Yesterday afternoon, Dr. Leonard Girardi scrubbed in for surgery for the fourth time this week. At about 4 p.m., he entered the operating room and donned a sterile blue gown as he has done dozens of times this month. Then, as he has done hundreds of times this year and thousands of times in his career, the doctor maneuvered around surgical equipment and stepped up to the operating table.

“Medium clips, size two,” he said, gazing into the patient’s open chest cavity, where a pale, pink heart throbbed rhythmically.

A boyish 44, Dr. Girardi operates at breakneck pace, logging 14-hour days as an associate attending cardiothoracic surgeon at NewYork-Presbyterian Hospital, where he performs between two and three surgeries a day, and up to 12 a week. According to the most recent data from the state’s Department of Health, Dr. Girardi performed 974 cardiac surgical procedures between 2002 and 2004, making him one of the state’s top performers.

“That work ethic, I think in my case, comes from being from a sort of blue-collar steel town like Pittsburgh,” he said in an interview at his office this week. Coming from a family of steelworkers, Dr. Girardi was one of the first of his relatives to attend college. He graduated from Harvard University with a degree in biochemistry and molecular biology in 1985, and subsequently earned a medical degree from Weill Medical College of Cornell University in 1989.

Reflecting on his upbringing, Dr. Girardi drew a parallel between himself and his father, an auto mechanic who taught his son to work with his hands. “I worked in the gas station at an early age, and learned how to do tune-ups, and change spark plugs, and do valve jobs,” Dr. Girardi said. “It’s not that much different from now.”

Dr. Girardi said he still enjoys working with his hands to solve problems. Over the years, Dr. Girardi has developed a specialty in repairing aortic aneurisms, enlargements of the aorta that make it prone to tears.

The complicated procedure is technically and mentally demanding, he said. “Fear of failure is something that I think is a great motivator,” he said. The doctor added that cardiac surgery, which he chose over sports medicine, is rewarding: “I like taking care of sick people. I like critical care.”

Related to his specialty, Dr. Girardi has also found a niche in treating patients with Marfan’s syndrome, a genetic condition that affects patients’ connective tissue, and often results in aortic aneurisms.

In his office, where medical journals line his desk, Dr. Girardi keeps a framed letter from a Marfan’s patient, who wrote to him after a successful surgery in 2005. “Thanks for saving my life,” the patient wrote.

“That’s probably my favorite letter I’ve gotten from a patient, bar none,” Dr. Girardi said.

To the extent that he has developed expertise among such patients, Dr. Girardi’s colleagues said he has drawn patients to NewYork-Presbyterian for treatment.

“A large number of the complex aortic procedures in the Northeast come to him,” the chairman of NewYork-Presbyterian’s department of cardiothoracic surgery, Dr. O. Wayne Isom said. Dr. Isom, who met Dr. Girardi in the 1980s when the younger physician was a medical student, likened Dr. Girardi to an elite athlete who operates well under pressure. “My only problem with him is to tell him he needs to slow down and spend time with his family,” Dr. Isom said.

Despite his high patient volume, Dr. Girardi has a high success rate, according to health department statistics. Out of 605 cardiac bypass procedures he performed between 2002 and 2004, only four patients died. According to health department statistics, that represents a 0.66% mortality rate, compared with a statewide average of 2.09% for the same procedure.

Such skill has captured the attention of the hospital’s senior leadership. NewYork-Presbyterian’s president and CEO, Dr. Herbert Pardes, recently referred to him as a “rising star,” and described Dr. Girardi’s “impeccable” success rate. “He’s a doctor’s doctor in that regard,” Dr. Pardes said.

Dr. Girardi said he believes the most significant medical advance in the past decade has to do with patient care, and he praised his clinical staff for their efforts in that regard. “We are just so much better at taking care of sick people now,” he said.

Taking care of sick people does take time, leaving few hours for Dr. Girardi, who lives in Mount Kisco, N.Y., to spend at home with his wife, a urologist on Long Island. He said his most prized commodity is spending time with his four sons, ages 11, 9, 7, and 5. “You will never hear me complain about the 6 a.m. hockey game,” he said. “I’m happy to be there. I’d sure rather be at the rink than here, I can promise you that.”

In the operating room yesterday, Dr. Girardi was all business in his interactions with a student operating at his side.

“He thinks outside the box, that’s what gives you confidence that he can handle difficult situations,” an attending anesthesiologist working with him yesterday, Dr. Shanna Hill, said. Around 4:20 p.m., Dr. Hill stopped the patient’s heart while Dr. Girardi performed a bypass procedure.

A mere hour and 15 minutes later, the surgery was over. Dr. Girardi left the operating room, another day and another surgery behind him.