For their study, the researchers examined 32 patients who were being treated in hospital for their COVID-19 disease. In 18 study participants, elevated levels of the biomarker troponin indicated that the heart was damaged. Fourteen patients did not have elevated troponin levels. The researchers were able to measure weakened heart function in both groups, which affected 66 percent of patients overall. "This high proportion surprised us, because it was more than we would have expected based on the symptoms," says Dr. Ludwig Weckbach from the Medical Clinic and Polyclinic I at LMU Hospital. Sixteen of the COVID-19 patients with elevated troponin levels had worsened heart function, compared to five people in the group without elevated troponin levels.

The examination of cardiac function took place between the fifth and 21st day of hospitalization. Very sensitive ultrasound methods, such as 3D ultrasound and so-called strain ultrasound, were used for this purpose. "These methods can also be used to detect restrictions that would not be noticeable using conventional ultrasound," explains Weckbach. He and his colleagues use them to measure how much blood the heart ejects and how well it relaxes again after contraction.

In most patients, both ventricles were affected, particularly in the group with myocardial damage. Here, the values for both ventricles had deteriorated in 80 percent of patients. "The good news is that heart function has recovered in most patients," says Weckbach. This was the result of a follow-up check after two months.

The patient group examined was very heterogeneous. In addition to previously healthy people, some already had previous illnesses such as high blood pressure or diabetes. The average age was 62 years. According to the Munich researchers, their study participants were therefore roughly the same as the groups of hospitalized COVID-19 patients who were examined in larger studies. Compared to the group without damage to the heart, patients with heart damage were older, had more pre-existing conditions and had to be treated and ventilated more frequently in the intensive care unit.

The first COVID-19 patients treated in a hospital in China were found to have elevated troponin levels. Researchers worldwide now estimate that acute damage to the heart can occur in 30 percent of COVID-19 patients. What this damage means for heart function is now gradually being researched. "Our study has shown that advanced ultrasound methods are more suitable for detecting how SARS-CoV2 infection affects heart function," says Weckbach. Larger controlled studies are now needed to find out what the temporarily worsened heart values mean for the long-term course of the disease.