Nope! Special class II is all the general class II requirements plus the special rules: https://www.fda.gov/medical-devices/overview-device-regulati...
Specifically in this case I chose this classification because the only difference is the alarm. Without an alarm or alert, you're normal Class II. The alert bumps you up to the special rules. A wearable device would have an alert.
> See the "clinical studies" section
I see where it says "clinical studies will not be needed for most arrhythmia detector and alarm devices [...] FDA will always consider alternatives to clinical testing when the proposed alternatives are supported by an adequate scientific rationale."
They recommend ANSI guidelines and standards for algorithms to measure ST length and for the electrodes. They don't even require following them. The clinical requirements are for all of the crazies who want to do crazy things like sell mood rings for heart attacks. It is very unlikely they would require a premarket clinical trial(NOTE that they allow many products to register as investigative!) for something like an apple watch.
Medical device regulations are a paper tiger. The effort in development is the concern- you can't register until the development is paid for, so if you're rejected then you've wasted all that money. Registering could be zero effort and that would not change. Especially for companies like apple, it is much more convincing that they are more concerned with patient lawsuits than problems with the FDA.