Hello there and welcome, Well Seizure in other word Convulsion or fits can be of several types and due to several reasons. From you descriptions , on going shortness of breath can cause Hypoxia(decreased oxygenation to the cells of body) which in-turn causes seizure but its not a common entity in otherwise healthy individual (are you sure that shortness of breath is the only problem?? there can be something else too which apparently may look fine). Well either way having a seizure out of nowhere is never fine, so its better to get checked to a Neurologist to get a thorough evaluation done as well as get a MRI-Brain and complete metabolic profile check-up done at the earliest to clarify the reason for the seizure. Thanks a lot for contacting HCM , get well soon