Pre-Arrest Symptoms Were Common Across Young Cardiac Arrest Victims
Out-of-hospital cardiac arrest in people aged 12 to 49 years is rare, but when it occurs the clinical path is often visible before collapse. In this nationwide Norwegian analysis, symptoms of cardiovascular disease appeared in most victims before arrest, and those symptoms were not confined to exercise. They also surfaced during rest and ordinary daily activity, which makes the clinical signal harder to dismiss and more relevant to routine primary care, sports medicine, and emergency evaluation.
The cohort included 134 individuals with presumed cardiac OHCA, drawn from the Norwegian Cardiac Arrest Registry between 2015 and 2017 and cross-referenced with medical records, autopsy reports, and questionnaires. Among these patients, 81 survived and 53 died. CVD symptoms were reported by 78% of survivors and by 60% of next-of-kin describing the deceased. Only 12% had symptoms exclusively during exercise. In practical terms, the data argue against a narrow assumption that exertional complaints are the only warning sign in younger people with occult cardiac disease.
One sentence captures the bedside reality: symptoms were usually already present before the arrest, but they were not always obvious to the patient, family, or clinician.
Ischaemic Heart Disease Led the Aetiologic Pattern
The dominant cause of OHCA in this cohort was ischaemic heart disease, which accounted for 58% of cases in males and 38% in females. Structural, non-ischaemic heart disease followed. In individuals aged 35 years or younger, sudden unexpected death syndrome was most common, a pattern that fits the broader epidemiology of younger sudden death, where inherited or otherwise unrecognized substrate often replaces the atherosclerotic burden seen later in life.
The age split matters because it shifts the likely differential diagnosis. In the youngest patients, structural disease and unexplained sudden death remain important considerations; in older adolescents and adults up to 49 years, coronary disease becomes more prominent. That mix can reflect different mechanisms of electrical instability, scar-related arrhythmia, coronary plaque rupture, or exercise-triggered ischemia. The underlying biology is not one disease but several pathways converging on the same final event: a malignant rhythm with no timely resuscitation.
Among females, the proportion with ischaemic disease was lower than in males, but still substantial. The study does not suggest a benign profile in women; it suggests a different balance of causes that still demands careful symptom review and risk assessment.
Risk Factors Clustered Even When Exercise Volume Did Not
Cardiovascular risk factors were present in 74% of the cohort. Family history of CVD was the most common, affecting 51%, and overweight was present in at least 33%. These are not subtle background findings. They are the kind of risk markers that often sit in the chart, in the family history, or in the patient’s own description long before an arrest event occurs.
Exercise volume before arrest did not separate the cohort into meaningfully different groups. There were no significant differences in symptoms, risk factors, or OHCA aetiology related to exercise volume prior to the event. That finding is important because it resists a simplistic framing in which exercise itself becomes the main explanatory variable. Exercise can be cardioprotective over the long term, yet at high intensity or in the setting of concealed disease it may expose a vulnerable myocardium to arrhythmic stress. This analysis did not identify a measurable pre-arrest signature based on exercise volume alone.
For clinicians, the practical implication is straightforward: a high activity level should not dilute concern when symptoms or family history are present. Athletic or otherwise active status does not erase inherited susceptibility, early coronary disease, or structural pathology. If anything, repeated exertional symptoms may make the case for evaluation more urgent, not less.
Symptoms During Daily Life Should Not Be Relegated to the Background
The symptom profile deserves particular attention because it reached beyond sport. Most victims had symptoms during both rest and exercise, and the excess of symptom reporting among survivors versus next-of-kin for the deceased suggests that symptom capture may be incomplete after fatal events. Even so, the pattern remained clear enough to matter clinically: exercise-only symptoms were uncommon.
That has two implications. First, pre-arrest evaluation should not focus only on exertional chest pain, dyspnoea, palpitations, or presyncope during training. Second, clinicians should ask whether symptoms emerge during ordinary activity, recovery periods, or emotional stress, because those contexts may reveal ischemia, arrhythmia, or cardiomyopathy just as effectively as exercise. The substrate often declares itself in more than one setting.
The study’s use of registry data, records, autopsy findings, and questionnaire information strengthens the clinical relevance of the signal, although retrospective designs always depend on the quality of prior documentation and recall. The difference between survivors and next-of-kin reporting also reminds readers that symptom burden may be underestimated in fatal cases.
Prevention Hinges on Earlier Recognition of Risk and Aetiology
This nationwide analysis supports a more aggressive approach to pre-arrest assessment in young Norwegians with concerning symptoms, regardless of how much they exercise. The data do not support waiting for symptoms to become severe or exclusively exertional. They also do not support assuming that regular physical activity protects a young person from underlying disease if family history or other risk factors are present.
A family history of CVD, overweight, recurrent chest discomfort, unexplained exertional limitation, syncope, palpitations, or symptoms during ordinary activity should trigger a lower threshold for investigation. Depending on the clinical setting, that may include cardiac examination, ECG, imaging, exercise testing, and genetic or specialist referral when inherited disease is suspected. The study does not prescribe a single pathway, but it does show where the risk is concentrated.
The broader message is embedded in the cause-of-arrest pattern itself: ischaemic heart disease led the aetiology even in a relatively young population, while sudden unexpected death syndrome remained important in those 35 and younger. Exercise volume, by itself, did not explain who arrested or why. The challenge now is not to identify a new exercise threshold. It is to recognize symptoms and risk factors early enough to change the clinical course before collapse occurs.