The ad campaign for the cholesterol-lowering drug Lipitor that features artificial heart pioneer Dr. Robert Jarvik has been halted by drug maker Pfizer. A U.S. Congressional committee examining consumer drug advertising has been looking into whether the ads misrepresented Jarvik and his credentials.

Jarvik has a medical degree, but isn't a cardiologist and isn't licensed to practice medicine, The New York Times reported. In addition, former colleagues of Jarvik complained that the ads erroneously identified Jarvik as the "inventor of the artificial heart." Pfizer subsequently changed the ads to identify him as inventor of the Jarvik heart, the newspaper said.

One of the ads depicted Jarvik as a skilled rower skimming across a mountain lake. But the ad featured a body double for Jarvik, who doesn't row, the Times reported.

"The way in which we presented Dr. Jarvik in these ads has, unfortunately, led to misimpressions and distractions from our primary goal of encouraging patient and physician dialogue on the leading cause of death in the world -- cardiovascular disease," Ian Read, Pfizer's president of worldwide operations, said in a prepared statement.

Read said Pfizer would be committed to "greater clarity" in its advertising in the future, the Times reported.