This is the most common cause of an unusual,or abnormal, heartbeat in older adults.

VOA: special.2009.09.22

This is the most common cause of abnormal heartbeat in older adults.

VOA: special.2009.08.12

The most common cause is pollen from flowering plants and trees.

VOA: special.2010.12.21

The most common cause of COPD is long-term smoking or years of exposure to second-hand smoke.

VOA: standard.2010.06.21

The goal is to search for common genes that may cause the disease.

VOA: special.2009.04.07

Down syndrome is the most common genetic cause of mental retardation.

VOA: special.2009.09.09