Makindo Medical Notes

📖 About

• Also called Sick Sinus Syndrome (SSS) or Tachy-Brady Syndrome.
• Results from dysfunction or damage of the sinus node, the heart’s natural pacemaker.
• Leads to alternating episodes of bradyarrhythmias 🐢 and supraventricular tachyarrhythmias ⚡.
• More common in elderly patients due to sinus node fibrosis.

📈 ECG Features

• Sinus bradycardia (HR <60 bpm) 🐢
• Sinus node arrest or pause (absent/delayed P waves ⏸️)
• Episodes of supraventricular tachyarrhythmias (SVT, AF, flutter) ⚡
• Tachy-Brady alternation → paroxysmal atrial fibrillation/flutter followed by sinus pauses
• QRS rate may be <60 or >100 bpm depending on phase

⚠️ Causes

• Degenerative fibrosis of the sinus node (most common, age-related 👴)
• Ischaemic heart disease / myocardial infarction ❤️
• Infiltrative disease (amyloidosis, sarcoidosis) 🧬
• Cardiac surgery or trauma (esp. post-atrial surgery)
• Drugs: beta-blockers, digoxin, CCBs 💊
• Hypothyroidism 🦋

🧪 Investigations

• 12-lead ECG (look for sinus bradycardia, pauses, tachy-brady episodes)
• Holter or event monitoring 🎧 to capture intermittent episodes
• Bloods: U&E, LFTs, TFTs (thyroid especially), FBC
• Consider echocardiogram to assess structural disease

🛠️ Management

• Asymptomatic → may not require specific treatment ✅
• Review medications that worsen bradycardia (BBs, CCBs, digoxin) 💊
• Pacing: Symptomatic bradycardia, sinus pauses, or syncope → permanent pacemaker 💓
• Tachyarrhythmias: Use rate-controlling drugs carefully (after pacing if brady risk high)
• Atrial fibrillation/flutter: Anticoagulation as per CHA₂DS₂-VASc 🩸

📚 Case Example

👩 A 74-year-old woman presents with dizziness and two syncopal episodes. ECG: Sinus bradycardia at 42 bpm 🐢. Holter shows paroxysmal AF ⚡ alternating with long sinus pauses. ✅ Diagnosis: Sinus Node Disease (Tachy-Brady Syndrome). 🛠️ Management: Permanent pacemaker 💓 + anticoagulation for AF 🩸.