This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
A patient develops sudden palpitation with HR 150/ min, regular. What could be the cause - 
Select and explain. 
A. PSVT, B. Sinus tachycardia, C. Ventricular tachycardia, D. Atrial flutter with block
A: PSVT
Answer: A: PSVT 
Explanation: Paroxysmal supraventricular tachycardia (PSVT) is a type of supraventricular tachycardia.Often people have no symptoms.Otherwise symptoms may include palpitations, feeling lightheaded, sweating, shoness of breath, and chest pain.Episodes sta and end suddenly The cause is not known.Risk factors include alcohol, caffeine, nicotine, psychological stress, and Wolff-Parkinson-White syndrome which often is inherited from a person's parents. The underlying mechanism typically involves an accessory pathway that results in re-entry.Diagnosis is typically by an electrocardiogram (ECG) which shows narrow QRS complexes and a fast hea rhythm typically between 150 and 240 beats per minute Ref Harrison 20th edition pg 1435