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.
Symptoms of AFib. The symptoms of AFib may feel similar to those of a heart attack: 1  Heart palpitations. 2  Chest discomfort or pressure. 3  Chest pain. 4  Lightheadedness. 5  Abdominal pain. 6  Shortness of breath.7  Fatigue. 8  Lack of energy.hen a person experiences a heart attack, they are likely to feel: 1  Chest discomfort or pressure. 2  Chest pain. 3  Shortness of breath. 4  Confusion. 5  Extreme fatigue. 6  Dizziness. 7  Sweating. 8  Nausea. 9  Pain that travels down the arm(s). 10  Pain that goes into the jaw, back, or stomach.