Hypertension, most commonly referred to as "high blood pressure", HTN or HPN, is a medical condition in which the blood pressure is chronically elevated. It was previously referred to as arterial hypertension, but in current usage, the word "hypertension" without a qualifier normally refers to arterial hypertension. Hypertension can be classified either essential or secondary. Essential hypertension indicates that no specific medical cause can be found to explain a patient's...