lead [[ECG]] ,[[Perfusion]]/[[reperfusion]] in patients with acute [[myocardial infarction]], [[Oxygenation]] and [[ventilation]],temperature controlling, treatment of  reversible causes.Management  of patients in  post-cardiac arrest status include treatment of the underlying disorder, hemodynamic stability, respiratory support, controlling the [[neurologic]] complications. Effective measures for the [[primary prevention]] of [[sudden cardiac death]] in individuals who are at risk of [[SCD]] but have not yet experienced an aborted [[cardiac arrest]] or [[life-threatening arrhythmias]] include [[ICD]] implantation based on the guideline. [[Secondary prevention]] strategy following aborted sudden cardiac death include [[revascularization]] in patients with [[ischemic heart disease]] and  [[ICD]] implantation in patients with reduced [[left ventricular ejection fraction]] who had an experience of lethal [[arrhythmia]].
The optimal approach to prevention of [[SCD]] following [[ST-elevation MI]] ([[STEMI]]) has been evaluated in multiple randomized trials. In general, [[post-STEMI]] [[patients ]]should be treated with evidence-based therapies that have been associated with a reduction in [[SCD]] including [[beta-blockers]], [[ACE-inhibitors]] (or [[ARB]]s in [[patients]] who are [[ACEI]] intolerant) and [[statins]]. In [[patients]] who have symptomatic [[congestive heart failure]] ([[CHF]]), an [[aldosterone antagonist]] may be a reasonable additional therapy. Despite the intuitive benefits of antiarrhythmics, [[amiodarone]] and [[sotalol]] have not been shown to reduce all-cause [[mortality]] following [[STEMI]], although [[amiodarone]] may be useful in reducing the frequency of [[shocks]] in [[patients]] with [[ICD]]s who have unacceptably high rates of [[shock]]. In general terms, [[ICD placement]] is indicated in those [[patients]] with a reduced [[left ventricular]] [[ejection fraction]] at 40 days [[post-MI]] and/or 3 months following [[revascularization]] ([[PCI]] or [[CABG]]) for [[STEMI]] given the survival benefits in this population. [[Cardiopulmonary resuscitation]] and [[advanced cardiac life support]] are not always in a person's best interest. This is particularly true in the case of terminal illnesses when resuscitation will not alter the outcome of the disease. Properly performed [[CPR]] often fractures the [[rib]] cage, especially in older [[patients]] or those suffering from [[osteoporosis]]. [[Defibrillation]], especially repeated several times as called for by [[advanced cardiac life support|ACLS]] protocols, may also cause electrical burns. Some people with a [[terminal illness]] choose to avoid such measures and die peacefully. [[People]] with views on the treatment they wish to receive in the event of a [[cardiac arrest]] should discuss these views with both their [[physician|doctor]] and with their family. A [[patient]] may ask their [[doctor]] to record a [[do not resuscitate]] ([[DNR]]) order in the [[medical record]]. Alternatively, in many jurisdictions, a person may formally state the wishes in an advance directive or [[advance health directive]].


==Historical perspective==
==Historical perspective==

Revision as of 16:06, 18 July 2023

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Sara Zand, M.D.[2] Edzel Lorraine Co, DMD, MD[3]

Overview

Historical perspective

Sudden cardiac death (SCD) occurs abruptly and unexpectedly in a person who is not known to have cardiac disease. It usually happens within one hour of onset of symptoms. About twenty-five percent of human deaths can be attributed to SCD, with the most common mechanism being the ventricular fibrillation (VF). This concept was first proposed by MacWilliam more than 120 years ago, during the time when the electrocardiogram was not yet invented.

