Our three week old baby was diagnosed with supraventricular tachycardia – our story and experiences.

I want to share our personal experiences with having our youngest boy (3 week old) diagnosed with supraventricular tachycardia. It is meant to inform other parents, their families and medical staff. We are a Dutch family, living in Rotterdam Netherlands, English is my second language, I am not a medical professional. Our son is now 2 years old and thriving.

How it started

The night that our baby boy had an episode of supraventricular tachycardia he was not drinking (breastfeeding) and he vomited several times. He was crying softly with his eyes closed. I took his temperature, but it was normal. First, I thought it was my own sleep deprivation and mild hypochondria. With my oldest son I had gone to the emergency unit once while there was nothing wrong with him. Coming from a medical family I could not bare the humiliation of having to admit that I ran with a completely healthy baby to the emergency unit twice.

A week earlier I had noticed the exact same symptoms, when he was ten days old. Again, not drinking, crying, vomiting (clear difference with his normal refluxing/spitting up), no fever. That time I had given some milk on a small spoon between his lips which provoked a small gag-reflex, and this made him “reset” right before me eyes. He started drinking immediately and fell asleep. I hindsight I think I might have unknowingly ended an episode of SVT.

This second time at three weeks old, he was clearly unhappy, not nursing (I was feeling engorged) and I put my hand on his chest intuitively and thought there was something strange about his heartbeat. I googled what a normal baby heartbeat should be (120-180 bpm) and tried to count and realized a heartbeat of 150 bpm is fast, but you can still count it. The heartbeat of my son was too fast to count. If his heartbeat would have been 180 bpm, it would have been three beats per second, and this was much higher. I decided to call my midwife who still do home visits in the Netherlands after birth. She came to our home quickly and listened with a stethoscope to my baby’s heart. She immediately said to go to the hospital and she drove us herself. My husband called his father to stay with our oldest son while the midwife, my baby and me drove to the hospital.

His heartrate was through the roof: more than 300 beats per minute. Soon we were joined by more hospital staff and although the assistant pediatrician told me his life was not in danger, it was clear from their body language that the medical staff was concerned. My baby was clearly in a bad state. They tried to stop the attack by putting ice in his neck and later by intravenous administration of a drug called adenosine twice. None of this stopped the episode and they couldn’t drive down his heart rate.

Around midnight it was decided we would move to another hospital in the same city where they have a neonatal intensive care unit. We were joined in the ambulance by the pediatrician and were almost running through the hospital corridors. I thought that I might lose my baby at this point.

He had been crying for a few hours by that time. The NICU-doctor who took over his care told us: I can see your child is very upset and I can see he is getting tired so I am first going to help him sleep. She administered the drug midazolam (not sure of the dosage) through his IV and he immediately fell asleep. Next, they administered a new dose of adenosine and this finally stopped the attack and his heart rate fell to 150 beats per minute.

Later the pediatric cardiologist that was on call that night and the NICU-doctor told us that midazolam is actually not an “evidence-based” drug to end an episode of supraventricular tachycardia for infants. But it already had worked several times for them and they used it regularly. During a lecture on supraventricular tachycardia at a conference that the pediatric cardiologist attended a few weeks after our hospital visit, he saw that several possible drugs were listed to be used to end an SVT episode, but midazolam was not amongst them.

After the episode was stopped, finally a bout of good news arrived. An ultrasound was made and his heart did not show any congenital problems or other deformities. We were told that our son has supraventricular tachycardia, a rather “benign” cardiac arrythmia, that is not very dangerous, can be treated well and most babies will outgrow within their first year. Unfortunately this was followed by a new bout of bad news, because as soon as he woke up he went straight into another attack and his heart rate was over 300 bpm. Again he was administered adenosine and this stopped the attack. After his third attack they decided to start him on a medicine called propranolol, a beta blocker. In the hours afterwards he had a few other attacks, including one where they had to take him from my arms while breastfeeding, but luckily they started to last shorter and he was able to overcome them by himself and could recover in a minute or two without adenosine.

His last attack was probably a few hours after starting the drugs and a few days later we were discharged. I nursed him in the hospital, and for many months afterwards.

Life with a baby with SVT

We struggled with administering the medicine in the beginning because it is quite a big volume and can be very hard with a breastfeeding refluxing baby. I got quite nervous several times about how much he had actually received and how much he had spit out. The official recommendation is to give the medicine 1 hour after feeding but we never adhered to this recommendation and this has worked fine for us. The medicine turned out to be effective in preventing new SVT episodes.

