Cardiac arrhythmias associated with severe traumatic brain injury and hypothermia therapy

Severe head trauma and/or severe hypothermia (< or =32 degrees C) can cause cardiac arrhythmias. Effect of moderate hypothermia (32-33 degrees C) on cardiac arrhythmias in children after severe traumatic brain injury is not well characterized. The objective is to determine the effect of moderate and short-term (24 hrs) hypothermia therapy on the incidence and severity of cardiac arrhythmias in children with severe traumatic brain injury compared with normothermic control subject using a 24-hr Holter recording.

Prospective ancillary study of a multicenter randomized, controlled clinical trial.

A Canadian university-affiliated pediatric intensive care unit in a level III trauma center. PATIENTS Patients <18 yrs with severe traumatic brain injury.

Holter recording during moderate hypothermia (HYPO group; esophageal temperature 32-33 degrees C) or normothermia (NORMO group; 36.5-37.5 degrees C) induced for 24 hrs started within 8 hrs after a severe traumatic brain injury.

Sixteen patients who had a median age of 12.7 yrs (range, 7.2-17.0 yrs) were enrolled. The time from the injury to the start of the cooling process was 7.3 hrs (range, 6.6-7.8 hrs). The temperature when Holter recording began was 32.9 degrees C (range, 31.6-34.4 degrees C) in the HYPO group. Overall, 44% of all patients (seven of 16 patients) had arrhythmias (two of nine in the NORMO group and five of seven in the HYPO group, p = .13). The most frequent arrhythmias were isolated premature atrial contractions. Hypothermic patients had lower heart rates than normothermic patients (p = .01), but none had a severe bradycardia. In the NORMO group, one patient had accelerated junctional rhythm associated with hypotension. In the HYPO group, one patient had nonsustained monomorphic ventricular tachycardia.

Arrhythmias are frequent in severe pediatric traumatic brain injury. Further studies are needed to characterize the epidemiology and clinical impact of arrhythmias associated with severe pediatric head trauma and moderate hypothermia.