WE WERE LIKE a rifle squad of draftees who know damn well that tomorrow's mission is going to be dangerous, no matter what our officers tell us the night before. Only we were hospital patients, about to undergo open heart surgery, and our officers and sergeants were doctors and nurses.

"It's perfectly natural to be scared," said the cardiologist as he made the night-before visit to each of our rooms, like a fatherly colonel. A male nurse, like a sergeant demonstrating a grenade launcher, dragged in a breathing machine to show how he would plug us into it to keep our lungs from filling up after the surgery. The surgeon himself-Dr. J. with the golden hands-was the last to stop by.

"Get a good night's sleep," I urged Dr. J., waving off any long explanation of what he intended to do to me at first light. I was scheduled to be the first of our squad operated on the next day. As I lay there in the dark, I regretted how much my reportorial instincts had driven me to learn about open heart surgery. I already knew more than I needed to know.

I knew, for example, that someone on the open heart surgery team was going to run a radial saw down the middle of my breastbone so my chest could be pried open to give Dr. J. access to my heart and arteries.

I also knew that my heart would be stopped and the job of keeping me alive would then be subcontracted to a man-made machine. This is an unnerving prospect for one who has seen some of the most carefully crafted military equipment malfunction.

Once my chest was pried wide open, Dr. J. would cut a vein out of my leg and cut it into strips called "bypasses." They take blood around obstructions that build up inside arteries. Each length of vein would be sewed into the artery someplace above the obstruction and anchored below it. More than one bypass would be used for each obstruction, in case the first one sewed in place filled up with junk or collapsed.

Heart disease is an egalitarian affliction-striking the grand and the humble, the rough and the refined, without favor. I was surrounded at the hospital by an all-American collection of people, all there for the same operation. Fast Eddie, a Las Vegas pit boss. A doctor from Minnesota. A 31-year-old lumberjack from Michigan whose friends gave him a wild send-off party with gallons of beer and whiskey. A high school teacher. A minister. A cheese taster. A businessman who wouldn't stop smoking, even after surgery.

Like combat veterans, we became important to one another, sharing the same foxhole. Somebody dubbed us "the zipper squadron" because each of us ended up with a lone zipper scar running down the chest, from just below the throat to just above the navel. Partly because of the scarf I wore to hide that scar, somebody named me "squadron commander" - the officer in charge of morale, complaints and other vague duties.

It helped. We helped each other. I am not using their full names or even the names of the doctor and the hospital out of respect for their privacy. I was there as a patient, not a reporter. Still, I feel I should pass on what I learned.

Like a soldier who never expects to be shot, I never expected to be lying in a bed in a Midwest hospital awaiting open heart surgery. Even the doctors who sent me there shook their heads with incredulity as they said such things as this:

"You certainly are an anomaly."

Never smoked, never overweight, normal blood readings, active physically, no family history of heart disease. Even an 85-year-old mother who has never been hospitalized for illness.

"We'd feel better about recommending this surgery if only you had more pain."

Most people afflicted with the nation's number one killer, heart disease, experience chest pains or shortness of breath or feel their heart galloping away from them, sometimes in the middle of the night. I had merely experienced peculiar pains on the inner surface of my elbows and down my shoulder joints after jogging. I ignored those pains for months, trying to jog them away by increasing the distance, but finally I decided to submit to a stress test in hopes of getting assurance that nothing was wrong. I had run and pole vaulted competitively in college and knew that these pains were different.

A stress test is simple. You can go to a hospital, a doctor's office or, in some cities like Washington, the YMCA to get wired up so the electrical pulses of your heart profile its performance by making marks on paper. The standard electrocardiogram most of us settle for merely shows what your heart does at rest, not under strain. I had passed those tests regularly. But in a stress test, you walk and then run on a treadmill so your heart is taxed.

My stress test came out "positive," meaning something was wrong. The heart was not getting enough blood when heavy demands were placed upon it, provoking those muscle pains when severely strained, as in a hard jog, but not in any ordinary business or social activity.

However, even a severe stress test does not tell the cardiologist reading the marks on the paper exactly what is wrong within the network of veins and arteries. It takes another, more elaborate test to get that detailed information - an angiogram. This consists of a doctor, hopefully one with good hands, cutting a slit in the artery which surfaces near the groin and then feeding a flexible plastic tube, the thickness of a straw, into that artery. The tube is pushed through the artery back toward the heart.

