"cardiac (ACS) or pulmonary embolism (PE)"
"A large retrospective Swiss study reviewing 1,866 out-of-hospital cardiac arrests (over a 10-year-period) demonstrated that the most frequent cause of pulseless electrical activity was hypoxia, accounting for almost 25% of all cases. Acute coronary syndrome was cited as the primary cause in 12.5% cases. Other cardiac dysrhythmias, such as long QT syndrome, were also common aetiologies. Most interestingly was the discovery that intracranial haemorrhage, in 80% of cases subarachnoid haemorrhage, was the underlying precipitant of PEA in almost 7% of all cases 1."