Sign Up
You are not currently logged in. Please log in to CEUfast to enable the course progress and auto resume features.

Course Library

Cardiac Emergencies: Sudden Death

1 Contact Hour including 1 Pharmacology Hour
Listen to Audio
CEUfast OwlGet one year unlimited nursing CEUs $39Sign up now
This peer reviewed course is applicable for the following professions:
Advanced Practice Registered Nurse (APRN), Certified Nurse Midwife, Certified Nurse Practitioner, Certified Registered Nurse Anesthetist (CRNA), Clinical Nurse Specialist (CNS), Licensed Practical Nurse (LPN), Licensed Vocational Nurses (LVN), Midwife (MW), Nursing Student, Registered Nurse (RN), Registered Nurse Practitioner
This course will be updated or discontinued on or before Saturday, July 27, 2024

Nationally Accredited

CEUFast, Inc. is accredited as a provider of nursing continuing professional development by the American Nurses Credentialing Center's Commission on Accreditation. ANCC Provider number #P0274.


This course discusses conditions and diseases that can cause sudden cardiac death (SCD).


After completing this module, the learner will be able to:

  1. Identify the correct definition of sudden cardiac death.
  2. Discuss the prevalence of sudden cardiac death.
  3. Discuss five warning signs of sudden cardiac death.
  4. Describe risk factors and triggers for sudden cardiac death.
  5. Identify causes of sudden cardiac death.
CEUFast Inc. and the course planners for this educational activity do not have any relevant financial relationship(s) to disclose with ineligible companies whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or on patients.

Last Updated:
  • 0% complete
Hide Outline
Playback Speed

Narrator Preference

(Automatically scroll to related sections.)
Cardiac Emergencies: Sudden Death
To earn of certificate of completion you have one of two options:
  1. Take test and pass with a score of at least 80%
  2. Reflect on practice impact by completing self-reflection, self-assessment and course evaluation.
    (NOTE: Some approval agencies and organizations require you to take a test and self reflection is NOT an option.)
Author:    Dana Bartlett (RN, BSN, MA, MA, CSPI)


Sudden cardiac death (SCD) is typically defined as “an unexpected death without obvious extracardiac causes that occurs in association with a witnessed rapid collapse or within 1 h of symptom onset.” (Albert & Sauer, 2022). It is usually presumed that SCD is preceded by a cardiac arrest that was caused by sustained ventricular tachycardia (V.T.) or ventricular fibrillation (V.F.) (Podrid, 2022). However, most cases of SCD are unwitnessed, an autopsy is not done, and the cause of the SCD remains unknown (Albert & Sauer, 2022). In addition, some deaths are classified as SCD if, in the preceding 24 hours, the patient had been healthy (Albert & Sauer, 2022), and many non-cardiac conditions can cause SCD (Podrid, 2022), and this could complicate determining the cause of SCD.


Sudden cardiac death is a significant public health problem in the United States (Albert & Sauer, 2022; Podrid, 2022). It has been estimated that each year in the United States, there are 350,000 cases of SCD (Albert & Sauer, 2022), and information from death certificates suggests that SCD accounts for ~ 13% to 15% of the total mortality in the United States (Podrid, 2022). There is no national surveillance system or requirements for reporting SCD (Albert & Sauer, 2022). Cases of SCD may go undetected or unconfirmed, or death may be mistakenly categorized as an SCD. Given these limitations, the true incidence of SCD is unknown (Albert & Sauer, 2022).

  • The incidence of SCD is lower in women (Albert & Sauer,2022).
  • African Americans are likelier to have unwitnessed SCD (Albert & Sauer, 2022).
  • Asian and Hispanic Americans are less likely than African Americans and white Americans to suffer SCD (Albert & Sauer, 2022).

Warning Signs of Sudden Cardiac Death

Sudden cardiac death is, by definition, sudden and unexpected, but SCD is often preceded by warning signs (Podrid, 2022). Commonly occurring warning signs of SCD are:

  • Chest pain
  • Dizziness
  • Exertional dyspnea
  • Seizures
  • Syncope (González et al., 2022; Podrid et al., 2022; Mellor & Behr, 2021; Tsang & Link, 2021; Wylie & Garlitski, 2021)

Some conditions like epilepsy may cause SCD, which is preceded by signs and symptoms specific to the disease. SCD can occur without warning signs and symptoms, it can occur during sleep, and in some conditions/diseases, SCD may be the first indication of the presence of a condition or illness (Han et al., 2020; O’Gara et al., 2022; Minners et al., 2020).

