PURPOSE: To determine whether abnormal cardiac repolarization and other electrocardiography (ECG) predictors for cardiac mortality occur in epilepsy patients and whether they are associated with an increased risk for sudden unexpected death in epilepsy (SUDEP). METHODS: In a matched-pair case-control study, recordings of adult patients with pharmacoresistant focal epilepsies who died from SUDEP and who had previously had presurgical video-EEG (electroencephalography) telemetry were reviewed. Living controls were matched for age, gender, and date of admission for video-EEG telemetry. Periictal heart rate (HR), corrected QT interval (QTc), postictal HR recovery, HR variability, and cardiac rhythm were assessed. QT dispersion was analyzed with 12-lead ECG. RESULTS: A total of 38 patients (19 per group) had 91 recorded seizures. QTc was prolonged above pathologic upper limits in 9 of 89 seizures and 5 of 38 patients. Nine of 34 patients displayed pathologic QT dispersion. Presence of neither pathologic cardiac repolarization nor other ECG features were specifically associated with SUDEP. SUDEP patients were, however, more likely to lack pathologic cerebral magnetic resonance imaging (MRI) findings, less likely to experience antiepileptic drug reduction during telemetry, and had more secondarily generalized tonic-clonic seizures (SGTCS) per year. DISCUSSION: Our study did not reveal a clear-cut ECG predictor for SUDEP. Pathologic cardiac repolarization is not uncommon in adult patients with pharmacoresistant focal epilepsy and could favor occurrence of fatal tachyarrhythmia as one plausible cause for SUDEP. SGTCS are a risk factor for SUDEP, have, as compared to complex-partial seizures, a greater, unfavorable impact on heart activity, and may thereby additionally compromise cardiac function.