American Electric Power Co., Inc. said Tuesday that it has appointed Brian Tierney as executive vice president and chief financial officer, effective October 1.<br /><br />Tierney, 42, previously served as executive vice president - AEP Utilities East, responsible for the distribution, customer service, and financial performance of AEP's utility operating companies in the states of Indiana, Kentucky, Michigan, Ohio, Tennessee, Virginia, and West Virginia.<br /><br />Tierney replaces Holly Koeppel, who served as AEP's chief financial officer since September 1, 2006. Koeppel will continue with the company as an executive vice president through the fourth quarter for financial reporting continuity and to assist Tierney during the transition. Venita McCellon-Allen, 49, will replace Tierney as executive vice president - AEP Utilities East. She previously served as executive vice president - AEP Utilities West, responsible for distribution and customer service operations in the states of Arkansas, Louisiana, Oklahoma and Texas.<br /><br />Charles Patton, 50, will replace McCellon-Allen as executive vice president - AEP Utilities West. He previously served as senior vice president - Regulatory & Public Policy.