Use email to send a pulse to a heartbeat check

We have a few business process that we’d like to monitor with heartbeat checks, but the processes are not capable of invoking a web service. Those processes are capable of sending email, so we’d like to see a way to send a pulse to a heartbeat check via email.

We can accomplish this today only by either paying for a third party service that can act as a bridge or building something ourselves. If uptime.com supported this functionality natively, we would be likely to use more heartbeat checks.