Electrocardiographic effects of dexmedetomidine in patients with congenital heart disease.

OBJECTIVE

Assessment of electrocardiographic (ECG) effects of dexmedetomidine.

DESIGN

Prospective observational study including children 0-17 years of age with congenital heart disease (CHD) and children following cardiothoracic surgery. Patients who did not receive dexmedetomidine were used as a control group. All patients had two ECGs: one baseline, pre-dexmedetomidine (T1) and one during dexmedetomidine infusion (T2).

MEASUREMENTS AND RESULTS

Fifty-one patients, median age of 0.5 years (IQR = 3.4), and 25 patients, age 0.25 (IQR = 2.9), were included in the dexmedetomidine and control groups, respectively. Forty received a dexmedetomidine-loading dose of 1 microg/kg (IQR = 0.5). At T2, the dexmedetomidine infusion was 1 microg/kg/h (IQR = 0.5). In the dexmedetomidine group, heart rate (HR) decreased from 140 +/- 22 to 115 +/- 23 (P < 0.001); PR, PRc and PR index changed from 115 +/- 28 to 122 +/- 29 ms (P = 0.01), 174 +/- 38 to 167 +/- 35 ms (P = 0.07) and 15,882 +/- 3,565 to 13,792 +/- 3,311 (P < 0.001), respectively. QRS decreased from 84 +/- 21 to 80 +/- 21 ms (P = 0.02), and QTc had no change (433 +/- 47 to 435 +/- 36 ms). When compared to the control group, none of the ECG intervals had any difference other than a trend towards lower HR (P = 0.08). Neonates and infants had a bigger drop in the HR compared to older children (P < 0.001), while other parameters were similar. At T2 none of the dexmedetomidine group patients had atrioventricular block or other arrhythmia. Four patients in the control group had accelerated junctional rhythm.

CONCLUSIONS

Use of dexmedetomidine in patients with CHD and patients following cardiothoracic surgery is not associated with any significant ECG interval abnormalities other than a trend towards lower HR.