Classification

There are some definitions related to sudden death including Sudden cardiac death which is defined as sudden and unexpected death within one hour of being symptomatic such as palpitation, chest pain, shrtness of breath or within 24 hours in an asymptomatic patient due to arrhythmia or hemodynamic instability.Sudden cardiac arrest is suddenly cessation of cardiac activity,unresponsive patient with gasping respiration or no respiratory movement and unpalpable pulses due to cardiac etiology such as arrhythmia, pump failure. Aborted cardiac arrest is explained as unexpected circulatory collapse within one hour of being symptomatic, which is reversible after successful cardiopulmonary resuscitation. SIDS (sudden infant death syndrome) is sudden death when there is normal structural heart without any specific findings in autopsy or toxicology.

Pathophysiology

The pathogenesis of cardiac arrest is characterized by the myocardial inflammatory process in the setting of atherosclerosis, structural heart disease, genetic disorders, and environmental factors. The SCN5A, KCNH2, KCNQ1, RYR2, MYBPC3, PKP2, DSP genes mutation are associated with the development of inherited causes of cardiac arrest and sudden cardiac death.

Causes

Sudden cardiac arrest may be caused by coronary artery abnormality such as coronary atherosclerosis, acute MI, coronary artery embolism, coronary arteritis , hypertrophy of myocardium such as HCM, hypertensive heart disease, primary or secondary pulmonary hypertension , myocardial disease such as ischemic cardiomyopathy, non-ischemic cardiomyopathy, myocarditis ,valvular heart disease such as aortic stenosis, aortic insufficiency, mitral valve prolapse, endocarditis , congenital heart disease such as congenital septal defect with eisenmenger physiology , abnormality in conducting system such as Wolf-Parkinson-White syndrome , electrical instability such as (CPVT, LQTS).

Definition and Diagnosis

The diagnosis of sudden cardiac arrest is made when the following diagnostic criteria are met: the absence of a palpable pulse of the heart due to abrupt cessation of pump function , absent carotid pulse,gasping respiration or NO respiration, loss of consciousness due to cerebral hypoperfusion.Following an initial diagnosis of cardiac arrest, healthcare professionals further categorize the diagnosis based on the ECG rhythm. There are 4 rhythms that result in a cardiac arrest. Ventricular fibrillation (VF) and Pulseless Ventricular tachycardia (VT) are both responsive to a defibrillator and so are colloquially referred to as Shockable rhythms, whereas Asystole and Pulseless Electrical Activity (PEA) are non-shockable. The nature of the presenting heart rhythm suggests different causes and treatment and is used to guide the rescuer as to what treatment may be appropriate.

Epidemiology and Dermographics

The prevalence of sudden cardiac death is approximately 1.40 per 100,000 individuals in women to 6.68 per 100.000 individuals in men worldwide. In 2015, the incidence of adult in-hospital cardiac arrests was estimated to be 970 cases per 100,000 individuals in the united states. Cardiac arrest is more commonly observed within the first year of life due to sudden infant death syndrome and also between 45-75 years old due to increased risk of coronary artery disease. There is a significant decrease in sudden cardiac death at age 75 and older due to decreasing risk of coronary artery disease. Men are more commonly affected with sudden cardiac death than women in all age groups. Black individuals are more likely to develop cardiac arrest.

Risk factors

Common risk factors related to underlying coronary artery disease and inherited causes in the development of sudden cardiac arrest are hypertension, male gender ,Diabetes mellitus, hyperlipidemia, obesity, smoking, older age, obstructive sleep apnea due to hypoxia, early VF (within 48 hours of ACS increasing in-hospital mortality five times), early repolarization patten in early phase of MI, family history of sudden death.

Screening

Screening should be done based on the presentation of risk factors associated with sudden cardiac death.

