â¢ One plate is pushed beneath the other, or equivalent description. â¢ A trench may be formed at the subduction zone. (ii) Explain how subduction leads to volcanic activity. (2 points: 1 point for a correct explanation of one plate being pushed down and melted and 1. point for a correct explanation of molten material /magma rising to the surface near the zone)
Symptoms of atrial fibrillation occur when the upper chambers of the heart (atria) beat in a disorganized fashion. Atrial fibrillation is a type of arrhythmia. Characteristic symptoms include shortness of breath, palpitations, and lightheadedness.
Very often people with atrial fibrillation have no symptoms and do not know they are in AFib. On the other hand, those who notice when they are having atrial fibrillation can have symptoms ranging from mild to debilitating. Symptoms of atrial fibrillation include: 1  Rapid beating, pounding, or fluttering sensation in the chest (palpitations)  Lightheadedness.