Cardiac arrest (CA) is the abrupt cessation of mechanically effective heart activity, resulting in a lack of perfusion and, consequently, insufficient oxygen delivery to the organs. When there is an efficacious resuscitation, the restoration of the circulation is termed return of spontaneous circulation (ROSC). The incidence of CA is about 7 per 1,000 population per year, with an increase with age. Approximately 20% of CAs occur in a hospital setting, while the majority occur outside of hospitals. CA is one of the global epidemics of the 21st century, and its early recognition and treatment would improve prevention and outcomes. However, numerous factors make its early recognition challenging.
The sudden onset of CA usually occurs in an otherwise healthy person, and witnesses do not know the medical history. Understanding of the earlier warning signs of CA in these scenarios is limited. Moreover, after ROSC, the person can be in a comatose state, making it impossible to obtain a direct history. Even those who achieve ROSC with conscious status may have retrograde amnesia and may report nonspecific symptoms after resuscitation (Lazzarin et al., 2022). Basic Life Support (BLS) algorithms and AEDs (automated external defibrillators) have been designed to improve detection and responses. However, there are concerns regarding the algorithm’s false alarm rate, especially in young children and those with an implantable cardioverter-defibrillator (ICD), which rarely prevents death but results in anxiety and unnecessary medical interventions. Improved understanding of the pathophysiology of early stages of CA helps create models for enhanced monitoring and decision support systems to prevent or minimize the health effects of CA (J.L. Mitchell et al., 2020).
Definition and Basics
Cardiac arrest (CA) is a very serious health problem that can happen suddenly and without warning. When it happens, the patient loses consciousness within seconds, does not breathe normally, and has no pulse or blood pressure. Cardiopulmonary resuscitation (CPR) and defibrillation are strongly recommended for patients with CA. They can restore blood circulation and reverse the cardiac rhythm to normal. If the blood flow does not resume, however, many organs will be damaged, and brain death will occur. Studies estimate that for each minute of no blood flow, the chance of survival decreases by approximately 10% (Papastylianou and Mentzelopoulos, 2012).
CA can result from many diseases, and the causes of CA are not the same for every age group. In young patients, CA is usually caused by congenital heart disease, hypertrophic cardiomyopathy, arrhythmia, and accidents. In older patients, it is more likely to be caused by coronary artery disease, myocardial infarction, and heart failure (Lazzarin et al., 2022). Factors such as being overweight, drinking alcohol, drug use, and lack of exercise increase the risk of heart disease. These are also risk factors for CA.
Epidemiology of Cardiac Arrest in Men
Cardiac arrest is the sudden cessation of mechanical function of the heart and leads to death within minutes without prompt resuscitative efforts. The etiology of cardiac arrest is variable and context dependent (J.L. Mitchell et al., 2020). Cardiac arrest is categorized as in-hospital (IHCA) or out-of-hospital (OHCA). In many developed countries, epidemiological data on cardiac arrest is systematically collected with efforts toward analysis and dissemination. The systematic capture, analysis and dissemination of cardiac arrest data informs contemporary practice and highlights potential differences in care (Uzendu et al., 2024). A paucity of truly population-based cardiac arrest datasets in less wealthy and less technologically advanced nations limits the ability to understand the epidemiology of cardiac arrest in these regions of the world.
Understanding the causes and risk factors for cardiac arrest is important in efforts to prevent arrest from occurring in the first place. Research has demonstrated that 5 factors account for the majority of cardiac arrests, which are serious heart conditions, past heart attack, coronary artery disease, heart failure and irregular heart rhythms or arrhythmias. Research has also identified a subgroup of individuals with life threatening heart conditions, yet they are unaware and unmonitored. By knowing what causes cardiac arrest and which patients are at risk, interventions may be developed and monitored to help prevent cardiac arrest in high-risk individuals. Detecting arrest is important to trigger a resuscitation response, however this is often not automatic or instantaneous. Some of the earliest signs of cardiac arrest include absence of signs of life, abnormal movement or breathing and abnormal colour. Wearable technology and electronics embedded in clothing is a new and potentially feasible option to detect cardiac arrest and trigger a response.
Prevalence
In 2019, global estimates of coronary artery disease indicated that men were about 1.5 times more likely than women to die from ischemic heart disease (IHD) (J.L. Mitchell et al., 2020). Furthermore, a higher proportion of cardiac deaths were due to sudden cardiac death (SCD), defined as death occurring within an hour of an acute onset of symptoms. Research suggests that the global power imbalance between genders in cardiovascular disease morbidity and mortality may be partly attributable to biological sex differences. A protective effect is observed in women before menopause, which is compounded by social determinants such as smoking, obesity, sedentary behavior, and diabetes; having a male sex partner; psychosocial stress; and working as a blue-collar worker being linked to a negative cardiovascular risk profile for both sexes (Uzendu et al., 2024).
