Symptoms. When atrial tachycardia occurs, the heart has more difficulty than normal with getting oxygenated blood to all parts of the body. This means that oxygen does not get to the tissues and organs of the body quick enough, which can result in several uncomfortable and potentially dangerous symptoms. Lightheadedness and shortness of breath can occur as the oxygen does not reach the brain quick enough, and the lungs struggle for a larger oxygen intake. Chest pain and an uncomfortable sensation of racing or flopping in the region of the chest called palpitations can also result as the heart works increasingly harder to pump blood. If the heart rate stays very elevated for a period of time, some individuals may faint or lose consciousness due to a lack of adequate oxygen to the brain.