Repolarization Abnormalities and Outcomes Among Patients with Cardiac Arrest.

Background: Changes in ventricular repolarization, observed as QTc prolongation, are frequently observed following cardiac arrest. The T-peak to T-end (TpTe) interval represents a period of increased susceptibility to ventricular arrhythmia. We posit that TpTe prolongation may be associated with adverse clinical outcomes in patients resuscitated from cardiac arrest.

Methods: We included patients aged ≥18 years with both out-of-hospital and in-hospital cardiac arrest following return of spontaneous circulation (ROSC) who had an electrocardiogram (ECG) obtained within 24 hours following ROSC. The first ECG obtained was evaluated to determine the QTc and TpTe intervals. Hierarchical logistic regression was used to evaluate the association between prolongation of the QTc and TpTe intervals and clinical outcomes (in-hospital mortality and favorable neurologic outcome at hospital discharge).

Results: We included 443 patients, with a median age of 61 years (IQR: 50-72 years), 60.5% male, 65.7% OHCA, and 29.8% with initial shockable rhythm. Overall, 310 patients had QTc prolongation (70.0%), and 284 had TpTe prolongation (64.1%). Patients with TpTe prolongation had a greater incidence of initial shockable rhythm (35.6% vs 19.5%, P<0.001) and higher initial lactate (8.6 vs 7.4 mmol/L, P=0.03). QTc prolongation was not associated with in-hospital mortality (odds ratio [OR]:1.27, 95% confidence interval [CI]: 0.75-2.14, P=0.37) or favorable neurologic outcome (OR:0.88, 95% CI: 0.50-1.54, P=0.65). TpTe prolongation was independently associated with in-hospital mortality (OR: 1.69, 95% CI: 1.01-2.85, P=0.05) but not favorable neurologic outcome (OR: 0.78, 95% CI: 0.45-1.37, P=0.39).

Conclusions: TpTe interval prolongation, but not QTc interval prolongation, was associated with increased in-hospital mortality in patients resuscitated from cardiac arrest.