New information regarding COVID-19 continues to emerge daily. This content was based on the sources available at the time of writing.

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To counteract the novel coronavirus, SARS-CoV-2, clinicians must stay vigilant and informed about morbidity and mortality among more vulnerable patient populations. The limited evidence gathered from COVID-19 patients suggests that the virus affects a disproportionate number of individuals with preexisting cardiovascular disease (CVD), as well as other comorbid conditions including diabetes and chronic respiratory disease.

As the number of COVID-19 cases continues to grow worldwide, cardiologists must be prepared for a greater influx of infected patients who also live with cardiovascular issues. In time, our understanding of this virus, its potential complications, and possible therapies will evolve, enabling providers to better care for these affected individuals.

COVID-19 and Cardiovascular Disease

According to the American College of Cardiology's (ACC) COVID-19 Clinical Guidance, 2.3% of patients diagnosed with COVID-19 eventually succumb to the disease. Patients with COVID-19 who also have preexisting cardiovascular issues experience a 10.5% fatality rate, the highest of any comorbid patient population to date.

In comparison, fatality rates related to other comorbid conditions, while certainly higher than average, reflect the severity of COVID-19 for those with CVD. Fatality rates based on current available data are as follows:

• Diabetes: 7.3%
• Chronic respiratory disease: 6.3%
• Hypertension: 6.0%
• Cancer: 5.6%

Reported Cardiovascular Complications of COVID-19

Preliminary data based on reported cases indicates that patients with preexisting CVD are more prone to acute myocardial injury during the course of their infection. One study, published in JAMA Cardiology, hypothesizes that SARS-CoV-2 may actually damage myocardial cells via:

• Aggravated hypoxia
• Destabilized coronary plaque
• Systemic inflammatory responses

Additionally, previous studies involving severe acute respiratory syndrome (SARS) positively identified the virus inside the heart muscle itself, indicating the possibility of direct damage to cardiomyocytes by the virus. It may be that SARS-CoV-2 also acts on heart tissue to cause direct injury.

In light of the potential for myocardial injury, patients with CVD and concurrent COVID-19 infection are more likely to experience significant complications. Anecdotal and published reports, including the ACC's COVID-19 Clinical Guidance bulletin, confirm cases of acute heart failure, cardiac arrest, myocarditis, and myocardial infarction linked to the virus. Additionally, research published in the Journal of the American College of Cardiology shows that as many as 16.7% of patients develop abnormal arrhythmias as a result of infection. These complications roughly equal those associated with other coronaviruses, such as SARS and Middle East respiratory syndrome (MERS).

Clinical Characteristics Indicating Cardiac Involvement

Patients with CVD who come to acute care facilities with suspected COVID-19 infections may be evaluated for several blood markers, which can indicate potential cardiac complications. A recent article from TCTMD notes that patients diagnosed with COVID-19 have exhibited a heightened inflammatory response, as evidenced by higher-than-normal levels of:

• CD4 and CD8 glycoproteins
• C-reactive protein
• Interleukin-6

A second JAMA Cardiology study found that patients who died as a result of infection also had higher levels of:

• C-reactive protein
• High-sensitivity troponin
• Interleukin-6
• Myoglobin
• Serum ferritin

Since elevated levels of high-sensitivity troponin indicate cardiac injury, this finding may have significant prognostic value in determining the likelihood of mortality. However, further research is necessary to verify this correlation.

A third study, published in The Lancet, found that most of the COVID-19 patients studied had abnormal myocardial zymograms. 76% of patients in the study showed elevated levels of lactate dehydrogenase, and 13% showed an increase in creatine kinase, indicating that heart or muscle damage may occur in infected individuals.

Learning from Other Viruses

Currently, it is not known whether the diagnosis of any one type of cardiovascular disease assures a greater likelihood of fatality after infection with COVID-19. However, cardiologists can use lessons learned from other viruses, such as influenza, to determine which patients may be at highest risk.

A 2019 study in JACC: Heart Failure found that patients with heart failure may be particularly likely to experience negative outcomes if they contract influenza. Compared to patients without heart failure, hospitalized heart failure patients with the flu were more likely to experience:

• Acute respiratory failure (36.9%)
• Acute respiratory failure requiring mechanical ventilation (18.2%)
• Longer hospital stays (5.9 days on average)

Heart failure patients diagnosed with COVID-19 may also be at high risk of developing serious complications, but further research is needed to confirm whether any specific cardiac conditions make worse outcomes more likely.

What Cardiologists Can Do

Cardiologists must understand and anticipate that patients with CVD face an elevated risk of a poor prognosis when infected by COVID-19. To best assist these high-risk patients, it is essential for cardiologists to:

• Advise all cardiovascular patients on the risks of COVID-19 infection
• Advocate for compliance with current vaccination requirements, including the pneumococcal and influenza vaccines
• Encourage preventative measures in accordance with the Centers for Disease Control and Prevention
• Opt for telehealth consultations rather than in-office visits for patients with stable CVD to help avoid possible infection

COVID-19 patients who also demonstrate symptoms of arrhythmia, heart failure, cardiomegaly, or any other cardiovascular condition can still benefit from echocardiography. The ACC COVID-19 Clinical Guidance bulletin notes that this may be especially important for patients expressing symptoms of acute myocardial infarction, as this condition may be underdiagnosed while clinicians work to treat COVID-19.

Clinical understanding of SARS-CoV-2 and COVID-19—and the exact risks to cardiovascular patients—continues to evolve. Since these patients are at higher risk for poorer outcomes, it is especially important for cardiologists to stay informed and take steps to help patients get the best care possible.