Cardiac Disease Specialists has become the third major cardiovascular physician group to join the Piedmont Heart Institute, making PHI Physicians one of the largest cardiovascular specialists in the Southeast, the hospital company said Friday.

Terms of the arrangement were not immediately available.

Cardiac Disease Specialists has 17 physicians in 11 locations. Its sleep disorders center also will become part of the Piedmont Heart Institute, the company said.

"The addition of Cardiac Disease Specialists to PHI signifies the coming together of some of the best and brightest cardiovascular physicians in the field, complementing the membership of [Atlanta Cardiology Group] and [Atlanta Cardiology Group], which seven months ago became the first practice to join the Piedmont Heart Institute.

The Piedmont Heart Institute includes more than 60 cardiovascular specialists and "continues to initiate new programs in cardiovascular research, education an excellence in prevention, arrhythmias, coronary and vascular intervention, stroke and cardiac imaging, PHI said in a statement.