If you think about it, that does not really make much sense. The actual sneeze lasts only a fraction of a second, less than a heartbeat. Your heart tissue is an immensely complex mechanism with millions and millions of components. They do not simply stop at any particular point, certainly not if they are to restart. You would be unlikely to be able to detect any disturbance to your heart's rhythm, other than a sudden speeding up to support the exertion of the sneeze. (After all, a sneeze takes a lot of energy!)
Cheers,
Jon
