Effects of Calcium, Magnesium, and Potassium Concentrations on Ventricular Repolarization in Unselected Individuals.

Background

Subclinical changes on the electrocardiogram are risk factors for cardiovascular mortality. Recognition and knowledge of electrolyte associations in cardiac electrophysiology are based on only in vitro models and observations in patients with severe medical conditions.

Objectives

This study sought to investigate associations between serum electrolyte concentrations and changes in cardiac electrophysiology in the general population.

Methods

Summary results collected from 153,014 individuals (54.4% women; mean age 55.1 ± 12.1 years) from 33 studies (of 5 ancestries) were meta-analyzed. Linear regression analyses examining associations between electrolyte concentrations (mmol/l of calcium, potassium, sodium, and magnesium), and electrocardiographic intervals (RR, QT, QRS, JT, and PR intervals) were performed. The study adjusted for potential confounders and also stratified by ancestry, sex, and use of antihypertensive drugs.

Results

Lower calcium was associated with longer QT intervals (-11.5 ms; 99.75% confidence interval [CI]: -13.7 to -9.3) and JT duration, with sex-specific effects. In contrast, higher magnesium was associated with longer QT intervals (7.2 ms; 99.75% CI: 1.3 to 13.1) and JT. Lower potassium was associated with longer QT intervals (-2.8 ms; 99.75% CI: -3.5 to -2.0), JT, QRS, and PR durations, but all potassium associations were driven by use of antihypertensive drugs. No physiologically relevant associations were observed for sodium or RR intervals.

Conclusions

The study identified physiologically relevant associations between electrolytes and electrocardiographic intervals in a large-scale analysis combining cohorts from different settings. The results provide insights for further cardiac electrophysiology research and could potentially influence clinical practice, especially the association between calcium and QT duration, by which calcium levels at the bottom 2% of the population distribution led to clinically relevant QT prolongation by >5 ms.

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Title	Effects of Calcium, Magnesium, and Potassium Concentrations on Ventricular Repolarization in Unselected Individuals.
Date	June 25th, 2019
Issue name	Journal of the American College of Cardiology
Issue number	v73.24:3118-3131
DOI	10.1016/j.jacc.2019.03.519
Authors	Noordam R, Young WJ, Salman R, Kanters JK, van den Berg ME, van Heemst D, Lin HJ, Barreto SM, Biggs ML, Biino G, Catamo E, Concas MP, Ding J, Evans DS, Foco L, Grarup N, Lyytikäinen LP, Mangino M, Mei H, van der Most PJ, Müller-Nurasyid M, Nelson CP, Qian Y, Repetto L, Said MA, Shah N, Schramm K, Vidigal PG, Weiss S, Yao J, Zilhao NR, Brody JA, Braund PS, Brumat M, Campana E, Christofidou P, Caulfield MJ, De Grandi A, Dominiczak AF, Doney ASF, Eiriksdottir G, Ellervik C, Giatti L, Gögele M, Graff C, Guo X, van der Harst P, Joshi PK, Kähönen M, Kestenbaum B, Lima-Costa MF, Linneberg A, Maan AC, Meitinger T, Padmanabhan S, Pattaro C, Peters A, Petersmann A, Sever P, Sinner MF, Shen X, Stanton A, Strauch K, Soliman EZ, Tarasov KV, Taylor KD, Thio CHL, Uitterlinden AG, Vaccargiu S, Waldenberger M, Robino A, Correa A, Cucca F, Cummings SR, Dörr M, Girotto G, Gudnason V, Hansen T, Heckbert SR, Juhl CR, Kääb S, Lehtimäki T, Liu Y, Lotufo PA, Palmer CNA, Pirastu M, Pramstaller PP, Ribeiro ALP, Rotter JI, Samani NJ, Snieder H, Spector TD, Stricker BH, Verweij N, Wilson JF, Wilson JG, Jukema JW, Tinker A, Newton-Cheh CH, Sotoodehnia N, Mook-Kanamori DO, Munroe PB & Warren HR
Keywords	cohort studies, electrocardiographic intervals, electrolytes, epidemiology, meta-analysis
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