Romano–Ward syndrome is the most common form of congenital Long QT syndrome (LQTS), a genetic heart condition that affects the electrical properties of heart muscle cells. Those affected are at risk of abnormal heart rhythms which can lead to fainting, seizures, or sudden death. Romano–Ward syndrome can be distinguished clinically from other forms of inherited LQTS as it affects only the electrical properties of the heart, while other forms of LQTS can also affect other parts of the body. Romano–Ward syndrome is caused by abnormal variants in the genes responsible for producing certain proteins used to transport charged particles (ion channels) within the heart. These abnormalities interfere with the electrical signals that heart cells use to coordinate contractions, causing the heart to take longer to recharge in between beats. The condition is usually diagnosed using an electrocardiogram, but other tests sometimes used include Holter monitoring, exercise testing, and genetic testing. It may be treated using medications such as beta-blockers, an implantable cardioverter-defibrillator, or surgery to disrupt the sympathetic nervous system. Romano–Ward syndrome is estimated to affect 1 in every 7,000 people. Signs and symptoms
Romano–Ward syndrome increases the risk of abnormal heart rhythms or arrhythmias. These are typically a form of ventricular tachycardia known as Torsades de pointes which can cause faints, seizures, or even sudden death. Less dangerous arrhythmias such as atrial fibrillation also occur, causing symptoms of heart racing or palpitations. However, many of those with Romano–Ward syndrome will remain free from arrhythmias and therefore free from symptoms.
Unlike alcohol, the onset and disappearance are near instantaneous. A diver may be quite clear-headed at 20 meters, and yet giddy and silly at 30 meters. Ascending to 20 meters will almost instantly clear the head. High pressure nervous syndrome (HPNS)
Barotrauma
Barotrauma is injury caused by pressure effects on gas spaces. This may occur during ascent or descent. The ears are the most commonly affected body part. The most serious injury is lung barotrauma, which can result in pneumothorax, pneumomediastinum, pneumopericardium, subcutaneous emphysema, and arterial gas embolism. All divers, commercial air travelers, people traveling overland between different altitudes, and people who work in pressurized environments have had to deal with some degree of barotrauma effect upon their ears, sinuses, and other air spaces. At the most extreme, barotrauma can cause ruptured eardrums, bleeding sinuses, exploding tooth cavities, and the lung injuries described above. This is the reason why divers follow a procedure of not holding their breath during ascent. By breathing continuously, they keep the airways open and avoid pressure differences between their lungs and ambient pressure. Arterial gas embolism (AGE)
Arterial gas embolism (AGE) is a complication of lung barotrauma of ascent. It occurs when breathing gas is introduced to the circulation on the arterial side via lung over-pressure trauma. AGE can present in similar ways to arterial blockages seen in other medical situations. Affected people may suffer strokes, with paralysis or numbness down one side; they may suffer heart attacks; they may suffer pulmonary embolism with shortness of breath and chest pain.