For now, what we know, heart patients should not have any problems, except for those with a pacemaker. You can apply the device on the solar plexus, which is exactly at the length of Lucha T8’s neckband, that is, under the xiphoid process of the sternum.
This is where the effect on the entire organism is most optimal, and at a decent distance from the sinoatrial node of the heart, which is the natural cardiac pacemaker. If you feel any deterioration (you shouldn’t) or an unusual disturbance of the heart and heart rhythm, stop using it and contact a cardiologist for a consultation.