A critical medical equipment crashed during a heart procedure due to a timely scan triggered by the antivirus software installed on the PC to which the said device was sending data for logging and monitoring.

The device in question is Merge Hemo, a complex medical equipment used to supervise heart catheterization procedures, during which doctors insert a catheter inside veins and arteries in order to diagnose various types of heart diseases.

The incident happened in February 2016

Merge Hemo consists of two main modules. The main component is the actual medical device, connected to the catheters, through which data acquisition takes place. This component is connected to a local PC or tablets via a serial port.

The second component is a software package that runs on the doctor's computer or tablet and takes recorded data and logs it or displays it on the screen via simple-to-read charts.

Just like any other software package, Merge Hemo is subject to the same limitations and dangers that other applications face, and sometimes may crash. When something like this happens, and doctors report the event, the software vendor must investigate and file an Adverse Event Report with the FDA (US Food and Drug Administration).

According to one such report filed by Merge Healthcare in February, Merge Hemo suffered a mysterious crash right in the middle of a heart procedure when the screen went black and doctors had to reboot their computer.

Fortunately, the patient was sedated, and the doctors had five minutes at their disposal to wait for the computer to finish rebooting, start the Merge Hemo application again, and complete their procedure without any health risks for the patient.

An improperly configured antivirus caused the crash

Merge investigated the issue and later reported to the FDA that the problem occurred because of the antivirus software running on the doctors' computer. The antivirus was configured to scan for viruses every hour, and the scan started right in the middle of the procedure.

Merge says the antivirus froze access to crucial data acquired during the heart catheterization. Unable to access real-time data, the app crashed spectacularly.

The company claims that they included proper instructions in their documentation, advising companies to whitelist Merge Hemo's folders in order to prevent crashes from happening, so it seems that the whole incident was nothing more than an oversight on the medical unit's side.