Risk Factors and Triggers of Sudden Cardiac Death

Some of the factors that increase the risk of SCD and factors that can trigger SCD are:

  • Alcohol abuse
  • Cigarette smoking
  • Diabetes
  • Emotional stress
  • Epilepsy
  • Exercise
  • Family history of SCD
  • Obstructive sleep apnea

Binge drinking and heavy alcohol drinking increase the risk of SCD (Tu et al., 2022). Binge drinking is defined as having five or more drinks (men) or four or more drinks (women) at the same time, at least one day a month (National Institute on Alcohol Abuse and Alcoholism (N.D.). Heavy drinking is defined as > 4 drinks on any day or > 14 drinks per week (men), > 3 drinks on any day, or > 7 drinks per week (women) (National Institute on Alcohol Abuse and Alcoholism (N.D.).

Cigarette smoking significantly increases the risk of SCD (Albert & Sauer, 2022; Ip et al., 2022), even in people who do not have coronary heart disease (CHD) (Albert & Sauer, 2022). In the United States, cigarette smoking is the most preventable cause of SCD (Ip et al., 2022). The risk of SCD associated with cigarette smoking can be reversed with smoking cessation (Ip et al., 2022).

The incidence of SCD in a diabetic patient is 3- to 8-fold higher than in the general population (Remme, 2022). Cardiovascular (CV) diseases are common in diabetic patients, but diabetes appears to be an independent risk factor for SCD (Remme, 2022). Lynge et al. (2020) found that in diabetic patients ages 1 to 35 (presumably many without significant cardiac disease), the presence of diabetes increased the risk of SCD by 8-fold. In the Lynge study, 26% of cases of SCD in diabetic patients in which an autopsy was performed, no evidence of cardiac disease was found (Lynge et al., 2020).

Emotional stress can cause SCD In patients with certain cardiac diseases, e.g., catecholaminergic polymorphic ventricular tachycardia and stressed-induced cardiomyopathy (Giudicessi et al., 2021; Singh et al., 2022). Sudden death is a leading cause of death in patients who have epilepsy (González et al., 2022) and accounts for approximately 2% to 18% of all deaths in epileptic patients (Suna et al., 2021).

In certain patient populations (young athletes) and patients with certain cardiac diseases like an inherited arrhythmia syndrome, SCD can happen during or after heavy exercise (Albert & Sauer, 2022; Kim & Chelu, 2021). A family history of SCD increases the risk of SCD (Albert & Sauer, 2022), and many non-structural heart diseases that can cause SCD have a strong heritable component. Obstructive sleep apnea (OSA) increases the risk of developing cardiovascular morbidities like arrhythmias and H.F. (Heilbrunn et al., 2021), and OSA is an independent risk factor for SCD (Gami et al., 2013; Ottaviani & Buja, 2020).

Causes of Sudden Cardiac Death

Most cases of SCD happen in patients with common structural heart diseases like heart failure (H.F.) or coronary heart disease (Albert & Sauer, 2022). Non-structural heart disease and non-cardiac conditions, e.g., epilepsy, can also cause SCD (Albert & Sauer, 2022), but they account for only a small percentage of SCDs.

Structural heart diseases are the most common cause of SCD. Some of the structural heart diseases that can cause SCD are:

  • Aortic Stenosis
  • Cardiomyopathy
  • Congenital Coronary Artery Anomalies
  • Coronary Heart Disease
  • Heart Failure
  • Left Ventricular Hypertrophy
  • Mitral Valve Prolapse
  • Myocarditis 
  • Spontaneous Coronary Artery Dissection (Albert & Sauer, 2022; Podrid, 2022)

Non-structural arrhythmic diseases and channelopathies associated with SCD are:

  • Acquired Long QT Syndrome
  • Brugada Syndrome
  • Catecholaminergic Polymorphic Ventricular Tachycardia
  • Congenital Long QT Syndrome
  • Early Repolarization
  • Idiopathic Ventricular Fibrillation
  • Short QT Syndrome
  • Wolff- Parkinson-White (Albert & Sauer, 2022; Podrid, 2022)

These conditions and diseases are uncommon causes of SCD.

