Not every heart attack arrives with the dramatic, crushing chest pain that people commonly associate with a cardiac emergency. Some heart attacks can occur with mild, vague or even no noticeable symptoms. These are often referred to as silent myocardial infarctions.
A person may experience nothing more than unusual fatigue, breathlessness, sweating, nausea, dizziness or indigestion-like discomfort. They may recover and continue with their routine without realizing that the heart has been deprived of blood flow. In some cases, the event is discovered much later, when an ECG, echocardiogram or cardiac imaging shows evidence of previous heart muscle damage.
What happens during a silent heart attack?
A heart attack occurs when blood flow to part of the heart muscle is reduced or blocked, causing injury to the affected tissue. When the symptoms are subtle, a person may not seek medical attention at the time.
Small areas of heart muscle can be injured during episodes of reduced blood supply. If such events occur repeatedly, the cumulative effect may result in scar formation. Over time, this can contribute to reduced heart function, heart failure or a higher risk of future cardiovascular events.
The absence of severe pain does not mean that there has been no damage. The extent of injury can vary, and only appropriate medical evaluation can determine whether a previous event has occurred.
Why diabetes can make symptoms harder to recognize
Silent heart attacks are particularly important in people with diabetes. Nerve damage associated with diabetes can blunt the perception of pain, which means a person may not experience the typical warning symptom of a heart attack.
Older adults and people with established cardiovascular risk factors may also be more likely to have less typical symptoms. This makes it important to pay attention to changes in how you feel and how much activity you can comfortably manage.
For example, if you previously walked for 30 minutes without difficulty but now become unusually breathless after 10 or 15 minutes, that change should not simply be attributed to age or being tired. It deserves attention, particularly if you have diabetes, hypertension, high cholesterol, smoke or have a strong family history of coronary artery disease.
Do not assume every raised troponin means a heart attack
There is also an important distinction between myocardial injury and myocardial infarction.
Troponin is a blood marker that indicates injury to the heart muscle. A raised troponin level does not, by itself, prove that a person has had a heart attack. Myocardial injury can occur with several other conditions, including myocarditis, rapid heart rhythms, severe anemia, kidney disease and prolonged low blood pressure.
A diagnosis of myocardial infarction requires the right combination of clinical findings, ECG changes, biochemical evidence and, where appropriate, imaging or other cardiac investigations.
This distinction matters because the cause of the heart muscle injury determines what treatment and follow-up are needed.
Symptoms you should not ignore
You do not need to have severe chest pain to seek medical attention. Persistent or unexplained breathlessness, unusual fatigue, reduced exercise tolerance, sweating, nausea, dizziness or intermittent chest discomfort can sometimes indicate a cardiac problem.
Indigestion-like discomfort can also be misleading, particularly when it occurs with other symptoms or during physical activity.
If you have diabetes or other cardiovascular risk factors, a new or unexplained change in your symptoms should be evaluated rather than dismissed. Your doctor may recommend an ECG, blood tests, echocardiogram or other cardiac investigations based on your symptoms and risk profile.
Prevention still matters
The best approach is to identify and manage cardiovascular risk factors before heart muscle is damaged. Keep your blood pressure, blood sugar and cholesterol under control. If you smoke, stopping can significantly reduce cardiovascular risk. Regular physical activity, a suitable diet, maintaining a healthy weight and taking prescribed medicines consistently also matter.
People with diabetes, hypertension, high cholesterol or a strong family history of coronary artery disease may need regular cardiovascular assessment, even when they feel well.
The absence of severe chest pain should never be taken as proof that your heart is healthy. A silent heart attack may cause few or no obvious symptoms, but the injury to the heart can still be real. Recognizing subtle changes, getting appropriate evaluation and addressing cardiovascular risk factors early can reduce the chance of a silent event becoming a larger cardiac problem.
(By Dr Narasimha Pai, HOD and Consultant Cardiology, KMC Hospital, Mangalore)
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