MBBS OSCE · cardiology
OSCE — Supraventricular Tachycardia
Eight-minute OSCE station on Supraventricular Tachycardia: focused history, examination priorities, investigations, emergency and definitive management.
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Brief (to candidate)
You will assess a patient with a presentation consistent with Supraventricular Tachycardia. You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
SVT is a rapid tachycardia originating at or above the AV node with a narrow QRS (under 0.12 s). AVNRT is the commonest regular supraventricular tachyarrhythmia. Paroxysms start and stop abruptly; induced SVT raised urine flow from 3.2 to 7.6 mL/min with a rise in ANP. If unstable — synchronised DC cardioversion; if stable — modified Valsalva (43% vs 17%) then IV adenosine 6 mg, then 12 mg if necessary (57.4% then 93.4%). WPW with pre-excited AF: no AV-nodal blockers — electrical cardioversion, then accessory-pathway ablation. [2][1][4][10][15]
Candidate tasks
- Clarify onset, severity, associated features, and red-flag symptoms.
- State focused examination priorities.
- List first-line investigations and any named score/criteria.
- Give immediate resuscitation steps.
- Outline definitive management with doses/routes where standard.
- Name complications and disposition (ward / HDU / theatre / discharge safety-net).
- Mention one special-population modifier (pregnancy, child, elderly, CKD).
Examiner checklist
| Domain | Pass behaviours |
|---|---|
| Definition | Narrow-QRS tachycardia at or above the AV node; AVNRT commonest regular SVT |
| Assessment | Abrupt onset/offset, polyuria, frog sign; stability (hypotension, syncope, ischaemic pain, heart failure) |
| Investigations | 12-lead ECG; RP ≤90 ms favours AVNRT; visible P with RP ≥100 ms favours AVRT; look for WPW after termination |
| Emergency care | Unstable = synchronised DC cardioversion; do not delay for drugs |
| Definitive care | Modified Valsalva (REVERT 43% vs 17%); adenosine 6 then 12 mg; verapamil 5 then 7.5 mg |
| Safety | Pre-excited AF: never AV-nodal blockers — electrical cardioversion; asthma: consider alternatives to adenosine |
| Communication | Ablation for recurrent AVNRT (95% acute / 93% long-term); safety-net for WPW |
Model outline
Lead with the working diagnosis and life threats. Resuscitate before definitive tests when unstable. Use trial-standard therapy with named agents and doses (REVERT; DiMarco adenosine/verapamil). Document escalation criteria and follow-up. A safe candidate is specific, structured, and never delays cardioversion of unstable SVT or gives AV-nodal blockers in pre-excited AF.