Meditation makes my heart beat too hard and fast

Sometimes meditation will go just right and i’ll feel at ease, like i’m floating and it’s amazing. However many times part way through around 10-15 mins in by body will decide to release some anxiety/ stress hormone or something and my heart will be beating extremely hard and all the veins will pop out in my hands and head and it makes me feel extremely uncomfortable normally resulting in me having to end the meditation.

Any thoughts or tips to stop this?

Thanks in advance