Allen Stanford, the Texas financier accused of a $7 billion fraud, is still hospitalized and will undergo tests to determine if there is blockage of veins or arteries in his heart, his lawyer's office, said on Monday.

Stanford, 59, was hospitalized in Conroe, Texas with a racing pulse on Thursday, hours before he was due in federal court in Houston for a hearing.

He will undergo angioplasty or have a heart catheter inserted, a representative for his attorney, Dick DeGuerin, said. No other details were available.

The former billionaire is accused of masterminding a Ponzi scheme that U.S. regulators describe as massive.

Stanford duped investors through the sale of fraudulent certificates of deposit issued by his offshore bank in Antigua and used those funds to bankroll a lavish lifestyle, according to U.S. prosecutors.

Stanford is under increasing pressure related to the case.

On Thursday, his former Chief Financial Officer James Davis pleaded guilty to three criminal charges related to the alleged fraud. Davis is cooperating with prosecutors.

Stanford has denied any wrongdoing. He is being held in a federal detention center about 40 miles north of Houston until his trial.

Lawyer