Hypercalcemia; EKG changes; Cellular Level

Hey guys... it is 1147 pm right now I worked the day shift and then taught an aerobics class all today. I am tired and just want to ask one question! hehe

On a cellular level... why does Hypercalcemia cause widened QRS and shortened QT interval?

I was writing an email to my nurse educator and honestly i am so tired i just am confused!

"Hypercalcemia and widened QRS and shortened QT"
Widened QRS - Increased Ventricular Depolarization (Increased Contraction)
Shortened QT - Decreased Ventricular Repolarization (Unable to fill ventricular volume)
WIth these both do they explain the reason why he was Tachycardic and Hypertensive on admission because of increased Myocardial Contractility?

Looking @ the Ventricular Myocyte Cardiac Curve and the phases... i see that the Calcium influx is mainly in Phase 2 (Plateau)... this is where i get tired and don't wnat to move on and come to you guys!

If you can help let me know. Otherwise I will retry this again tomorrow. Thanks!
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