The CredibleMeds® website lists drugs that can cause QT interval prolongation or Torsades de Pointes (TDP), and the list is continually updated. The site can be accessed with this link: Examples of drugs that can prolong the QT interval are:

  • Antiarrhythmics, e.g., procainamide, quinidine, sotalol
  • Antidepressants, e.g., selective serotonin reuptake inhibitors, tricyclic antidepressants
  • Antiemetics, e.g., droperidol, ondansetron
  • Antifungals
  • Antimalarials
  • Antipsychotics, atypical and typical, e.g., chlorpromazine, iloperidone
  • HIV antiretrovirals
  • Loperamide
  • Macrolide antibiotics
  • Methadone (Berul, 2020; Campleman et al., 2020; Khatib et al., 2021; Li & Ramos, 2017).

Risk factors for TPD are:

  • Advanced age
  • Bradycardia
  • Drug-drug interaction, e.g., the use of 2 or more drugs that cause prolonged QT interval
  • Female gender
  • Electrolyte abnormalities: Hypocalcemia, hypokalemia, hypomagnesemia
  • Heart disease, e.g., H.F. and LVH
  • High drug dose
  • QT interval > 500 msec (Berul, 2020; Khatib et al., 2021; Li & Ramos, 2017)

Miscellaneous causes of SCD include: 

  • Airway obstruction
  • Chronic kidney disease
  • Commotio Cordis
  • Drug intoxication
  • Epilepsy
  • Exertional
  • Familial
  • Near drowning
  • Obstructive sleep apnea
  • Pulmonary embolism
  • SIDS
  • Tension pneumothorax
  • Trauma

Case Study

A 65-year-old female self-referred to an emergency room because she had been feeling dizzy, had palpitations, and possibly had an episode of syncope.

The patient said she had several episodes of dizziness in the previous four weeks. Some of these were accompanied by palpitations, and she may have briefly lost consciousness during one episode. The last time the patient felt dizzy was one hour before she arrived. The dizziness began after she stood up, it continued for approximately 10 minutes after she returned to a sitting position, and she felt her heart fluttering. She did not have chest pain, shortness of breath, or other symptoms.

The patient has a past medical history of heart failure with reduced ejection fraction, hypertension, and depression. She takes furosemide 40 mg once a day, lisinopril 20 mg once a day, and fluoxetine 60 mg daily. Her psychiatrist had recently (approximately six weeks ago) prescribed escitalopram 10 mg once a day because the signs and symptoms of the patient’s depression had been worsening.

Temperature, 99°F, pulse 86, respiratory rate 16, and blood pressure, 146/74 mm Hg. Orthostatic vital signs were normal.

The patient is awake, alert, and oriented. Nothing abnormal was noted during the physical examination. Aside from the episodes of dizziness, the patient has been in good health, but she said she “had not been eating well lately.”

Laboratory test results:

  • BUN and creatinine: 17 mg/dL and 1.0 mg/dL.
  • Electrolytes: Sodium 142 mEq/L, potassium 3.0 mEq/L, chloride 104 mEq/L, carbon dioxide 26 mEq/L, anion gap of 12.
  • AST and ALT:  12 IU/L and I14 IU/L.
  • Serum calcium and magnesium: 8.4 mg/dL and 1.5.1 mg/dL.
  • 12-lead ECG: Rate 89, PR interval 140 msec, QRS, 85 msec, QTc, 525 msec. No evidence of old or acute ischemia. A 12-lead ECG was done one year ago; at that time, the QTc was 430 msec.
  • C.T. scan of the head was normal.

The patient was admitted and placed on continuous ECG monitoring. Potassium and magnesium supplementation was given, and continuous ambulatory ECG monitoring was started. The 24-hour ECG monitoring recorded one 30-second episode of TDP. It happened when the patient was resting, and the clinical staff did not see the arrhythmia on the telemetry monitor. The patient was found apneic and pulseless, and she could not be resuscitated.

Diagnosis: Sudden cardiac death caused by drug-induced QTc prolongation and TDP.

Analysis: The QTc was abnormally long, and TDP was documented. The patient had several contributing risk factors for QTc prolongation and TDP: Age, female gender, heart failure, hypokalemia, hypomagnesemia, a QTc > 500 msec, and QTc > 60 msec from the previous QTc duration. In addition, escitalopram can cause QTc prolongation, and it has a known risk of TDP. Fluoxetine can cause QTc prolongation, and it can, in certain circumstances, cause TDP, e.g., the presence of hypokalemia or the concurrent use of another drug that causes QTc prolongation.


Most cases of SCD happen in patients with common structural heart diseases like heart failure (H.F.) or coronary heart disease (CHD). Non-structural heart disease and non-cardiac conditions, e.g., epilepsy, can also cause SCD, but they account for only a small percentage of SCDs.

