THE HUMAN BODY is its own country, complete with its own laws and its own language. Navigating its diverse terrain requires a spirit of adventure and an ability to translate the blueprint our chemistry has written inside us.
Over the past century, collaborative efforts, advances in technology, and a full embrace of the scientific method have created a detailed map of this country. This dramatic expansion of our scientific knowledge base has had significant consequences for human health, but blank spots still remain. My husband and I stumbled onto one of them halfway through my first pregnancy.
When I was twenty-five weeks pregnant, my gynecologist used a handheld Doppler to measure the fetal heart rate. She said the baby’s heart rate was “on the low side of normal” and sent me home to rest and drink fluids. Unhappy to stray from a normal checkup, I remained horizontal and consumed my body weight in liquids for two days. I planned to drown the problem, whatever it was.
But water and rest didn’t do the trick, and I was quickly handed off to a fetal cardiologist, who, after examining me, thought we needed to be in the skilled hands of the high-risk OB practice at the hospital.
The high-risk doctor who briefed us on the diagnosis said he hadn’t seen a case like ours in ten years, despite working in a major hospital, serving one of the biggest cities in the United States. Upon hearing this admission, my instinct was to shake the doctor’s hand, thank him for his time, and find the nearest exit. I knew that doctors relied on documented case histories, as well as their personal experience of past successes and failures, to guide their decision-making. Haven’t seen a case like yours in ten years sounded like a very thin script to work from.
But my legs wouldn’t move. And where would I go? I was at one of the biggest hospitals in the city: a teaching hospital with a great reputation.
In the course of the appointment, during our introduction to the terra incognita into which the pregnancy had advanced, the doctor threatened an emergency delivery to take place that evening, told us the baby’s chances of survival were limited whether the delivery happened or not, and informed us of an autoimmune problem I had, which he predicted would ruin all future pregnancies. Ultimately, the delivery was called off when an intern knocked at the door with an article she’d found on the Internet, seemingly moments before she’d entered our room. This article reported that some babies like ours lived if they made it to term.
GIVEN THE JARRING LEVEL of medical uncertainty introduced in the high-risk appointment, I was surprised the next day by the fetal cardiologist’s intricate description of the human heart. Her account of the issues my daughter would face contained a stunning level of detail. But this knowledge sat pressed up against mysteries still too complicated to unlock.
Some of these mysteries are surprisingly elemental. Take that very first flare of electricity in the heart, that jolt of energy that makes your heart beat. That spark is spontaneously conjured—our own internal big bang. Scientists have developed hypotheses about this spark, but there is no accepted theory that explains its emergence in specialized heart cells. While doctors have deciphered the complicated chemistry responsible for a beating heart, they don’t know how a heartbeat gets its start.
This spark is the difference between animated and not animated, growing and not growing. You exist at first as an embryo, fed nutrients and oxygen by the yolk sac, and then, at the beginning of week four of gestation—BAM!—you outgrow your rudimentary circulatory system and need an early form of a heart that can beat.
As the heart develops, specialized cells take up residence in two nerve bundles strategically located in the heart. One bundle, the sinoatrial (SA) node, sits high on the wall of the right atrium. Translating the body’s demand for oxygen into action, this node generates an electrical impulse that tells the heart how fast to beat. This impulse gets passed, cell to cell, through the heart muscle to the atrioventricular (AV) node, stationed at the base of the right atrium—the link between the upper and lower chambers of the heart.
Electrical signals sweep across the different cells of a normal functioning heart in a precise orchestration, working every minute of every day of your life. It’s no small task to fill in this part of the map of medical knowledge.
Unfortunately, our developing baby’s problem wasn’t in this well-defined part of the map. Her diagnosis was autoimmune-associated complete heart block. The doctors thought this problem arose when cells from my blood mistakenly destroyed the baby’s AV node. Without the AV node, the critical connection between atria and ventricles was lost. Nothing was telling her ventricles how fast to beat. In my cartoon imagination of the problem, I thought about the AV node as a burned out light bulb; a blackened filament that could no longer ferry electricity down to the bottom chambers of her heart.
In fact, our doctors didn’t understand why baby girl’s heart was beating at all. According to the reigning theories of cardiac function, if her heart continued to beat, it would likely do so in a disorganized fashion, not at all in concert with her body’s needs. The high-risk team thought her heart would likely fail. They were certain her future was in limbo. They didn’t want to risk an early delivery because then she would be a premature baby with a critical heart problem. Babies born too early have the chemistry of a fetus but live in the world of the newborn, which is extremely taxing for them. One of the biggest challenges is breathing; many, many preemies succumb to respiratory problems because their lungs have not yet become pliable enough to expand and contract. The odds that a preemie with a serious heart defect would survive were very low.
