More specifically, fulminant myocarditis is characterized by a distinct, rapid onset of severe heart failure symptoms, such as shortness of breath and chest pain, that develop over the course of hours to days. Additionally, treatment requires the use of medications or mechanical devices to improve heart function.Acute non-fulminant myocarditis has a less distinct onset in contrast to fulminant myocarditis, and evolves over days to months. While the symptoms of acute myocarditis overlap with those of fulminant myocarditis, they do not typically occur at rest, and treatment does not require the use of mechanical circulatory support. Causes
While many causes of myocarditis are known, there are many cases in which a causative agent cannot be identified. In Europe and North America, viruses are common culprits. Worldwide, however, the most common cause is Chagas disease, an illness endemic to Central and South America that results from infection with the protozoan Trypanosoma cruzi. Overall, myocarditis can be caused by infections, immune conditions, toxins, drug reactions, and physical injuries to the heart. These different etiologies are detailed below. Myocarditis is a rare adverse side effect from mRNA COVID-19 vaccines. Infections
The most common causes of myocarditis are infectious organisms. Viral infections are the most common cause in developed countries, with a majority of cases being caused by those with single-stranded RNA genetic information such as Coxsackie viruses (especially Coxsackie B3 and B5). Globally, Chagas disease is the leading cause of myocarditis, which results from infection with the protozoan Trypanosoma cruzi.
This can involve the use of inotropes, or medications that make the heart contract with greater force, as well as antiarrhythmic drugs such as adenosine or carvedilol. In patients that have stable and adequate heart function, further treatments are based on heart failure guidelines. ACE inhibitors can have a protective benefit to the heart, so they are typically used in any patient with symptomatic myocarditis. Simultaneously, beta blockers are used in patients that can tolerate their heart beating at a slower rate. Shortness of breath at rest and swelling can be relieved with diuretics such as furosemide, and the addition of aldosterone receptor blockers can augment the diuresis while preventing the excess loss of potassium. In patients with symptoms while resting, additional medications can be added such as digoxin. Mechanical support
Mechanical support is used in cases of myocarditis in which medications alone do not lead to adequate heart function and the body requires additional support to achieve organ perfusion. Myocarditis cases that require mechanical circulatory support are categorized as fulminant by definition. People that require additional support with their heart function can benefit from the use of ventricular assist devices like intra-aortic balloon pumps. In people with myocarditis severe enough to cause cardiac arrest, extracorporeal membrane oxygenation (ECMO) is used to adequately pump blood and provide oxygen if needed. Both ventricular assist devices and ECMO can be used as bridge therapy until heart transplantation in patients that are candidates. Heart transplantation is reserved for those that do not respond to the aforementioned conventional medical therapies.