2. A vessel approaching a blind bend in a river can sound one prolonged blast on the ships' whistle to alert any other vessels to its presence, if another vessel is nearby then they will respond with one prolonged blast on the ships' whistle.
Atrial fibrillation, known as AF or Afib, is an irregular and often very fast heart rate. This may cause symptoms like heart palpitations, fatigue, and shortness of breath. Treating atrial fibrillation is important because it may cause a stroke and negatively impact your quality of life.
Symptoms of atrial fibrillation, also called afib, can be debilitating. They may include palpitations, shortness of breath, fatigue, and weakness. But trying to reduce these symptoms through drugs that control the abnormal heart beat, called anti-arrhythmic drugs, can come with serious side effects.