Sudden cardiac death is, by definition, sudden and unexpected, but SCD is often preceded by signs and symptoms, i.e., warning signs like chest pains, dizziness, palpitations, and syncope. However, SCD can occur without warning signs and symptoms.

Risk factors and triggers of SCD include alcohol abuse, cigarette smoking, diabetes, emotional stress, epilepsy, exercise, family history of SCD, and obstructive sleep apnea.

Select one of the following methods to complete this course.

Take TestPass an exam testing your knowledge of the course material.
No TestDescribe how this course will impact your practice.

Implicit Bias Statement

CEUFast, Inc. is committed to furthering diversity, equity, and inclusion (DEI). While reflecting on this course content, CEUFast, Inc. would like you to consider your individual perspective and question your own biases. Remember, implicit bias is a form of bias that impacts our practice as healthcare professionals. Implicit bias occurs when we have automatic prejudices, judgments, and/or a general attitude towards a person or a group of people based on associated stereotypes we have formed over time. These automatic thoughts occur without our conscious knowledge and without our intentional desire to discriminate. The concern with implicit bias is that this can impact our actions and decisions with our workplace leadership, colleagues, and even our patients. While it is our universal goal to treat everyone equally, our implicit biases can influence our interactions, assessments, communication, prioritization, and decision-making concerning patients, which can ultimately adversely impact health outcomes. It is important to keep this in mind in order to intentionally work to self-identify our own risk areas where our implicit biases might influence our behaviors. Together, we can cease perpetuating stereotypes and remind each other to remain mindful to help avoid reacting according to biases that are contrary to our conscious beliefs and values.


