Cardiac arrest – unexplained or uninvestigated?


Take Home Messages
  • The cause of sudden cardiac arrest is usually identifiable following routine investigations in most cardiac arrest survivors. However, there is still a small but significant number of cases of unexplained cardiac arrest.
  • Systematic investigation of unexplained cardiac arrest will yield a diagnosis in up to 50% of cases.
  • A specific diagnosis might have implications on treatment, family screening, counselling, and research.
  • If no specific diagnosis is found following currently available investigations, a diagnosis of idiopathic ventricular fibrillation is assigned.

Sudden cardiac death (SCD) accounts for approximately 50% of deaths due to cardiovascular disease in developed countries.(1) Cardiac arrest survival rates are improving, providing an opportunity to thoroughly investigate for an underlying cause in the sudden cardiac arrest (SCA) survivor.(2) Coronary heart disease (CHD) is the cause in approximately 80% of survivors.(3) However, a cause may not be identified after initial assessment with an ECG, echocardiogram, and coronary assessment in a significant proportion of SCA survivors, leading to a diagnosis of unexplained cardiac arrest (UCA).(2,4)

This article will highlight the current available investigations for a SCA survivor with UCA.