Slow-onset heart attack: the trickster that fools us


by Carolyn Thomas    @HeartSisters

As I’ve noted here previously, there were a number of very good reasons that I believed that Emergency Department physician who sent me home with an acid reflux misdiagnosis. Despite my textbook heart attack symptoms of central chest pain, nausea, sweating and pain down my left arm, these reasons included:

1.  He had the letters M.D. after his name;

2.  He misdiagnosed me in a decisively authoritative manner;

3.  I wanted to believe him because I’d much rather have indigestion than heart disease, thank you very much;

4.  The Emergency nurse scolded me privately about my questions to this doctor, warning me: “He is a very good doctor, and he does not like to be questioned!”  (The questions I’d been asking included, not surprisingly: “But Doctor, what about this pain down my left arm?”);

5.  Most of all, what I had always imagined a heart attack looking like (clutching one’s chest in agony, falling down unconscious, 911, ambulance, sirens, CPR) was not at all what I was experiencing. Instead, despite my alarming symptoms, I was still able to walk, talk, think and generally behave like a normally functioning person, i.e. one who is definitely NOT having a heart attack!*

So it all made sense to me as I was being sent home from Emergency that day, feeling very embarrassed because I had clearly been making a big fuss over nothing.

My experience, however, might have been what researchers in Ireland refer to as “slow-onset myocardial infarction”.  

Dr. Sharon O’Donnell, lead author of a study published in the Journal of Cardiovascular Nursing, interviewed heart attack survivors in Dublin between 2-4 days following their hospital admission. She explained in her paper that slow-onset MI is the gradual onset of relatively mild heart attack symptoms, while fast-onset MI describes the immediate onset of sudden, continuous, and severe heart attack symptoms, particularly chest pain. (1)

”      Over 60 per cent of our study’s participants experienced slow-onset MI, but had expected the severe symptoms associated with fast-onset MI. The mismatch of expected and experienced symptoms for participants with slow-onset MI led to both their mislabeling of symptoms to a non-cardiac cause, as well as protracted help-seeking delays.”

Study participants who had experienced the more severe symptoms of fast-onset MI, however, quickly chalked up their symptoms to a cardiac cause, which meant significantly faster decisions to seek medical help.

This makes perfect sense.  No wonder we wait far longer than we should in mid-heart attack when we’re experiencing non-severe or atypical cardiac symptoms. As Dr. O’Donnell explained:

“Educational information provided to the public needs to be reviewed. Slow-onset MI and fast-onset MI provide plausible definition alternatives, and possibly a more authentic version of real MI events than what is currently used. They also provide a unique ‘delay’ perspective which may inform future educational initiatives targeted at decision delay reduction.”

She also pointed out that both slow-onset and fast-onset presentations are associated with uniquely distinct behavioral patterns that significantly influence how long that important pre-hospital delay turns out to be. With slow-onset symptoms, patients can wait dangerously longer than they should (believing symptoms to be “nothing serious”) while in fast-onset, patients seek emergency help faster because severe symptoms convince them that “this IS serious!”

In a later follow-up study published in the Journal of Emergency Medicine, Dr. O’Donnell  looked at the phenomenon of slow-onset symptoms among patients presenting to hospital with Acute Coronary Syndrome (ACS) – a term used for any condition brought on by sudden, reduced blood flow to the heart muscle – including heart attack or unstable angina. (2)