  • Albert, C. & Sauer, W.H. (2022). Chapter 306: Cardiovascular Collapse, Cardiac Arrest, and Sudden Cardiac Death. J. Loscalzo, A. Fauci, D. Kasper, S. Hauser, S Longo & J.L. Jameson (Eds). In: Harrison’s Principles of Internal Medicine (21st ed). McGraw-Hill Education. Online edition. Accessed April 16, 2022. Visit Source.
  • Berul, C.I. (2020). Acquired long QT. syndrome: Definitions, causes, and pathophysiology. UpToDate. November 6, 2020. Accessed May 20, 2022. Visit Source.
  • Campleman, S.L., Brent, J., Pizon, A.F., Shulman, J., Wax, P., Manini, A.F. & Toxicology Investigators’ Consortium (ToxIC). (2020). Drug-specific risk of severe QT prolongation following acute drug overdose. Clinical Toxicology (Phila), 58(12), 1326-1334. Visit Source. Epub 2020 April 7.
  • Gami, A.S., Olson, E.J., Shen, W.K., Wright, R.S., Ballman, K., O Hodge, D., Herges, R.M., Howard, D.E. & Somers, V.K. (2013). Obstructive sleep apnea and the risk of sudden cardiac death: a longitudinal study of 10,701 adults. Journal of the American College of Cardiology, 13;62(7), 610-616. Visit Source. Epub 2013 June 13.
  • Giudicessi, J.R., Ackerman, M.J., Fatkin, D. & Kovacic, J.C. (2021). Precision Medicine Approaches to Cardiac Arrhythmias: JACC Focus Seminar 4/5. Journal of the American College of Cardiology, 77(20), 2573-2591. Visit Source.
  • González, A., Haugaa, K.H., Brekke. P.H., Hopp, E., Ørn, S., Alvestad, S., Taubøll, E. & Aurlien, D. (2022). Cardiac Structure and Function in Epilepsy Patients with Drug-Resistant Convulsive Seizures. Case Reports Neurology, 14(1), 88-97. Visit Source. eCollection Jan-Apr 2022.
  • Han, H.C., Parsons, S.A., The, A.W., Sanders, P., Neil, C., Leong, T., Koshy, A.N., Vohra, J.K., Kalman, J.M., Smith, K., O’Donnell, D., Hare, D.L., Farouque, O. & Lim, H.S. (2020). Characteristic Histopathological Findings and Cardiac Arrest Rhythm in Isolated Mitral Valve Prolapse and Sudden Cardiac Death. Journal of the American Heart Association. 2020 Apr 7;9(7): e015587. Visit Source. Epub 2020 April 1.
  • Heilbrunn, E.S., Ssentongo, P., Chinchilli, V.M., Oh, J. & Ssentongo, A.E. (2021). Sudden death in individuals with obstructive sleep apnoea: a systematic review and meta-analysis. BMJ Open Respiratory Research. 2021 Jun;8(1): e000656. Visit Source.
  • Ip, M., Diamandis’s, E., Haptonstall, K., Choroomi, Y., Moheimani, R.S., Nguyen, K.H., Tran, E., Gornbein, J. & Middlekauff, H.R. (2022). Tobacco and electronic cigarettes adversely impact ECG indexes of ventricular repolarization: implication for sudden death risk. American Journal of Physiology. Heart and Circulatory Physiology, 318(5), H1176-H1184. Visit Source. Epub 2020 March 20.
  • Khatib. R., Sabir, F.R.N., Omari, C., Pepper. C. & Tayebjee, M.H. (2021).  Managing drug-induced QT prolongation in clinical practice. Postgrad Medical Journal, 97(1149):452-458. Visit Source.
  • Kim J.A. & Chelu, M.G. (2021). Inherited Arrhythmia Syndromes. Texas Heart Institution Journal. 2021 Sep 1;48(4): e207482. Visit Source.
  • Li, M. & Ramos, L.G. (2017). Drug-induced QT prolongation and torsades de pointes. P.T., 42(7), 473-477. PMID: 28674475.
  • Lynge, T.H., Svane, J., Pedersen-Bjergaard, U., Risgaard, B., Winkels, B.G. & Tfelt-Hansen J. (2020). Sudden cardiac death among persons with diabetes aged 1-49 years: a 10-year nationwide study of 14 294 deaths in Denmark. European Heart Journal, 41(28), 2699-2706. Visit Source.
  • Mellor, G.J. & Behr, E.R. (2021).  Cardiac channelopathies: diagnosis and contemporary management. Heart. 2021 Feb 15: heartjnl-2019-316026. doi: 10.1136/heartjnl-2019-316026. Online ahead of print.
  • Minners, J., Rossebo, J., Chambers, J.B., Gohlke-Baerwolf, C., Neuman, F-J., Wachtell, K. & Jander, N. (2020). Sudden cardiac death in asymptomatic patients with aortic stenosis. Heart, 106(21),1646-1650. Visit Source. Epub 2020 July 31.
  • O’Gara, P.T. & Loscalzo, J. (2022). Chapter 261: Aortic Stenosis. J. Loscalzo, A. Fauci, D. Kasper, S. Hauser, S Longo & J.L. Jameson (Eds). In: Harrison’s Principles of Internal Medicine (21st ed). McGraw-Hill Education. Online edition. Accessed April 16, 2022. Visit Source.
  • Ottaviani, G. & Buja, L.M. (2020). Pathology of unexpected sudden cardiac death: Obstructive sleep apnea is part of the challenge. Cardiovascular Pathology. Jul-Aug 2020; 47:107221. Visit Source. Epub 2020 April 18.
  • Podrid, P.I. (2022). Overview of sudden cardiac arrest and sudden cardiac death. UpToDate. January 19, 2022. Accessed April 15, 2022. Visit Source.
  • Remme, C.A. (2022). Sudden Cardiac Death in Diabetes and Obesity: Mechanisms and Therapeutic Strategies. Canadian Journal of Cardiology, 38(4), 418-426. Visit Source. Epub 2022 January 10.
  • Singh A, Everest, S., Nguyen, L., Casey, B. & Bhandari, M. (2022) Stress-Induced Cardiomyopathy Raising Concern for Myocardial Ischemia. Cureus. 2022 Feb 10;14(2): e22091. Visit Source. eCollection 2022 Feb.
  • Suna, N., Suna, I., Gutmane, E., Kande, L., Karelis, G., Viksna, L. & Folkmanis, V. (2021). Electrocardiographic Abnormalities and Mortality in Epilepsy Patients. Medicina (Kaunas). 2021 May 16;57(5):504. doi: 10.3390/medicina57050504.
  • Tsang, D.C. & Link, M.S. (2021). Sudden Cardiac Death in Athletes. Texas Heart. Institute Journal, Sep 1;48(4): e207513. Visit Source.
  • Tu, S., Gallagher, C., Elliot, A.D., Linz, D., Pitman, B.M., Hendriks, J.M.L., Lau, D.H., Sanders, P. & Wong, C.X. (2022). Alcohol consumption and risk of ventricular arrhythmias and sudden cardiac death: An observational study of 408,712 individuals. Heart Rhythm, 19(2),177-184. Visit Source. Epub 2021 December 21.
  • Wylie, J.V. & Garlitski, A.C. (2021). Brugada syndrome: Clinical presentation, diagnosis, and evaluation. UpToDate. November1, 2021. Accessed May 24, 2022. Visit Source.