Dr. Rosenfeld wrote more than a dozen books, several of them best sellers, including “Modern Prevention: The New Medicine” (1986), “The Best Treatment” (1991), “Dr. Rosenfeld’s Guide to Alternative Medicine” (1997) and “Live Now, Age Later: Proven Ways to Slow Down the Clock” (1999).
The unabashed physician also made a cameo appearance as a professor presenting a ceremonial pen to the mathematician John Nash (played by Russell Crowe) in the 2001 film “A Beautiful Mind.”
A Canadian-born son of Jewish refugees who had fled Russia after the revolution, Dr. Rosenfeld was told by his mother that “good and obedient children grow up to be either doctors or lawyers,” he recalled in his memoir, “Doctor of the Heart: My Life in Medicine” (2009).
He decided between the two careers when he was only 4 years old, after a severe cold gave him a 104-degree fever and convulsions. His parents summoned a doctor, Phineas Rabinovitch, who lived down the block.
“I begged her not to call him,” Dr. Rosenfeld wrote. “I remembered vividly the last time I’d been to a doctor — how he had hurt me with what seemed like a three-foot-long needle! I trembled when I heard the doorbell ring.”
But Dr. Rabinovitch was different. He explained that he, too, had recently been sick. He handed his young patient a flashlight and asked him to look down the doctor’s throat to see if any “green gremlins” lingered.
“I told him I saw lots of red and pink things in his throat, but no green gremlins,” Dr. Rosenfeld recalled. “That, in effect, was the beginning of my medical career. At four years of age, I had examined my first patient — and he was a doctor!”
When Dr. Rabinovitch learned that the boy’s father had been a successful businessman in Russia but was scraping by on $6 a week selling farm equipment, he waived the 75-cent fee for a house call.
“From that moment on,” Dr. Rosenfeld wrote, “my mother never again mentioned the legal profession to me.”
He was born Ezra Rosenfeld on Sept. 7, 1926, in Montreal to Morris Rosenfeld and the former Vera Friedman. After his mother saw so many signs for store owners with the name Isadore, she changed his name from Ezra, thinking it would sound more Canadian. Their neighborhood, as it turned out, was predominantly Jewish.
He earned a bachelor of science degree from McGill University in Montreal in 1947 and went on to receive a medical degree there. He decided to specialize in cardiology because his father had angina.
In 1956, he married Camilla Master and joined the practice of her father, Dr. Arthur M. Master, a New York cardiologist who helped develop a precursor to the common stress test for heart disease. The couple lived in Purchase, N.Y., after moving there from Manhattan. Dr. Rosenfeld died in nearby Greenwich Hospital.
In addition to his wife and his son Stephen, he is survived by two other sons, Arthur and Herbert; a daughter, Hildi Silbert; and nine grandchildren.
Writing in The New York Times Magazine in 1981, Dr. Rosenfeld acknowledged that patients had valid complaints about the cost and quality of medical care.
In the article, titled “A Doctor Defends His Calling,” he recommended better monitoring of the profession by fellow doctors and state regulators, more realistic insurance reimbursement policies, medical school training that would encourage personal contact between physicians and their patients, and caps on malpractice awards.
Dr. Rosenfeld sought to explain the evolution in bedside manner since 1930, when he had been treated at home by Dr. Rabinovitch. Advances like antibiotics and the proliferation of specialists had helped prolong life, he said, but most modern medical practitioners “are often perceived as more concerned with pathology than with patients.”
“From their point of view, their task is to cure you, not hold your hand,” he wrote. “The great pity is that they don’t seem to think that they can or should do both.”
Still, he added, “I suspect that, given the choice, most patients would prefer to be cured, however impersonally, rather than die with tender, loving care.”