Heart Attack

Your heart muscle beats continuously throughout your life, requiring a constant supply of oxygen-rich blood delivered through coronary arteries. A heart attack occurs when one of these arteries suddenly becomes completely blocked, cutting off blood flow to a section of heart muscle. Without oxygen, that muscle begins dying within minutes—time truly equals heart muscle. The classic symptom is crushing chest pressure, but heart attacks can appear differently, particularly in women, older adults, and people with diabetes. What makes heart attacks particularly critical is that treatment effectiveness depends entirely on how quickly blood flow is restored—the faster treatment begins, the more heart muscle is saved.

Overview

A heart attack, medically called myocardial infarction, occurs when blood flow to part of your heart muscle is suddenly blocked, causing that tissue to die from lack of oxygen. This is a medical emergency—every minute counts.

Your heart has three main coronary arteries branching across its surface, delivering oxygen-rich blood to heart muscle. These arteries can develop plaque buildup over years through a process called atherosclerosis. Most heart attacks happen when a plaque suddenly ruptures or breaks open. This triggers immediate blood clot formation at the rupture site, completely blocking the artery within minutes.

Once blood flow stops, the affected heart muscle begins dying almost immediately. The longer the artery remains blocked, the more muscle dies. After about 30 minutes without blood flow, irreversible damage begins. After several hours, most of that heart muscle section is dead, replaced by scar tissue that can’t contract. This is why the mantra in heart attack treatment is “time is muscle”—every minute of delay means more permanent heart damage.

Heart attacks are classified by severity. STEMI stands for ST-elevation myocardial infarction, indicating complete artery blockage visible on electrocardiogram as a specific pattern. These are large, dangerous heart attacks requiring immediate treatment to open the blocked artery. NSTEMI means non-ST-elevation myocardial infarction, where the artery is severely narrowed or temporarily blocked but some blood still flows. While less immediately dangerous than STEMI, NSTEMI still requires urgent treatment.

The amount of heart muscle damaged depends on which artery is blocked, where along that artery the blockage occurs, how long blood flow is interrupted, and whether other arteries can provide some backup circulation to the affected area.

Heart attack is the leading cause of death in both men and women worldwide. In the United States, someone has a heart attack every 40 seconds. About one in five heart attacks is silent—the person doesn’t realize it happened and discovers damage only later through testing.

Survival and recovery depend critically on how quickly treatment begins. With modern treatment started within the first hour or two, most people survive and many recover well. Delays of several hours dramatically worsen outcomes.

Causes

Heart attacks result from sudden complete blockage of a coronary artery, almost always due to blood clot formation at a ruptured plaque site.

• Plaque buildup, called atherosclerosis, develops over years or decades inside artery walls. These deposits contain cholesterol, inflammatory cells, calcium, and other substances. Some plaques grow slowly, gradually narrowing arteries and causing chest pain with exertion—this is stable angina. These aren’t the plaques that typically cause heart attacks.
• The dangerous plaques have thin caps covering soft cores. These “vulnerable plaques” can rupture suddenly, exposing their contents to blood flowing through the artery. Blood cells immediately form a clot at the rupture site, and this clot grows within minutes, completely blocking the artery. This is how most heart attacks start—sudden rupture of a plaque that might not have been causing any symptoms.
• Risk factors for developing the plaque that leads to heart attacks include high cholesterol, particularly elevated LDL cholesterol depositing into artery walls. High blood pressure damages artery linings, making them more susceptible to plaque formation. Smoking is one of the most powerful risk factors, damaging arteries and promoting blood clotting. Diabetes dramatically accelerates plaque development. Family history matters—if close relatives had heart attacks at young ages, your risk increases significantly.
• Age increases risk as more time allows plaque accumulation. Men typically develop heart attacks earlier than women, with risk rising after age 45 in men and after menopause in women.
• Less common heart attack causes include coronary artery spasm, where an artery suddenly constricts, cutting off blood flow. This can occur in arteries with or without significant plaque. Cocaine and methamphetamine commonly cause spasm-induced heart attacks in young people. Spontaneous coronary artery dissection, where the artery wall tears, occurs occasionally, particularly in young women, sometimes during or after pregnancy.
• Very rarely, blood clots from elsewhere in the body travel to coronary arteries and lodge there, blocking blood flow. Certain inflammatory conditions can affect coronary arteries, causing blockages.

