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This elevated extracellular K+ concentration
A. Increased the propagation velocity of the myocardial action potentials
B. Decreased the repolarization refractoriness of the myocardial cells
C. Increased the resting (phase 4) transmembrane potential to a less negative value
D. Diminished the automaticity of the myocardial cells
E. Decreased the likelihood of reentry dysrhythmias

answer is C....

c u tomorrow

Thnx for the Qs and nice detailed explanations!!

Wouldn't increase of K cause hyperpolarization?

The answer is C. With an accumulation of extracellular potassium, the transmembrane
potential will become less negative. Interstitial potassium is elevated because of Na+/K+-
ATPase pump hypoxic failure. Choice A is incorrect because elevation of extracellular
potassium (via the Nernst equation) will partially depolarize the resting membrane potential,
thereby decreasing phase 0 amplitude and decreasing the conduction velocity.
Choice B is incorrect because repolarization of myocardial cells requires potassium extrusion
from the interior of the cell. This is more difficult with elevated extracellular
potassium. Choice C is incorrect because automaticity (firing frequency) is related to
the time to reach threshold potential, which is decreased in the less negative cells closer
to their threshold potential. Choice E is incorrect because a decrease in ventricular
muscle conduction velocity will increase the likelihood of reentry dysrhythmias