degree relatives of the SCD victims, particularly young victims. In a nationwide Danish study from 2000 to 2006, 470 victims of SCD were identified who were 35 years of age or younger [32]. Among a cohort of 3073 first- and second-degree relatives of the SCD victims who were followed for up to 11 years, cardiovascular disease (CVD) was significantly more likely to be present than in the general population (standardized incidence ratio [SIR] for CVD 3.5, 95% CI 2.7-4.7). In contrast, among relatives of elderly (greater than 60 years of age) victims of SCD, there was no difference in the rates of CVD compared with the general population (SIR 0.9, 95% CI 0.8-1.1). A general cardiologic evaluation of first- and second-degree relatives of victims of unexplained SCD can yield the diagnosis of a heritable disease in up to 40 percent of families as illustrated by the following observations [33-35]. In a study of 32 families of victims of unexplained SCD, a general cardiologic evaluation (ECG, echocardiogram, Holter monitor and, less commonly, stress testing) was completed in 107 first-degree relatives [33]. Seven families (22 percent) were diagnosed with a heritable disease: four with long QT syndrome, one with nonstructural cardiac disease, one with myotonic dystrophy, and one with HCM. These findings were extended in a second report that evaluated 43 families with 183 surviving first- and second-degree relatives of victims of unexplained SCD at age 40 [34]. Careful history identified 26 additional cases of unexplained SCD at age 40. Cardiology evaluation included ECG, echocardiogram, exercise tolerance testing (ETT), and https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 13/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate measurement of serum lipids. Additional testing, as indicated, included flecainide challenge for suspected Brugada syndrome or cardiac MR for suspected ARVC. (See "Brugada syndrome or pattern: Management and approach to screening of relatives".) When a clinical diagnosis was established, genetic testing for the suspected disease was performed. Where a genetic abnormality was confirmed, additional screening was done in another 150 family members. The following findings were noted: A heritable disease was identified in 17 families (40 percent): five with catecholaminergic polymorphic VT, four with long QT syndrome, two with Brugada syndrome, one with Brugada/long QT syndrome, three with ARVC, one with HCM, and one with familial hypercholesterolemia. Genetic analysis confirmed the diagnosis in 10 families. An average of 8.9 asymptomatic carriers per family was identified, many through the secondary genetic analysis. Identification of a specific disease was more likely if 2 unexplained SCD events occurred in the family, and if more family members underwent evaluation. The increased yield in the second study may reflect the more extensive evaluation, including ETT, and the inclusion of more family members. Consistent with these findings, it has been recommended that first-degree family members of patients with SCD in the absence of structural heart disease be informed of the potentially increased risk and that an assessment should be offered at a center with experience in the diagnosis and management of inherited cardiac diseases [24]. Routine genetic screening for inherited disorders is not feasible although, in the presence of an identifiable condition, the genetic evaluation of family members may be undertaken at some centers. NEUROLOGIC AND PSYCHOLOGIC ASSESSMENT Patients who have been resuscitated from sudden death should be given a complete neurologic examination to establish the nature and extent of impairment resulting from the arrest. The physical examination, rather than imaging studies or other testing, is the most useful way of elucidating the patient's degree of neurologic function, mental impairment, and of determining prognosis. A 2004 meta-analysis of 11 studies found that the following clinical signs predicted a poor clinical outcome following cardiac arrest with 97 percent specificity [36]: Absence of pupillary light response after 24 hours Absence of corneal reflex after 24 hours https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 14/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Absent motor responses to pain after 24 hours Absent motor responses after 72 hours (See "Hypoxic-ischemic brain injury in adults: Evaluation and prognosis".) Equally important is an assessment of the patient's psychologic state. Posttraumatic stress disorder (PTSD) may occur in SCD survivors. This was suggested in a study of 143 patients who had been resuscitated and discharged with no or only moderate neurologic disability [37]. All patients completed a self-rating questionnaire at a mean of 45 months after cardiac arrest: 39 (27 percent) fulfilled criteria for PTSD. (See "Posttraumatic stress disorder in adults: Epidemiology, pathophysiology, clinical manifestations, course, assessment, and diagnosis" and "Management of posttraumatic stress disorder in adults".) MANAGEMENT At present, most survivors of SCD are treated with an ICD. The use of ICDs in SCD survivors, the role of adjunctive