A 90% blocked artery that feels like nothing. A heart attack with a “normal” ECG. In this exclusive conversation with Know Your Doctor Magazine, Dr. Rashi Khare, Cardiologist, separates the myths from the warning signs and shares the one rule that could save your heart before it has to fight for its life.
1. Can a person have a 90–100% heart blockage and still feel completely normal? How is that possible?
Yes. A person can sometimes have a very severe coronary artery blockage without obvious symptoms.
The key is that the percentage of blockage seen on an angiogram does not always directly predict how a person feels.
If a coronary artery gradually becomes narrowed over months or years, the heart may have time to adapt. The body can develop collateral blood vessels—small alternative pathways that help deliver blood around the severely narrowed area. Because the narrowing develops slowly, the person may also unconsciously reduce activity or adapt to exertion.
Another important point is that not every 90–100% blockage produces symptoms at rest. A person may feel completely comfortable sitting, sleeping or doing light activity, but develop symptoms only when the heart needs more oxygen—for example, during brisk walking or climbing stairs.
There is also a condition called silent ischaemia, in which reduced blood supply to the heart occurs without the classic chest pain. This is particularly important in people with diabetes and some older adults.
However, a completely blocked artery can sometimes be an emergency, particularly when the blockage is acute—for example, when a cholesterol plaque ruptures and a blood clot suddenly forms.
So, “I feel perfectly normal” does not guarantee that the coronary arteries are normal.
2. Can a heart attack strike someone who has a completely normal ECG and routine health reports?
Yes.
A routine ECG is extremely useful, but it is essentially a snapshot of the heart’s electrical activity at that moment. It does not directly show whether a coronary artery has a dangerous plaque.
Some heart attacks—especially certain early or smaller heart attacks—may not initially produce the classic ECG changes.
Similarly, routine blood tests such as cholesterol, blood sugar and kidney function can be completely normal while a person still has coronary plaque.
Even more importantly, a heart attack can develop suddenly. A person might have a plaque that has been relatively stable for years. If that plaque suddenly ruptures, the body’s clotting system can form a thrombus over it and abruptly reduce or completely stop blood flow.
That’s why doctors don’t diagnose or exclude a heart attack based on one normal ECG alone.
When someone has concerning symptoms, doctors may use:
Repeat ECGs
High-sensitivity troponin blood tests
Clinical examination
Echocardiography, when appropriate
Coronary CT angiography or invasive coronary angiography in selected situations
So, the message is:
A normal check-up is reassuring, but it is not a lifetime guarantee against a heart attack.
3. How do you tell the difference between acidity, anxiety and the early warning signs of a heart attack?
This is one of the most difficult questions because there can be significant overlap.
Heart-related discomfort can feel like:
Pressure
Tightness
Heaviness
Burning
Indigestion
Discomfort in the upper abdomen
It can sometimes radiate towards the arm, shoulder, back, neck or jaw.
Symptoms that become concerning include discomfort that:
Occurs with exertion
Keeps returning
Is associated with sweating
Comes with breathlessness
Causes nausea or vomiting
Is accompanied by unusual weakness or dizziness
Feels like pressure or squeezing rather than a brief, pinpoint pain
But there is an important warning:
You cannot reliably diagnose “gas” versus “heart” based only on how the sensation feels.
Anxiety can produce chest tightness, rapid heartbeat, breathlessness and a feeling of impending danger. Acid reflux can cause burning chest discomfort. A heart problem can sometimes feel exactly like indigestion.
Therefore, if someone has new, unexplained or significant chest discomfort, particularly with breathlessness, sweating, faintness or radiation to the arm, jaw or back, it should be treated seriously rather than automatically labelled as acidity or anxiety.
4. Why are seemingly healthy people in their 20s and 30s suffering heart attacks today—and who is actually at risk?
Heart attacks in younger adults are less common than in older adults, but they certainly occur.
The important point is that looking healthy isn’t the same as having low cardiovascular risk.
Risk can come from:
Smoking or tobacco exposure
High LDL cholesterol
Diabetes or insulin resistance
High blood pressure
Obesity
Strong family history of premature coronary disease
Physical inactivity
Poor sleep
Chronic stress
Certain inflammatory or autoimmune conditions
Some inherited lipid disorders, particularly familial hypercholesterolaemia
Certain drugs or stimulants
There are also situations where a heart attack doesn’t come from the traditional gradual cholesterol blockage. For example, coronary artery spasm, spontaneous coronary artery dissection or other less common conditions can cause an acute coronary event.
Family history deserves particular attention. Someone can be young, physically active and apparently healthy while carrying very high inherited LDL cholesterol.
That’s why prevention shouldn’t simply be:
“I exercise, therefore I’m safe.”
A better approach is knowing your blood pressure, cholesterol profile, blood sugar status, smoking or tobacco exposure and family history, and discussing unusual or significant risk factors with a doctor.
5. If a blockage is found, does it always mean you need a stent?
No. Absolutely not.
Finding a blockage does not automatically mean that a stent should be inserted.
Doctors consider several things:
1. Is the blockage actually causing ischaemia?
A narrowing may look severe on an angiogram but may not be responsible for a significant reduction in blood flow in some circumstances.
2. Where is the blockage?
The location matters enormously. A lesion involving an important major vessel may have different implications from a smaller branch vessel.
3. How severe is the disease overall?
4. Is the patient having an acute heart attack or stable coronary disease?
5. Would bypass surgery be better?
6. Can medication and lifestyle treatment control the condition safely?
In stable coronary artery disease, many patients can be managed with optimal medical therapy, including appropriate cholesterol-lowering treatment, blood-pressure control, diabetes management when needed, exercise, dietary measures and smoking cessation.
