Cardiac injury in refractory status epilepticus

We sought to describe the spectrum of cardiac injury in refractory status epilepticus (RSE).

We reviewed all patients with RSE between 1999 and 2011 at Mayo Clinic. RSE was defined as generalized convulsive or nonconvulsive status epilepticus (SE) that continued despite initial therapies. Exclusion criteria were age <18 years, anoxic SE, psychogenic SE, simple partial SE, absence SE, and repeat RSE. Patients were divided into those with (transient left ventricular [LV] dysfunction; electrocardiography [ECG] abnormality-new T-wave inversion, ST elevation or ST depression, or QTc prolongation; and/or elevated blood troponin T levels) versus those without evidence of cardiac injury.

We identified 59 consecutive patients with RSE. In 24 patients no cardiac-specific diagnostic studies were obtained. Twenty-two of the remaining 35 patients demonstrated markers of cardiac injury. General anesthesia was necessary for control of seizures in 31 of 35 patients for 10.5 ± 17.4 days. Twenty-three patients had troponin levels drawn at onset of SE, of which nine were abnormal. ECG findings at onset of SE included ST elevation (11.4%), ST depression (5.7%), new T-wave inversion (37.1%), and nonspecific ST changes (37.1%). Cardiac arrhythmias included ventricular tachycardia/fibrillation (11.4%), atrioventricular block (2.9%), atrial fibrillation/flutter (20.0%), sinus bradycardia (48.6%), and sinus tachycardia (65.7%). Intervention was required for cardiac arrhythmias in 42.9%. QTc was prolonged in 22.9% of patients. One patient met criteria for non-ST-elevation myocardial infarction (NSTEMI). Three of 14 patients evaluated with ECG during SE demonstrated reversible systolic dysfunction. In-hospital mortality was 34.3%. Outcome was worse in the group with markers of cardiac injury but the difference was not statistically significant (p = 0.14).

Markers of cardiac injury are common in RSE and may be underrecognized in this population. These disturbances may require specific treatment and are often reversible. Routine performance of ECG and troponin followed by an echocardiography in those with repolarization abnormalities is probably justified. This was a biased sample of patients with severe RSE who had cardiac studies performed. The prevalence of findings in this study refers to this subgroup only.