Heart attack
What is a heart attack?
A heart attack, also known as myocardial infarction (MI) or acute coronary syndrome (ACS), occurs when there is damage to the heart muscle due to a disruption in blood supply. This disruption typically happens when plaques in the coronary arteries rupture, triggering the activation of clotting molecules in the blood. Consequently, a sudden clot forms and blocks the blood flow to a specific area of the heart.
Heart attacks can range in severity. Minor heart attacks are relatively common and may not have a significant impact on overall heart function or quality of life. On the other hand, major heart attacks involve substantial injury to the heart muscle. Prompt emergency intervention is crucial in these cases to open the blocked blood vessels and restore blood supply, thereby limiting or preventing damage to the affected segments.
It’s important to note that heart attack, acute coronary syndrome, and acute myocardial infarction are different terms used to describe the same condition—an interruption of blood supply resulting in heart muscle damage.
Are there different types of heart attacks?
Yes, the determination of a heart attack is typically based on your 12-lead ECG findings and your symptoms. In cases of a sudden and complete blockage of a coronary artery, there is usually ST segment elevation observed on the ECG in the corresponding areas. This type of heart attack is referred to as ST elevation myocardial infarction (STEMI). On the other hand, when individuals experience a heart attack without ST segment elevation on the ECG, it is known as non-ST elevation myocardial infarction (NSTEMI). An NSTEMI can occur when there is severe narrowing of a blood vessel, causing intermittent blood flow disruption. However, it can also be caused by conditions unrelated to the heart arteries, such as rapid heart rhythms or direct muscle damage like myocarditis.
It’s important to note that not all individuals with elevated levels of troponin (a protein released during heart muscle damage) necessarily require a coronary angiogram or intervention. In the case of STEMI, immediate intervention is generally needed to restore blood flow.
How do you know if I am having a heart attack?
A heart attack is typically characterized by a sensation of crushing central chest pressure, which can radiate to the lower jaw, left shoulder, and upper arm. Additional symptoms may include shortness of breath and sweating. It’s important to note that women and individuals with diabetes may experience different or less severe symptoms, and some individuals may not experience any symptoms at all.
If you suspect you are having a heart attack, it is crucial to seek urgent medical attention.
When a heart attack is suspected, doctors will perform an electrocardiogram (ECG) and a blood test. The blood test is used to measure a marker called troponin, which is a special protein found in the heart muscle. When the heart is injured due to a lack of blood supply, troponin is released into the bloodstream. The troponin test is often repeated once or twice to monitor changes, providing valuable information about the timing and severity of the heart attack. It’s important to understand that not all elevations in troponin levels are necessarily indicative of muscle damage caused by blocked arteries.
There are specific clues and characteristic changes on an ECG that can help identify a heart attack. These findings, along with the troponin levels, assist in making an accurate diagnosis.
What do you do when someone is having a heart attack?
In addition to the necessary tests, individuals experiencing a heart attack are typically administered blood thinners, such as aspirin and a stronger form of aspirin, along with a blood-thinning injection. These medications aim to prevent the worsening of blood clots and further damage.
Managing your symptoms is crucial, and various medications, injections, and pain relief measures are employed to provide relief.
For individuals with ST-segment elevation myocardial infarction (STEMI), an urgent angiogram is generally performed to assess the extent of blockage. This procedure, known as percutaneous coronary intervention (PCI), involves placing a stent to restore blood flow in the blocked artery. In cases where immediate PCI is not feasible due to geographical constraints, thrombolysis, a special clot-busting medication, may be administered, followed by transfer to a hospital capable of performing PCI. More information on coronary angiogram and PCI can be found in the corresponding section.
In certain situations where PCI is not suitable, surgical intervention may be necessary to address the blocked arteries. This surgical procedure is known as coronary artery bypass grafting (CABG).
Not all people with a troponin elevation are considered to have had a heart attack or require angiogram or stent or surgery.
What happens following a heart attack?
The main aim is to preserve or improve your heart function and to prevent future heart attacks. You will likely need lifelong medications to prevent another heart attack. Medications called antiplatelets are commonly used together with cholesterol lowering medications. Aspirin is the most common antiplatelet in common use. A second antiplatelet is often used following heart attack for a prespecified period. In some cases, you may need short term or long-term medications to assist the heart. These are called beta blockers, and ACE inhibitors.
You will generally be recommended to attend cardiac rehabilitation programme closer to home which will focus on education, medication use, healthy living and improving your cardiovascular health.
Addressing modifiable coronary artery disease risk factors is critical in your management. Please refer to the coronary artery disease section.