As you lay there, fully conscious, on a shaped table which rotates to give the cameras pointed at your chest a series of views, the pictures appear on a screen in the darkened room. You see the tube moving inexorably up toward the heart. And then, photogenic dye is shot into the tube so its flow through the various passages will show up clearly in this eerie movie. You feel a flush on the forehead, but in my case no pain.

But the eerie feeling persisted in the projection room as the cardiologists and I watched the movie of the dye flowing in and out of my heart. The experts pointed to a narrowing in one artery - the left anterior descending, or LAD - caused by a block of fibrous material. The doctors said that tests have suggested that almost all American males have some degree of fatty deposits inside their arteries. One suspect is the high intake of meat, giving the body more cholesterol than it can handle. Another is excessive stress which impels the body to manufacture its own cholestrol. Put a meaty diet together with lots of stress and some specialists contend it greatly increases the risk of contracting atherosclerosis.

None of my doctors pretended to know what had caused the deposit to build up in that artery taking oxygen-rich blood into my heart. One doctor, after hearing me describe the typical day of Washington newspersons, said it would be enlightening to study the prevalence of heart disease among them. My question was not what caused it, but what to do about it. Here again, there are no absolute rights and wrongs. Competent physicians differed as they dispensed their best advice:

"You might go 20 years this way with no trouble."

"Why don't you watch it carefully by taking a stress test every month. Maybe the blockage will not get any worse."

"I feel sure that the artery is going to close the rest of the way eventually. That would destroy part of your precious heart muscle."

"You know, less than half the people who have a heart attack make it to the hospital. They die."

My best friend, who was among the cardiologists I consulted, said: "If I were you, I would grit my teeth and undergo the surgery."

He reasoned that I had a perfect heart which would be at least partly destroyed if the artery, which appeared to be 80 to 90 percent blocked, closed all the way. Also, I was a good risk to survive open heart surgery.

If I did opt for open heart surgery, advised my doctor friend, go to a hospital with a team which is highly skilled from doing a lot of operations. Open heart surgery , he explained, is like landing a plane in bad weather. You want a pilot who has had lots of practice.

Dr. J's team in the Midwest was my friend's first choice because of his skill and experience in performing bypass operations. And that is where I went, flying out of Washington right after the big February snowstorm. As I got to know my fellow patients, I could not help but compare them to draftees thrown together by accident. Contracting heart disease, like getting drafted, seems largely a matter of chance, the random distribution of bad luck.

Allan was a 31-year-old lumberjack from Michigan's Upper Peninsula. Just before he left for the hospital, his friends threw him a giant party at a road house, complete with gallons of whiskey, barrels of beer and three bands playing everything from rock-and roll to the sissy stuff the old folks could dance to. One of his boyhood friends at the party threw his arm across Allan's shoulders and began sobbing.

"I told him, 'Hey, I'm not going out there to die. I'll be back.'"

"Nobody is very formal aroung where I live," Al told me as he described the party that roared far into the night. His friends drank and danced and kidded Al but then, as the mood heavied, they went up to him with a farewell gift. They had passed the hat. It was loaded with $1,400 to help Al pay for his operation.

Then there was Dick, a 53-year-old general practitioner from St. Pual. He had already suffered a heart attack that was keeping him from his beloved practice of medicine. After surveying bypass surgeons, he chose Dr.J. "I'm looking forward to it," said Dick that night before the surgery, which was to prove especially painful to him.

And there was Fast Eddie, a pit boss from the gambling tables of Las Vegas wo at one point gave up hope of ever leaving the hospital alive. George, a Wisconsin cheese taster who suffered great agony after the operation but broke into song despite it.Barry, a young high school teacher from a tiny Michigan town who experienced the horror of hearing the surgeons talk over him during his own open heart surgery. Beatrice, a divorce from Switzerland who bought a whole row of airline seats so she could lie down during the flight to the states. Jerry, a former Maryland motel owner retired to Miami who, along with his wife, projected compassion to everyone. A young New Jersey minister; a 78-year-old farmer; and Donald, a businessman who had not been able to work for two years because of his heart problems.

