Yogurt made with heavy cream
This is a very normal thing to do. The result is not called yogurt, but sour cream. You can use yogurt, especially lactobacillus yogurt, as a starter for full-fat sour cream of the Eastern European type. The fermentation process is the same as for yogurt. It gets a very nice characteristic smell which is different from that of yogurt. It might stay slightly soupier than yogurt, even after sitting in the fridge, that's normal. 

There is nothing special you need to consider, just go ahead and make it.