After a while I had enough of the big syringes and volumes. Moreover, the pharmacy experienced a shortage of the 1 mg/mL drink. We wanted a higher concentration. I even tried to prepare this myself in the kitchen but I didn’t succeed in dissolving the propranolol tablets. After calling around we found a pharmacist prepared to make a custom drink at 10 times the concentration (10 mg/mL). He added a berry aroma to mask the bitter taste. This has made our life a lot easier since I only needed to administer onetenth of the volume (for instance 0,3 mL instead of 3 mL). But it is also a hazard: if you make a mistake and give the “old” volume you give your baby an overdose of the medicine. To be safe I only have 1 mL syringes in the house so babysitters or grandparents can not accidentaly give him too much.

At home we had a few scares. We bought a stethoscope to be able to track his heartbeat but overestimated our own ability to distinguish between normal and abnormal heart rate. I ran to the emergency room twice suspecting a new SVT episode but in hindsight I am pretty sure that I had mistaken the heartbeat.

Six months after the attack in agreement with our pediatric cardiologist we decided to see if he had already outgrown the condition and wean him off the medicine. We took three weeks to get to 0 doses propranolol. Unfortunately, not even a week had passed until his next episode. Our “guest mother” (in home daycare) found him floppy and quiet and called us immediately. This time I could hear very clearly through the stethoscope what a real SVT sounds like and when the ambulance arrived their pO2 sensor indeed confirmed a heart rate over 300. I administered his medicine in the ambulance, when the syringe reached his lips he vomited and this stopped the attack immediately. We drove to the hospital anyway but he was happy and smiling at the doctors. That night we started the medicine again and to our knowledge he never had experienced an episode since.

How are we doing now?

Our baby boy has grown a lot since those days in the NICU, he is two years old now. He was already trying his first steps at 10 months, and is now speaking very well. Sometimes I still feel his pulse, when he is whining or restless or sick, sometimes we even take out a stethoscope. I have learned to recognize his heartbeat and am reassured very quickly when hearing it. He gets three times a day in total 2 mg/kg body weight /day propranolol-HCL drink. We have our own drink custom made in the pharmacy at a ten times higher concentration. The recommendations is to leave 8 hours between the dosages but this is unpractical. We give him his medicine when he wakes up (mostly between 6-7 AM) then at 2 PM or 3 PM, whenever he wakes up from his nap. His last dosage is at 8PM before bed.

We are unsure of the side effects of the propranolol. I suspect he may be more energetic without the medicine, since I saw a change in his energy level when we stopped when he was 6 months old. Our boy has experienced more than 20 infection in his first winter and also this summer. Every time it is nothing serious, no ear infections, no pneumonia, just a mild fever and coughing and short of breath. Although his second winter has been much better, his shorteness of breath is lasting longer after the infection although it doesn’t seem to bother him. This may be due to propranolol: bronchospasm or broncheal hyperreactivity are known side effects of the medicine. We are considering changing to a different medicine (flecainide) or even attempt to stop once more to see if he has outgrown it.

Overall, we live a normal life. We go on vacation like normal people, even to remote areas, he stays with babysitters and our parents. We have agreed with our cardiologist there is no need to call an ambulance immediately in case he will get another episode but we will administer an extra dose of the medicine and wait for 30 minutes before making our way to the hospital (we live around the corner). The normal treatment plan is to stop medication when he turns 3 or 4 and he can make it clear that his heart is behaving strangely, or he is not feeling well. If he still gets SVT episodes we can attempt a treatment strategy where he only gets the medication in case of an episode. If he still experiences a lot of attacks we will go back to regular medicine intake. When he reaches 30 kilogram and he has many episodes we can try for cardiac ablation surgery if he has many episodes.

What would have happened if we wouldn’t have noticed the SVT?

To be honest: this was one of the most important questions on our mind. What if the SVT would have gone unnoticed? Would he have reversed it himself? Would his heart at some point just stopped? Or get damaged? Would he have survived? We have asked ourselves and our physiucian this question many times. In general, babies with SVT’s have very low chances of succumbing to the attack. The condition has low “mortality” as they call it. That is reassuring. Still, the medical professionals urge us to not wait to long and when we arrived in the hospital they were clearly adamant in reversing the episode quickly. Probably the answer is: we do not know.

Sharing our story.

By sharing our story I hope to give an insight in life with a baby with SVT. Of course every patient is different and there is a wide variety in experiences and outcomes. The first night in the NICU I recall spending the whole night on my phone researching the condition and experiences from other parents. What did this diagnosis mean? For our baby? For his life? Would he grow old healthy and happy? And what did his condition mean for our family? The stories of other parents in my situation were a reassurance and a comfort for me, because although the SVT-episodes can be scary, the prognosis are not scary. With this story I wanted to make a contribution to the online collection of SVT-stories. If you have any questions please comment below.

I wish you and your family all the best and lots of health and prosperity.

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