Dizziness pre-cardiac arrest can indicate that there may be issues with your heart and if they happen often they should be investigated by a doctor.
However, it’s not uncommon for cardiac arrest survivors to report feeling dizzy, lightheaded, a giddy ill feeling or having issues with their balance. In this case, it could be down to either medication or because of an acquired brain injury.
Some types of medication, such as blood pressure or anti-seizure drugs can cause these issues. If you are on any medication then you should talk to your doctor about whether they may be the source of the problem. Changing the type or dose may improve things.
Just a few minutes of oxygen deprivation can cause damage to fragile brain cells and this can lead to various problems such as dizziness and so it may be worth investigating whether this is the problem.
Balance and dizziness problems are common after brain injury and manifest themselves in a wide variety of ways. There is no easy way of dealing with the problems but there are treatments and strategies that can help. The most important thing initially is to seek assessment and treatment from a specialist with experience in vestibular problems, such as a neuro-physiotherapist.
Resources
Headway
Brain and Spine Foundation
Dizziness and balance problems
Youtube
Video discussion between a patient and doctor regarding why people are dizzy after a brain injury. Note that this is not specific to the acquired type of brain injury that most cardiac arrest survivors experience,