Silent Heart Attack: Recognizing the Signs

What Is A Silent Heart Attack?  

A silent myocardial infarction (silent heart attack) is a heart attack that causes few, if any, symptoms or causes symptoms that are not typical of heart attacks. People who have a silent heart attack may not realize they have had one. However, just like a typical heart attack, a silent heart attack causes damage to the heart muscle.

A 2015 study found that the prevalence of silent myocardial infarctions (the presence of myocardial scars with no history of recognized heart attacks) was approximately 5 times higher in men compared to women. 

How Do Silent Heart Attacks Differ from Typical Heart Attacks?  

The main difference between a silent heart attack and a typical heart attack is in the type and severity of symptoms. 

A silent heart attack may not cause severe chest pain, shortness of breath, sharp pain in the jaw, neck, or arm, sweating, or dizziness—symptoms characteristic of a typical heart attack. 

Instead, a silent heart attack may cause less severe symptoms, such as mild chest discomfort, nausea, or cold sweats. As a result, it can be mistaken for less dangerous health problems, such as acid reflux, an upper respiratory infection, the flu, a strained chest muscle, or simply overwork, lack of sleep, and fatigue. 

What Causes Silent Heart Attacks?

The cause of a silent heart attack is the same as that of a typical heart attack. A heart attack occurs when the heart muscle does not receive enough oxygen-rich blood. The most common cause of a heart attack is coronary artery disease or ischemic heart disease, which is a buildup of plaque in the coronary arteries that supply blood to the heart. The plaque causes narrowing or blockage of blood flow in the coronary arteries, leading to a heart attack.

Less commonly, the cause of a heart attack is a coronary spasm (a brief tightening of a coronary artery). Usually, a coronary artery spasm causes sudden chest pain called angina. Learn the difference between a heart attack and angina.

Who Is At Risk of a Silent Heart Attack?  

The following risk factors for a silent heart attack are the same as the risk factors for a traditional heart attack:

• Being overweight or obese

• Eating an unhealthy diet with excess amounts of saturated fat, processed foods, and red meat

• Lack of regular physical activity

• Smoking cigarettes or using other tobacco products

• High blood pressure

• High cholesterol

• Type 2 diabetes

Risk factors for silent heart attacks and traditional heart attacks that you cannot change include:

• Age (men older than 45 and postmenopausal women above age 55). Recognize the symptoms of heart attack in women.

• Native American, Black American, Hawaiian, or Mexican American ethnicity

• A family history of heart disease

Triggers for Silent Heart Attacks

A silent heart attack can occur at any time of the day, even when you’re asleep. Potential triggers include: 

• Severe physical or emotional stress

• Rapid or intense physical exertion

Demographics At Risk

• Research suggests that the risk of a silent heart attack increases with multi-vessel coronary artery disease (reduced blood flow in more than one blood vessel supplying the heart muscle).

• The prevalence of silent ischemia is higher in people with diabetes mellitus and two additional risk factors. 

• Studies have shown that a higher coronary artery calcium score is linked to a higher risk of silent heart attacks.

Gender-Specific Risk Considerations

Studies suggest that females are at a higher risk of silent heart attacks than males. Moreover, women and their physicians are more likely to attribute silent heart attack symptoms to stress, anxiety, or fatigue.

How to Tell if You’ve Had a Silent Heart Attack

It can be hard to tell that you’ve had a silent heart attack. This is because silent heart attack symptoms are hard to recognize. They can feel like the flu, a sore chest muscle, heartburn, indigestion, generalized fatigue, or an ache in your jaw, neck, or arm. 

Symptoms of Silent Myocardial Ischemia

As mentioned, silent ischemic episodes cause no apparent signs or symptoms. However, it’s essential to seek immediate medical attention if you notice subtle symptoms of silent myocardial ischemia, such as:

• Chest discomfort lasting several minutes at a time that may come and go. 

• An uncomfortable pressure, pain, or squeezing sensation in the center of the chest.

• Discomfort in the upper body, including the jaw, neck, upper back, left or right arm, or upper stomach.

• Shortness of breath before or during the chest symptoms.

• Other symptoms include cold sweats, nausea, indigestion, dizziness, and lightheadedness.

What to Do if You Suspect a Silent Heart Attack 

• If you suspect you are having a silent heart attack, call 911 for emergency medical care. 

• Take nitroglycerin while waiting for emergency medical services to arrive if this medicine has been prescribed to you. 

• If someone isn’t breathing or does not have a pulse, start cardiopulmonary resuscitation (CPR).

Can You Have a Heart Attack and Not Know It?  

