Hello and thank you for your question. There are many heart healthy foods listed here https://www.webmd.com/food-recipes/features/11-top-heart-healthy-foods#1. The number one item on the list for a heart healthy food? Salmon. The best fruit for heart health? Raspberries! This is followed by RED grapes. Take a look at the list and you will notice there are pretty common things to add to your diet but do remember to check with your doctor before starting any new diet.
Here is an entire article on having a heart healthy diet. https://www.mayoclinic.org/diseases-conditions/heart-disease/in-depth/heart-healthy-diet/art-20047702. The first thing on the list of having a heart healthy diet is to take into consideration portion control. Second is to eat more fruits and vegetables.
With regards to apples in particular, they are indeed healthy for you overall including your heart. https://www.healthline.com/nutrition/10-health-benefits-of-apples. They have a positive effect on cholesterol because they provide soluble fiber. Studies have shown apples to be quite effective in lowering total cholesterol.
Hope this helps.