What types of cardiac arrhythmia are caused by hypomagnesemia?

Updated: Oct 30, 2020
  • Author: Tibor Fulop, MD, PhD, FACP, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Hypomagnesemia can cause cardiac arrhythmia. [40, 41, 42] Changes in electrocardiogram findings include prolongation of conduction and slight ST depression, although those changes are nonspecific. Patients with magnesium deficiency are particularly susceptible to digoxin-related arrhythmia. Intracellular magnesium deficiency and digoxin excess act together to impair Na+/K+ -ATPase. The resulting decrease in intracellular potassium disturbs the resting membrane potential and repolarization phase of the myocardial cells, enhancing the inhibitory effect of digoxin. Intravenous magnesium supplementation may be a helpful adjunct when attempting rate control for atrial fibrillation with digoxin. [43]

Non–digitalis-associated arrhythmias are myriad. The clinical disturbance of greatest importance is the association of mild hypomagnesemia with ventricular arrhythmia in patients with cardiac disease. At-risk patients include those with acute myocardial ischemia, congestive heart failure, or recent cardiopulmonary bypass, as well as acutely ill patients in the intensive care unit. [40]


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