PSVT is a type of abnormal heart rhythm where the heart suddenly beats much faster than normal due to electrical signals starting in the atria or the atrioventricular (AV) node. Episodes begin and end abruptly, often lasting seconds to hours, and may cause palpitations, dizziness, chest discomfort, or shortness of breath. It is usually not life-threatening but can be distressing and disruptive. Common triggers include stress, caffeine, alcohol, or certain medications, and treatment may involve vagal maneuvers, medications, or catheter ablation in recurrent cases.