A beating heart has its own sonic signature, the steady lub-dub of the chambers opening and closing as blood flows, backs up and flows again through the only muscle in the body that never rests. To the trained ear, these murmurs, whooshes, gallops and rubs speak volumes, and provide clear information about heart disease or defects.

For more than three decades, teaching the language of heart sounds to medical students has been the job of Lawrence S. Cohen, M.D., the Ebenezer K. Hunt Professor of Medicine. Deliberate, concise and always impeccably dressed, Cohen is the sort of professor whom medical students notice enough to honor with a nickname, recalls Jeffrey R. Bender, M.D., who served as a resident under Cohen in the early 1980s.

“He was known as ‘Larry the Heart,’ ” recalls Bender, now the Robert I. Levy Professor of Preventive Cardiology, “and he was the consummate teacher.”

At 74, Cohen still teaches every Yale medical student how to listen to the heart; he estimates that he’s instructed some 3,000 students over the past three decades. When he thinks back to the early days of his academic career, the advancements in cardiac care fill him with wonder. “The No. 1 difference between then and now,” he says, “is that someone practicing today has the tools to prevent heart disease and reverse its course.”

Those tools exist in part thanks to Cohen, who was a key player in studies showing that heart attacks are caused by the rupture of a plaque from coronary artery walls and the clotting that follows. He was also the principal investigator at Yale for the first three Thrombolysis in Myocardial Infarction (TIMI) trials, which were multicenter studies demonstrating that clot-busting drugs could limit or prevent damage during heart attacks and dramatically increase survival rates.

Known for his calm, effective approach to decision-making, Cohen has served as deputy or special advisor to medical school deans for 16 years, overseeing faculty appointments and promotions, raising money for endowed professorships and promoting the responsible conduct of scientific research. Cohen recently stepped down from this role and will be succeeded by Linda C. Mayes, M.D., the Arnold Gessell Professor of Child Development in the Child Study Center. However, he is continuing on full-time as a practicing and teaching cardiologist.

That’s good news for the medical school, says John A. Elefteriades, M.D., the section chief and William W.L. Glenn Professor of Cardiothoracic Surgery (see “Top Heart Surgeon is Named Glenn Professor”), who himself learned to listen to the heart from Cohen as a member of the School of Medicine’s Class of 1976. In February, Elefteriades and Cohen published their second book (Cohen’s fourth), Your Heart: An Owner’s Guide (Prometheus Books).

Cohen is “the cardiologists’ cardiologist. When any of us is ill, we go to him,” Elefteriades says. “And whenever there’s a difficult or complex case that requires exceptional judgment, cardiologists from all over the region will send their patients to him.”

The Brooklyn-bred Cohen came to Yale in 1958 as an intern, following college at Harvard and medical school at New York University. Twelve years later, after stints at Johns Hopkins, Harvard, the National Institutes of Health and the University of Texas, he returned to Yale as chief of cardiology.

Cohen has mentored dozens of influential cardiologists and leaders in academic medicine. John M. Lasala, M.D., Ph.D., director of interventional cardiology at Washington University in St. Louis, was a fellow under Cohen in 1989 and 1990. Lasala recalls, “The most amazing thing was his ability to synthesize great amounts of information into simple and factually correct assessments. He could say an awful lot with very little.”

Cohen has no intention of putting aside his clinical duties any time soon.

“Being able to make a difference in patients’ lives” he says, “is a privilege.”