Feeling faint, light-headed or dizzy may be due to a reduction of blood flow to the brain. Sudden loss of consciousness usually means that the blood supply to the brain is seriously reduced.

Blood flow to the brain may be reduced when the heart rate or rhythm is abnormal (too slow or too fast) or when the heart cannot pump blood adequately because blood flow is blocked, for example, by narrowing of a valve. It could also be due to a heart attack.

Fainting or loss of consciousness is a potentially serious situation and medical attention should be called for immediately.

Dizziness, especially when standing up too quickly, is an extremely common symptom for people with heart failure. It may be due to abnormal heart function or rhythm or due to narrowing of a valve. It may also be due to a rapid but temporary drop in blood pressure, called postural hypotension, caused by getting up too quickly.

Dizziness is a common side effect of the medications used to treat heart failure. Diuretics, ACE inhibitors, ARBs and beta blockers will all reduce blood pressure. This will improve heart function and your breathing. However, because your blood pressure is lower than usual, you may often feel dizzy, especially when standing up from sitting or lying down. Click here for tips on how to minimise this dizziness.