What I wish I knew back then: “What happens to heart muscle during a heart attack?”

by Carolyn Thomas    ♥   @HeartSisters

Researchers tell us that women wait significantly longer than our male counterparts to seek medical help – yes, even in mid-heart attack!  In fact, trying to figure out WHY women wait dangerously longer than we should has become a unique field of cardiac study on what’s known as “treatment-seeking delay behaviour“.

“What I Wish I Knew Back Then”  is a back-to-basics summer series of posts here on Heart Sisters that will revisit some of the most frequently asked questions from new heart patients. Today, Part 2 continues with another basic that often accompanies a heart attack: “What happens to heart muscle if I wait too long to get urgent help?” 

First, a wee anatomy refresher:  cardiac muscle (also called myocardium) is one of three distinct types of muscle in our bodies, along with skeletal muscle (attached to our bones and, in some areas, our skin – like the muscles in our faces, for example) and smooth muscle (found in the walls of our hollow organs like the bladder, stomach, intestines, lungs, etc).

Cardiac muscle makes up the thick middle layer of the heart, in charge of pumping blood out and then relaxing to let blood back in. This amazing muscle is known as the hardest-working in the human body.

I like how Dr. Sian Harding – a cardiac researcher, professor of medicine and author of the fascinating book called The Exquisite Machine  – describes the heart’s pumping role:

“The heartbeat needs to squeeze out blood strongly enough to circulate around the whole body, so the heart muscle must generate strong and rapid force. However, it’s also very important for the heart to relax quickly in between beats; otherwise, there is not enough time for it to fill with blood before the next beat. The faster it can do this, the more efficient the beat.”

Here’s why it’s so important to call 911 immediately if you think you might be having a heart attack. A heart attack (or myocardial infarction) is the result of heart muscle cells dying due to something blocking the flow of oxygenated blood supply to that muscle. This blockage is most often due to a buildup of plaque in coronary arteries (a process called atherosclerosis).  Plaque is made up of fatty particles, cholesterol, cellular waste products and other yuck that can take years to build up. But if a plaque ruptures, a blood clot can quickly form inside the artery – which may cause a heart attack. In about 5 per cent of heart attacks, blood flow to the heart muscle can be blocked not by a blood clot, but by a spasm in a coronary artery.

So if this oxygenated blood supply to the heart muscle is severely blocked, irreversible damage may begin within minutes. This damage means that the heart muscle affected by a lack of blood flow can no longer work as it should – and permanent scar tissue can begin to form. Depending on the location of the blocked coronary artery and how much heart muscle is deprived of oxygenated blood flow downstream from that blockage, disability, sudden cardiac arrest, or death can result.

Unlike skeletal muscles of the body (which can often repair themselves after an injury), the heart can’t quite promise that same result. If you pull your calf muscle, for example, it will slowly begin to heal itself within a few days. The heart may have some ability to heal itself, but this regeneration can’t typically fix the kind of heart muscle damage caused by a heart attack, as Dr. Harding further explains:

“In someone aged 75, individual cardiac muscle cells would have been beating for 75 years continuously, more than two billion contraction/relaxation cycles. This is perfection on an almost unbelievable scale. There would be a tiny smidgeon of regeneration too (about half a per cent of these cells are renewed in one year). That’s just enough to cover you for cell loss due to general wear and tear, the daily grind of anxiety and effort, starvation and natural insults. But it is nowhere near enough for the train wreck of severe cardiac disease. The body’s defenses are completely overwhelmed by the massive destruction of a heart attack.”

Time equals muscle, as cardiologists like to say about that heart muscle.

Immediate medical intervention – ideally within the first hour following the onset of cardiac symptoms – is aimed at restoring adequate blood flow to that battered heart muscle to minimize damage. This intervention may include:

• invasive procedures (opening up the blocked arteries with the help of a coronary stent or bypass graft surgery)
• optimal medication management of the condition in lower-risk patients (e.g. beta blockers, calcium blockers, statins, aspirin therapy, and forms of nitroglycerin)
• thrombolytic therapy (the use of medications to break up or dissolve blood clots in the case of either heart attack or stroke)

Again, no matter what the treatment recommendation of the cardiologist may be, the faster you are medically assessed and a treatment plan is put into place, the better. Researchers point to women’s treatment-seeking delay behaviour as one reason our cardiac outcomes tend to be more deadly than men’s. Women tend to wait too long to ask for help in the first place.

But here’s another reason:  women are significantly more likely to be misdiagnosed in mid-heart attack compared to our male counterparts. The European Society of Cardiology reported a 2021 study, for example, that found physicians are significantly more likely to consider heart disease as the cause of chest pain in men compared to women.(1)  This gender bias was maintained “regardless of the number of risk factors or the presence of typical cardiac chest pain in women. And women with cardiac symptoms were significantly more likely than men to present late to the hospital (defined as waiting 12 hours or longer after symptom onset).”

One of this study’s authors, Dr. Gemma Martinez-Nadal, added that physicians and women alike need to be far more aware of this implicit gender bias:

“The low suspicion of heart attack occurs in both women themselves and in physicians – leading to higher risks of late diagnosis and misdiagnosis.”

The key take-away message here: women cannot control the existing systemic bias in medicine, but we  do have control over our personal decision to seek immediate care for symptoms we believe are heart-related.

More details on those specific warning symptoms in Part 1 of this series: What I Wish I Knew Back Then:  Am I Having a Heart Attack?

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Sources:  Dr. Sian Harding, Harvard University, European Society of Cardiology,  Mayo Clinic, Cleveland Clinic, British Heart Foundation, Heart & Stroke Foundation

Floral image: Debannja, Pixabay

© 2023 Carolyn Thomas  www.myheartsisters.org

1.  “Stress, Psycho-Social and Cultural Aspects of Heart Disease: Cardiovascular Disease in Women.” 12 March 2021. Acute CardioVascular Care 2021, European Society of Cardiology (ESC).

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Coming up next Sunday: “6 Reasons Women Delay Seeking Help During a Heart Attack”

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NOTE FROM CAROLYN:  My book “A Woman’s Guide to Living with Heart Disease“ reads like the“Best Of” Heart Sisters blog archives.  You can ask for it at your local library or bookstore (please support your favourite independent bookseller!) or order it online (paperback, hardcover or e-book) at Amazon – or order it directly from my publisher Johns Hopkins University Press (use their code HTWN to save 30% off the list price).

See also:

Women’s heart disease: an awareness campaign fail?

‘Knowing & Going’ – act fast when heart attack symptoms hit

Women fatally unaware of heart attack symptoms

Is it heartburn or heart attack?

What is causing my chest pain?

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