Scenario — SVT at a city marathon event

intermediate Cardiac · Adult · 35yr · male

Patient Information

Dispatch	A 35YO male has walked into the FAP complaining of a racing heart and feeling dizzy. (Marcus Holt)
Patient	Marcus Holt — 35yr (80kg)
Incident History	Pt was cheering on runners at the Perth City Marathon when he suddenly felt his heart 'take off'. States onset was abrupt approximately 8 minutes ago. Denies chest pain. Feels light-headed and clammy.
Emergency Contact	Sarah Holt (Wife) — 0412 774 338

Initial Rapid Assessment

Response	Alert
Airway	Patent. Nil airway obstructions. Speaking in short sentences.
Breathing	Slightly increased rate. Nil audible wheeze or crackles. Mild dyspnoea.
Circulation	Rapid, regular, weak radial pulse. Skin pale and diaphoretic. Nil visible bleeding.
Disability	GCS 15 (E4V5M6). Orientated to time, place and person. Anxious.
Exposure	Nil rashes or visible injuries. Wearing civilian clothing — spectator at event.

Vitals

Time	SpO2	Resp Dist	RR	Pulse	BP	CRT	GCS	PERL	Temp	BGL	Pain
Initial	97% (RA)	Mild	20	178	96/68	<2s	15	4 4 ++	37.1	5.4 mmol/L	2
10 mins	99% (O2 simple mask 6L)	Nil	16	168	108/72	<2s	15	4 4 ++	37.1	5.4 mmol/L	1

History Taking

Scenario Progression and Treatment Objectives

Diagnosis

This patient is suffering from Supraventricular Tachycardia (SVT) with haemodynamic compromise indicated by borderline hypotension, diaphoresis, and symptoms of reduced cardiac output.

Facilitator Triggers — if trainees miss a critical step

! (If the trainee does not limit patient exertion — e.g., allows patient to stand or walk — patient reports worsening dizziness and nearly faints; HR remains at 178 bpm)
! (If oxygen is not applied within 3 minutes, patient's respiratory rate increases to 24 and reports feeling more short of breath)
! (If the trainee does not take a blood pressure before any other intervention, facilitator prompts: 'The patient asks if everything is okay — what are you checking first?')
! (If the trainee asks about GTN for the chest discomfort without first checking BP, facilitator prompts: 'What does the BP need to be before you consider GTN?')
! (If the trainee attempts to administer GTN — note: GTN is not an authorised EHS treatment for cardiac dysrhythmia; facilitator prompts: 'Check the CPG — what indication does GTN have here?')
! (If no reassessment vitals are taken at 10 minutes, facilitator states: 'Five minutes have passed — the patient asks if the ambulance is coming; what are you doing right now?')

Treatment Objectives

1. Ensure scene safety and don appropriate PPE
2. Perform Primary Survey — confirm patent airway, assess breathing and circulation
3. Seat patient — limit all exertion; do not allow patient to stand or walk
4. Perform Vital Sign Survey — HR, BP, RR, SpO2, BGL, GCS, pain score, temperature
5. Apply oxygen via simple face mask at 6–8 L/min — titrate to SpO2 target 94–98%
6. Perform history taking using IMISTAMBO / SAMPLE framework
7. Reassure patient continuously — explain all actions calmly
8. Do NOT administer GTN — GTN is not indicated for cardiac dysrhythmia at EHS scope; chest discomfort is secondary to the rapid rate, not ischaemic in origin
9. Recognise SVT: HR ~178 bpm, sudden onset, regular, rapid, with signs of reduced cardiac output (borderline BP, diaphoresis, dizziness)
10. Recognise this patient is time critical — haemodynamically compromised SVT requires Priority 1 transport
11. Request ambulance upgrade / Priority 1 transport with pre-notification to receiving facility
12. Monitor patient persistently — record full observations every 10 minutes (or 5 minutes given time critical status)
13. Position patient seated and at rest; do not allow mobilisation
14. Document pre- and post-intervention pain scores
15. Consider Methoxyflurane (Penthrox) 3 mL inhaled via Penthrox inhaler — ONLY if chest pain escalates above 3/10 AND it can be safely self-administered; monitor for dizziness or over-sedation
16. Prepare resuscitation equipment at bedside — defibrillator, BVM, suction — given peri-arrest risk
17. Scenario ends on arrival of ambulance and IMISTAMBO handover
18. Attention to hand hygiene will be given throughout the scenario.

Clinical references: Cardiac Dysrhythmia · Chest Pain / Acute Coronary Syndrome · Oxygen · Methoxyflurane · Glyceryl Trinitrate · Primary Survey · Pulse Oximetry · Blood Pressure · Pain Assessment

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Signs/Symptoms	Racing heart, light-headedness, mild shortness of breath, feeling clammy. Denies chest pain, syncope or visual disturbance.
Allergies	Nil known drug allergies.
Medications	Nil regular medications.
Pertinent History	No known cardiac history. Nil previous episodes of palpitations. Nil history of hypertension or thyroid disease. Drinks 2–3 coffees per day. Had 3 coffees this morning.
Last Oral Intake	Coffee 45 minutes ago. Breakfast 2 hours ago.
Events Leading	Pt was standing watching runners near the 10km mark of the Perth City Marathon. Had not been running himself. Onset was spontaneous and abrupt.
Treatment Prior	Nil. Wife encouraged him to come to the FAP.

Onset	Sudden onset approximately 8 minutes ago at rest while standing in the spectator area. No warning or prodrome.
Pain	Mild chest tightness 2/10 — pt describes it as pressure from the pounding heart rather than cardiac pain.
Quality	Pounding, 'fluttering' sensation in the chest. Constant since onset.
Radiates	Nil radiation.
Severity	2/10 chest discomfort. Significant distress from rapid heart rate and dizziness.