Stents are extremely valuable when appropriately indicated—particularly in acute coronary syndromes and in selected patients with significant, symptomatic or ischaemia-producing disease.
But:
“Blockage found = stent required” is an incorrect equation.
The decision should be based on the patient’s symptoms, anatomy, physiology, clinical situation and overall risk.
6. What actually happens inside the heart during a heart attack, and why does every minute matter?
A heart attack usually occurs when blood flow through a coronary artery becomes critically reduced or completely blocked.
A common mechanism is:
Atherosclerotic plaque → plaque disruption → blood clot formation → coronary artery obstruction → reduced oxygen delivery to heart muscle.
The heart muscle supplied by that artery suddenly doesn’t receive enough oxygen.
If blood flow isn’t restored, heart muscle cells begin to become injured and can eventually die.
That’s why doctors use the phrase:
“Time is muscle.”
The longer the heart remains without adequate blood supply, the greater the potential amount of irreversible myocardial damage.
A heart attack can also cause dangerous complications such as:
Abnormal heart rhythms
Reduced pumping function
Cardiogenic shock
Mechanical complications
Cardiac arrest
Rapid recognition and restoration of blood flow—when indicated—can limit myocardial injury and improve survival.
This is why someone with symptoms suggesting an acute coronary syndrome shouldn’t spend hours trying different home remedies or waiting to see whether the discomfort disappears.
7. Can intense stress, anger, lack of sleep or sudden physical exertion actually trigger a heart attack?
They can contribute, particularly in someone who already has underlying cardiovascular disease.
Strong emotional stress can increase sympathetic nervous system activity, causing increases in heart rate, blood pressure and stress hormones.
Sudden intense physical exertion can similarly place a substantial demand on the cardiovascular system.
For a person with vulnerable coronary plaque, these physiological changes may contribute to plaque disruption and an acute coronary event.
There is also a recognised phenomenon sometimes called “broken-heart syndrome” (Takotsubo syndrome), in which severe emotional or physical stress can temporarily weaken the heart. It is different from a typical coronary blockage heart attack, although it can look similar clinically.
But we should be careful about the message.
The answer isn’t:
“Never exercise because exercise can trigger a heart attack.”
Regular, appropriately prescribed physical activity is one of the most important ways to reduce cardiovascular risk.
The concern is particularly about unaccustomed, extreme exertion, especially in someone with undiagnosed cardiovascular disease.
Likewise, chronic sleep deprivation and persistent psychological stress are important health issues, but they don’t mean that every stressful day causes a heart attack.
8. After a stent, is the heart “fixed”, or can a person still have another heart attack?
A stent treats a specific narrowed or blocked section of a coronary artery.
It does not remove the underlying tendency to develop atherosclerosis.
Think of it this way:
The stent treats the traffic jam; it doesn’t eliminate the road-building problem.
A person can still develop:
New plaque elsewhere
Progression of existing coronary disease
Stent-related complications, although modern stents have made these much less common
Another heart attack
That’s why treatment after PCI remains extremely important.
Depending on the individual situation, this may include:
Appropriate antiplatelet medication
Aggressive cholesterol management
Blood-pressure control
Diabetes management
Smoking or tobacco cessation
Regular physical activity
Heart-healthy nutrition
Cardiac rehabilitation, when appropriate
Long-term medical follow-up
One of the biggest mistakes is thinking:
“My stent is in, so I can go back to everything I was doing before.”
The stent is an important part of treatment, but secondary prevention is what protects the patient going forward.
9. What is the one symptom people most commonly dismiss before a heart attack that they should never ignore?
If I had to choose one particularly important symptom, it would be:
New or unexplained chest pressure or discomfort—especially if it occurs with exertion or is associated with breathlessness, sweating, nausea or unusual weakness.
People often describe it as “gas”, “indigestion”, “acidity” or “something I ate”.
But there isn’t one universal symptom that appears before every heart attack.
Some people have classic chest discomfort. Others may primarily experience breathlessness, unusual fatigue, upper abdominal discomfort, nausea or discomfort in the arm, back, neck or jaw.
And some heart attacks occur without obvious warning symptoms at all.
Therefore, the most important rule isn’t memorising one symptom.
It’s recognising a new, unexplained or concerning change from your normal state and not dismissing it automatically.
If symptoms are severe, persistent, worsening or associated with fainting, significant breathlessness, sweating or other concerning features, urgent medical assessment is appropriate.
10. If you could give every person just one rule to protect their heart and prevent a heart attack, what would it be?
If I had to reduce cardiovascular prevention to one principle, I’d say:
Know your cardiovascular risk early—and actively control it before you develop symptoms.
Don’t wait for chest pain to start taking care of your heart.
Know your:
Blood pressure
LDL cholesterol
Blood sugar/HbA1c, when appropriate
Smoking or tobacco exposure
Family history
Weight and physical activity pattern
And then act on abnormal findings.
The biggest cardiovascular risk factors are often silent. High blood pressure doesn’t necessarily cause symptoms. High LDL doesn’t necessarily cause symptoms. Diabetes can exist for years before someone feels unwell.
So, prevention isn’t simply about taking a test once and saying, “Everything is normal.”
It’s about maintaining cardiovascular health over decades.
And perhaps the most important practical rule is:
Never ignore a new or unexplained symptom simply because you consider yourself “too young” or “too healthy” to have a heart problem.
Early recognition, prevention and appropriate treatment can make an enormous difference.
Bottom line: A heart attack is often the final event in a disease process that may have been developing silently for years. The goal of modern cardiology isn’t just to treat the heart attack—it is to identify risk early, prevent the first event and prevent the next one.
BLURB:
“I feel perfectly normal” does not guarantee that the coronary arteries are normal.
“Blockage found = stent required” is an incorrect equation.
Know your cardiovascular risk early—and actively control it before you develop symptoms.