Fever is not a symptom of cardiomyopathy because fever is usually associated with a infection and cardiomyopathy is not. The usual symptoms of cardiomyopathy are: Breathlessness, swelling of members, bloating of the abdomen, fatigue, uneven heartbeats and dizziness.
Physical activity prevents cardiovascular diseases. All the other alternatives are risks factors for a cardiovascular condition. Obesity can cause obstruction of blood vessel, diabetes causes circulation system problems and tobacco use damages tissues and blood vessels.
In research when a significant result is found that means it has been shown through statistical tests that one variable has had an effect on another. If it is a low effect size though it means that the effect is not large enough to prove a hypothesis.