St. Jude Medical Inc.'s recalled Riata wires, used to connect lifesaving defibrillators to the heart, can short-circuit, a defect that may have led to 22 deaths, researchers said.

An analysis of the U.S. Food and Drug Administration's safety database turned up 133 deaths linked to St. Jude's Riata or Medtronic Inc.'s Quattro Secure leads, according to the report from Dr. Robert Hauser, a cardiologist at the Minneapolis Heart Institute. The 22 deaths that stemmed from failures of the wires used to connect St. Jude's Riata and Riata ST to the heart were typically caused by short circuits between high-voltage components, the study found.

St. Jude, based in Arden Hills, stopped selling the wires, known as leads, in December 2010 and recalled them a year later amid reports they could break through the insulation coating and fail to work properly. The deaths weren't caused by the flaw, known as externalized conductors, Hauser said. The wires remain in about 79,000 patients.

Riata and Riata ST wires "are prone to high-voltage failures that have resulted in death," according to the study to be published in the journal Heart Rhythm that was obtained by Bloomberg News and confirmed by Hauser. "These failures appear to be caused by insulation defects that resulted in short-circuiting between high-voltage components."

St. Jude officials weren't available for comment. The company announced Sunday it had appointed Population Health Research Institute, an academic health science research institute, to analyze data from three registries of the newer Riata ST Optim and Durata leads to determine their performance.

The analysis of the deaths is a further look at a review by Hauser released Sunday that found the failed leads had multiple defects. Surgery to remove the wires still in use may present higher risks than keeping them in, U.S. regulators have said.