Yes, you can have a heart attack and not know it. This is called a silent heart attack. Silent myocardial ischemia (reduced blood flow to the heart muscle) causes subtle symptoms often missed or brushed off as relatively minor health problems. As a result, many people who experience a silent heart attack do not know they’ve had a heart attack.

Diagnostic Methods and Early Detection

As noted, silent heart attack symptoms are easily missed. However, a health care professional may suspect it on a physical exam due to a fast and irregular pulse and unusual sounds in your lungs. A definitive diagnosis of a silent heart attack can be made based on the results of:

• Blood tests

• Electrocardiogram (ECG or EKG)

• Echocardiogram

• Imaging tests such as computed tomography (CT or CAT) scan or magnetic resonance imaging (MRI) scan

• Exercise stress test

• Nuclear stress test 

• Cardiac catheterization

• Coronary angiography

Treatment Options  

If you are diagnosed with a silent heart attack, the treatment plan may include: 

• Cardiac monitoring

• Supplemental oxygen

• Medications including:

  • Pain medication

  • Aspirin

  • Thrombolytics to break up blood clots

  • Beta-blockers or calcium channel blockers to reduce the number and duration of silent ischemic episodes

  • Statins (cholesterol-lowering drugs)

People who have experienced a silent heart attack may also be recommended procedures such as:

• Coronary angioplasty to open up a narrowed or blocked blood vessel

• Stent placement to keep a blood vessel open

• Coronary artery bypass graft (CABG) to create a new pathway for blood flow around a clogged artery

Can a Heart Attack Resolve Itself?  

Yes, some heart attacks resolve themselves. For example, if a blood clot dissolves or is absorbed by the body, the heart attack may resolve. However, heart attacks can cause permanent damage. The heart muscle heals by forming scar tissue over several weeks. While the heart can continue functioning, it may become weak over time and be unable to pump blood like it should. 

Complications 

People experiencing a silent heart attack are at an increased risk of serious complications, including sudden cardiac death, because they do not have any obvious symptoms, do not realize they are having a heart attack, and therefore do not seek prompt medical attention in the emergency room.

A silent heart attack can increase the risk of another heart attack in the future. Damage to the heart muscle from multiple silent heart attacks can lead to heart failure.

Preventive Care

Things you can do to prevent a silent heart attack are the same as other heart attack prevention strategies, including:

• Eating a heart-healthy diet consisting of fruits, vegetables, whole grains, healthy fats, low-fat dairy, lean protein, nuts and seeds. 

• Limiting the intake of processed foods, high-salt foods, saturated fats, and red meat.

• Getting regular physical activity. Experts recommend 150 minutes of moderate-intensity aerobic exercise each week.

• Staying at a healthy weight. 

• Avoiding tobacco use.

• Drinking alcohol in moderation.

• Managing stress levels with techniques such as deep breathing, yoga, tai-chi, meditation, and progressive muscle relaxation.

• Getting enough high-quality sleep. Experts recommend 7-9 hours of sleep each night.

Managing Long-Term Health After a Silent Heart Attack  

Based on your risk factors for heart disease, your healthcare professional will prescribe medications to lower the risk of future heart attacks. It is important to take all prescribed medications. These may include aspirin, antihypertensives to lower high blood pressure, diabetes medications to keep blood glucose under control, and statins to lower cholesterol levels. 

Lifestyle Changes 

According to the American Heart Association, healthy lifestyle changes are the best defense against heart disease. The strategies mentioned under preventive care above can help optimize heart health and reduce the risk of silent and symptomatic heart attacks.

Follow-Up Care  

People who have had one heart attack are at an increased risk of having another one. It’s, therefore, vital that you follow your healthcare provider’s instructions for lifestyle modifications as well as the prescribed treatment plan. Your doctor may refer you for cardiac rehabilitation, which combines educating patients and physical therapy to help in recovery from a heart attack. 

Emotional and Psychological Considerations

Research suggests that mental stress is a known trigger for silent ischemia, especially in people with underlying coronary artery disease. Therefore, stress reduction techniques can be beneficial in people with heart disease and may lower the risk of silent heart attacks. 

What Is The Life Expectancy After a Silent Heart Attack?

The Iceland MI Study in 2018 found that the long-term survival rates for people who experience silent heart attacks are the same as those with recognized heart attacks. The researchers reported that:

• At 5 years, mortality rates were 8% for people with no heart attacks, 13% for those with silent heart attacks, and 19% for those with recognized heart attacks.

• At 10 years, mortality rates were 30% for people with no heart attacks, 49% for those with silent heart attacks, and 51% for those with recognized heart attacks.

However, it is worth noting that people who experience silent heart attacks are at an increased risk of heart failure, cardiac arrhythmias, and stroke.