Globally, there is significant variation in the burden of SCD; however, such data for low- and middle-income countries are sparse. In addition to variations in estimated mortality, there are also differences in underlying causes, with ischaemic heart disease (IHD) accounting for up to two thirds of deaths in high-income countries, but only one third in the African and South-East Asian regions. To support the development of preventive strategies, information on both the extent and nature of the problem is needed. Thus, this study aimed to explore the available global epidemiologic data on cardiac arrest and heart failure, with a specific focus on highlighting the gaps in knowledge.
Risk Factors for Cardiac Arrest in Men
Cardiac arrest occurs when the heart suddenly stops pumping blood effectively. It is a life-threatening emergency that requires immediate emergency treatment. Cardiac arrest is not the same as a heart attack, which is caused by a blocked artery leading to the heart. A heart attack can trigger cardiac arrest, but cardiac arrest can also happen without a heart attack. Sudden cardiac arrest claims the lives of nearly 500,000 people in the United States each year.
People of all ages can have a cardiac arrest, but certain risk factors increase the likelihood of this event. Risk factors for cardiac arrest can be categorized as nonmodifiable or modifiable. Nonmodifiable risk factors might include age or genetic predisposition, while modifiable risk factors can include smoking, stress, or diet (L A Smits et al., 2022). Different elements elevate the risk of experiencing cardiac arrest.
Heart problems. The most important risk factor for sudden cardiac arrest is having a heart condition. Coronary artery disease, which restricts blood flow to the heart muscle, is responsible for the majority of cases. Other heart problems may include dilated cardiomyopathy, hypertrophic cardiomyopathy, or abnormal heart rhythms.
Family history. Sudden cardiac arrest can run in families. A person with a parent or sibling who has experienced sudden cardiac arrest may have a higher risk of cardiac arrest.
Age and gender. Sudden cardiac arrest can occur at any age; however, people age 65 and older are at highest risk. Generally, men are at greater risk than women, particularly at younger ages.
Age
Age plays a crucial role regarding the health of men. Men under the age of 40 are at a substantially lower risk for having a cardiac arrest than women. However, that risk continues to rise dramatically after age 40 and especially after age 50 (Gao et al., 2021). Among men, cardiac arrest is more common after age 50 than after age 40; among women, it is more common after age 60 than after age 50. Men age 60 and older experience 32 times more cardiac arrests than women of the same age.
Family History
A family history of cardiac disease is a well-established risk factor for cardiac arrest. A family history of sudden cardiac death raises a person’s own risk for a fatal arrhythmia in both men and women. However, the strength of the association is much larger for cardiac arrest in women, as family history bears greater weight in the susceptibility of women (L A Smits et al., 2022). Familial aggregation studies, which often rely on relatives of individuals with disease, have convincingly demonstrated that prevalence rates of cardiac arrest are elevated among family members of individuals with such events. Distinct from many early investigations that sought to elucidate whether heart attacks run in families or whether the risk for heart attacks is mediated through social or environmental factors, familial aggregation studies pursue the genetic or physiological basis whereby cardiac events and risk factors for cardiac events are passed down through generations. Their findings in proband investigations convincingly link a family history of cardiac events – heart attacks, high blood cholesterol levels, and hypertension – to a markedly increased susceptibility to similar events.
Lifestyle Factors
Lifestyle factors such as smoking, ergonomic and occupational exposure, leisure time physical activity as well as a diet high in saturated fats and low in fruits and vegetables are major contributors to the risk of fatal coronary heart disease and ischemic stroke (Forslund et al., 2013). Nevertheless, little is known about lifestyle factors preceding cardiac arrest among survivors. As men have an increased risk of cardiac arrest, it is of particular importance to investigate their lifestyle factors as prior risk factors for cardiac arrest. Cardiac arrest is a critical health condition suffered more often by males compared to females. The substantial sex difference has been attributed to gender factors such as increasing age, co-morbidity (poor health), as well as lifestyle-related factors (smoking, alcohol consumption, and leisure-time physical activity) (L A Smits et al., 2022).
Acute myocardial infarction (AMI) is often an underlying cause of cardiac arrest (CA) outside of the hospital. For this reason, risk factors of developing AMI such as a high body mass index, diabetes, high levels of low-density lipoprotein (LDL) cholesterol, hypertension, as well as an absence of physical activity, have all been linked with increased risk of CA. Nevertheless, few studies have examined lifestyle prior to CA. Additional lifestyle risk factors besides those associated with AMI may be beneficial to investigate, such as ergonomic exposure as well as dietary habits.