Donald rebelled against hospitalization. He continued to snitch cigarettes right up to his operation. He was a desperation case, undergoing surgery for the second time.

Lots of people go through this. Cardiovascular disease is the biggest killer of Americans: 997,766 of them in 1976, according to the American Heart Association, representing 52 percent of all the deaths in the nation from all causes. Cancer was a poor second.

For various reasons, more of us gathered in the Midwest hospital had concluded that the potential payoff of open heart surgery was worth the risk. I, for one, felt that walking around with a loaded gun pointed at my heart was too distracting. Better to spike that gun before the risk increased.

I tried to remember that rationale as the attendant came the next morning to wheel me into surgery. I did manage to relax before the needle full of anesthesia took hold.

The next thing I remember is looking through the haze at my wonderfully supportive wife, Joan, and holding up two fingers. I had tubes in my nose and throat so I could not talk that first day. She knew I was asking if the doctors had inserted two bypasses. Joan smiled and held up three fingers. Dr. J. had decided to sew in a third bypass aroung another suspicious-looking place - one that had not shown up on the angiogram film.

That first night, I asked for paper and pencil so I cold make a stunning disclosure to the doctor looking down at me in the extensive care ward.

"The deeper I breathe," I wrote, "the more it hurts."

With gentle sarcasm, the doctor replied that a man with an IQ of 50 would make the same observation. I reached into my fogged brain for a riposte, but could only manage to write down this weak rejoinder: "You're documenting the obvious."

That exchange, pale as it was, did give the nurses in the intensive care ward something to chatter about - especially after they learned I wrote for a living.

Yet breathing did turn out to be the most painful part of the whole operation for many of us. One reason is that plastic drain tubes, which looked to me as a thick as garden hoses, are inserted into the stomach during the operation and kept there for a few days. Breathing deeply and coughing - both of which you are exhorted to do to clear fluid out of the lungs - pushes the lungs against the tubes, generating ripples of pain. The morphine flowing into you through an intravenous tube in your arm (surgery is just one tube after another) only blunts that pain. Every noise seems to hurt. Someone slams a door and you shudder and it hurts. I bitched to the doctor and the nurse and anyone else who would listen about unnecessary noise.

Life brightened on the second day in intensive care because all the tubes except the intravenous one, the IV, had been taken out. I sought to assert my independence, asking the nurse if I could walk across the ward on my own to use the john rather than be attended to in bed. She said the walk would be good for me if I could manage it. The IV was on a wheeled stand which I pushed along as I tried my first post-operative walk. Watching me closely from his bed across the room was Dr. Dick. After I had made the trip safely, he decided to do the same thing. But because he was a medical doctor, he told the nurse to give him a suppository laxative to make sure his painful trip was not wasted. Dr. Dick, a delightful human being, did not make it across the room before his stimulated bowels exploded. He gamely quipped: "A little knowledge is a dangerous thing."

George, the Wisconsin cheese taster with a Santa Claus build, was in the bed to my left. He had been a heavy smoker. Clearing out George's lungs while he was lying down proved so difficult that the male nurses had to resort to walking him around the ward. He cried out in pain on that walk. Any sane person hearing his cries at the moment would have given up smoking forever. But minutes afterward, George was back in bed humming and singing Nordic drinking songs. Truly inspirational. I thought to myself: What a magnificent man to share a foxhole with.

Eventually, we all ended up in single rooms in the same wing of the hospital. This was a period of emotional ups and downs; of needles plunging into the arms every morning to draw blood for test; of being wheeled to rooms full of fancy machinery and cameras for more tests; of trying to talk cheerfully to visitors and telephone callers; of walking rectangular track of hallway around the hospital courtyard, telling yourself you were getting stronger.

During those walks, I wore a Snoopy scarf around my neck to hide the part of my scar that showed above the pajama top. Some of my fellow patients decided the scarf , if nothing else, entitled me to become commander of our zipper squadron of scarred veterans. I still get letters from them addressed: "Dear Squadron Commander:" My biggest challenge as "commander" came from Fast Eddie, the Vegas dealer.

"Ed won't eat or get out of bed," his wife told me, trying to hold back the tears. She explained that Fast Eddie had decided he was never going to recover from his surgery and might as well die peacefully in his hospital bed. Nurses, doctors and a psychiatrist had failed in their efforts to fire up his will to live. He was losing weight steadily, getting weaker all the time, and would not do much exercise. Would I try to get through to him?

