Explain supraventricular tachycardia to a frightened parent — OSCE

Candidate instructions

You are the paediatric registrar. You have five minutes to speak with Mrs Patel, whose four-month-old son Arjun was admitted an hour ago after going pale, floppy, and breathing fast. The team gave him adenosine and his heart rate came down from 250 to a normal 130 within seconds. The echocardiogram shows a structurally normal heart, and the post-termination ECG shows no Wolff-Parkinson-White pattern. Mrs Patel watched the episode at home and is terrified. Explain what supraventricular tachycardia is in plain language, what happened to Arjun, what the medication is for and how long he will need it, what to watch for at home, and the long-term outlook. Answer her questions, check her understanding, and agree a plan. [1]

Actor brief (parent — Mrs Patel)

You are frightened and near tears. You watched your baby turn pale, go floppy, and breathe fast, and you thought he was dying. You have been told his heart was beating too fast and that a medicine brought it back to normal. You want to know: (1) What is wrong with his heart — is it damaged or diseased? (2) Will it happen again, and what do I do if it does? (3) What is this medicine he now needs to take, and for how long? (4) Will he grow out of it? (5) Is it your fault — could you have done something differently? Push back if the candidate uses jargon, dismisses your fear, or overpromises. You calm when you feel heard, understood, and given honest, clear information with a concrete plan. [2]

Exemplar candidate approach

Open and acknowledge. "Mrs Patel, please sit down. I can see how frightened you are, and I am so sorry you had to go through that. Arjun is stable now, his heart is back to a normal rhythm, and he is comfortable. I want to explain clearly what happened, what we found, and what the plan is, and I will answer every question you have." [1]

Explain the diagnosis in plain language. "Arjun had an episode of a condition called supraventricular tachycardia, or SVT for short. It means his heart suddenly started beating very fast — about 250 times a minute — because of a tiny extra electrical pathway he was born with. The pathway makes the electrical signal go round in a loop instead of passing through normally. When that happens, the heart beats so fast that it does not have time to fill properly between beats, which is why he went pale and floppy. The good news is that we gave him a medicine called adenosine through a drip that broke the loop within seconds, and his heart went straight back to normal. His heart is structurally normal — the echo scan confirmed that — so this is an electrical problem, not a structural one." [1] [3]

Explain the medication and the natural history. "Because the extra pathway is still there, there is a chance it could happen again, especially in the first year. So we will start him on a medicine called propranolol, which is a very well-established medicine that helps prevent the loop from starting. It is a small dose, given three times a day, and most babies tolerate it very well. The really reassuring news is that most babies — about 70 to 80 per cent — actually grow out of this by their first birthday, because the extra pathway matures and stops conducting as the heart grows. So we plan to keep him on the medicine until he is about 12 months old, and then we will try to wean it off and see how he goes." [2]

Explain what to watch for and what to do. "Here is what to look out for at home: if Arjun suddenly goes pale, becomes floppy or irritable, is not feeding well, or seems to be breathing fast, it may be happening again. The most important thing is to bring him in straight away — do not wait to see if it passes. If you can, you can try gently placing a cold pack wrapped in a cloth on his face for a few seconds — sometimes that is enough to break the loop. But always call us or bring him in. We will also give you a card explaining the condition to show any doctor you see." [1] [2]

Address the guilt question. "I understand why you ask whether you could have done something differently. This is nothing you did — Arjun was born with this extra pathway, and it is not caused by anything you ate, did, or missed. You did exactly the right thing by bringing him in immediately, and that is why we were able to fix it so quickly. You are a wonderful mother, and you did exactly what Arjun needed." [1]

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: Arjun stays with us overnight so we can watch his heart rhythm and start the medicine. Tomorrow, if he is well, he goes home with you on the propranolol, and we will see him in the cardiology clinic in a few weeks to check how he is doing. You can call the ward or the cardiology team at any time if you are worried. Is there anything else you want to ask?" [2] [4]

Mark scheme (10 marks)

• Empathy and relationship (2): acknowledges terror and guilt, sits and listens, plain language, does not dismiss. [2]
• Explains the diagnosis clearly (2): SVT as an extra electrical pathway causing a rapid loop, structurally normal heart, not the parent's fault. [1]
• Explains the medication and natural history without overpromising (2): propranolol to prevent recurrence, weaned at 12 months, 60 to 80 per cent outgrow it. [2]
• Gives a clear safety-netting plan (2): what to watch for, what to do at home (cold to face), when to bring him in, written information. [1]
• Checks understanding and agrees a plan (2): invites questions, checks comprehension, sets out next steps and ongoing availability. [4]