Flash

You could be inadvertantly crnsoepsimg one or both of the carotid sinuses. These are small bulges in the carotid arteries these bulges or sinuses' are usually located between the top of the adam's apple and the jaw. They have whats termed baroreceptors' in them nerves which monitor the blood pressure in the carotid arteries. If blood pressure increases acutely, the nerves send signals to the heart to slow down thereby lowering the pressure a bit. In some people, this reflex is very sensitive, and can be activated by pressing on this area with one or 2 fingers, and the heart can slow dramatically for a few seconds Then when the heart rate returns to normal a thud' may be felt as the extra blood collected while the heart has been slowed down, is ejected in the next one or two beats.My carotid sinuses are quite sensitive I can press gently in this area on one side and feel the pulse one the other side with my other hand and detect the sudden heart rate decrease. Sometimes it can make you feel slightly light-headed followed by a couple of palpitations'.