A Committee of the European Medicines Agency recently concluded that diclofenac is associated with an increased risk of heart attacks compared to other non-steroidal anti-inflammatory drugs (NSAIDs). The conclusion, based on robust evidence, further states that increased vascular risks are particularly associated with high-dose or long-term use of the drug. Thus the Committee recommends that patients with "serious... heart or circulatory conditions... should not use diclofenac."
Diclofenac is a painkiller marketed in the United States under various names, such as Cambia, Flector, and Voltaren (the full list is available by searching for "diclofenac" at http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm).
Source: European Medicines Agency, http://www.ema.europa.eu/ema/index.jsp?curl=pages/news_and_events/news/2013/06/news_detail_001816.jsp&mid=WC0b01ac058004d5c1