From philly.com:
An FDA commissioner told Congress on 6/6/07 hat the FDA was ordering GlaxoSmithKline and Takeda Pharmaceutical Co. Ltd. to add "black box" warnings to their diabetes drugs Avandia and Actos, strengthening existing warnings about heart failure, a condition where the heart does not adequately pump blood.
Congestive heart failure (CHF), or heart failure, is a condition in which the heart can't pump enough blood to the body's other organs. This can result from
- narrowed arteries that supply blood to the heart muscle — coronary artery disease
- past heart attack, or myocardial infarction, with scar tissue that interferes with the heart muscle's normal work
- high blood pressure
- heart valve disease due to past rheumatic fever or other causes
- primary disease of the heart muscle itself, called cardiomyopathy.
- heart defects present at birth — congenital heart defects.
- infection of the heart valves and/or heart muscle itself — endocarditis and/or myocarditis
Source: Here.