FAQ

Memory difficulties are one of the most common and distressing effects of cardiac arrest, and they are a normal consequence of how cardiac arrest affects the brain.

During cardiac arrest, the brain is deprived of oxygen. The hippocampus — the brain structure most important for forming and retaining new memories — is particularly vulnerable to oxygen deprivation. Even a relatively brief period of hypoxia can result in lasting changes to memory function.

Common memory difficulties after cardiac arrest include trouble retaining new information, forgetting things shortly after being told them, losing track of conversations, difficulty remembering names, and problems with prospective memory (remembering to do things). Some survivors also have a gap in memory around the time of the arrest itself — they have no recollection of collapsing or of their time in ICU. This memory gap is normal and is not the same as ongoing memory impairment.

The good news is that memory often improves significantly over the first year of recovery, as the brain heals and adapts. Strategies such as writing things down, using calendars and reminders, reducing cognitive load, and being patient with yourself can all help in the meantime.

If memory difficulties are significantly affecting your daily life or your ability to work, ask your GP for a referral to a neuropsychologist or cognitive rehabilitation service.

Fatigue is one of the most common and most underestimated effects of cardiac arrest. Many survivors find that they tire far more easily than before — sometimes feeling exhausted after activities that previously required no effort at all.

This fatigue has several causes. The brain and body undergo significant physiological stress during cardiac arrest and the subsequent period of intensive care. The brain in particular may have experienced a period of reduced oxygen (hypoxia), which requires significant energy to recover from. Heart function, medications, disturbed sleep, and the psychological impact of trauma can all contribute to fatigue.

Fatigue often improves over time, but it can be frustrating to live with, particularly in the early months of recovery. Some practical strategies that can help include pacing yourself — doing activities in shorter bursts with rest periods rather than pushing through — prioritising sleep, being honest with people around you about your energy levels, and gradually building activity levels with guidance from your cardiac rehabilitation team or physiotherapist.

If fatigue is significantly affecting your daily life, discuss it with your GP or cardiac team. An assessment of your heart function, anaemia, thyroid, and sleep quality may identify treatable contributing factors.

Recovery from cardiac arrest is highly individual, but most survivors experience recovery as a gradual process that continues for 12 months or more — not a single moment of being "better."

Physical recovery from the cardiac arrest itself and any procedures (such as ICD implantation) typically takes weeks. Cognitive recovery — improvements in memory, concentration, and mental fatigue — often continues over the first year, with many survivors noticing meaningful improvement month by month. Psychological recovery, including processing the trauma of the event and adjusting to life with an ICD, can take longer and is not always linear.

Factors that affect the pace and extent of recovery include how long the brain was without oxygen during the arrest, how quickly CPR and defibrillation were given, the underlying cause of the arrest, age and general health, and access to rehabilitation and psychological support.

It is important not to compare your recovery to someone else’s. Many survivors make an excellent recovery and return to work, exercise, and a full life. Others are left with lasting cognitive or physical effects that require longer-term support and adjustment. Both experiences are valid.

If you feel that your recovery is not progressing or that you are struggling with the psychological impact, talk to your GP or cardiac team. Cardiac rehabilitation, neuropsychological support, and talking therapies can all play a role.

Some survivors of cardiac arrest experience medical problems, including impaired consciousness and cognitive deficits. Functional recovery continues over the first six to 12 months after out-of-hospital cardiac arrest in adults. It is common for survivors to have memory loss and to experience depression and anxiety for some time after their event.