Serum Magnesium and Ventricular Repolarization in Adolescents Without Documented Cardiovascular Disease: A Retrospective Study

Abstract

Objective: To evaluate the association between serum magnesium status and electrocardiographic parameters, particularly ventricular repolarization, among adolescents without documented cardiovascular disease.

Methods: This retrospective analytical study included 150 records of adolescents aged 10–19 years with available serum magnesium measurements and 12-lead electrocardiograms. Serum magnesium was evaluated continuously and categorized as low (<1.7 mg/dL) or normal (1.7–2.4 mg/dL). Heart rate, PR interval, QRS duration, QT interval, and corrected QT (QTc) interval were analyzed. Correlation and multivariable linear regression analyses were performed to assess the relationship between serum magnesium and QTc.

Results: Of 150 eligible records, 29 (19.3%) had low serum magnesium. Adolescents with low magnesium demonstrated higher resting heart rate (82.5 ± 11.8 vs. 77.7 ± 11.1 beats/min; P=0.039) and longer QT (385.8 ± 27.1 vs. 372.3 ± 25.8 ms; P=0.014) and QTc intervals (431.0 ± 22.7 vs. 414.6 ± 23.3 ms; P=0.001). PR interval and QRS duration did not differ significantly between groups. Serum magnesium was inversely correlated with QTc (r=−0.32; P<0.001) and remained independently associated with QTc after adjustment for age, sex, and heart rate (β=−0.27; P=0.001).

Conclusion: Lower serum magnesium was associated with longer ventricular repolarization intervals among adolescents without documented cardiovascular disease. Prospective studies are required to determine the clinical and preventive significance of this association.