Dr. J. Willis Hurst, the cardiologist for Lyndon B. Johnson from the time of his first heart attack in 1955 and the principal editor of “The Heart,” a widely used textbook on cardiovascular disease, died Oct. 1 in Atlanta. He was 90.

The cause was complications of a stroke, his son Philip W. Hurst said.

Hurst met his most famous patient in summer 1955, when Johnson, then the majority leader of the Senate, suffered a serious heart attack and was admitted to Bethesda Naval Hospital in Maryland, where Hurst was the cardiologist on call.

“Lyndon had turned gray; he didn’t look alive, didn’t look like he was breathing,” Lady Bird Johnson wrote in a foreword to “LBJ: To Know Him Better,” by Hurst and Dr. James Cain, Johnson’s personal physician. “It was a heart-stopping moment for me, and it lasted for the next six weeks, which was the routine stay then for heart attack patients. Hurst became the most important man in my life. He would either save Lyndon or not.”

Willful, moody patient

Hurst and Cain, of the Mayo Clinic, oversaw Johnson’s treatment and recovery, not always a joyous task. Willful, moody and hyperactive, Johnson showed great guile in circumventing restrictions imposed by his two doctors, especially their ban on radio, television and newspapers.

Claiming that he missed listening to country music, Johnson persuaded Hurst to let him have a radio. Permission was granted on the condition that he not listen to news broadcasts. Very little country music was heard coming from the radio, but very many news broadcasts were, along with loud cursing by the patient when reports from Capitol Hill were not to his liking.

Hurst did succeed in getting Johnson to quit his three-pack-a-day smoking habit, to cut out caffeine and to lose weight. After talking to Lady Bird Johnson and getting a better sense of his patient’s emotional makeup, Hurst concluded that rather than too much activity, too little was more likely to bring on a second heart attack.

He lifted the news blackouts and gave up on limiting visitors, a hopeless goal in any case. After issuing a warning to Johnson that he had exceeded his visitor quota, Johnson replied with a sly smile, “Oh, now, look, Doctor, you’re not going to count Republicans, are you?”

The two developed a close relationship that lasted until Johnson’s death in 1973. During Johnson’s vice presidency in the Kennedy administration, Hurst traveled with him to 15 countries.

At one point, Johnson proposed that Hurst join the Naval Reserve so that he would be on duty when he traveled and off duty when he returned. When Hurst showed a lack of enthusiasm for the idea, Johnson snapped, “I can draft you, you know!” Hurst took the threat seriously.

“He later brought it up again, and for years I was concerned that I would receive some sort of draft notice in the mail,” Hurst wrote in his memoir, published in 1995.

On the day of President John F. Kennedy’s assassination, Dr. Janet G. Travell, the White House physician, urgently summoned Hurst from Manhattan, where he had been attending a meeting at the American Heart Association, to the Johnson home in Washington.

“There had been reports from Dallas that LBJ had been holding his left arm as if it ached — a possible sign of a heart attack,” Hurst wrote.

The reports turned out to be incorrect, and for the rest of the evening Hurst, Lady Bird Johnson and the Johnsons’ daughter Lynda Bird, along with top aides like Bill Moyers and Jack Valenti, watched television with Johnson, newly sworn in as president, as he struggled to collect his thoughts.

“Whenever LBJ looked at a TV replay of the assassination scene, he grimaced,” Hurst wrote. “More than once he said how much he had thought of the fallen young president. He sipped orange juice and tipped his glass to a portrait of his old friend and mentor, Sam Rayburn, who had recently died. LBJ repeatedly thanked Rufus Youngblood, the Secret Service agent who had forced him into the floor of the convertible and covered him with his own body when the shots were heard. He never forgot that act of bravery.”

Declined White House

Hurst was later offered the post of White House physician but declined, preferring to remain at Emory University’s school of medicine in Atlanta, where he had taught since 1950.

Hurst wrote dozens of books on cardiology and the teaching of medicine, notably “The Heart,” which he edited with Dr. R. Bruce Logue. It became one of the most widely used medical textbooks in the world. First published in 1966, it has been revised through 13 editions. Since 1986, it has been titled “Hurst’s The Heart.”

His other books include “Four Hats: On Teaching Medicine and Other Essays” (1970) and “The Bench and Me: Teaching and Learning Medicine” (1992).