"Eddie," I said as I carried a bootleg cup of soup into his room, "my wife, Joanie, got this soup for you from outside this lousy hospital. And I know you're too much of a gentleman to let her down.

Eddie spooned down the soup. I told him that the only compelling reason either of us had for getting out of the hospital right away was fishing season. I drew him out on the 20-pound catfish he had caught in Lake Mead outside Las Vegas. Fishing was Ed's morning therapy after running his gambling pit all night.

By now, Eddie was out of bed and sitting in the chair, eating the thick soup. In one of his rare trips out of bed the previous day, he had watched me gray out in the exercise class. Just before going to physical-therapy class, I had taken a hot shower - not knowing this could kill me by opening up my blood vessels so wide that my blood pressure could not be sustained in my weakened condition.

After a short burst of exercise, my blood pressure started to fall, making me feel faint. I struggled to stay conscious. I was put in a wheelchair. But my blood pressure still kept dropping. One of the nurses, with rare panic in her voice, kept calling out the falling numbers as the knowing patients in the class watched helplessly. Somehow, my wife kept standing over me dry-eyed, like a reassuring Madonna, signaling it was going to be all right if I only hung on a little longer. Finally, the team arrived to rush me back into bed. I was given an EKG for fear that I had provoked the very heart attack I had undergone surgery to avoid. Those were dark moments, waiting for the results of the EKG. They proved negative - no heart attack. The pump was still undamaged.

"You saw what happened to me yesterday," I reminded Fast Eddie. He eyed me warily, perhaps incredulous that I had joined the long line of exhorters who had come into his room.

"Yeah, I was there."

"Well, look. To get out of here, I've got to get walking again. And so do you. Will you go with me, right now? I need your help."

Arm in arm, Fast Eddie and I walked past the hospital reception room where all those heroic wives and other relatives and friends spent their hours between bedside visits. Betty, Eddie's wife, started to move toward us, her eyes brimming over with tears. Thinking better of it, she froze in place, afraid to break the spell that had gotten Eddie out of bed and on the road leading home.

The moments of drama on the cardiology floor were relieved by humor-black humor and slapstick.

"I could hear everything they were saying over me," Barry told us. He was awake when the operating team thought he was deeply under. Barry remembered:

"Somebody said, 'Hey, this guy is fat. He'll take forever to sew up. We're never going to get out to dinner.'"

One day Beatrice, the personable divorcee from Switzerland, rushed up to me and gushed about "my lover Joey from Washington." Joe, a writer at The Post, had tried to call me one night from the phone in a Washington watering spot, only to misdial and get Beatrice's room instead.

"Hey, you sound sexy," Joe told her. His phone conversation apparently continued on the same high plane.

"I had just gotten all those tubes out and felt so uggh," Beatrice told me. "And to have somebody say I was sexy was just so wonderful."

The time came, of course, for the zipper squadron to disband and go home. I was released from the hospital first. I felt almost guilty about leaving the others. My last act as "commander" was to go into George's room-he was still havinng a rough time. I ceremoniously put the commander's scarf around his neck and said: "Now you've got to get everybody out of here."

I am no expert on heart disease, but I would make two suggestions on the basis of my experience.First, the medical profession should foster the kind of camaraderie that meant so much to us by talking to patients about the upcoming surgery in a group, rather than just making those quick one-on-one hits the night before.

Second, on the basis of long talks with other patients, I came to suspect that sudden, unexpected stress-a divorce, the loss of job, a grave injury to a loved one-is a leading cause of cardiovascular problems. Sure, diet is important. But I discovered so many cases of unanticipated stress that I wonder if it is not a bigger culprit.

From the telephone calls and "Dear Commander" letters, I thought that everybody from our zipper squadron made it safely. But I got another "Dear Commander" letter the other day. It said Donald had collapsed and died at home. heart surgery is impressive, but every war has its casualties. CAPTION: Picture, George Wilson, 51, has been military correspondent for The Washington Post since 1966, covering the Pentagon and combat in Vietnam. He is the author of "Bridge of No Return: Ordeal of the U.S.S. Pueblo." A 1949 graduate of Bucknell University, Wilson served in the Navy Air Corps during World War II.