Explain complete heart block and the pacemaker to a parent — OSCE

Candidate instructions

You are the paediatric registrar. You have seven minutes to speak with Mrs Tran, whose two-day-old daughter Mai was found at the routine postnatal check to have a heart rate of fifty-five beats per minute. Mai is mildly mottled and feeding slowly, and a twelve-lead ECG has shown complete heart block with a narrow-QRS escape rhythm. Mrs Tran has systemic lupus erythematosus and is known to be anti-Ro positive. She saw the registrar's worried face and overheard the word pacemaker. Explain what complete heart block is in plain language, what caused it and whether her lupus is to blame, what the pacemaker involves and whether Mai will need it for life, what the prognosis is, and what it means for any future pregnancies. Answer her questions, check her understanding, and agree a plan. [2]

Actor brief (parent — Mrs Tran)

You are frightened and guilt-ridden. Your baby was born two days ago and seemed fine, and now a doctor has been called because her heart is "too slow" and they are talking about a pacemaker. You have lupus and you have read online that lupus can affect babies, so you are terrified that your illness has harmed your daughter. You want to know: (1) What is complete heart block, and is it dangerous — could she die from a slow heart? (2) Did my lupus cause this, and is it my fault? (3) What is a pacemaker, will she need surgery, and will she have it forever — can she still be a normal child? (4) Could her brothers (you have two older sons, aged four and six, from a previous partner who is not the father of this baby) have it too? (5) If I have another baby, will this happen again? Push back if the candidate uses jargon, minimises the slow heart as "nothing," or dodges the question about lupus and guilt. You calm when you feel heard, told the truth, and given a clear plan. [2]

Exemplar candidate approach

Open and acknowledge. "Mrs Tran, please sit down. I can see you are frightened, and I am glad you are here — you overheard us talking about Mai's heart, and you deserve to understand exactly what is going on. Mai is safe and she is being watched very closely. I want to explain clearly what we found, what it means, what the plan is, and I will answer every question you have, including the one about your lupus. Take your time." [2]

Explain the diagnosis in plain language. "Mai was born with a condition called complete heart block. The heart has its own electrical wiring — a signal starts at the top, passes through a junction box in the middle called the AV node, and spreads to the pumping chambers at the bottom. In Mai, that junction box was damaged before she was born, so the signal from the top cannot get through, and the bottom of her heart is beating on its own at a slower backup rate — about fifty-five instead of the hundred-and-twenty a newborn should run. That is why her heart rate was low at the check. The backup rhythm is holding her circulation for now, but it is not as reliable as a normal heart beat over the long term, and that is why we take it seriously." [2] [4]

Address the cause and the guilt honestly. "You asked whether your lupus caused this, and I want to be straight with you. Yes — there is a connection, but it is not your fault, and I want to explain why. In lupus and a related condition called Sjögren syndrome, the body makes antibodies called anti-Ro. Those antibodies are part of your immune system, and in you they do no harm. But during pregnancy, some of those antibodies cross the placenta into the baby, and in a small number of babies they settle on the developing junction box of the heart — the AV node — and cause scarring. Once scarred, that tissue cannot conduct. This is not something you did, and it is not something you could have prevented or known — the antibodies are just there, and in about one or two in a hundred pregnancies like yours they affect the baby's heart. You did not cause this, and there is nothing you could have done differently." [4]

Address the danger honestly. "I want to be honest because you asked whether it is dangerous. Yes, an untreated slow heart in a baby can be serious — over time the slow backup rhythm can fail, and that can cause fainting spells or worse. The reason we are taking it so seriously now is that we can fix it very effectively with a pacemaker, and once that is in place the danger is taken away. Mai is being watched, she is safe, and we have a clear plan." [3]

Explain the pacemaker and the prognosis. "A pacemaker is a small device, about the size of a fifty-cent piece, that we place under the skin, usually here in the upper abdomen or chest in a baby, with thin wires called leads that sit on the surface of her heart. It listens to her heart beat, and whenever it senses that the rate is too slow, it sends a tiny electrical pulse to keep her heart beating at the right speed. Because the scarring in her heart is permanent — it does not heal — she will need this device for life, with the box changed every several years as she grows and as the battery runs down, and regular checks in our pacing clinic. I know the word surgery is frightening. The operation is done by our congenital heart surgeons, it is well established, and most babies recover quickly. The prognosis with a pacemaker is excellent — Mai is expected to grow, go to school, play, and live a full life, with some sensible precautions about contact sport. She will be a normal child who happens to have a device." [1] [3]

Address siblings and future pregnancies. "You asked about your two sons. Because this is caused by your antibodies and not by something the boys inherited from you, they are not at risk from this — the antibodies only affect a baby during pregnancy, and the boys are past that. What matters for a future pregnancy is that because you are anti-Ro positive, there is a chance, about fifteen to twenty per cent, that another baby could also develop heart block. That sounds frightening, but there is good news — we know how to watch for it. In a future pregnancy, our fetal cardiology team will do regular ultrasound scans of the baby's heart from about sixteen weeks, and if we catch the very early stages, we sometimes have treatments that can stop it progressing to complete block. So you will be very closely looked after. You have not been given this information to frighten you, but so that if you plan another pregnancy, we are ready." [1] [4]

Check understanding and agree a plan. "Can I check — what is your biggest worry right now, and have I explained anything unclearly? Here is what happens next: Mai stays with us on the neonatal unit with continuous monitoring, our cardiology team will review her today, and we will plan the pacemaker with the surgeons. We will keep you informed at every step, you can be with her, and you can call me or the team at any time. We will also arrange for our fetal medicine team to meet you before any future pregnancy. Is there anything else you want to ask?" [2]

Mark scheme (10 marks)

• Empathy and relationship (2): acknowledges fear and guilt, sits and listens, plain language, does not minimise the slow heart or dodge the lupus question. [2]
• Explains the diagnosis clearly (2): the blocked electrical pathway and the slow backup escape rhythm, without frightening unnecessarily. [4]
• Addresses the cause and guilt honestly (2): anti-Ro antibodies crossing the placenta, not the parent's fault, could not have been prevented. [4]
• Explains the pacemaker, prognosis, and restrictions (2): device and leads, for life with generator changes, excellent prognosis, activity precautions. [1] [3]
• Addresses siblings and future pregnancies and agrees a plan (2): siblings not at risk, fifteen-to-twenty per cent recurrence, fetal surveillance from sixteen weeks, clear next steps. [1] [4]