Abstract and Introduction
Abstract
Sudden cardiac death (SCD) has been associated with diabetes, although it is unclear whether diabetes is a risk factor for SCD. Diabetes is a risk factor for common preventable comorbidities associated with SCD, including coronary artery disease (CAD), myocardial infarction, and heart failure. Researchers are seeking ways to measure susceptibility to SCD, but because of SCD's multifactorial development, most likely no single test will be able to identify at-risk individuals. Until tests with proven predictive value are available, preventive efforts should focus on slowing the progression or development of cardiovascular diseases that frequently cause SCD. This can be accomplished by promptly initiating ACE inhibitors, angiotensin receptor blockers, beta-blockers, antiplatelet agents (aspirin), and possibly statin therapy for CAD, hypertension, and/or hypercholesterolemia. SCD prevention strategies for the general population are the same as those for patients with diabetes.
Introduction
Sudden cardiac death (SCD) is an event that can occur in asymptomatic individuals, as well as in those with advanced cardiovascular (CV) disease. SCD typically manifests as a structural abnormality coupled with a disturbance in cardiac electrical activity that leads to fatal arrhythmias. However, in 5% to 10% of SCD cases, no definable structural cardiac abnormality exists. Patients may either be asymptomatic or experience symptoms including palpitations, chest pain or discomfort, dyspnea, fatigue, or syncope. Sudden cardiac arrest (SCA), in which an electrical malfunction causes the heart to stop abruptly, may occur in these patients; if the heart is not quickly shocked back into rhythm, SCD ensues. At least 90% to 95% of SCA cases in the community setting end in death before the patient receives medical assistance.
In the United States, the annual number of SCDs is estimated to be between 250,000 and 300,000, with a predominance in males and an increased incidence with age for both genders. SCD is the first cardiac event in approximately 55% of men and 68% of women, while in other cases SCD follows multiple cardiac events. Unfortunately, the prevalence of SCD is difficult to determine since there previously was no unified definition of the condition. In general, SCD is defined as unexpected death occurring within a specific time frame after initial onset of cardiac symptoms. Depending upon the study being reviewed for SCD, the time frame between symptom onset and death varies greatly, from less than 1 hour up to 24 hours.
The most common preventable comorbidities associated with SCD include coronary artery disease (CAD), myocardial infarction (MI), and heart failure (HF). Since diabetes is a risk factor for these comorbidities, it has been deemed to have an association with SCD. The association between diabetes and SCD may involve a combination of macrovascular and microvascular complications that can affect the electrical system controlling cardiac rhythm, thus increasing the propensity for SCD. With the number of diabetes patients growing in epidemic proportions (approximately 29.9 million in the U.S.), there is an urgent need to determine whether having diabetes increases one's risk for SCD.