The modern technological advances allow IMDs to be accessed and controlled wirelessly, making them more vulnerable to a variety of security attacks. In this work, we propose a new approach of dual input channel to the runtime monitor that takes both ECG and PPG sensing techniques to monitor safety policies of an IMD. The monitor can be deployed on a wearable device that senses ECG and PPG signals non-invasively to verify if the IMD is not diverging from a safe baseline. We present the formal dual input channel monitor synthesis framework. Our experiments using the Pacemaker safety policies validate the developed correlation of ECG and PPG signals and the proposed runtime monitoring approach. © 2021 Owner/Author.