Can an increase of blood level cause palpitation?

Depends. Well, i don't know what you mean. Blood level of what? If you mean blood pressure, high blood pressure can be related to rhythm problesm such as atrial fibrillation, so the answer could be yes.
PALPITATIONS W/U. Palpitations that symptomatic deserve a prompt W/U: exam/labs especially TFTS/EKG/Event Monitor/ECHO andThe discussion of treatment options with your doctor. While you are waiting eliminate caffeine focus on staying hydrated. If palpitations worsen or syncope develops go directly to the ER stick to a GF diet ANXIETY AND HYPERVENTILATION CAN CAUSE NUMBNESS.
Blood level? an increase in what blood level? Sometimes increased levels of thyroid hormone could. Or caffeine or other stimulants. But I don't know what you mean. .