This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluids and Electrolyte Imbalance, Subject name: Medicine
Hea block is seen in: 
Select and explain. 
A. Hypermagnesemia, B. Hypomagnesemia, C. Hypernatremia, D. Hypocalcemia
A: Hypermagnesemia
Answer: A: Hypermagnesemia 
Explanation: Hypermagnesemia slows the hea and leads to hea block Hypomagesemia leads to cardiac arrhythmias like SVT and VT