A 55-year-old man, previously healthy and active, presents after a syncopal episode while cycling. He reports brief loss of consciousness with no warning signs and quick recovery. He denies chest pain, palpitations, or recent illness, but mentions feeling more tired lately. No past cardiac history.
On examination:
- BP: 130/85 mmHg, HR: 45 bpm (regular)
- No murmurs or neurological deficits
- ECG shows sinus bradycardia with intermittent dropped P waves
- Labs: Normal electrolytes, thyroid function normal
- Troponin: Negative
He is not on any medications. Family history reveals his father died suddenly at age 60 while walking.
What’s the most likely diagnosis and cause of his syncope? What investigations would you pursue next? When would you consider pacemaker insertion in such patients?
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Based on the information provided looks like bradycardia-tachycardia syndrome,
Causes:
Age-related degeneration of the conduction system can lead to bradycardia and sinus pauses.
Ischemic heart disease
Familial or inherited conditions
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To assess for any transient arrhythmias, pauses, or further characterization of the bradycardia over 24-48 hours.
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Echocardiogram.
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Exercise Stress Testing.
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Electrophysiological Study (EPS).
Pacemaker insertion should be considered in patients with symptomatic bradycardia, particularly if they experience:
Recurrent syncopal episodes related to bradycardia.
Significant pauses (usually >3 seconds) during Holter monitoring.
Persistent bradycardia with symptoms such as fatigue, dizziness, or syncope that do not improve with medical management.
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Most likely diagnosis: sick sinus syndrome causing bradycardia-related syncope.
Next: Holter monitoring, echocardiogram, and exercise stress test.
Pacemaker considered if symptomatic bradycardia or pauses cause syncope.