Survivors of heart attack plus cardiac arrest at increased risk of early death

Patients who survive a heart attack together with sudden cardiac arrest are at increased risk of dying within six years following hospital discharge. This is the conclusion of new research published in the Journal of the American Heart Association.

A heart attack is when blood flow to the heart is blocked, and sudden cardiac arrest is when the heart malfunctions and suddenly stops beating unexpectedly. Cardiac arrest can be fatal if not treated immediately. Most heart attacks do not lead to sudden cardiac arrest. But when sudden cardiac arrest occurs, a heart attack is a common cause.

The study, by researchers from the National Institute of Health Research Health Informatics Collaborative (NIHR-HIC) led by Imperial College Healthcare NHS Trust and Imperial College London, draws on data from 13,444 patients collected between 2010 and 2017. The study was funded by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre (BRC).

It shows for the first time that patients who had heart attacks and then a sudden cardiac arrest were at a greater risk of developing further complications. Those who had a cardiac arrest at the time of their heart attack were twice as likely as those suffering heart attack alone to go on to develop abnormal heart rhythms known as ventricular arrhythmia (VA). Those with a cardiac arrest were also 36 percent more likely to die on average within three years following discharge from the hospital.

The researchers suggest that this small subgroup of patients may benefit from additional treatments such as an implantable cardioverter-defibrillator (ICD) – a small device that treats people with abnormal heart rhythms – to see if it improves their long-term health outcomes. This is because in some cases heart attacks can lead to a condition called ventricular arrhythmia (VA) – a type of abnormal heartbeat where the heart begins beating faster before going into a spasm and stops pumping completely- which can cause sudden cardiac arrest.

Dr. Fu Siong Ng, the senior author of the study and Clinical Senior Lecturer in Cardiac Electrophysiology at Imperial College London, said, “Most patients who have heart attacks do not experience a cardiac arrest. However, our study has revealed that there are a small group of patients who do, and if they survive the initial cardiac arrest they are at increased of further complications and early death. This study has highlighted that we may need to look at how we treat these types of patients and our current guidelines may need to be updated. There is a case that in addition to the current treatments on offer to heart attack patients these patients may benefit from ICDs. However, we would need to carry out a clinical trial to validate this theory.”

Arunashis Sau, the first author of the study and Clinical Research Fellow at Imperial College London, added, “This is the first study to have found a link between patients who have heart attacks together with sudden cardiac arrests and early death after surviving the initial event.”