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 is often referred to as sick sinus syndrome because the sinoatrial (sinus) node in the right atrium controls the electrical impulses. The cause of atrial fibrillation is not always known. Conditions that can cause damage to the heart and lead to atrial fibrillation include: 1  high blood pressure.  congestive heart failure.
Atrial Fibrillation. 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.