antiarrhythmic medications and catheter ablation, and exceptions to the use of ICDs are discussed in detail separately. (See "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy".) SUMMARY AND RECOMMENDATIONS Evaluation of the survivor of SCD includes the following: Identification and treatment of acute reversible causes, including (see 'Etiology of SCD' above and "Pathophysiology and etiology of sudden cardiac arrest", section on 'Etiology of SCD'): Acute cardiac ischemia and myocardial infarction Antiarrhythmic drugs or other medication (eg, QT prolonging drugs), toxin, or illicit drug ingestion Electrolyte abnormalities, most notably hypokalemia, hyperkalemia, and hypomagnesemia Heart failure Autonomic nervous system factors, especially sympathetic activation (eg, physical or psychologic stress) https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 15/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Evaluation for structural heart disease Initial evaluation including history, physical examination, laboratory testing (eg, electrolytes, blood gas, toxin screen, etc), and electrocardiogram (see 'Initial evaluation' above) Evaluation for structural heart disease, which may include one or more of echocardiography, coronary angiography, cardiac magnetic resonance imaging, depending of the clinical scenario (see 'Evaluation for structural heart disease' above) In patients without obvious arrhythmic triggers or cardiac structural abnormalities, an evaluation for primary electrical diseases Primary electrical diseases include Brugada syndrome, long QT syndrome, short QT syndrome, Wolff-Parkinson-White, catecholaminergic polymorphic VT, commotio cordis, and idiopathic ventricular fibrillation (see 'General issues' above) The evaluation for primary electrical disease may include one or more of electrophysiology studies, exercise testing, ambulatory ECG monitoring, and pharmacologic challenge (see 'Evaluation for primary electrical diseases' above) Neurologic and psychologic assessment (see 'Neurologic and psychologic assessment' above) In selected patients with a suspected or confirmed heritable syndrome, evaluation of family members (see 'Evaluation of family members' above) ACKNOWLEDGMENT The editorial staff at UpToDate acknowledges Jie Cheng, MD, who contributed to an earlier version of this topic review. 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Topic 970 Version 35.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 19/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate GRAPHICS Treatable conditions associated with cardiac arrest Condition Common associated clinical settings Acidosis Diabetes, diarrhea, drug overdose, renal dysfunction, sepsis, shock Anemia Gastrointestinal bleeding, nutritional deficiencies, recent trauma Cardiac Post-cardiac surgery, malignancy, post-myocardial infarction, pericarditis, trauma tamponade Hyperkalemia Drug overdose, renal dysfunction, hemolysis, excessive potassium intake, rhabdomyolysis, major soft tissue injury, tumor lysis syndrome Hypokalemia* Alcohol abuse, diabetes mellitus, diuretics, drug overdose, profound gastrointestinal losses Hypothermia Alcohol intoxication, significant burns, drowning, drug overdose, elder patient, endocrine disease, environmental exposure, spinal cord disease, trauma Hypovolemia Significant burns, diabetes, gastrointestinal losses, hemorrhage, malignancy, sepsis, trauma Hypoxia Upper airway obstruction, hypoventilation (CNS dysfunction, neuromuscular disease), pulmonary disease Myocardial infarction Cardiac arrest Poisoning History of alcohol or drug abuse, altered mental status, classic toxidrome (eg, sympathomimetic), occupational exposure, psychiatric disease Pulmonary embolism Immobilized patient, recent surgical procedure (eg, orthopedic), peripartum, risk factors for thromboembolic disease, recent trauma, presentation consistent with acute pulmonary embolism Tension pneumothorax Central venous catheter, mechanical ventilation, pulmonary disease (eg, asthma, chronic obstructive pulmonary disease), thoracentesis, thoracic trauma CNS: central nervous system. Hypomagnesemia should be assumed in the setting of hypokalemia, and both should be treated. Adapted from: Eisenberg MS, Mengert TJ. Cardiac resuscitation. N Engl J Med 2001; 344:1304. Graphic 52416 Version 8.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 20/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate 12-lead electrocardiogram (ECG) from a patient with the Brugada syndrome shows downsloping ST elevation ST segment elevation and T wave inversion in the right precordial leads V1 and V2 (arrows); the QRS is normal. The widened S wave in the left lateral leads (V5 and V6) that is characteristic of right bundle branch block is absent. Courtesy of Rory Childers, MD, University of Chicago. Graphic 64510 Version 10.