Although an early delivery might prove to be life-threatening, maintaining the pregnancy was also risky. We planned to have an emergency delivery if her heart rate slipped at all. Somehow we’d know her heart was faltering. She’d send up a flare from inside me—some discernable signal in a language we both spoke. Importantly, she’d do it so we’d have enough time to extract her from my womb and elevate her heart rate. The less optimistic scenario was that she would suffer heart failure and die inside me before we’d have time to intervene.
At every opportunity, our high-risk team reminded me they didn’t think she would survive. Her heart rate was fifty beats per minute at a time in her development when it should’ve been 150. To my eye, the fetal cardiologist, whom I admired, always looked nauseous after our weekly echocardiograms. Leaving her office, I often thought it would be fitting to have a cash bar in the waiting room, at the very least for the doctors who were nominally managing cases like ours.
It took us a few weeks to understand the literal translation—in practical terms—of our inchoate position on the map. Rare cases don’t gestate under the security of double-blind studies and practiced protocols; if you’re lucky, there are a handful of relevant studies published on the subject. More than a decade ago, when we faced this problem, there were a few articles that considered this issue in rats or rabbits and three relevant articles about autoimmune-associated heart block in humans. The largest sample had data on a hundred and five mothers who gave birth to heart block babies over a twenty-seven-year period.
I was neck-deep in economics graduate school at the time and spent my days wading through data sets with hundreds of thousands of observations. I understood how critical it was to have a “large enough” sample to support research results. A hundred and five mothers provided a snapshot; we needed a full-length feature if we hoped to wring any insights from experience. I viewed the too-thin stack of articles as evidence that we’d have no real medical guidance. I was slow to accept that medical practice wasn’t linear; it’s a complicated, messy affair, filled with the kind of uncertainty that could easily erode a stomach lining.
Our doctors followed the practices described in these articles—not because they had been tested on large samples (they hadn’t), not because they had worked in the few cases on which they were tried (the results were uneven), but because there was no other medical wisdom to follow. Knowing their advice wasn’t based on real data, I wanted to reject it. Knowing that our doctors had much more experience at the margin of life and death than I did, I was afraid to contradict them.
Against my better judgment, I consented to taking steroids—every day for weeks. I took the steroids because our doctors strongly encouraged me to, often repeating that they were very worried our baby would die. I took them despite the fact that the prescribed steroids didn’t have a track record for our particular problem. I took them even though we didn’t know if they would help or harm our baby.
I KNEW MY FUTURE DAUGHTER by the unmistakable sound of her heartbeat. Its sluggish throb dominated each weekly appointment during the seventy-four days we lived with her heart problem; the repetitive pumping of blood through valves sounded like a jaguar growling over and over again. More than anything, I wanted to hear the sound of her outside my body.
Once we made it to thirty-seven weeks, the doctor assigned her a due date. Although I’d worked hard to keep my mind from wandering too close to the possibility of a stillbirth, I understood that this delivery was the end—either her rescue or her ruin. One way or another, it was the end of our wait.
In my mind, death would be marked by silence. The doctors, hunched over my womb, with bloody surgical instruments still in their gloved hands, would recognize before we did that she didn’t make it. My husband and I would be left to translate the stillness. Before the C-section, I would have traded anything for the assurance of the sound of crying—and not my own—at the birth.
On May 1st, just after noon, I found myself in an operating room, my gurney attended by a ring of white lights. As nurses and doctors readied themselves for the task ahead, the lead surgeon looked at my husband and me. He said, “The moment a baby is born, dramatic physiological changes have to happen to let the baby draw air into its lungs. The circulatory system reconfigures itself, and blood flow reverses so it can flow to and from the lungs. A duct has to close in the heart, and blood pressure in the heart increases almost immediately. It puts a lot of stress on the newborn.”
I’d known our doctors were concerned she might die during birth; I hadn’t known the details of the strain that birth would put on her little body—all the feats her heart and lungs had to accomplish so she could live outside my body. Ultimate test of strength and fitness: how does any baby survive this crossing?
As the surgeon pulled her from my womb, I felt a strong tugging sensation, as if the doctor could win the stuck baby’s freedom only through keen exertion. He held her up above the curtain erected to keep us from an intimate view of my insides. She had skin the color of a not-ripe strawberry and a generous tuft of black hair. I stared at her wide-eyed. The sight of her, out in the world, made me catch my breath. “She’s so beautiful,” I whispered to my husband. Then the nurse whisked her away, and I got my bearings. “Why isn’t she crying?”
Amidst the commotion, my husband kept trying to point out signs of life. “Did you hear that? She’s crying. Can you hear her?”
But it sounded like a seagull, too far down the beach, whose faint call was blown away by the wind. It was hard to focus on her little voice while the doctors tending to me were moving organs displaced by the baby back to their old addresses. It felt like being on a wild roller coaster—my insides pitching around.
We’d hoped the excitement of birth would provide her newborn body with enough adrenaline to increase her heart rate. The fetal cardiologist told us to hope for four solid days after birth before she’d need heart surgery.