Out of almost 900 ACS patients studied, she and her team found that 65% of them experienced slow-onset symptom presentation.  And just like her earlier study, this group of patients had been significantly more likely to wait longer at home before going to hospital to seek emergency help (3.5 hours, vs. 2 hours for those with fast-onset symptoms).
I’m particularly interested in treatment-seeking delay, because I personally became the all-time unofficial poster child for this phenomenon.  After being misdiagnosed and sent home from hospital – embarrassed and humiliated – on that fateful day, it took me two full weeks before I finally returned to Emergency – and only because my increasingly debilitating bouts of continuing cardiac symptoms had by then become truly unbearable.  Well, that plus the fact that I could no longer walk five steps without having to stop because of pain.
Most of us are socialized from childhood to not make a fuss over every little twinge or ache.  We regularly dismiss all kinds of suspicious symptoms because they frequently do get better on their own, or after a good night’s sleep.  Or we simply become used to putting up with symptoms as merely the annoyance of getting older. Or because a Real Life Doctor tells us we’re fine. (And really, if we rushed to Emergency over every single bubble and squeak, our health care systems would be even more impossibly overwhelmed).
Careful consideration of new or puzzling symptoms is important – but so is knowing when to get help.
Most heart attacks do start slowly. Most involve discomfort in the center of the chest that lasts more than a few minutes, or symptoms that go away and come back later over hours or even days as mine did. Cardiac symptoms can feel like uncomfortable pressure, squeezing, tightness, fullness as well as pain. Around 8-10% of women (some studies suggest that could even be as high as 40%) experience no chest symptoms at all in mid-heart attack – instead reporting signs like crushing fatigue, shortness of breath, pain in either or both arms, jaw, throat, shoulders, or nausea/vomiting.(3)
Ironically, even the most painful cardiac symptoms don’t necessarily mean more serious heart muscle damage than less severe pain does.
Not surprisingly, it’s very common for those people affected to feel unsure about what’s wrong with them, and then to wait too long before getting help.  See also: How women can tell if they’re headed for a heart attack
So we silently monitor any new aches or pains, tallying them on an invisible abacus, ranking their severity on a secret leaderboard. It’s often only when we can no longer stand to quietly tolerate the intolerable that we force ourselves to pro-actively seek help. But this delay can be a dangerous and often deadly decision if those symptoms are due to a cardiac event.
And those slow-onset symptoms are the easiest to ignore. When that Emergency physician told me to see my family physician for an antacid prescription, well, that was all I needed to hear.  Nobody had to tell me twice.  When I returned home that morning, I dutifully called my family doc’s office as directed, made an appointment for two weeks down the road when she’d be back from vacation, and then got right on with the rest of my life.
And when the cardiac symptoms returned two days later (of course they did!), this time while sitting quietly at my desk at work, I knew instantly there was no way I was going back to Emergency. Hadn’t a highly trained, experienced physician told me in a decisively authoritative manner:
“You’re in the right demographic for acid reflux!”
And when those same cardiac symptoms kept on returning (of course they did!), I began to normalize them even as they grew increasingly debilitating: This must just be what acid reflux is like.  How can other people with acid reflux stand this?  Acid reflux is BRUTAL.  Where’s my Gaviscon . . . ?
Most other studies that investigate treatment-seeking delay behaviours in heart patients have tended to overlook slow-onset symptoms.  See also: Downplaying symptoms: just pretend it’s NOT a heart attack

 The bottom line:

If you are experiencing symptoms that might be signs of a heart attack (whether they’re slow- or fast-onset!), call 9-1-1 or your emergency response number. As with men, women’s most common heart attack symptom is chest pain or discomfort. But women are somewhat more likely than men to experience some of the other common symptoms, particularly shortness of breath, unusual and extreme fatigue, nausea/vomiting, and back/throat/jaw pain. . Learn these signs, but remember this: even if you’re not sure it’s a heart attack, get checked out by a physician.
(1) O’Donnell, S. et al.  Slow-Onset Myocardial Infarction and Its Influence on Help-Seeking Behaviors. Journal of Cardiovascular Nursing, August 2012. Volume 27  Number 4. Pages 334 – 344.
(2) O’Donnell, S. et al. Slow-onset and fast-onset symptom presentations in acute coronary syndrome (ACS): new perspectives on prehospital delay in patients with ACS. J Emerg Med. 2014 Apr 11; 46(4):507-15.
(3) S. Dey et al, “GRACE: Acute coronary syndromes: Sex-related differences in the presentation, treatment and outcomes among patients with acute coronary syndromes: the Global Registry of Acute Coronary Events”, Heart  2009;95:1 2026.


NOTE FROM CAROLYN:   I wrote much more about women’s heart attack symptoms (slow and otherwise) in Chapter 1 of my book, A Woman’s Guide to Living with Heart Disease” . You can ask for it at your local bookshop, 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).



   Q:  Did you or somebody you care about wait too long before seeking help because of ‘slow-onset’ symptoms?

* My own misconception about what a heart attack really looks like was actually more like sudden cardiac arrest (an electrical problem) than a heart attack (a plumbing problem!)
See also:

When heart attack symptoms disappear – and then return

This is NOT what a woman’s heart attack looks like

How to communicate your heart symptoms to your doctor

The symptomatic tipping point during heart attack

“You’ve done the right thing by coming here today”

The heart patient’s chronic lament: “Excuse me. I’m sorry. I don’t mean to be a bother…”

Why we ignore serious symptoms

Denial and its deadly role in surviving a heart attack

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


109 thoughts on “Slow-onset heart attack: the trickster that fools us

  1. My wife complained of fatigue and shortness of breath and said she had indigestion bad for 2 weeks. Then one night she said she needed to go to hospital, said she could not breathe. I called 911, fire department got there first. They did CPR and put a hole in her throat trying to get her air, unfortunately I lost my wife.

    They said she had lungs full of fluid and a heart attack. Could this have been prevented? She also had small veins, they tried to put stents in 15 year ago, said veins were too small.


    1. Oh, Roger. I’m so sorry for your loss.

      There’s no way of knowing for sure of course if this tragedy could have been prevented or not. It sounds like your wife has had heart issues for at least 15 years since the stent discussion happened.

      Sometimes, serious conditions can take a long time to develop without the person even realizing something is very dangerously wrong. And some of us delay seeking prompt medical help because symptoms “don’t feel that bad.”

      My condolences to you and all of your family on the tragic death of your wife.


  2. Because of this article I am in the ER now. I have had many symptoms for 6 days. I am waiting on results from blood work, chest X-ray, ECG. Thank you SO much for urging people to go. Had I not read this, I wouldn’t have come. Thanks again.

    Liked by 1 person

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