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 21/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate 12-lead electrocardiogram showing the Wolff-Parkinson- White pattern The 2 main electrocardiographic features of Wolff-Parkinson-White pattern include a short PR interval (<0.12 seconds) and a delta wave (arrows). The QRS complex is wide (>0.12 seconds) and represents a fusion beat; the initial portion (delta wave) results from rapid ventricular activation via the accessory pathway (preexcitation), while the termination of ventricular activation is via the normal conduction system, leading to a fairly normal terminal portion of the QRS. Graphic 75578 Version 10.0 ECG of sinus rhythm to Normal electrocardiogram (ECG) Normal sinus rhythm at a rate of 71 beats/minute, a P wave axis of 45 , and a PR interval of 0.15 seconds. https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 22/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate ECG: electrocardiogram. Courtesy of Morton Arnsdorf, MD. Graphic 58149 Version 5.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 23/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate 12-lead electrocardiogram showing ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy Ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy usually arises from the free wall of the right ventricle, resulting in a left bundle branch morphology. With permission from Podrid PJ, Kowey PR (Eds), Cardiac Arrhythmia - Mechanisms, Diagnosis, and Management, Williams & Wilkins, Baltimore, 1995. Graphic 56591 Version 9.0 Normal ECG https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 24/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Normal electrocardiogram showing normal sinus rhythm at a rate of 75 beats/minute, a PR interval of 0.14 seconds, a QRS interval of 0.10 seconds, and a QRS axis of approximately 75 . Courtesy of Ary Goldberger, MD. Graphic 76183 Version 4.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 25/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate 12-lead electrocardiogram showing epsilon wave and T wave inversions in arrhythmogenic right ventricular cardiomyopathy 12-lead electrocardiogram in a patient with arrhythmogenic right ventricular cardiomyopathy showing deep T wave inversions in V2 to V4, compatible with right ventricular disease, and epsilon waves representing delayed right ventricular depolarization just after the QRS complex (arrows). Data from: Jaoude S, Leclercq JF, Coumel P. Eur Heart J 1996; 17:1717. Graphic 60781 Version 9.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 26/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Single-lead electrocardiogram showing a prolonged QT interval The corrected QT interval (QTc) is calculated by dividing the QT interval (0.60 seconds) by the square root of the preceding RR interval (0.92 seconds). In this case, the QTc is 0.625 seconds (625 milliseconds). Graphic 77018 Version 7.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 27/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Single lead electrocardiogram (ECG) showing polymorphic ventricular tachycardia (VT) This is an atypical, rapid, and bizarre form of ventricular tachycardia that is characterized by a continuously changing axis of polymorphic QRS morphologies. Graphic 53891 Version 5.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 28/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Major causes of sudden death Ischemic heart disease Coronary artery disease with myocardial infarction or angina Coronary artery embolism Nonatherogenic coronary artery disease (arteritis, dissection, congenital coronary artery anomalies) Coronary artery spasm Nonischemic heart disease Hypertrophic cardiomyopathy Dilated cardiomyopathy Valvular heart disease Congenital heart disease Arrhythmogenic right ventricular dysplasia Myocarditis Acute pericardial tamponade Acute myocardial rupture Aortic dissection No structural heart disease Primary electrical disease (idiopathic ventricular fibrillation) Brugada syndrome (right bundle branch block and ST segment elevation in leads V1 to V3) Long QT syndrome Preexcitation syndrome Complete heart block Familial sudden cardiac death Chest wall trauma (commotio cordis) Noncardiac disease Pulmonary embolism Intracranial hemorrhage Drowning Pickwickian syndrome Drug-induced https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 29/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Central airway obstruction Sudden infant death syndrome Sudden unexplained death in epilepsy (SUDEP) Graphic 62184 Version 3.0 https://www.uptodate.com/contents/cardiac-evaluation-of-the-survivor-of-sudden-cardiac-arrest/print 30/31 7/6/23, 10:41 AM Cardiac evaluation of the survivor of sudden cardiac arrest - UpToDate Contributor Disclosures Philip J Podrid, MD, FACC No relevant financial relationship(s) with ineligible companies to disclose. Brian Olshansky, MD Other Financial Interest: AstraZeneca [Member of the DSMB for the DIALYZE trial]; Medtelligence [Cardiovascular disease]. All of the relevant financial relationships listed have been mitigated. Scott Manaker, MD, PhD Other Financial Interest: Expert witness in workers' compensation and in medical negligence matters [General pulmonary and critical care medicine]; National Board for Respiratory Care [Director]. All of the relevant financial relationships listed have been mitigated. Nisha Parikh, MD, MPH No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. 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