ABC | Volume 114, Nº5, May 2020

Viewpoint Costa et al. Cardiovascular Implication of Covid-19 Arq Bras Cardiol. 2020; 114(5):834-838 neoplasms, diseases due to external causes and diseases of the respiratory system. 7 Studies show that a higher frequency of comorbidities is commonly related to older age. The mortality rate of COVID-19 can be nine times higher among people with some chronic disease compared to that of patients without any pre-existing pathology. Data provided by the World Health Organization (WHO) in February show that in the group of infected people without comorbidities, only 1.4% died. Among patients with some cardiovascular disease, for example, the rate reached 13.2%. Considering all infected patients, lethality was 3.8%, but it is worth mentioning that, due to the progress of the pandemic, new statistical data has been added to the studies. The severe form of the disease was observed in older patients 8,9 who had a more significant number of comorbid conditions compared to non-severe patients. These findings suggest that age and associated comorbidities may be one of the risk factors for critically ill patients. Besides, the elderly and immunosuppressed patients may manifest atypical symptoms and other forms of presentation, including mild, moderate and severe pneumonia and, in more severe cases, severe acute respiratory syndrome, sepsis, septic shock and death. 4 In a case report of 138 patients hospitalized with COVID-19, 16.7% of patients developed arrhythmia and 7.2% suffered acute cardiac injury, in addition to other complications related to COVID-19. Published reports indicate cases of acute onset heart failure, myocardial infarction, myocarditis and cardiac arrest. 10 Moreover, cases of myocardial damage, with increased troponin I, acute cardiac damage, shock and arrhythmia, were found. 11,12 In the acute phase of severe viral conditions, not only in COVID-19, but also in other Coronavirus illnesses, the patient may present tachycardia, hypotension, bradycardia, arrhythmias and sudden death. Abnormal findings on electrocardiograms and increased troponin signal myocardial involvement in the form of myocarditis. 11,12 Cohort studies published to date show rates of acute heart failure, shock and arrhythmia of 7.2%, 8.7% and 16.7%, respectively. Cardiovascular involvement is due to a mismatch between the increased metabolic/inflammatory demand triggered by the virus and reduced cardiac reserve. The inflammatory state makes the environment more prone to thrombotic phenomena. Therefore, the recommendation has been that patients’ chronic medications should be maintained, with their withdrawal/replacement being assessed on an individual level and in accordance with the guidelines in force so far. It is worth noting that new recommendations may emerge as new studies in progress come out. 13,14 Chronic diseases, such as hypertension, diabetes, diseases of the respiratory system, cardiovascular diseases and their conditions of susceptibility, share some standardized states with infectious diseases, such as pro-inflammatory state and the attenuation of innate immune response. Diabetes, for example, occurs partly because the accumulation of innate immune cells activated in metabolic tissues leads to the release of inflammatory mediators, especially IL-1 β and TNF α , which promote insulin resistance and damage to β cells. 15 Moreover, metabolic disorders can lead to depression of the immune function, impairing the function of macrophages and lymphocytes, 16 which can make individuals more susceptible to complications and aggravations of COVID-19. 9 Many of the older patients who become seriously ill have evidence of underlying diseases, such as cardiovascular diseases, liver diseases, kidney diseases or malignant tumors. 17-19 These patients usually die from their original comorbidities. Therefore, the accurate assessment of all original comorbidities of individuals with COVID-19 must be rigorously analyzed and considered from an individualized therapeutic perspective. Other studies add that the respiratory failure aggravated by SARS-CoV-2 occurs due to massive alveolar damage. This virus is capable of infecting human respiratory epithelial cells through an interaction between the viral S protein and the angiotensin-converting enzyme 2 receptor in human cells. Although there is evidence in the literature that the presence of severe lung infections can affect the long-term prognosis of individuals with heart diseases, there is no data to confirm that patients recovered from COVID-19 infection will experience long-term effects. 20,21 Thus, not only capable of causing pneumonia, COVID-19 can also cause damage to other organs, and patients end up dying from multiple organ failure, shock, acute respiratory distress syndrome, heart failure, arrhythmias and kidney failure. 22 Potential injuries tomultiple organs and their protection and prevention should be monitored in the treatment of COVID-19. 23 In these critical patients, the necessary protective measures include mechanical ventilation, glucocorticoids, antivirals, symptomatic treatments and shock therapy. Another important factor would be the approach to estimating the transmissibility of a virus by calculating its reproductive number (R0), which represents a measure of its attack rate, that is, it translates the number of secondary infections that occur from an infected individual in a susceptible population. Preliminary studies pointed out that this new coronavirus, responsible for COVID-19, would be associated with R0 rates of 1.5 to 3.5, with the most recent data suggesting an R0 of 4.08 (i.e., for each case, on average , there would be four new infected individuals). 7 As it has a high potential for dissemination1 and, knowing that it is an RNA virus, enveloped and contaminated by respiratory droplets or contact, hygiene measures must be improved and put into practice. These are: washing our hands with soap and water to destroy the morphological structure of the virus, using 70% alcohol-based hand sanitizer, covering our mouth when coughing or sneezing to prevent viral particles from spreading through the environment, avoiding crowds and staying in a well-ventilated area. 3,4 According to the literature, the average incubation period for coronavirus is 5 days, with intervals that can be as long as 12 days. Preliminary data for SARS-CoV-2 suggest that transmission may occur even without the appearance of signs and symptoms. 4,5 When there are no complications, the symptoms consist of fever, dry cough and tiredness. Runny nose and nasal congestion, sore throat and diarrhea may also occur. Furthermore, most of those infected are asymptomatic (about 835