How often is Ronald sneezing? Is he otherwise healthy? Does he do it when he's burrowing in his hay, or does it seem very random?
Guinea pigs do have a very fast heart rate. An irregular heartbeat is not normal, but due to the speed at which the heart beats it can be relatively "easy" to mistake the normal changes in speed of the heart (increasing when scared, decreasing when relaxed/relieved etc.) for an irregular beat. An experienced vet or rodentologist would need to have a careful listen to him with a stethoscope in order to determine if a heart problem is present.
Worming (or more accurately, the treatment or prevention of intestinal parasites and worms) is generally not considered essential; it is still very much a personal thing. Some people choose to worm with a herbal anti-parasitic (Four Seasons Anti-Parasitic) once a month, others give Ivomec and Panacur every three months, others do nothing. Personally I recommend that guinea pigs who graze outdoors are wormed, and guineas whose fresh vegetables and fruits are not rinsed/washed before feeding. I worm my piggies with Ivomec and Panacur; both very small amounts, just four times a year. I had a number of cases, prior to routinely worming, where some of my pigs lost weight and were unable to maintain weight for no apparent reason. In one case, one of my sows (Jasmine) had been losing around 2oz a week for three weeks; a total loss of around 6oz. At a loss for what to do - she was eating normally, she was healthy, had no symptoms at all other than the weight loss - I decided to give her a single, one-off dose of Panacur. This was enough to stop any more weight loss, and allowed her to gain the weight back that she had lost - whether she had some parasite in her system I'm not sure, but I have no doubt the Panacur solved the problem.