But the adrenaline, if it came at all, was too weak to register in her heart rate, which was down to forty beats per minute. We tried cardiac medicine given to adults with low heart rates, but that, too, was unsuccessful. Her heart rate was now too low to metabolize food. Waiting for a higher heart rate would only make her weaker.
Two days after her birth, a pediatric surgeon took our newborn, no bigger than a sack of sugar, back to the operating theater. He opened her thin, fragile chest and implanted a pacemaker, about the size of a silver dollar, in her abdomen. This small computer, her satellite AV node, was attached to her heart using special pacing wires. In adults, these wires are run through veins straight into the heart muscle, but her veins were too small to accommodate the wires, so her surgeon attached the wires to the outside of her heart, picking a spot at which her ventricles received the message to beat. Among cardiologists, the best point of attachment is still being debated.
She recovered from surgery in the pediatric intensive care unit, in a bed the size of a dresser drawer. At our request, a medical cavalry, whose expertise had been won over many decades and millions of patients, came crashing down on her, holding her in place, keeping her from slipping away. A large gray industrial-looking hose taped to the velvety skin around her mouth connected her to the respirator that helped her breathe; she was fed through an IV; a red wire connected her to a heart monitor; a green wire connected her to a machine that measured her oxygen levels. She wore a tiny blood pressure cuff that inflated at a time of its choosing. Paralytic drugs kept her from struggling free from all this life-saving machinery.
With each passing day, she gained a little more freedom. The respirator came off first, then the oxygen tent; the long line of deep red stitches that marched from her clavicle to her belly button gradually looked less swollen. We replaced the IV feeding tube with an actual bottle, albeit one that looked like a toy, not something you’d associate with a living, breathing baby.
Her doctors in the pediatric intensive care unit referred to her exclusively as “the miracle baby.” Despite their years of training and experience, they didn’t understand how she survived the pregnancy with such a low heart rate, how her heart and lungs adjusted to the demands of birth, how she recovered from her heart surgery.
HAVING ENCOUNTERED such a rare problem at birth, we are destined to visit blank spots on the medical map again. We don’t know what kinds of issues may arise for kids who have my daughter’s problem. For example, the effects of long-term pacing on the heart muscle are unknown; less than 1 percent of pacemakers are implanted in pediatric patients, at different ages, and for a host of issues. Data that is directly relevant to us is hard to come by.
But as I write this, scientists and doctors press on the boundary, changing what we don’t know into something less opaque. Theories about how my daughter’s heart problem develops have progressed tremendously since her birth. There are now two theories that can almost delineate the intricate series of molecular mistakes that have to occur for autoimmune-mediated heart block to take hold. Each assigns a different trigger to the inflammatory cascade that wipes out the AV node of the fetal heart. Both are plausible.
And treatment has advanced, too. For cases of fetal heart block caught early, while it’s still mild, steroids can reverse the cardiac decline. Babies whose problem is identified and treated quickly are born without a heart problem. They are normal. Totally normal. I cried when I read that result the first time. I cried for having been confronted with our problem at a time when this information wasn’t known, but seems to have been, retrospectively, within arm’s reach. We’d watched the heart block advance from mild to severe in a week’s time, starting steroids only when it was too late to undo the damage already done. But I also cried for the relief those pregnant mothers must’ve felt to watch their nascent fetal cardiac problem slowly evaporate. I waited our whole pregnancy for that feeling. I can only imagine it.
For those who develop the more serious version of the problem, as we did, other strategies are being explored. Babies who have the low heart rate like our daughter, and develop other signs of heart failure, are candidates for fetal cardiac pacemaker surgery. Shockingly, this term means what you think it means: surgery during the pregnancy to implant a pacemaker in the heart of the struggling fetus.
The implanted pacemakers doctors are using, called micropacemakers, are a tiny bit bigger than the diameter of a penny. Recent animal studies have had measured success—the heart rates of fetal lambs with heart block have increased with this pacing procedure, and the delicate approach to surgery has not led to premature birth. It seems an enormous job to turn around a developing heart in duress when it lives inside another patient. Add to that the difficulty involved in not upsetting the fragile chemistry of the pregnancy, and the stack of challenges seems insurmountable. To date, no fetal surgery for complete heart block in humans has been successful. All the babies have died.
But the risk is worth taking because for a fetus with a low heart rate and other signs of heart failure, death is all but inevitable.
Despite the current state of affairs, I am bowled over by the boldness of the approach. This effort, attention, creativity, and imagination will lead to better information both about the heart and fetal surgery, will get us over the unseen threshold that currently separates unsuccessful from successful surgery, will ultimately save more babies on the brink, and will fill in some of the blank spots on the medical map. This kind of research will one day make survivals like my daughter’s commonplace, not a miracle that’s in any way different from the miracle of any other child’s birth.