A new study has shown that the coronavirus that causes COVID-19 has the ability to directly infect the heart. Researchers in California have found that this is why even some COVID-19 patients with no underlying heart problems develop cardiac complications while battling the disease.

Published in the online journal Cell Reports Medicine on June 18, the study was conducted by researchers from Cedars-Sinai Smidt Heart Institute in California. The goal of the study was to discover why some COVID-19 patients suffer severe cardiac complications such as arrhythmia, viral myocarditis, and heart failure even when they do not have pre-existing heart conditions.

By testing lab-cultured heart muscle cells through stem cell technology, the researchers were able to confirm where the novel coronavirus directly enters and targets the cells. Researchers discovered that the coronavirus was able to penetrate the cells in cultured lab dishes, change their gene expressions, and multiply, causing the heart cells to stop beating 72 hours after the infection.

The researchers also discovered that treating COVID-19 with an ACE2 antibody could reduce viral replication on the heart cells. This suggests that the new coronavirus could enter the heart through the ACE2 receptor.

“We not only uncovered that these stem cell-derived heart cells are susceptible to infection by novel coronavirus, but that the virus can also quickly divide within the heart muscle cells,” said researcher Arun Sharma. “Even more significant, the infected heart cells showed changes in their ability to beat after 72 hours of infection,” he added.

While the DNA testing demonstrated the presence of RNA strains of the novel coronavirus in the heart, the researchers said performing an invasive procedure in a living COVID-19 patient would be too risky. Since obtaining actual heart muscle samples is a gold standard in establishing the conclusiveness of any study, the recent findings of the scientists at Cedars-Sinai Smidt Heart Institute cannot be considered irrefutable.

However, the findings shed light on why COVID-19 patients develop heart complications. Before the study, the causes of cardiac injury among COVID-19 patients without pre-existing heart conditions were unclear.

Coronavirus COVID-19 New York, USA A worker uses a forklift to move a body outside of the Brooklyn Hospital on March 31, 2020 in New York, United States. Due to a surge in deaths caused by the Coronavirus, hospitals are using refrigerator trucks as make shift morgues. Stephanie Keith/Getty Images