Course 03: Cardiovascular, Vascular and Hematology
Lesson 5 of 12. Read the diagnostic framework and case, then complete the 10-question practice set. All material is original educational content; high-risk presentations require emergency referral.
Rhythm approach
- Determine stability first: altered mental status, hypotension, ischemic chest pain, shock and acute HF indicate need for immediate resuscitation-level care.
- Read rate, regularity, P-QRS relation and QRS width; use 12-lead ECG when possible without delaying resuscitation.
- Sinus tachycardia is usually a response to an underlying cause such as fever, pain, hypovolemia, anemia or PE rather than a primary arrhythmia.
- Wide-complex tachycardia in a sick patient should be assumed ventricular until specialist assessment.
Atrial fibrillation and flutter
- Atrial fibrillation shows an irregularly irregular rhythm and lacks consistent discrete P waves; AF may be paroxysmal and absent on one ECG.
- Assess thromboembolic risk with a validated approach, bleeding modifiers, renal function and contraindications.
- DOACs are generally preferred to warfarin in eligible nonvalvular AF; mechanical valves and moderate/severe rheumatic mitral stenosis are important exceptions.
- Aspirin alone is not an adequate substitute for indicated anticoagulation for AF stroke prevention.
SVT, bradycardia and blocks
- Regular narrow-complex tachycardia suggests SVT; assess stability and look for accessory pathways before selecting medication strategies.
- Symptomatic severe bradycardia or high-grade AV block can cause syncope and low output and may require urgent pacing.
- Long QT is associated with torsades risk; review electrolyte abnormalities, congenital causes and QT-prolonging medications.
- Palpitations with a family history of sudden cardiac death, exertional syncope or structural heart disease deserve prompt specialist evaluation.
Syncope differentiation
- Distinguish vasovagal and orthostatic causes from cardiac syncope; ask posture, triggers, exertion, palpitations and recovery.
- High-risk clues include syncope during exertion, no prodrome, abnormal ECG, family history of sudden death, heart disease, hypotension and associated chest pain.
- Measure orthostatic vitals when safe; consider targeted rhythm monitoring and echo based on risk rather than ordering a battery of indiscriminate tests.
- Document driving and activity restrictions according to applicable local standards after concerning syncope.
Safety, medication review, communication
- Check reversible arrhythmia contributors: potassium, magnesium, thyroid status, ischemia, stimulants, alcohol and medications.
- Explain when to seek emergency help for fainting, persistent severe palpitations, chest pain or shortness of breath.
- Use informed discussions around anticoagulant bleeding risks, adherence, procedures and drug interactions.
Applied clinical case
A 74-year-old with hypertension and prior TIA has new irregularly irregular pulse and ECG-confirmed AF; vital signs are stable.
Show model clinical reasoning and disposition
Assess stroke risk and bleeding modifiers and arrange guideline-directed anticoagulation evaluation; do not rely on aspirin monotherapy as AF stroke protection.
Clinical self-check
- What factors determine stroke prevention?
- Which AF phenotypes require different anticoagulants?
- What features would make this unstable?
Guidelines and further learning
- AHA/ACC — Atrial Fibrillation Clinical Practice Guideline (external)
- AHA — 2025 Adult Advanced Life Support (external)
- Canadian Cardiovascular Society — Guidelines Library (external)