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.
1 Atrial fibrillation (AFib) is an irregular heartbeat (arrhythmia) often, but not always, resulting in a fast heart beat (greater than 100 bpm) at rest. 2  Causes of AFib are numerous; for example: 3  overactive thyroid,  alcohol use,