We have heard various opinions about the seriousness of myocarditis and pericarditis. The different ideas range from being something mild that usually passes without a problem, to be very serious. But Dr Dulce Brito, a cardiology specialist, warns that these are often silent and may go unnoticed.
In conversation with The Blind Spot, Dr Dulce Brito, a cardiologist at Santa Maria Hospital and assistant teacher of cardiology at the Faculty of Medicine, University of Lisbon, spoke to us about the severity of myocarditis and pericarditis and their frequency in post-covid and post-vaccine situations.
Dr Dulce Brito highlighted that the actual incidence of myocarditis is difficult to assess, but that the disease often affects young people more.
She also made it clear that even in the pre-covid era cases coded as “myocarditis” are not many and believes that many situations in the general population will go undetected.
The cardiology specialist points out that in post-vaccine cases, myocarditis may be more frequent after the second dose, in young people, based on a recently published study and that “the immune response plays a key role in the pathogenesis of inflammation of the heart”.
In fact, both in natural infections and after vaccination, the body’s own defences can become “aggressors” and when the person is younger the immune response is very defensive.
What is the percentage of severe cases of myocarditis and pericarditis today?
I do not have figures, and these will be difficult to estimate in any context, as in most cases affected patients will have nonspecific and mild symptoms and self-limited duration. Thus, they will easily go unnoticed and will not feel the need to seek a hospital. The actual incidence of myocarditis is difficult to assess. As I said, there are a few more serious cases, and these seek hospital support. Myocarditis often affects young people, appears in the course of a viral infection, and can cause chest pain, sometimes simulating myocardial infarction. Other times it can be expressed by heart failure or even arrhythmias. Personally, I do not recall having had any serious cases admitted in the last year.
“Most cases progress well and, in a few days only, as I mentioned, but in fact, it is always unpredictable, and vigilance is necessary.”
As I mentioned, myocarditis generally has a benign evolution, with mild symptoms and of short duration (a few days), since the organic defences (immune defence response) “win the battle”. And the aggression (generally viral) can be caused by many viruses, even by the most common ones, associated with the common “cold” with flu-like manifestations, muscular pain and sometimes also chest pain (which is often transient and little appreciated). However, the infection can also be in the heart (myocarditis) and leave sequelae that will manifest later. When symptoms bring the patient to the doctor and myocarditis is a possible diagnosis, hospital admission is indicated because not only is it necessary to carry out tests to confirm the diagnosis, but also to monitor the patient. Most cases evolve well and in just a few days, as I mentioned, but in truth, it is always unpredictable, and vigilance is required.
In very rare cases, for example from influenza or other viruses, myocarditis or pericarditis can result in sudden death?
The evolution of a cardiac inflammation situation (myocarditis) is unpredictable. And being unpredictable, arrhythmias and sudden death can occur. We say they are rare situations because they don’t really come into our view. But I don’t know if they are such rare situations. It should be noted that, especially when practising sport, care should be taken with “simple colds” that occur with fever or fever and muscular pains. Exercising in these situations could have serious consequences, as it could be a viral infection in which the heart could also be involved.
“(…) dilated myocardiopathy”
But a serious and frequent form of heart disease is dilated cardiomyopathy. The heart does not contract as it should and is usually dilated. One of its causes (and possibly one of the most frequent) is precisely a previous viral infection. Sometimes it takes years to set in and the heart weakens, dilates, and starts to function poorly, leading to chronic heart failure. Other times the process is quicker, and it sets in within days or weeks. Sometimes, after the acute infection, everything returns to normal. But when the process is chronic there is no return to the previous state.
One of the expressions that is commonly used to describe these sequelae is scarring. Does it make sense?
Yes, dilation and the evolution towards the chronic “dilated cardiomyopathy” phase often occurs because after the acute phase of inflammation, “scars” (fibrosis) are formed, and areas of the heart muscle no longer function or contract. The non-affected areas of the heart try to compensate for the more deficient areas, and there is an attempt at cardiac adaptation to the new situation. This adaptation often leads to dilation and, overall, to poor cardiac function and worse contractility of the heart. Not only inflammation in the acute phase can give fatal arrhythmias, but fibrosis (“scarring”) can also lead to severe arrhythmias, as well as heart failure.
What is your opinion on the frequency of post-covid and post-vaccine myocarditis?
