Collapse / Syncope OSCE - Cardiac Arrhythmia

Diagnosis: Cardiac Arrhythmia

Case Overview

  • Age/Sex: 79-year-old male
  • Occupation: Retired engineer
  • Setting: Lives alone, brought to ED by ambulance after a collapse at home
  • Chief complaint: "I collapsed — I think I blacked out"

Patient Script

Who I Am

I'm 79, retired, live alone in my flat, used to be fairly active but a bit slower these days.

What Brings Me In

I suddenly went black and woke up on the floor — someone called an ambulance.

My Story

A couple of mornings ago I felt a bit light-headed when I stood up, but today I suddenly felt my chest flutter and then I blacked out for a few minutes. I remember sitting at the kitchen table drinking my tea, then my wife’s neighbour found me on the floor when they checked because I didn’t answer the door. I was out for maybe a minute or two — I don’t really remember falling, but I did hit my head on the kitchen counter. I woke up feeling weak and sweaty and a bit confused.

Before this, for the last few months I’ve had occasional brief dizzy spells when I stand up too quickly — my GP said it was probably just low blood pressure from getting older. I had a cough and felt run down last week; I took some extra over-the-counter sleeping tablets two nights ago because I couldn’t sleep. I haven’t had chest pain like a squeezing pain, but I did notice my heart was beating funny for a short time before I went out.

My Medical Background

  • Past medical history: coronary artery disease (stent 7 years ago), hypertension, benign prostatic hyperplasia
  • Medications: metoprolol 50 mg twice daily, ramipril 5 mg daily, aspirin 75 mg daily, atorvastatin 20 mg nightly, tamsulosin as needed
  • Allergies: none known
  • Social: lives alone, ex-smoker (20 pack-years, quit 15 years ago), drinks about 6 units alcohol per week
  • Family history: father died of a heart attack in his 70s

What I Think & Worry About

  • I’m worried it might be my heart — I keep thinking I might have had a heart attack or something serious.
  • I’m anxious about living alone and not being able to look after myself if this happens again.
  • I hope it’s nothing I did — I took a couple of extra sleeping tablets but I don’t think I overdosed.

If You Ask Me About Other Symptoms...

  • Chest pain: "No sharp or crushing chest pain — just the fluttering before I went out."
  • Breathlessness: "A bit short of breath after I woke up, but not before the blackout."
  • Palpitations: "Yes, I felt a strong, fast flutter in my chest for a short time just before I went out."
  • Head injury / headache / vomiting: "I hit my head on the counter; a bit sore and a lump, felt sick for a few minutes but stopped. No vomiting since."
  • Recent infection: "Had a cough and felt under the weather last week, but better now."
  • Fainting history: "Just those light-headed spells for months when I stand up — never proper falling down before."
  • Recent medication changes: "No, been on the same tablets for a while, except I sometimes take an extra bedsheet of herbal things — nothing strong."
  • Neurology: "No weakness now, my speech’s a bit slurred when I was dragged up but now it’s okay."

Clinical Summary

Examination

  • General: elderly man, diaphoretic, alert but a little slow to answer; small scalp contusion over right temple
  • Airway: patent
  • Breathing: RR 20/min, SpO2 95% on air, lungs clear bilaterally
  • Circulation: HR 34 beats/min (slow and regular), BP 82/50 mmHg, cool peripheries, capillary refill 3 seconds
  • Neurology: GCS 14 (disoriented to time), pupils equal/reactive, no focal limb weakness, speech slightly slurred but comprehensible
  • Cardiovascular: slow heart sounds, no added murmurs, no raised JVP
  • Abdomen: soft, non-tender

Investigations

  • ECG: complete heart block (third-degree AV block) with ventricular escape rhythm at 34 bpm (AV dissociation) (consistent)
  • 12-lead ECG rhythm strip: ventricular broad QRS escape, no acute ST-elevation
  • Bedside glucose: 5.8 mmol/L (normal)
  • Troponin I: 0.05 ng/mL on arrival, repeat 3 hours: 0.22 ng/mL (mild rise suggesting myocardial injury)
  • Serum electrolytes: Na 138 mmol/L, K 4.1 mmol/L, creatinine 95 µmol/L
  • Chest X-ray: heart size within normal limits for age, lungs clear
  • CT head (post-fall): no acute intracranial bleed
  • Continuous cardiac monitor: persistent bradycardia with intermittent ventricular escape rhythm

Diagnosis

Primary diagnosis:

  • High-grade atrioventricular block (complete heart block) causing syncope
    • Evidence: witnessed collapse with brief loss of consciousness, profound bradycardia (HR ~34), ECG demonstrating AV dissociation/complete heart block, hypotension, history of cardiac disease and beta-blocker use.

Differential diagnoses:

  • Bradyarrhythmia secondary to beta-blocker excess or interaction (metoprolol contributing) — plausible given regular metoprolol and bradycardia but ECG shows complete heart block rather than simple sinus bradycardia.
  • Acute myocardial ischemia causing conduction disturbance — supported by troponin rise; needs assessment for acute coronary syndrome as precipitant.
  • Ventricular tachyarrhythmia with transient collapse — less likely given current bradycardia and ECG findings.
  • Vasovagal syncope — unlikely given severe bradycardia and hemodynamic compromise.
  • Non-cardiac causes of syncope (hypoglycaemia, seizure) — excluded by normal glucose and lack of prolonged post-ictal state; CT head normal after fall.

Management

  • Immediate:
    • ABCs; place on continuous cardiac monitoring and establish two large-bore IV lines
    • Oxygen via nasal cannula if needed (SpO2 95% on air currently)
    • Hold any rate-lowering medications (withhold metoprolol)
    • Administer IV atropine 500 µg bolus; repeat every 3–5 minutes up to 3 mg if needed
    • If inadequate response or instability persists: prepare for urgent transcutaneous pacing and discuss transvenous temporary pacing with cardiology/electrophysiology
    • Consider isoprenaline/dopamine infusion if atropine ineffective and pacing not immediately available
  • Further:
    • Admit to high-dependency unit/CCU for monitoring and management
    • Serial troponins and consider urgent cardiology review for coronary angiography if ongoing ischemia suspected
    • Arrange echocardiography to assess LV function
    • Plan for definitive management with permanent pacemaker insertion if high-grade AV block persists after reversible causes addressed
    • Address head injury: local wound care for scalp contusion and routine neurosurgical input if any neurological deterioration
    • Social: involve occupational therapy and social services as he lives alone; ensure safe discharge planning if appropriate

Key Learning Points

  • Elderly patients with sudden syncope and profound bradycardia should prompt immediate consideration of high-grade AV block; recognition and rapid stabilization (atropine, pacing) are critical.

  • Medication review is essential: rate-limiting drugs (beta-blockers, calcium channel blockers, digoxin) can precipitate or exacerbate bradyarrhythmias, but an ECG is required to distinguish drug-induced sinus bradycardia from complete heart block.

  • Always treat the ABCs first, monitor continuously, and consider reversible causes (ischemia, electrolytes, drug effects) while arranging urgent definitive therapy (temporary pacing and likely permanent pacemaker) in symptomatic high-degree AV block.

Want more? Generate and iterate on custom cases with Oscegen.

Visit app