Edmund Sonnenblick, 74; was cardiologist, pioneer in heart failure treatment

NEW YORK - Dr. Edmund H. Sonnenblick, a cardiologist whose research formed a basis for the modern treatment of heart failure, which has extended the lives of millions of people, died Saturday at his home in Darien, Conn. He was 74.

The cause was esophageal cancer, said his son-in-law, Dr. Kenneth Offit.

Dr. Sonnenblick's findings about the structure and function of heart muscle cells and how the heart muscle contracts and relaxes contributed to the development by others of a new class of lifesaving drugs, called ACE inhibitors. He and other researchers also adapted beta blockers for use in heart failure.

Dr. Eugene Braunwald, an international leader in cardiology at Harvard, likened Dr. Sonnenblick's basic research work to "what a brilliant mathematician or theoretical physicist does that ultimately allows you to go into space."

Dr. Sonnenblick's research began in the 1960s at Presbyterian Hospital in Manhattan. It continued at the National Heart, Lung and Blood Institute in Bethesda, Md.; Harvard; and the Albert Einstein College of Medicine of Yeshiva University in the Bronx, where he was a distinguished university professor of medicine.

For providing a framework for understanding normal and abnormal heart function, "Ed Sonnenblick occupies an honored place in the pantheon of the greatest heart and blood vessel physiologists of the 20th century," said Braunwald, who worked with Dr. Sonnenblick at Harvard and at the heart institute.

Edmund Hiram Sonnenblick was born Dec. 7, 1932, in New Haven. After graduating from Wesleyan University in 1954 and Harvard Medical School in 1958, he trained in internal medicine at Presbyterian.

In the 1960s, doctors knew that a healthy heart could adjust to pump more blood when less flowed into it - after severe bleeding, for example - and to pump less after transfusions. But doctors did not understand the best ways to treat a failing heart that was unable to make such adjustments.

In his research, Dr. Sonnenblick applied principles that other scientists had learned from studying skeletal muscle.

A major accomplishment was showing that the amount of blood the heart pumped depended on muscle mechanics. As the muscle stretches and widens in heart failure, the heart becomes more spherical. The tension in the heart wall increases just as it does in a balloon when more air is blown into it.

The heart can maintain pumping to meet the body's needs, but at the cost of being stretched out, said Dr. Michael Lesch, who trained with Dr. Sonnenblick and is now the chairman of the department of medicine at St. Luke's-Roosevelt Hospital Center in Manhattan.

Dr. Sonnenblick is also credited as the first to use the powerful new electron microscope to image heart muscle under scientifically controlled conditions, accomplishing the feat in 1963 at Columbia, where he correlated measurements of heart muscle structure and the force of its contractions.

Dr. Sonnenblick showed his electron micrographs at what was then the most prestigious scientific meeting in biomedical research: the plenary session of the American Society for Clinical Investigation, held in Atlantic City, N.J.

"A hush fell over the audience," Braunwald said, as Dr. Sonnenblick showed how heart muscle contractions were dependent on the alignment of certain molecules in the cells.

Dr. Sonnenblick also provided an understanding that enabled other scientists to develop the drugs Enalapril and other ACE inhibitors to reduce the workload of a failing heart. (The acronym stands for angiotensin converting enzyme.)

In 1975, Dr. Sonnenblick became chief of the division of cardiology at the Albert Einstein College of Medicine, a position he kept until 1996.

With Dr. William Frishman at Einstein, Dr. Sonnenblick was a pioneer in bringing beta blockers into widespread use for heart failure. Until then, doctors used beta blockers to lower high blood pressure, but they considered them too dangerous for treating heart failure.

Dr. Sonnenblick trained more than 300 cardiologists and researchers and received the Distinguished Scientist Award from the American College of Cardiology in 1985.

This year, the American Heart Association named him the recipient of one of its highest prizes, the Research Achievement Award, which is to be given at its annual meeting in November.

He leaves his wife of 52 years, Linda Bland Sonnenblick; two daughters, Dr. Emily Sonnenblick of Manhattan and Charlotte Van Doren of Manhattan; and five grandchildren.