Silent Heart Attacks

Heart attacks occur when the heart receives little or no oxygen-rich blood to nourish the tissues of the heart muscle. This causes heart muscle damage and may cause scarring that can lead to future problems with heart and circulatory health.

Silent heart attacks are more common than people realize. In this study, about 45% of the heart attacks that occurred were silent.

Problems within the coronary arteries that nourish the heart muscle — blockages, atherosclerosis — are the usual sources of this oxygen-deprived state. Most commonly, a blockage from build-up of plaque is the underlying reason. Less commonly, a spasm of the artery causes a temporary stoppage in blood flow.

The severity of a heart attack depends on the amount of heart muscle that is deprived of oxygen and its location. The results can be partial to complete recovery, ongoing disability or death.

The common signs of heart attacks in both men and women are:

Chest pain or discomfort usually in the center or left side of the chest. The discomfort typically lasts for more than a few minutes or goes away and comes back. It can feel like pressure, squeezing, fullness, or pain. It also can feel like heartburn or indigestion. The feeling can be mild or severe.

Upper body discomfort, pain or discomfort in one or both arms, the back, shoulders, neck, jaw or upper part of the stomach (above the belly button).

Shortness of breath. This may be the only symptom, or it may occur before or along with chest pain or discomfort. It can happen at rest or during activity.

Other symptoms include:

Breaking out in a cold sweat;

Feeling unusually tired for no reason;

Nausea and vomiting;

Light-headedness or sudden dizziness.

People experiencing heart attacks require urgent medical attention to have the best chance for recovery. The presence of underlying health conditions such as diabetes can influence the outcome of heart attacks, as does the time from heart attack to treatment.

Treatment often involves unblocking the clogged arteries, perhaps by the insertion of a stent. Long-term interventions include coronary artery surgery, medications and lifestyle changes to improve overall heart health and prevent recurrences.

Of course, for timely treatment to take place, patients and their doctors need to realize a heart attack has occurred. This is not always the case.

People experiencing heart attacks require urgent medical attention to have the best chance for recovery.

Silent heart attacks, those that go unrecognized but still cause heart damage, are common, a recent study confirms. These are heart attacks that may be without symptoms or have non-specific symptoms that are not recognized by the patient as related to the heart. The person may attribute them to fatigue, indigestion, flu, pulled muscle or even anxiety; and so they may not seek medical care at the time.

That you have had a heart attack may not be recognized until you have an EKG (electrocardiogram) showing certain characteristic abnormalities. (Once a heart attack occurs, the tracing typically shows an abnormality called a Q wave.) This means that they have missed the opportunity for early, and potentially life-saving interventions.

Wake Forest School of Medicine researchers studied data on over 9400 individuals who had no cardiovascular disease at the start of the study. They followed their study patients regularly, starting in 1987, using EKGs performed at four follow-up visits (through 1998) to determine whether a silent myocardial infarction had occurred. They continued to follow the group for another 13 years to monitor their long-term cardiac health.

They found that from the first visit through the four surveillance visits, 317 (3.3%) of the participants developed silent heart attacks. Another 386 (4.1%) developed clinical myocardial infarction.

Both those who had both silent and clinical myocardial infarctions had an increased risk of death from coronary artery disease during the 13-year follow-up period.

Both the silent and clinical myocardial infarctions (CMI) were more common in men than in women. The rates of silent MIs (SMI) were similar for black and white individuals, but whites had a higher rate of CMI than blacks. Black women had more SMIs than CMIs, while white men had more CMIs.

More importantly, both those who had silent and clinical MIs had an increased risk of death from coronary artery disease during the 13-year follow-up period.

The findings make clear that silent heart attacks are more common than people realize. Among the participants in this study, about 45% of the heart attacks that occurred were silent. Those with both silent and clinical heart attacks are also at increased risk for future heart disease, disability and death.

The added danger is that when patients have silent heart attacks, they miss out on the benefit of medical interventions to decrease their short- and long-term cardiac risk. They are less likely to receive potentially life-saving treatment of blocked coronary arteries, appropriate medications, advice on lifestyle changes including diet and exercise, and stress management.

When a silent heart attack is missed, the person is also not counseled about the importance of sticking to medication regimens, managing any other underlying chronic health conditions they may have — such as diabetes and high blood pressure — or made aware of the subtle symptoms of cardiac incidents they should look for and seek prompt medical care for.

Both patients and providers need to be more aware of how common silent heart attacks are and more attentive to subtle signs of heart problems. The study is published in Circulation.