Natural history, Complications, Prognosis

Sudden cardiac arrest occurs due to sudden disturbance in cardiac electrical propagation or failure of the heart to pumping the blood into vital organs. Early clinical features include abrupt palpitation, presyncope, syncope, chest pain, dyspnea, hypotension within one hour before terminal event. Patients may progress to develop cardiac arrest , sudden collapse, loss of effective circulation, loss of consciousness. If left untreated or failed resuscitation, biological death may occur within minutes to weeks. Common complications in survivors of cardiac arrest include pneumonia, gastrointestinal bleeding, injuries related to resuscitation, liver function test disturbance, acure renal failure, electrolytes disturbances, seizure.Two-thirds of patients with out-of-hospital cardiac arrest admitted in intensive care unit die of neurological complications.Most of the in-hospital cardiac death occur due to multiorgans dysfunction and one forth death is due to neurological complications. Factors associated poor prognosis after in-hospital cardiac arrest include age > 70 years old, concomitant underlying disorders such as pneumonia, hypotension, renal dysfunction, hepatic dysfunction,non shockable rhythm such as asystole or pulseless electrical activity. Factors associated with better prognosis after in-hospital cardiac arrest include early detection of cardiac arrest or being witnessed during arrest,shockable rhythm such as VF, VT, women between 15-45 years old. Prognosis of in-hospital cardiac arrest is generally better than out-of- hospital cardiac arrest and the 1-year survival rate of patients who survived to hospital discharge was approximately 25% in the GWTG-R registry. Survival after out-of-hospital cardiac arrest and in-hospital cardiac arrest has continued to improve over time according to the guideline.

History and symptoms

Symptoms related to arrhythmia or underlying heart disease within one hour before cardiac arrest may include , palpitation , lightheadedness , syncope , Dyspnea at rest or on exertion , orthopnea , paroxysmal nocturnal dyspnea , chest pain, edema.

Physical Examination

Patients with cardiac arrest usually appear cyanotic. Physical examination maybe remarkable for heart rate and regularity, blood pressure, Jugular venous pressure, Murmurs , Pulses, bruits , Edema , Sternotomy scars.

Laboratory Findings

An elevated concentration of brain natriuretic peptide (BNP) has been shown as the predictor of ventricular arrhythmia and sudden cardiac death.

Electrocardiogram

An ECG may be helpful in the diagnosis of Sudden cardiac death. Findings on ECG associated with sudden cardiac arrest include Sinus tachycardia (39%), abnormal T-wave inversions (30%), prolonged QT interval (26%), left/right atrial abnormality (22%), left ventricular hypertrophy (17%), abnormal frontal QRS axis (17%), delayed QRS-transition zone in precordial leads (13%), pathological Q waves (13%), intraventricular conduction delays (9%), multiple premature ventricular contractions (9%), normal ECG (9%).

X-Ray

A chest x-ray may be helpful in the diagnosis of the underlying cause of cardiac arrest such as cardiomegaly, pulmonary edema, massive pericardial effusion, widening aorta silhouette.

Echocardiography

Echocardiography may be helpful in the diagnosis the cause of lethal arrhythmia and sudden cardiac arrest by assessment of ,Regional wall motion abnormality,systolic function of left ventricle, evidence of myocardial infarction, valvular heart disease such as aortic stenosis,right ventricular cardiomyopathy ,pericardial effusion, Tamponade, aorta dissection.

CT scan

Cardiac CT scan may be helpful in the diagnosis of the causes of cardiac arrest by evaluation of left ventricular volumes, Ejection fraction,Cardiac mass , anomalous origin of coronary arteries , coronary arteries calcification , pulmonary embolism ,aorta dissection.

MRI

Cardiac MRI is an accurate modality for diagnosis of structural and functional causes of cardiac arrest by the evaluation of chamber volumes, left ventricular mass , left ventricular size and function , right ventricular size and function , regional wall motion abnormality

Other Diagnostic Studies

For survivors of sudden cardiac death due to lethal arrhythmia from ischemic heart disease, coronary angiography and probable revascularization is recommended. Electrophysiology study is recommended for induction of bradyarrhythmia , ventricular tachyarrhythmia, determination the indication for ICD implantation in dilated cardiomyopathy,ARVC, HCM. Electrophysiology study is not recommended in long QT syndrome (LQTS), cathecolaminergic polymorphic ventricular tachycardia (CPVT), short QT syndrome (SQTS).

