Undiagnosed heart disease may be common in people with heart attacks not caused by clots

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More than two-thirds of people who have a type of heart attack not caused by a blood clot may also have undiagnosed heart disease, according to a small study from Scotland.

The study, published in the journal Circulation of the American Heart Association, focused on people who had what are known as type 2 heart attacks, which result from the stress caused by an illness such as infections or a fast heartbeat that can lower blood pressure or heart rate. oxygen in the heart. blood. But when the researchers performed advanced imaging of the heart, they found that the study participants also had conditions like narrowed arteries or weakened heart muscles that often went undiagnosed. Less than a third of these patients were being treated for heart disease.

“This is the first evidence from a study that demonstrates that underlying heart disease and cardiac weakness are common in this condition,” said senior study author Dr. Andrew Chapman of the BHF Center for Cardiovascular Science at the University of Edinburgh in Scotland.

In the most commonly recognized type of heart attack, called a type 1 myocardial infarction, the blood supply to the heart is cut off, usually by a blood clot, causing the heart muscle in that area to die. A type 2 myocardial infarction occurs when the heart muscle is damaged by the strain of not getting enough oxygen due to impaired blood supply.

In recent years, highly sensitive blood tests that detect levels of troponin, a protein released into the blood when heart muscle is damaged, have made it easier to quickly diagnose heart attacks. Up to half of all people with elevated troponin levels are thought to have type 2 heart attacks. However, less than a third of these patients are treated by cardiologists and less than 20% are screened for underlying cardiovascular disease, according to a 2020 study published in Circulation: Cardiovascular Quality and Outcomes.

The new study included 93 people, average age 66, diagnosed with a type 2 heart attack. Advanced imaging tests of the heart showed that 68% had signs of coronary artery disease – a buildup of plaque in the arteries. Among them, 3 out of 5 were undiagnosed. And 34% of the full group had left ventricular systolic dysfunction, a weakening of the heart muscle that can lead to heart failure or sudden death. This condition was undiagnosed in 84% of the patients who had it. Only 10 patients had normal cardiac images.

Failing to diagnose these conditions likely contributes to the high death rates experienced by people with type 2 heart attacks, Chapman said.

Studies show that these people “have very poor long-term outcomes,” he said. “We know that 1 in 6 patients have a typical (subsequent) heart attack resulting from an artery blockage or cardiovascular death within a year, and only a third of patients are alive five years later.”

One of the reasons type 2 heart attacks are so difficult to diagnose — or treat — is because they can be caused by many different illnesses and conditions, including arrhythmias, bleeding, or sepsis, said Dr. Jason Wasfy, a cardiologist at Massachusetts General Hospital and an associate professor of medicine at Harvard Medical School in Boston.

And because these conditions are so different, it’s difficult to establish or conduct trials that explore treatment options, he said.

“Traditional treatments may be effective in this population, but this has not been validated,” said Wasfy, who was not involved in the study. “There isn’t a single treatment strategy that has been validated in this population. None. The fact that this is so common and so deadly and there isn’t a single randomized controlled trial showing us how to treat this is a huge gap in the literature.”

Antiplatelet or anticoagulant therapies, typically used with stents inserted into an artery to improve blood flow after Type 1 heart attacks, can be problematic for people who have had a Type 2 heart attack because they can cause bleeding, Wasfy said. “It could make things worse, but we don’t even know that.”

Previously, there was a lack of evidence to guide investigation or treatment decisions, Chapman said. But the new findings show that underlying heart disease may be common. So, he said, it emphasizes the need to involve cardiologists in how these patients are cared for.

“Patients with this condition are treated throughout the hospital on medical wards, surgical wards and often in critical care,” Chapman said. “The primary disease is often not the heart, but the heart is damaged as a result. It is often appropriate for these patients to be treated elsewhere, but cardiologists may become involved if there is a suggestion of underlying heart disease.”

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Undiagnosed heart disease may be common in people with heart attacks not caused by clots

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