What Happens During a Heart Attack? Symptoms, Causes, Heart Failure vs Heart Attack and Prevention

Every 33 seconds, someone in India dies from a cardiovascular disease. According to the Indian Heart Association, Indians experience heart attacks at a younger age than most other populations globally — with a significant proportion of first events occurring before age 50, and a growing number before age 40. For many patients in Pune, Pimpri Chinchwad, and across Maharashtra, the first indication of a problem is the heart attack itself — because the underlying coronary artery disease that causes it had no noticeable symptoms for years. A heart attack, clinically known as a myocardial infarction (MI), occurs when blood flow through one or more of the coronary arteries — the vessels that supply oxygenated blood to the heart muscle — is severely reduced or blocked entirely, causing the affected region of heart muscle to become ischaemic, damaged, and, if the blockage is not cleared quickly enough, to die. Understanding what happens during a heart attack, recognising the symptoms early, and knowing which blood tests to monitor before an event occurs are the three most important steps for anyone with cardiac risk factors in Pune. healthcare nt sickcare — an ISO 9001:2015 certified online medical laboratory with transparent pricing — offers cardiac risk blood panels with home sample collection and a direct walk-in facility.

What Happens During a Heart Attack? The Physiology Step by Step

A heart attack does not begin at the moment of chest pain. It begins years earlier, with a process called atherosclerosis — the gradual build-up of cholesterol-rich plaque inside the walls of the coronary arteries. Here is what happens, in sequence:

Stage 1 — Plaque Build-Up (Years Before the Event)

Low-density lipoprotein (LDL) cholesterol deposits in the arterial wall, triggering an inflammatory response. Over years, this deposit grows into a plaque — a mixture of cholesterol, calcium, cellular debris, and fibrous tissue — that narrows the coronary artery lumen and reduces blood flow. This phase is entirely silent; no symptoms are felt. This is why a lipid profile test and an hs-CRP test in your 30s and 40s — available at healthcare nt sickcare — provide genuinely life-saving early warning. Book: lipid profile test and hs-CRP test.

Stage 2 — Plaque Rupture (The Triggering Event)

The outer fibrous cap of the plaque becomes unstable — often triggered by sudden physical or emotional stress, a surge in blood pressure, or an inflammatory episode. When the cap ruptures, the fatty and inflammatory contents of the plaque are exposed directly to the bloodstream. This triggers the coagulation cascade: the body interprets the rupture as a vessel injury and responds by forming a blood clot (thrombus) at the site.

Stage 3 — Coronary Artery Blockage

The forming thrombus rapidly grows and may completely occlude the coronary artery within minutes. Blood flow to the section of heart muscle downstream from the blockage is cut off entirely. The heart muscle begins to experience ischaemia — oxygen and glucose deprivation — almost immediately.

Stage 4 — Myocardial Ischaemia and Damage

Within 20–40 minutes of complete occlusion, heart muscle cells in the affected region begin to die — a process called myocardial necrosis. This is the phase during which cardiac biomarkers — particularly troponin — are released into the bloodstream and become measurable in blood tests. Troponin elevation is the diagnostic hallmark of acute myocardial infarction in a hospital setting. Book: high-sensitivity troponin T test.

Stage 5 — Scar Formation and Cardiac Remodelling

After the acute event and restoration of blood flow (via emergency angioplasty or clot-dissolving medication), the damaged myocardial tissue heals as scar tissue. Scar tissue is less contractile and less electrically conductive than healthy heart muscle, which is why the long-term consequences of a heart attack — reduced ejection fraction, arrhythmia risk, and heart failure — depend heavily on how much muscle was lost and how quickly the blockage was cleared.

Heart Attack Symptoms — What to Recognise

The classic heart attack symptom is chest pain or pressure — described as tightness, squeezing, crushing, or a heavy weight on the chest — that may radiate to the left arm, jaw, neck, back, or stomach, lasting more than a few minutes or coming and going. However, many heart attacks — especially in women, diabetics, and elderly patients — present with atypical or "silent" symptoms:

• Chest discomfort or pressure — the most common symptom in men; may feel like indigestion in women
• Shortness of breath — with or without chest pain; may come on suddenly at rest
• Pain radiating to the left arm, jaw, or back
• Cold sweat, nausea, and lightheadedness
• Unexplained fatigue — particularly in women, fatigue in the days before a heart attack can be an early warning sign
• Silent MI — approximately 25% of heart attacks are clinically silent, detected only on ECG or blood tests. This is particularly common in diabetic patients whose neuropathy may blunt pain sensation

In India, emergency services should be called immediately if any combination of these symptoms persists for more than a few minutes. While awaiting emergency care, chewing a regular 325 mg aspirin tablet (if not contraindicated) slows clot formation and reduces infarct size.

