**2. Risk factors**

The two major risk factors are previous myocardial infarction and coronary artery disease (CAD). However, there are other risk factors which include age, gender (predominant in males), ethnicity, reduced ejection fraction, a previous sudden cardiac arrest, familial predisposition to SCD, bradycardia, ventricular fibrillation, heart defects at birth, coronary artery abnormalities due to atherosclerosis, dilated cardiomyopathy, hypertrophic cardiomyopathy, significant changes in blood levels of potassium and magnesium, obesity, diabetes, recreational drug abuse and taking drugs that are "pro-arrhythmic" which may increase the risk for life-threatening arrhythmias [4].

#### **3. Management of SCD**

In order to prevent SCD, it is imperative to impose an aggressive management of cardiovascular risk factors at all levels including schools, universities, clinics, workplace and others. These include performing moderate exercise regularly, educating patients about the dangers of CVDs, promoting a healthy diet, restricting stress, reducing consumption of sugar, saturated fat and salt and stop smoking to promote a heart healthy behavior to all, particularly in young children and adolescents.

Finally, a preclinical prediction of patients at risk of SCD and early detection of the disease is crucial for early intervention and definitely these will reduce the incidence of SCD dramatically [4, 5]. Screening of family members who are susceptible to arrhythmias and SCD can help with early diagnosis and also and managing the arrhythmias [6].

### **4. Epidemiology of diabetes-induced sudden cardiac death**

SCD is responsible for more than 100,000 deaths annually in the UK and 400,000 in the USA, far more than cancer and other individual non-communicable disease. It is estimated that 27,000 patients in the UK and 80,000 patients in the USA die annually from diabetes-induced SCD. Globally, SCD is responsible for half

**137**

**Figure 1.**

*Mechanisms of Diabetes Mellitus-Induced Sudden Cardiac Death*

tance to understand the structure and function of the heart.

**5. Anatomy and physiology of the heart**

and other diseases is responsible for SCD.

of all deaths due to heart disease [7]. Most cases of SCD are related to undetected cardiovascular diseases. SCD are directly linked to DM and CVDs are responsible for over 80% of the mortality in the diabetic population [8]. Epidemiological data show that macro-vascular complications including coronary artery disease (CAD), peripheral vascular disease (PVD) and SCD are 2–4 times more common among diabetic patients when compared with nondiabetic people [9]. According to the Framingham study, the frequency of CAD is twice more common in diabetic patients of both sexes than nondiabetic individuals [10]. This review will now focus on the mechanisms of diabetes-induced SCD, but first it is of paramount impor-

The mammalian heart is a four-chambered muscular organ, which is located in the anterior mediastinum, posterior to the sternum and encapsulated by the pericardium. The pumping action of the heart is central to the functioning of the circulatory system. The CVS composed of the blood, the heart and blood vessels [11]. The heart is a strong muscular organ, which continues to pump blood to different parts of the body throughout our lives. It beats continuously using up a vast amount of energy daily [12]. The structure of the heart is depicted in **Figure 1** and it is composed mainly of three layers of muscles, namely the epicardium or the external layer, the middle layer or myocardium and the inner most layer or endocardium. Damage to these muscles and other conduction tissues in the heart due to diabetes

The larger and strong muscular tissue of the myocardium is responsible for ventricular contraction, and it is also divided into left and right sides by a septal wall. Each side of the heart is made up of two chambers consisting of the upper atria and the lower ventricles [12]. The left side of the heart pumps oxygen-rich blood to the different parts of the body via the aortic valve to the aorta (systemic circulation), while the right side delivers blood to lungs via the pulmonary valve and the pulmonary artery for oxygen replenishment in the lungs (pulmonary circulation). The heart has four valves which allow for unidirectional flow of blood thereby

*The mammalian heart. Components are described in the text (image courtesy www.beyondbiology.org).*

*DOI: http://dx.doi.org/10.5772/intechopen.93729*

#### *Mechanisms of Diabetes Mellitus-Induced Sudden Cardiac Death DOI: http://dx.doi.org/10.5772/intechopen.93729*

*Sudden Cardiac Death*

cases there are no prior symptoms [4, 5].

**2. Risk factors**

**3. Management of SCD**

the arrhythmias [6].

pumping action of the heart due to a disturbance in its electrical system that results in irregular and dangerously fast beating of the heart [1]. The ventricles may flutter or quiver (ventricular fibrillation), disrupting the pumping action of the myocardium, thereby stopping blood flow to the body. The blood flow to the brain is a matter of grave concern for the patients since reduced oxygenated blood supply to the brain can lead to unconsciousness and permanent damage to the brain. As such, death can follow unless the patient receives emergency treatment [2, 3]. Therefore, time is extremely critical when someone or a clinician is helping an unconscious person whose heart is not pumping (no pulse). SCD represents a major challenge for the clinician especially in individuals without a previous history of cardiac diseases. Early prediction of individuals at risk of SCD can be life-saving. Currently, most individuals experiencing SCD may not be identified as being a high risk and as such, the patients do not have ready access to a defibrillator. As a result, there must be community-based public access to defibrillation programmes in order to save the lives of the potential victims. SCD seems to occur most frequently in adults in their mid-30s to mid-40s and during working age, affecting both men and women. With SCD, some patients experience tachycardia, dizziness and fainting while in some

The two major risk factors are previous myocardial infarction and coronary artery disease (CAD). However, there are other risk factors which include age, gender (predominant in males), ethnicity, reduced ejection fraction, a previous sudden cardiac arrest, familial predisposition to SCD, bradycardia, ventricular fibrillation, heart defects at birth, coronary artery abnormalities due to atherosclerosis, dilated cardiomyopathy, hypertrophic cardiomyopathy, significant changes in blood levels of potassium and magnesium, obesity, diabetes, recreational drug abuse and taking drugs that are "pro-arrhythmic" which may increase the risk for life-threatening arrhythmias [4].

In order to prevent SCD, it is imperative to impose an aggressive management of cardiovascular risk factors at all levels including schools, universities, clinics, workplace and others. These include performing moderate exercise regularly, educating patients about the dangers of CVDs, promoting a healthy diet, restricting stress, reducing consumption of sugar, saturated fat and salt and stop smoking to promote a heart healthy behavior to all, particularly in young children and adolescents. Finally, a preclinical prediction of patients at risk of SCD and early detection of the disease is crucial for early intervention and definitely these will reduce the incidence of SCD dramatically [4, 5]. Screening of family members who are susceptible to arrhythmias and SCD can help with early diagnosis and also and managing

**4. Epidemiology of diabetes-induced sudden cardiac death**

SCD is responsible for more than 100,000 deaths annually in the UK and 400,000 in the USA, far more than cancer and other individual non-communicable disease. It is estimated that 27,000 patients in the UK and 80,000 patients in the USA die annually from diabetes-induced SCD. Globally, SCD is responsible for half

**136**

of all deaths due to heart disease [7]. Most cases of SCD are related to undetected cardiovascular diseases. SCD are directly linked to DM and CVDs are responsible for over 80% of the mortality in the diabetic population [8]. Epidemiological data show that macro-vascular complications including coronary artery disease (CAD), peripheral vascular disease (PVD) and SCD are 2–4 times more common among diabetic patients when compared with nondiabetic people [9]. According to the Framingham study, the frequency of CAD is twice more common in diabetic patients of both sexes than nondiabetic individuals [10]. This review will now focus on the mechanisms of diabetes-induced SCD, but first it is of paramount importance to understand the structure and function of the heart.