Urgent Treatment

The mainstay of therapy for patients with cardiac arrest is starting cardiopulmonary resuscitation with minimizing interruption in chest compression.The rhythm should be reassessed. If the rhythm is VF or pulseless VT, the shock should be delivered immediately. If the rhythm is asystole or pulseless electrical activity (PEA), CPR should be resumed. Advanced life support (ALS) should be kept with minimizing interruption in chest compression including: advanced airway, continuous chest compressions, capnography, IV/IO access, vasopressors, antiarrhythmics therapy, correcting reversible causes including hypoxia, hypovolemia,hypothermia, hyperkalemia, hypokalemia,acidosis, tension pneumothorax, tamponade, toxins (benzodiazepines, alcohol, opiates, tricyclics, barbiturates, betablockers, calcium channel blockers). The followings should be considered immediately in post cardiac arrest patients: 12–lead ECG ,Perfusion/reperfusion in patients with acute myocardial infarction, Oxygenation and ventilation,temperature controlling, treatment of reversible causes.Management of patients in post-cardiac arrest status include treatment of the underlying disorder, hemodynamic stability, respiratory support, controlling the neurologic complications.

Post Arrest Care and Prevention

Effective measures for the primary prevention of sudden cardiac death in individuals who are at risk of SCD but have not yet experienced an aborted cardiac arrest or life-threatening arrhythmias include ICD implantation based on the guideline. Secondary prevention strategy following aborted sudden cardiac death include revascularization in patients with ischemic heart disease and ICD implantation in patients with reduced left ventricular ejection fraction who had an experience of lethal arrhythmia. The optimal approach to prevention of SCD following ST-elevation MI (STEMI) has been evaluated in multiple randomized trials. In general, post-STEMI patients should be treated with evidence-based therapies that have been associated with a reduction in SCD including beta-blockers, ACE-inhibitors (or ARBs in patients who are ACEI intolerant) and statins. In patients who have symptomatic congestive heart failure (CHF), an aldosterone antagonist may be a reasonable additional therapy. Despite the intuitive benefits of antiarrhythmics, amiodarone and sotalol have not been shown to reduce all-cause mortality following STEMI, although amiodarone may be useful in reducing the frequency of shocks in patients with ICDs who have unacceptably high rates of shock. In general terms, ICD placement is indicated in those patients with a reduced left ventricular ejection fraction at 40 days post-MI and/or 3 months following revascularization (PCI or CABG) for STEMI given the survival benefits in this population.

Ethical Issues

Cardiopulmonary resuscitation and advanced cardiac life support are not always in a person's best interest. This is particularly true in the case of terminal illnesses when resuscitation will not alter the outcome of the disease. Properly performed CPR often fractures the rib cage, especially in older patients or those suffering from osteoporosis. Defibrillation, especially repeated several times as called for by ACLS protocols, may also cause electrical burns.

Some people with a terminal illness choose to avoid such measures and die peacefully. People with views on the treatment they wish to receive in the event of a cardiac arrest should discuss these views with both their doctor and with their family. A patient may ask their doctor to record a do not resuscitate (DNR) order in the medical record. Alternatively, in many jurisdictions, a person may formally state the wishes in an advance directive or advance health directive.

  1. Virani SS, Alonso A, Benjamin EJ, Bittencourt MS, Callaway CW, Carson AP; et al. (2020). "Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association". Circulation. 141 (9): e139–e596. doi:10.1161/CIR.0000000000000757. PMID 31992061.
  2. Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB; et al. (2018). "2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society". J Am Coll Cardiol. 72 (14): 1677–1749. doi:10.1016/j.jacc.2017.10.053. PMID 29097294.
  3. Wong CX, Brown A, Lau DH, Chugh SS, Albert CM, Kalman JM; et al. (2019). "Epidemiology of Sudden Cardiac Death: Global and Regional Perspectives". Heart Lung Circ. 28 (1): 6–14. doi:10.1016/j.hlc.2018.08.026. PMID 30482683.
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