Hi Edward and welcome to the forum. The episode you describe is due to a vasovagal response and is very common among persons experiencing a panic threshold. The vagus nerve is responsible for maintaining tone to the extent that blood pressure is held within a specific range as the forces of gravity act upon the body. In order for this to occur, there must be a constant level of feedback. In the absence of the requisite feedback, vagal tone is reduced, sometimes very quickly and the result is lightheadness or even syncope(fainting).

The most common example of this is soldiers who stand at attention for extended periods without movement. Vagal tone can become diminished to the degree that perfusion to the brain is mildly diminished. The consequence is fainting and falling forward. Another common example of rapid vasovagal reaction is being suddenly startled. Many people experience a sudden drop in blood pressure after being frightened and will often faint. For those that only experience a drop in pressure, the internal carotid arteries in the neck contain baroreceptors which sense changes in blood pressure to the brain and send feedback to the cardiac center in the brain. The fastest method for the body to recover from sudden hypotension is to increaxse cardiac force and rate, which is experienced as pounding heart. It is a natural physiological response.

Cannabis contains tetrahydracannabinol, or THC, which has the capacity to alter blood/brain chemistry in a manner very similar to that suffered by persons who experience panic thresholds. It is a common presentation in the emergency department.

The collective episodes that you describe would in no way be indicative of heart disease, structural abnormalities or similar pathology.

Lastly, I'm far too old to offer lectures on drug use and experimentation is a fairly common event in the lives of young people these days. I will say that in the instance of panic thresholds, a latent pattern of panic can sometime ensue because patients who have experienced it dread a recurrence that often precipitates that very consequence. In other words, panic can become formed upon the fear of recurrence in the absence of drug use.

You're just fine and there's nothing at all wrong with your heart.

Best regards and Good Health