Obviously, a Covid-19 infection can give myocarditis as well as the vaccine. And the literature has been very rich in publications on this topic. However, I would like to cite a very recent paper (published in The Lancet, April 2022) in which a systematic review with meta-analysis of 22 studies found no significant difference in the incidence of myopericarditis pre-covid, pre-vaccine or post-vaccine. In post-vaccine cases and especially after the second dose, inflammatory heart disease has been shown to be more frequent in young people and males.
It is more noticeable in the second dose of the vaccine, that is, it is a situation in which the person was exposed once to the vaccine, then exposed a second time and their own defences, their own acquired immunity is what can be largely responsible for the inflammation. Moreover, autoimmune mechanisms are sometimes responsible for the perpetuation of inflammation after common virus myocarditis and in many situations of pericarditis or myopericarditis, there may be a recurrence of the infection.
“(…) the person was exposed once to the vaccine, then they have exposed a second time and their own defences, their own acquired immunity is what may be largely responsible for the inflammation.”
One of the issues that is usually noticed is a big difference namely in relation to the adverse effects of vaccination. There is a very big difference between younger people, namely men, but also for older people. Is there a mechanism or evidence that this is naturally so?
A viral infection triggers an inflammatory defence response. This is natural and just as well because otherwise we would die with every infection! However, depending on the attacking virus (its characteristics, its ‘attack power’, its load) and the host (greater or lesser defence capacity, greater or lesser fragility, other concomitant diseases, age, etc.), this defence response will not be the same. And that response manifests itself in symptoms, in complaints. Young people respond more exuberantly, they have more robust defences (if they are healthy), older people generally respond weaker, and the defence response is more “blunted”. And we cannot forget that age brings more associated pathologies, which weaken the individual, making him “at greater risk” in terms of the consequences of aggression, namely if he has previous cardiovascular pathology.
The vaccine stimulates immunity in a much more controlled way than natural viral infection. And the same factors I expressed above in terms of differences in immune response between younger and older individuals also apply.
“Young people respond more exuberantly, have more robust defences (if healthy), older people generally respond weaker (…)”
We are talking about myocarditis and pericarditis, but are there any other infections that have a significant impact, such as endocarditis?
If we are talking about viruses, the situations you are referring to now are totally different. The cause of endocarditis (which is always a serious situation) is usually bacterial, not viral. Myocarditis and/or pericarditis are usually viral (although they can also be caused by other agents). Endocarditis is an infection of the innermost structures of the heart. It may also involve the myocardium and even the pericardium (“pancarditis”), but this is not common.
In terms of diagnosis, when myocarditis is diagnosed what is the mortality rate?
The mortality rate is low, but I doubt you will find figures that reflect the global reality. There are, however, some figures from individual cases and they can give a rough idea of the reality. In the Portuguese Registry of Myocarditis, carried out about nine years ago by the Portuguese Society of Cardiology and in which 240 patients admitted with acute myocarditis in many Portuguese hospitals were included, over a period of one year, only one fatal case (with acute heart failure and cardiogenic shock) occurred. Of course, these are only the results of one register and over a certain period, but overall, and as I mentioned, mortality is low.
Can you describe to us the condition of any patient after the delay of diagnosis due to the pandemic?
The reality I can describe to you is the one that resulted from patients’ fear of going to the hospital during the pandemic period. Many cases of acute myocardial infarction and possibly myocarditis could not be diagnosed and later, after the pandemic and fear had passed, came to us in the form of severe and irreversible heart failure. But can we blame people for their fear of coming to the hospital when they were not feeling well? No. A general panic legitimised by the press was created because, in fact, the pandemic was fatal for millions of people in the world. We can’t blame anyone, but the truth is that fear had consequences.
” (…) the fear had consequences.”
In some Nordic countries, in the case of very old and frail people, the doctor has been given the autonomy to decide whether to take the vaccine…
I think there is always a greater risk of being infected by the virus compared to the possibility of reactions to the vaccine. And from what I have read, the truth is that most of the published studies suggest that virus infection is worse than any vaccine overreaction.
In your point of view, what is the state of cardiology in Portugal?
It is one of the best in the world. Is there room for improvement? There are always things to improve. However, our cardiology is really among the best in the world, although the conditions are not always so.
“Our cardiology really is some of the best in the world, although the conditions are not always so.”
In collaboration with: Nuno Machado, Director The Blind Spot
