Magnesium Lowers the Incidence of Postoperative Junctional Ectopic Tachycardia in Congenital Heart Surgical Patients: Is There a Relationship to Surgical Procedure Complexity?

Abstract

Magnesium sulfate was given to pediatric cardiac surgical patients during cardiopulmonary bypass period in an attempt to reduce the occurrence of postoperative junctional ectopic tachycardia (PO JET). We reviewed our data to evaluate the effect of magnesium on the occurrence of JET and assess a possible relationship between PO JET and procedure complexity. A total of 1088 congenital heart surgeries (CHS), performed from 2005 to 2010, were reviewed. A total of 750 cases did not receive magnesium, and 338 cases received magnesium (25 mg/kg). All procedures were classified according to Aristotle score from 1 to 4. Overall, there was a statistically significant decrease in PO JET occurrence between the two groups regardless of the Aristotle score, 15.3 % (115/750) in non-magnesium group versus 7.1 % (24/338) in magnesium group, P < 0.001. In the absence of magnesium, the risk of JET increased with increasing Aristotle score, P = 0.01. Following magnesium administration and controlling for body weight, surgical and aortic cross-clamp times in the analyses, reduction in adjusted risk of JET was significantly greater with increasing Aristotle level of complexity (JET in non-magnesium vs. magnesium group, Aristotle level 1: 9.8 vs. 14.3 %, level 4: 11.5 vs. 3.2 %; odds ratio 0.54, 95 % CI 0.31-0.94, P = 0.028). Our data confirmed that intra-operative usage of magnesium reduced the occurrence of PO JET in a larger number and more diverse group of CHS patients than has previously been reported. Further, our data suggest that magnesium's effect on PO JET occurrence seemed more effective in CHS with higher levels of Aristotle complexity.

Conflict of interest statement

Conflict of interest The authors declare that they have no conflict of interest.

Figures

Fig. 1

Aristotle score distribution in the two study groups. a Case distribution in non-magnesium group. b Case distribution in magnesium group. AL aristotle level. See text for explanation

Fig. 2

Univariate predictors for postoperative JET occurrence. Illustrated in this figure is the frequency of postoperative JET occurrence over different a Aristotle levels (1–4), b aortic cross-clamp times (from 0 to >61 min), c surgical times (from ≤2 to >4 h), and d CPB times (from ≤60 min to >2 h). CC crossing clamp. See text for explanation

Fig. 3

Adjusted rate of postoperative JET occurrence by treatment group (multivariate analysis). Relationship between Aristotle level and occurrence of PO JET in the two study groups (non-magnesium and magnesium) after the analysis was controlled for BSA, surgery time, aortic cross-clamp time, and dopamine and milrinone administration. See text for explanation

Fig. 4

Distribution of aortic cross-clamp times, cardiopulmonary bypass times, and surgical times separated into different Aristotle levels. See text for explanation