What Causes a Heart Attack? Cardiologist Explains the Silent Process Inside Arteries
A heart attack may appear sudden and dramatic, but in reality, it is the result of a slow, silent process that unfolds over years. Understanding what happens inside your arteries long before symptoms appear can help in early prevention.
In a conversation with HT Lifestyle, Dr Asseem Dhall, Director and Head of Cardiac Sciences at ISIC Multispecialty Hospital, explained that a heart attack is often the culmination of a “lengthy process” occurring quietly within the body.
What Happens Inside the Arteries?
Contrary to common belief, a heart attack doesn’t begin at the moment of chest pain. It starts much earlier with damage to the inner lining of the arteries.
Arteries are not just hollow tubes—they have a delicate inner lining made of living tissue. Over time, this lining can get damaged due to factors like high blood pressure, high cholesterol, smoking, and uncontrolled blood sugar.
In response, the body tries to repair this damage by depositing fatty substances along the artery walls. Over the years, this buildup hardens into plaque in a condition known as Atherosclerosis.
The Silent Build-Up
As plaque accumulates, it gradually narrows the arteries, restricting blood flow. What makes this process dangerous is that it often develops without any noticeable symptoms—even as early as a person’s twenties.
Many people remain unaware that their arteries are slowly becoming compromised.
What Actually Triggers a Heart Attack?
A heart attack doesn’t occur simply because arteries are narrowed. The real danger arises when plaque becomes unstable and ruptures.
When this happens, the body quickly forms a blood clot at the rupture site. If the artery is already narrowed, the clot can completely block blood flow. Without oxygen, the heart muscle begins to die—leading to a heart attack.
This means that even arteries that are not severely blocked can still trigger a cardiac event if the plaque is unstable.
Risk Factors That Worsen the Condition
Several lifestyle and health factors can accelerate plaque formation and increase the risk of rupture, including:
- High LDL cholesterol
- Uncontrolled blood pressure
- Smoking
- Diabetes
- Chronic stress
- Lack of physical activity
- Excess body weight
These factors often work silently, damaging arteries over time without obvious warning signs.
Early Warning Signs to Watch
Before a heart attack, the body may give subtle signals that are often ignored, such as:
- Unexplained fatigue
- Chest pain during exertion
- Shortness of breath
- Pain in the arm, jaw, or upper back
Prevention Is Key
Since a heart attack is the result of a long-term process, prevention plays a crucial role. Dr Dhall advises managing blood pressure and cholesterol, maintaining a healthy diet, exercising regularly, and avoiding smoking.
Regular monitoring of blood pressure, cholesterol, and blood sugar levels can also help detect risks early and protect heart health.


