As of today, 9 May 2020, there is a total of 3,935,828 confirmed cases of COVID-19 worldwide. There are also 1,319,306 people recovered from the disease globally, and 274,655 deaths. What is clear from the numbers is that the infection has gained momentum which indicates a high pathogenicity of the novel Coronavirus, SARS-CoV-2. But what is not clear from the albeit valuable numbers is the complexity of the disease and its often motley symptomatology. While it starts out as a respiratory disease, if it produces any symptoms at all, COVID-19 progresses to systemic infection, infecting the nose, esophagus, lungs, kidneys, liver, gallbladder, small and large intestine, brain and even the heart and blood vessels.
The deep cardiovascular implications of COVID-19 are relatively unknown to the general public, likely because of their association with more serious forms of the disease. But it’s nonetheless important to understand that COVID-19 has notable cardiovascular effects and the potential to produce at times severe cardiac problems such as cardiac arrest, myocardial infarction and other cardiovascular events. Given that cardiovascular disease is one of the leading causes of death worldwide and that those with pre-existing cardiovascular (and other) conditions are the most at risk for severe forms of COVID-19 and related complications, it is important to make these 5 cardiovascular side effects of COVID-19 known.
Arrhythmia due to Coronavirus infection is one of the most common cardiovascular side effects that can be seen in moderate to severe disease. In a report on the clinical characteristics and symptomatology of 138 hospitalized patients in Wuhan, China diagnosed with the novel Coronavirus SARS-CoV-2 it was recorded that 23 patients (16.7%) experienced arrhythmia as a symptom (source 1). The report further informs that 16 patients with COVID-19-related arrhythmia were from the intensive care unit, suggesting arrhythmia as one of the cardiac complications of COVID-19, present in more severe forms of the disease.
Arrhythmia is essentially an irregular heartbeat and includes tachycardia or a fast a heartbeat (that is, a resting heart rate of over 100 beats/minute) and bradycardia or a slow heartbeat (a resting heart rate of under 60 beats per minute). Symptoms of arrhythmia most commonly include palpitations (hard, rapid or irregular heartbeat that you are aware of and can sense in the chest), extrasystoles (such as an extra heartbeat, a premature heartbeat or a skipped heartbeat), but also lightheadedness, dizziness and fainting, shortness of breath, chest pain, tightness or pressure.
Hypertension, or high blood pressure in layman’s terms, is a medical condition of the cardiovascular system in which blood exerts higher pressure than normal on artery walls. Hypertension has also been revealed to be a common cardiovascular symptom and source of complications in COVID-19. It has been observed that severe infections that present with persistent states of high fever can lead to a rise in blood pressure. COVID-19 can cause hypertension as a result of symptoms such as a persistent high fever, but also dehydration caused by lack of appetite, vomiting and diarrhea.
If hypertension is pre-existing, there is also a higher chance of side effects and complications such as arrhythmia and cardiac injury resulting in an increased risk of cardiovascular events. In one report it was observed that, of 3 different groups of people (close to 1300 people) that tested positive for the novel Coronavirus SARS-CoV-2 and admitted to hospital, between 20% and 30% had hypertension.
Hypertension as a pre-existing condition appears to negatively impact disease outcomes (see source 1). It has been theorized that the culprit is a common high blood pressure medication known as ACE inhibitors, or angiotensin-converting enzyme inhibitors. It has been suggested that ACE inhibitors upregulate the expression of the ACE2 (angiotensin-converting enzyme 2) which allows the SARS-CoV-2 virus to attach to and infiltrate cells in the human body and produce infection, at the same time increasing risks for severe infection.
(3) Cardiac injury
Cardiac injury is injury to the heart muscle. Although rare, it can occur with COVID-19 and represents one of the more severe cardiovascular effects of the condition. The heart is what is known as a high-risk organ for COVID-19 infection. That is, it stands a high chance of being infected with the novel Coronavirus. The reason for this is the high level of angiotensin-converting enzyme 2 (ACE2) expression in heart muscle cells (cardiomyocytes). This enzyme acts as a receptor for SARS-CoV-2, making it possible for the virus to attach itself to heart muscle cells and infect them. After the virus infiltrates the heart cells via the ACE2 enzyme, it uses them for replication which means the cells no longer perform their functions.
At the same time, the infected heart muscle cells send out a distress signal to the immune system. In response, the immune system sends out immune system cells that produce inflammation via inflammatory cytokines to fight the infection. But the resulting inflammation, if extensive, can also cause damage to the heart muscle cells, resulting in what is known as acute cardiac injury. Data collected from 138 hospitalized COVID-19 patients from Wuhan, China showed that 7.2% suffered acute cardiac injury (see source 1). Blood vessels (arteries, veins and capillaries) also have a high level of expression for the ACE2 receptor-enzyme which means that blood vessels of the heart can be infected with SARS-CoV-2 as well, a contributing factor to cardiac injury.
(4) Cardiovascular events
When it comes to serious forms of COVID-19, the cardiovascular system is one of the most severely affected, particularly if there are pre-existing cardiovascular conditions. Both the heart muscle and its blood vessels are susceptible to direct infection by the novel Coronavirus SARS-CoV-2 due to a high expression of the angiotensin-converting enzyme 2 ACE2. In addition to direct damage caused by the virus, there is usually also damage caused by immune system intervention causing extensive inflammation at the site of the infection that can lead to heart muscle cell death and damage known as cardiac injury.
If there are pre-existing cardiac problems or related comorbidities such as hypertension, coronary heart disease or cerebrovascular disease, the cardiovascular impact of COVID-19 is even greater and may include serious cardiovascular events such as myocardial ischemia and myocardial infarction (source 2). Certain reports advance mortality rates as high as 10.5% in COVID-19 patients with underlying cardiovascular disease (source 3).
(5) Viral myocarditis
Viral myocardits is inflammation of the heart muscle and is caused by an infection with a virus. It is a type of viral inflammatory cardiomyopathy. By now it has been revealed that the novel Coronavirus SARS-CoV-2 causing the disease known as COVID-19 can infect the cardiovascular system, both heart muscle cells and blood vessel cells that have the ACE2 receptor on their surface. The resulting infection as well as immune system intervention causing inflammation at the site of the infection cause damage to the heart muscle. Individuals with pre-existing cardiovascular conditions are more at risk for cardiac complications and fatalities in case of a COVID-19 infection (source 4).
Viral myocarditis can progress to heart failure and cardiac arrest quite rapidly. Systemic complications that further lead to disruption of normal blood clotting mechanisms, together with direct and indirect damage to the heart muscle, can result in outcomes such as a heart attack. It is also possible that heart damage as a result of a more serious infection of the likes of COVID-19 can cause heart failure even years after the initial infection.
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