Bigeminy
（重定向自Bigeminal）
Bigeminy (Latin: bi-two, gemini-twins) is a descriptor for a heart arrhythmia in which there is a continuous alternation of long and short heart beats. Most often this is due to ectopic heart beats occurring so frequently that there is one after each sinus beat, typically premature ventricular contractions (PVCs). For example, a sinus beat is shortly followed by a PVC, then followed by a pause. The normal beat then returns, only to be followed by another PVC.