Heart Attack Causes — Risk Factors and Lifestyle Causes

A heart attack is caused by the rupture of an atherosclerotic plaque in a coronary artery, followed by thrombotic occlusion — but the underlying plaque is the result of years of accumulated cardiovascular risk exposure, both genetic and lifestyle-driven. The most significant causes and risk factors in the Indian population include:

Lifestyle Causes of Heart Attack

• Smoking and tobacco use — accelerates endothelial damage and platelet aggregation; smokers have 2–4× the heart attack risk of non-smokers
• Sedentary lifestyle — physical inactivity is an independent predictor of cardiac events, especially relevant for Pune's desk-bound IT workforce
• High-fat, high-sugar diet — drives LDL elevation, triglyceride accumulation, and insulin resistance
• Chronic psychological stress — cortisol elevation raises blood pressure, promotes plaque instability, and accelerates clot formation
• Excessive alcohol consumption — raises blood pressure and triglycerides
• Obesity and abdominal fat — visceral fat (belly fat) is a direct contributor to insulin resistance and low-grade systemic inflammation, both of which accelerate atherosclerosis. Read: how to test for diabetes

Medical Causes and Risk Conditions

• Hypertension (high blood pressure) — damages arterial walls and accelerates plaque formation. Read: how to test for hypertension. Explore: hypertension test packages
• Hypercholesterolaemia (high LDL) — the primary driver of atherosclerotic plaque. Read: guide to cholesterol testing
• Type 2 Diabetes — triples cardiovascular risk through endothelial damage, dyslipidaemia, and prothrombotic effects. Watch: test for diabetes and heart disease
• Genetic risk factors — including ABO Haplotype 2, which elevates Von Willebrand Factor and thrombotic tendency. Read: what is Haplotype 2 and its link to heart attack risk

Heart Attack vs Heart Failure — What Is the Difference?

A heart attack is an acute event — a sudden blockage of a coronary artery that causes immediate death of heart muscle tissue. Heart failure is a chronic condition — a progressive inability of the heart to pump sufficient blood to meet the body's demands — that often develops as a consequence of one or more previous heart attacks, but can also result from hypertension, valvular disease, cardiomyopathy, or longstanding diabetes.

The key differences are timing and mechanism. A heart attack is an emergency that happens suddenly; heart failure develops over months to years. A heart attack is caused by arterial blockage; heart failure is caused by structural damage to the heart muscle that impairs its pumping function. The two are connected: a heart attack that destroys a significant portion of the left ventricular myocardium is one of the most common causes of subsequent heart failure. Testing for heart failure includes NT-proBNP — a biomarker released when the heart muscle is under stress. Book: NT-proBNP test. Also see: the difference between a heart attack and cardiac arrest.

Heart Attack Life Expectancy — What the Research Shows

Life expectancy after a heart attack depends on three factors: how much heart muscle was permanently damaged (infarct size), how quickly treatment restored blood flow, and how aggressively risk factors are managed after the event. Modern interventional cardiology — emergency angioplasty within 90 minutes of symptom onset — has transformed outcomes: survival rates have improved dramatically over the past two decades. However, long-term prognosis is strongly determined by post-event lifestyle and medication adherence. According to data from the Indian Registry of Acute Coronary Events (iRACE), the 30-day in-hospital mortality for acute STEMI (the most severe type) in Indian hospitals ranges from 8–12%. For survivors who follow post-infarct cardiac rehabilitation, maintain optimal LDL, HbA1c, and blood pressure, and take prescribed antiplatelet therapy, five- and ten-year survival rates are comparable to patients without a prior event.

Tips to Avoid a Heart Attack — What Blood Tests Tell You Before an Event?

Most of the lifestyle advice for heart attack prevention (no smoking, regular exercise, healthy diet, weight management) is well-known. What is less understood is the specific role of annual blood testing in quantifying and tracking individual cardiovascular risk — giving both patient and physician actionable data rather than generic advice:

• Keep LDL below 100 mg/dL (below 70 mg/dL if you already have cardiovascular disease) — monitor with annual lipid profile
• Keep HbA1c below 5.7% to avoid the pro-atherogenic effects of chronic hyperglycaemia. Book: HbA1c test
• Keep homocysteine below 15 µmol/L — elevated homocysteine damages arterial walls and is independently predictive of cardiac events. Book: homocysteine test
• Keep hs-CRP below 1 mg/L — a marker of arterial inflammation. Elevated levels double cardiac event risk independent of cholesterol levels
• Monitor blood pressure annually — aiming for below 130/80 mmHg. Read: how to test for angina pectoris

The cardiac risk markers test profile at healthcare nt sickcare covers multiple key cardiac biomarkers in a single booking. The Healthy Heart test profile and VitalCare Heart Health Checkup are comprehensive annual panels for anyone with cardiac risk factors. Explore the full cardiovascular health test collection.

Watch: What Happens During a Heart Attack?

People Also Ask About Heart Attacks

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