In the United States an estimated 2.7 million have a heart condition called atrial fibrillation (afib), and more have other arrhythmias, including tachycardia, a very rapid heart rate. Among those with heart rhythm disorders are public figures like Elton John, Miley Cyrus, and former president George H. W. Bush pictured here. Afib is the most common form of arrhythmia, or irregular heart rhythm. Sometimes medical intervention is necessary to restore a regular heart rhythm, but other times the heart will return to a normal rate on its own. Read on to find out how these celebrities manage their conditions.