He had a runny nose and a cough for the past couple of days, and a few times he’d seen streaks of blood in what he coughed up, he told the nurse.

She was not at all sure the problem was in the man’s lungs.

But Shapiro was still worried that it was his heart and not his lungs that was failing him.

A muscular heart doesn’t pump as well as a normal heart and sometimes can’t keep up.

Wallach saw the patient the following day, just before he was discharged.

After hearing the man’s story, Wallach asked if he had been short of breath before.

The patient lasted only a few minutes before he was too out of breath to continue.

The man noticed the stairs had become a little harder on him over the past year or so, but, he asked Wallach with shrug and a smile, what can you do.

It was the EKG done in the emergency department that provided Wallach with the last clue he needed to make his diagnosis.

An EKG measures the electricity generated by the heart in order to make the muscles contract effectively.

A thick, muscular heart will make an EKG tracing that is bigger, more exaggerated than normal.

But this man’s heart generated a signal that was smaller than normal.

Was this man’s heart enlarged by something other than muscle.

A disease like that could account for all the man’s symptoms — the thick-looking walls, the overflow into the lungs, the strange EKG, the shortness of breath, even the hemoptysis.

“I think you might have something serious,” Wallach told the patient.

The patient got that test a few days later.

The images told the story: The man had a disease known as amyloidosis.

In both diseases, these serrated fibers travel through the body, invading and accumulating in muscle — often the heart muscle.

A biopsy of the heart muscle proved that it was the form of amyloidosis associated with aging.

The patient was referred to a cardiothoracic surgeon at Columbia University.

Three years passed before Wallach heard again from the patient.

He wrote to let Wallach know he’d received his heart transplant and was doing well.

I asked Wallach how he could make this diagnosis when other doctors had not.