Yes low dose Aspirin is usually standard therapy for heart conditions, studies have shown that asprin intake prevents some of the damage due to a heart attack. However, 81mg is not standard, there are other doses that doctors use (160mg-325mg everyday),
Yes, negative effects on muscles (myositis and rhabdomyolysis) can contradict someone for statin therapy, but usually it is controlled by lowering the dose of the statin. Talk to your local pharmacist about the condition and alternative therapies available (there are many)
Sorry, I have nothing on rhythmodan-Monocor. Talk to your doctor about it, check out webmd on the internet, and check out Pubmed for primary literature on the topic. The later will give you actual studies on the latest research.
Other than that, talk to your pharmacist or doctor rather than this forum. They are going to be able to give you the most accurate, relavent, and up to date information on your medication and medical condition questions.