Symptoms

Recognizing heart attack symptoms and acting immediately is crucial—the faster you get treatment, the better your outcome.

• Classic chest discomfort is described as pressure, squeezing, fullness, or pain in the center or left side of the chest. Many people describe it as an elephant sitting on their chest or a tight band around the chest. The discomfort typically lasts more than a few minutes or goes away and comes back. It’s usually steady once it starts, not sharp or stabbing, and not affected by breathing or moving.
• The discomfort can radiate to the shoulders, arms (particularly the left arm), back, neck, jaw, or stomach. Some people feel the discomfort primarily in these radiation sites rather than the chest.
• Shortness of breath often accompanies chest discomfort but can occur alone. You might feel like you can’t catch your breath or need to gasp for air.
• Cold sweats break out suddenly, often described as clammy or drenching sweats. You might feel cold and sweaty simultaneously.
• Nausea or vomiting occurs frequently, sometimes leading people to think they have stomach problems rather than heart problems.
• Lightheadedness or dizziness develops as your heart can’t pump effectively.
• Overwhelming fatigue appears suddenly and is more profound than normal tiredness.
• A sense of impending doom—feeling that something is seriously wrong—is common though hard to describe. Many heart attack survivors report knowing something terrible was happening.
• Importantly, symptoms vary significantly between individuals. Women, older adults, and people with diabetes often have atypical presentations without classic chest pressure. Women more commonly experience shortness of breath, nausea, back pain, or jaw pain as the primary symptom. Some people, particularly diabetics, have “silent” heart attacks with minimal or no symptoms.
• The key is that symptoms are new, sustained, and different from anything you’ve experienced before. If you think you might be having a heart attack, you probably are—trust your instincts and get help immediately.

Diagnosis

During a suspected heart attack, diagnosis and treatment happen simultaneously because time is critical.

• Calling emergency services immediately is crucial. Don’t drive yourself to the hospital—paramedics can begin treatment in the ambulance and notify the hospital so they’re ready when you arrive. This saves precious time.
• An electrocardiogram is performed within minutes of arrival, often in the ambulance. This shows the heart’s electrical activity and typically reveals specific changes indicating heart attack. The STEMI pattern indicating complete artery blockage is immediately recognizable and triggers the emergency team into action.
• Blood tests measure troponin, a protein released when heart muscle dies. Troponin levels rise within hours of a heart attack and remain elevated for days. However, treatment begins before troponin results are available—you don’t wait for blood tests when someone is clearly having a heart attack.
• Other blood tests check for conditions that might complicate treatment, assess kidney function before giving contrast dye, and establish baseline values.
• Echocardiography shows whether areas of heart muscle aren’t contracting normally, indicating damage. However, this test isn’t performed before emergency treatment—opening the blocked artery comes first.
• Coronary angiography is both diagnostic and therapeutic. Catheters threaded through blood vessels to the heart inject contrast dye while X-ray videos show blood flow through coronary arteries. The blocked artery is immediately visible. Once identified, the interventional cardiologist can open it during the same procedure using angioplasty and stenting.
• The entire process from arrival to artery opening should take less than 90 minutes for STEMI—preferably within 60 minutes. This “door-to-balloon time” is a critical quality measure for hospitals.

Treatment

Heart attack treatment has two phases—emergency treatment to restore blood flow, and long-term treatment to prevent future events.

