Before you randomly start popping supplements the first thing you should be doing if you care about maintaining a healthy cardiovascular system is getting regular blood tests, ideally at least one a year.

Not managing high triglycerides or high LDL cholesterol will put you at a much higher risk than not taking any specific supplement. Some people are genetically prone to heart disease in which case monitoring your cholesterol and taking pharmaceuticals to manage it (if needed) can significantly reduce your risk.

The other thing you should do before you start popping supplements is get your diet right. Reducing sugar, eating less processed foods, consuming healthy fats (especially EPA), and intermittent fasting – these will all help dramatically more than taking any supplement.

Then there is exercise. Doing a 20-30 mins of high intensity exercise a few days a week will help reduce your resting heart rate, improve your metabolism and help maintain a healthy cardiovascular system.

The only supplement I think there is currently good evidence to take for heart health is high dose EPA, but it's pretty expensive... I use Pharmepa Restore personally which I take due to a family history of heart disease. High quality fish oil supplements with DHA and EPA probably have a minor benefit, while cheap fish oil supplements are probably mostly useless for several reasons. If you're going to take fish oil for heart health take one that's pharma-grade and high in EPA.