The trigger-substrate interaction that may lead to “unexplained” sudden cardiac arrest

In our recent paper we start to unravel the mechanisms of “unexplained” sudden cardiac arrest.

Looking back, we often understand what happened when somebody had sudden cardiac arrest (SCA). Sometimes, we don’t know what happened, even after extensive diagnostics. Especially in young, apparently healthy individuals, unexplained SCA has a major impact, despite being rare. We employed electrocardiographic imaging (ECGI) in survivors of unexplained SCA to get more insight in the arrhythmia substrate. ECGI extends the clinical electrocardiogram by using many more electrodes and imaging. We used it to study electrical recovery that happens after each heartbeat. In survivors of SCA in Maastricht UMC+, we found (clinically concealed) abnormalities in the electrical recovery of their hearts. In particular, these SCA survivors often have regions of early recovery next to regions of late recovery, with steep recovery gradients in between, and premature beats originating from the early recovery region. In experiments with explanted hearts at IHU LIRYC and in computer models (with support of Philips) we show that these premature beats may interact with the recovery gradients and lead to life-threatening arrhythmias. A tl/dr summary can be found in this Twitter thread.

These findings may help to provide targets for early diagnosis and improved therapy for sudden cardiac arrest, which we will need to study with future work.