When one refers to night sweats: It's when one has excessive sweating during sleep, which in most cases one would have to get up and change clothing, bedding etc.
Since this doesn't occur each and every single night this is not considered a primary Hyperhidrosis. (Hyperhidrosis is characterized by excessive sweating)
Secondary Hyperhidrosis: This type is generally found to be a symptom of an underlying cause.
Severity of Hyperhidrosis can be classified as the following Mild: No bathing or changing of clothes required; may have to turn the pillow or remove blankets. Moderate: Sleep disturbed by need to arise and wash face or other affected body areas, but no clothing change. Severe: A bath or change of clothing required.
Click here for one site that explains about night sweating:
Going by all the information you have given and this appears to be due to something other than a medication etc. and since it may have began shortly after finding out about the irregular heartbeat, this is where it may be stemming from.
Especially with the blood work coming back normal etc. And even though you may have eaten certain foods for years, doesn't mean that it won't effect you at some point in your life. So either write down things you did or ate for a couple of weeks and see if there is something that is happening that connects your daily habits with sweating that night. Sometimes it's not obvious just thinking back, but if written down, then it may stand out clearer.
So to answer your question of this being typical symptoms, it's appears to be more secondary to something that may be going on vs something happening on it's own.
Hope this helps and makes sense. If you need anything else, just ask.