Treatment and Management of Cardiac Arrest in Men
The treatment and management of cardiac arrest in men are critical to ensuring a successful patient outcome. The first step in treating a cardiac arrest patient is to access an automated external defibrillator (AED) or call emergency services (Lazzarin et al., 2022). Proper AED use may include four steps: turning on the AED, attaching the pads, following the prompts, and performing CPR until additional help arrives. CPR is essential in all suspected cardiac arrests. CPR can help continue blood circulation, making it more likely that the heart can spontaneously start beating again. CPR consists of rescue breaths or chest compressions or both. In 2014, the American Heart Association recommended hands-only CPR, which consists of uninterrupted chest compressions without rescue breaths (Koliantzaki et al., 2014).
In hospitals, cardiac arrest is associated with severe acute brain injury due to hypoxia and ischemia. Cardiopulmonary resuscitation actions, either by blood flow restoration or direct neuroprotection, can improve outcomes. Patients who suffer from a cardiac arrest often suffer from severe hypoxic-ischemic injury of brain structures critical to cognition, consciousness, and autonomic regulation. Patients resuscitated from cardiac arrest often develop a post-cardiac arrest syndrome of global ischemia, contributing to multi-organ dysfunction. Management of patients after cardiac arrest develops in two stages: ventilation, perfusion, and stabilization during cardiopulmonary resuscitation; then neuroprotection and support for multiorgan system dysfunction following restoration of spontaneous circulation.
Emergency Response and CPR
Cardiac arrest is a medical emergency requiring immediate action. If a person collapses and is unresponsive or not breathing, call the emergency services (110 in the USA, 000 in Australia, 999 in the UK), or have someone else do so. Start CPR right away, pushing hard and fast on the chest at a rate of 100-120 beats per minute. If available, use an AED (automated external defibrillator) to deliver a shock if advised. Continue CPR until emergency responders arrive and take over, or an AED is available (DeMasi et al., 2024).
Initiating CPR within 3-5 minutes can double or triple a person’s chance of survival. The location of the cardiac arrest can also affect the outcome; for example, 45% of patients who have a cardiac arrest at home die, while those who have one in a hospital have a survival rate of S86% (Koliantzaki et al., 2014).
Defibrillation
Cardiac arrest is a time-critical illness in which the heart stops pumping blood, resulting in severe injury or death unless treatment is initiated (Suryanarayana et al., 2018). Defibrillation is a process in which an electrical impulse or shock is applied to the heart to restore a normal heartbeat. An electrical shock to the heart can control arrhythmias, specifically ventricular fibrillation and tachycardia. Phosphofructokinase, phosphocalmodulin, protein kinase A, protein kinase C, and calcium currents are all calcium-extruding pathways that are electrically coupled to myocytes and may vary. With defibrillation, existing defibrillators, poor medical care, and the cellular/biochemical response of the heart are applied. For successful defibrillation, factors affecting the strength and duration of the shock, as well as the impedance of the heart, must be considered. Understanding the hemodynamic, metabolic, and neurologic consequences of defibrillation injuries will help researchers to develop safer devices and treatments.
With contractile asynchrony following defibrillation, the timing of atrial and ventricular activation must be well coordinated to ensure rapid and synchronous contraction of both chambers. The interdependence of the electrical and mechanical activity of the heart is essential for normal cardiac physiology and post-defibrillation function. Synchronized atrial and ventricular pacing leads to coordinated contraction of the chambers, improves cardiac output, and supports hemodynamics. In contrast, asynchronous ventricle-only pacing may result in severe contractile dysfunction with reduced cardiac output (A.S. Beggs et al., 2018). Further research on the defibrillation mechanism and its ventricular mechanical effects may help to develop better defibrillation devices and treatment.
Medications and Therapies
The management of cardiac arrest during the resuscitation attempt is crucial. The International Guidelines have thoroughly described the pharmacological and therapeutic means in view of facilitating Return of Spontaneous Circulation (ROSC) and the main focus has been on Electric Shock (ES), drugs use, or Airway intervention, in this order. There have been scientific efforts to explore the pathophysiological consequences of the arrest but there are scarce studies that have specifically focused on macro- and microcirculatory function alteration during treatment (Papastylianou and Mentzelopoulos, 2012).
Firstly, QoC has gradually been introduced into the attendance of various emergent medical conditions including both adult and pediatric settings, where deduction of survival and good outcome chances requires the meticulous evaluation of the status triad: Function, Time, and Quality of the interventions. With respect to cardiac arrest, Function denotes the cardiac mechanical activity, Time is the elapsed time since the onset of the initial event until ROSC, and Quality represents the safety, the effectiveness, and the efficiency of measures during the resuscitation attempt in terms of the vital functions recuperation (Koliantzaki et al., 2014).