• Immediate emergency treatment begins the moment a heart attack is suspected. Chewing an aspirin immediately helps prevent the blood clot from growing. Paramedics typically give aspirin in the ambulance. Nitroglycerin under the tongue can relieve chest pain by dilating blood vessels. Oxygen is given if blood oxygen levels are low. Morphine relieves severe pain and anxiety.
• Opening the blocked artery as quickly as possible is the priority. Two approaches exist. Primary angioplasty with stenting is preferred when available—a catheter is threaded to the blocked artery, a balloon inflates to compress the clot and plaque, and a stent is placed to keep the artery open. This mechanical approach works immediately and has excellent success rates.
• Clot-busting medications called thrombolytics can be used if angioplasty isn’t quickly available. These drugs dissolve blood clots but take 30-90 minutes to work and aren’t as effective as mechanical opening. They’re used mainly in locations without immediate access to catheterization labs or when delays getting to one would be significant.
• Once the artery is open, blood flow returns to the heart muscle. Muscle that was merely stunned by lack of oxygen can recover. Muscle that was starting to die but hasn’t progressed too far might survive. But muscle that’s already dead becomes scar tissue.
• Additional medications given during and after a heart attack include beta-blockers to slow heart rate and reduce oxygen demand, ACE inhibitors to reduce heart workload and prevent remodeling, and stronger blood thinners temporarily to prevent new clots.
• After initial treatment, coronary artery bypass surgery might be needed if multiple arteries are blocked or if anatomy isn’t suitable for stenting.
• Long-term treatment prevents future heart attacks. Daily aspirin and often a second antiplatelet medication for a year prevent blood clots. Statins dramatically reduce future heart attack risk by stabilizing plaque and lowering cholesterol. Beta-blockers improve survival. ACE inhibitors or ARBs protect heart function.
• Cardiac rehabilitation programs combine supervised exercise, education, and counseling, significantly improving outcomes and quality of life.

What Happens If Treatment Is Delayed

Every minute of delay means more heart muscle dies, and the consequences become increasingly severe.

• Within the first 30 minutes of complete artery blockage, muscle begins sustaining permanent damage. By two hours, significant portions of the affected area are dying. After four to six hours, most of that heart muscle section is dead and will become scar tissue.
• The more muscle that dies, the weaker your heart becomes. Extensive damage leads to heart failure—your heart can’t pump enough blood to meet your body’s needs. This causes chronic shortness of breath, fatigue, and fluid retention requiring lifelong medication and limiting activities.
• Scar tissue can’t contract, so the remaining healthy muscle must work harder to compensate. Over time, this extra workload can exhaust even previously healthy muscle, causing progressive heart failure.
• Dangerous heart rhythms are more likely with extensive muscle damage. The scar tissue creates electrically unstable areas prone to fast, potentially fatal rhythms from the lower chambers.
• The damaged heart might develop blood clots in poorly contracting chambers. These clots can travel to the brain, causing strokes.
• Mechanical complications including torn heart muscle or valve damage are more likely with extensive infarctions.
• Survival decreases significantly with treatment delays. Someone receiving treatment within an hour has excellent survival chances and often good recovery. Someone waiting six hours has much worse outcomes—lower survival rates and more extensive permanent damage among survivors.
• This is why the message is so critical: at the first suspicion of heart attack, call emergency services immediately. Don’t wait to see if symptoms improve. Don’t drive yourself to the hospital. Don’t call your doctor’s office first. Call emergency services—every minute counts.

What to Watch For

Know the warning signs and act immediately if they occur.

• Call emergency services immediately for chest discomfort lasting more than a few minutes or that goes away and returns. Don’t wait to see if it improves—heart muscle is dying while you wait.
• Seek emergency care for chest discomfort with any of these accompanying symptoms: shortness of breath, cold sweats, nausea, lightheadedness, or pain radiating to arms, back, neck, jaw, or stomach.
• Women, older adults, and diabetics should seek emergency care for unusual shortness of breath, overwhelming fatigue, or upper stomach discomfort lasting more than a few minutes, even without chest pain.
• Some heart attacks are preceded by warning symptoms days or weeks before—new or worsening chest discomfort with activity, chest pain that’s different from your usual angina if you have coronary disease, or sudden decrease in exercise tolerance. Report these to your doctor promptly—they might indicate unstable coronary disease requiring urgent treatment before a full heart attack occurs.
• After surviving a heart attack, watch for symptoms suggesting complications: worsening shortness of breath, new or worsening swelling in legs, new chest pain, or palpitations. Contact your cardiologist promptly.

