Seems unusual for a 'coronavirus':

"A California woman who is thought to be the first person to die of COVID-19 in the U.S. suffered a ruptured heart, according to an autopsy report. The autopsy report signed by medical examiner Dr. Susan Parson said that Dowd complained of flu-like symptoms in the days leading up to her death. Dowd was described as "mildy obese" but had no known underlying conditions. The document showed that as well as her heart, COVID-19 had spread to her trachea, lungs, and intestines. Parson found evidence that Dowd's left ventricle had ruptured, and this was linked to COVID-19.

According to the San Francisco Chronicle, the Santa Clara medical examiner's office stored Dowd's tissue because she didn't test positive for viral infections like the flu but it was not possible to screen it for COVID-19 when she died. The U.S. Centers for Disease Control and Prevention on Tuesday confirmed COVID-19 played a role in her death.

CBS SF Bay Area reported the medical examiner of Santa Clara County has reclassified nine deaths from flu to coronavirus in the past week, including Dowd's.

Melinek [forensic pathologist] said: "It is possible that some deaths might be reclassified if the medical examiner or coroner looks back and identifies virus in autopsy tissue that wasn't initially recognized because of the lack of testing or lack of recognition of community spread at the time of the death."

She went on to stress that most COVID-19 deaths aren't reported to a medical examiner or coroner, "as they are not sudden, violent or suspicious."

newsweek.com/ruptured-heart-caused-first-covid-19-death-us-autopsy-states-1500594