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 (also referred to as AF or AFib) is the most common type of irregular heartbeat. It is found in about 2.2 million Americans. Its frequency increases with age. If you have AF, the electrical impulse does not travel in an orderly fashion through the atria.ou may have atrial fibrillation without having any symptoms at all. If you have symptoms, they may include: 1  Heart palpitations (a sudden pounding, fluttering, or racing feeling in the chest). 2  Fatigue or lack of energy. 3  Dizziness (feeling faint or light-headed).