Heart disease affects the cardiovascular system by plaque building up on the artery walls narrowing them making it harder for blood to flow through which could lead to heart attack or probably stroke if the plaque blocks it entirely or maybe almost entirely.
Heart disease may also affect our nervous system for there is higher risk to stroke and it is due to limited flow of blood to the brain and may lead to heart failure which may happen with heart disease that puts the stress on the brain and nerves.
The digestive system is affected by heart disease that causes the system to not get the right amount of oxygen and the nutrients that it needs from the blood.