Electrolytes

Question 1

Hypokalemia

Answer 1

EKG changes occur at <3
-PVCs
-U waves
-Potentiates effects of digitalis

Question 2

Hypercalcemia

Answer 2

AV blocks, bundle branch blocks and bradycardia related to increased contractility of the heart and shortening of the QT interval.
-Potentiates effects of digitalis.

Question 3

Hypocalcemia

Answer 3

-Bradycardia, ventricular ectopy and asystole because low calcium levels decrease contractility.
-Decreased cardiac output and hypotension.
-Decreased efficacy of digitalis.

Question 4

Hypermagnesemia

Answer 4

EKG changes occur with mag >5
-Usually associated with renal failure or over administration of magensium during replacement therapy.
-Prolonged PR and QT intervals and increased QRS duration with the risk of electrical conduction delays and bradycardia.
-Complete heart block and cardiac arrest may occur at >15

Question 5

Hypomagnesemia

Answer 5

Changes similar to those of hypocalcemia and hypomagnesemia
-Appearance of U waves, prolonged PR/QT interval, widened QRS complexes, peaked T waves followed by flattening of T waves, SVT, ventricular arrhythmias, torsades.
May cause hypertension and coronary/systemic vasospasms
Usually needs to be corrected before replacement theray of hypokalemia and calcemia can be effective.