One of the major problems with heart disease, whether CHD or heart failure, is low magnesium levels. Magnesium levels are low because the average processed food diet has most minerals, such as magnesium, stripped out during processing.
This along with the fact that prolonged stress causes depletion of magnesium means the heart is more often than short of magnesium.

Most heart problems from plaque build up, to increased CRP,IL6 and TNF(a) artery inflammation markers as well as higher BP can all be increased, along with other symptoms including atrial fibrilation and heart rhythm problems. Adequate Vitamin D is also a requirement for good heart health.

https://www.wellnessresources.com/hea...multiple_ways/

https://www.iherb.com/Now-Foods-Magne...50-Tablets/691

People with kidney failure should only supplement with magnesium under a doctors supervision.

Once I started taking magnesium, my heart no longer skipped beats! I take Natural Calm before bed, I like that its flavored. Also, its relaxing before sleep.

Even if you eat only whole foods they contain much lower levels of magnesium and the other nutrients due to soil depletion and selective breeding (for shelf life or appearance) that has caused a decline in nutritional content.