Recovery and Living After a Heart Attack

Recovery after a heart attack varies based on how much muscle was damaged, how quickly treatment was received, and your overall health.

• Hospital stays typically last several days for uncomplicated heart attacks. You’re monitored for dangerous rhythms, heart function is assessed, and medications are started and adjusted.
• Cardiac rehabilitation begins shortly after discharge and continues for weeks to months. These programs include supervised exercise gradually increasing your activity level, education about heart-healthy living, and counseling addressing the emotional impact of having a heart attack.
• Emotional recovery is as important as physical recovery. Anxiety and depression are common after heart attacks. Many people feel afraid of another heart attack, leading to excessive restrictions on activities. Others feel angry or in denial. Counseling and support groups help many people cope with these emotions.
• Most people can return to work within weeks to a few months, depending on job demands and how much heart muscle was damaged. Sedentary jobs allow quicker return than physically demanding ones.
• Sexual activity can usually resume within a few weeks if you feel ready and can climb two flights of stairs without symptoms.
• Driving restrictions typically last a few weeks, longer if serious complications occurred.
• Long-term outlook depends significantly on how much muscle was damaged. People with small heart attacks and good remaining heart function often live normal lifespans doing essentially everything they did before. Those with extensive damage and reduced heart function face chronic heart failure requiring lifelong treatment and activity modifications.
• Secondary prevention—preventing future heart attacks—is crucial. This means taking all medications as prescribed, never stopping them without consulting your cardiologist, making lifestyle changes including quitting smoking, eating a heart-healthy diet, exercising regularly, maintaining healthy weight, managing stress, and controlling blood pressure, cholesterol, and diabetes.
• Regular cardiology follow-up allows monitoring of heart function and medication adjustment.

Key Points

• A heart attack is a medical emergency where blood flow to heart muscle suddenly stops, causing that muscle to begin dying within minutes. Time is critical—the faster treatment begins, the more heart muscle is saved.
• Classic symptoms include chest pressure or discomfort, often described as an elephant sitting on the chest, lasting more than a few minutes or coming and going. Pain can radiate to arms, back, neck, jaw, or stomach.
• Women, older adults, and diabetics often have atypical symptoms without classic chest pressure. Any new, sustained symptoms including unusual shortness of breath, overwhelming fatigue, or upper stomach discomfort require evaluation.
• Call emergency services immediately at the first suspicion of heart attack. Don’t wait to see if symptoms improve, don’t drive yourself to the hospital, and don’t call your doctor’s office first—call 911. Paramedics begin life-saving treatment in the ambulance and notify the hospital so they’re ready when you arrive.
• Treatment effectiveness depends entirely on speed. Arteries should be opened within 90 minutes of arrival at the hospital, preferably within 60 minutes. This “door-to-balloon time” directly affects how much heart muscle survives.
• Modern treatments including emergency angioplasty with stenting can restore blood flow quickly, dramatically improving survival and recovery if performed promptly.
• After a heart attack, lifelong medications prevent future events. These include aspirin, other antiplatelet drugs, statins, beta-blockers, and ACE inhibitors or ARBs. Taking these medications consistently is crucial—they’ve been proven to reduce future heart attacks and improve survival.
• Lifestyle changes are as important as medications. Quit smoking immediately, eat a heart-healthy diet, exercise regularly, maintain healthy weight, manage stress, and control blood pressure, cholesterol, and diabetes.
• Cardiac rehabilitation significantly improves outcomes. These programs combine supervised exercise, education, and counseling, helping you recover physically and emotionally.
• Work closely with a cardiologist after a heart attack. Regular follow-up allows monitoring of heart function, medication adjustments, and assessment of your risk for future events. While a heart attack is a life-changing event, most people recover and live active, fulfilling lives with appropriate treatment and lifestyle modifications. The key is recognizing symptoms immediately and getting emergency treatment without delay, then following through with medications, lifestyle changes, and regular medical care to prevent future events and maintain the best possible quality of life.

Reference: Myocardial Infarction