I remember seeing one on YouTube last year about arrhythmias. It was so helpful but also hilarious. There's no sound with it but a so-called German doctor explains the various arrhythmias and shows how the heart works by using his body movements as a visual. It was so accurate and so funny. Best thing I've ever seen. We can't post links here but all I see as a title is "EKG." Not much to go on. The video would never replace seeing your cardiologist but for those of us with arrhythmias, it would brighten your day and help deal with the stress.
Yes, there is a lot of helpful information on the web. But, be careful some may not be as authoritative or accurate as it seems. If the web site is the cleveland clinic or the american heart association, for example, I'd take the information as factual, otherwise I look at the information as "interesting" and maybe helpful.