From the Guidelines
Cardiac ischemia in patients with diabetes and cardiac autonomic neuropathy often presents with atypical symptoms, including fatigue, dyspnea, and diaphoresis, rather than classic chest pain. These patients typically experience these symptoms during cardiac ischemic episodes because diabetes can damage the nerves that supply the heart (cardiac autonomic neuropathy), which alters how the body perceives and responds to cardiac pain signals 1. The autonomic nervous system dysfunction prevents the typical pain signals from being properly transmitted or interpreted by the brain. Instead of experiencing the classic crushing chest pain that radiates to the left arm, these patients may only feel unusually tired, have difficulty breathing, or sweat profusely during an ischemic event.
Key Points to Consider
- Cardiac autonomic neuropathy (CAN) is associated with mortality independently of other cardiovascular risk factors 1.
- CAN may be completely asymptomatic in its early stages and detected only by decreased heart rate variability with deep breathing 1.
- Advanced disease may be associated with resting tachycardia (>100 bpm) and orthostatic hypotension (a fall in systolic or diastolic blood pressure) 1.
- Healthcare providers should maintain a high index of suspicion for cardiac ischemia when diabetic patients with known or suspected autonomic neuropathy present with non-specific symptoms, especially during exertion or emotional stress.
Clinical Implications
- The atypical presentation of cardiac ischemia in patients with diabetes and cardiac autonomic neuropathy can lead to delayed diagnosis and treatment 1.
- It is essential to consider the possibility of cardiac ischemia in diabetic patients with known or suspected autonomic neuropathy who present with fatigue, dyspnea, or diaphoresis, even in the absence of classic chest pain symptoms 1.
- Optimize glucose control to prevent or delay the development of neuropathy in patients with type 1 diabetes and to slow the progression of neuropathy in patients with type 2 diabetes 1.
From the Research
Cardiac Ischemia in Patients with Diabetes and Cardiac Autonomic Neuropathy
- Cardiac autonomic neuropathy (CAN) is a frequent chronic complication of diabetes mellitus with potentially life-threatening outcomes 2.
- CAN is caused by the impairment of the autonomic nerve fibers regulating heart rate, cardiac output, myocardial contractility, cardiac electrophysiology, and blood vessel constriction and dilatation 2.
- Clinical symptoms associated with CAN generally occur late in the disease process and include early fatigue and exhaustion during exercise, orthostatic hypotension, dizziness, presyncope, and syncope 2.
Presentation of Cardiac Ischemia
- Cardiac ischemia in patients with diabetes and CAN may present with atypical symptoms, including fatigue, dyspnea, and diaphoresis.
- The presentation of cardiac ischemia in these patients can be attributed to the impaired autonomic nervous system, which can lead to asymptomatic myocardial ischemia and infarction 3, 4.
- The asymptomatic nature of cardiac ischemia in patients with CAN makes it challenging to diagnose and treat, highlighting the importance of early detection and management of CAN 5.
Diagnostic Methods
- Methods based on heart rate variability enable the diagnosis of CAN even at a preclinical stage, and these methods are simple and widely available for use in everyday clinical practice 4, 5.
- Electrocardiographic changes, such as tachycardia, shortening of the QRS and QT intervals, and increased dispersion of QT interval, can also be used to diagnose CAN 6.
- A combination of these diagnostic methods can help identify patients with CAN and cardiac ischemia, allowing for early intervention and management 2, 3.