Makindo Medical Notes

🚫 Beta blockers, particularly non-selective ones, are avoided in Prinzmetal angina because they block β2-mediated vasodilation, leaving unopposed α-adrenergic vasoconstriction → worsening coronary artery spasm.

📖 About Variant (Prinzmetal) Angina

• A form of angina caused by transient coronary artery vasospasm, sometimes on a background of fixed atherosclerosis.
• Presents with chest pain and transient ST-segment elevation (mimicking STEMI), but without plaque rupture.

🧬 Aetiology

• Focal or diffuse coronary vasospasm → transient myocardial ischaemia.
• ~75% have a coexisting fixed atherosclerotic lesion, but it can also occur in angiographically normal arteries.
• Hyperreactive vascular smooth muscle, endothelial dysfunction, and smoking are important contributors.

🩺 Clinical Features

• Chest Pain: Severe, often at rest, typically cyclical, common at night or early morning.
• Duration: Short-lived, usually <15 minutes.
• Relief: Resolves spontaneously or with nitrates.
• Associated: Palpitations, dyspnoea, dizziness; can rarely trigger ventricular arrhythmias.

🔍 Differential Diagnosis

• Acute coronary syndrome (STEMI/NSTEMI)
• Pericarditis
• Microvascular (syndrome X) angina

🧪 Investigations

• Bloods: FBC, U&E, LFTs, troponin (to exclude MI).
• ECG: ST-segment elevation during pain, normalises after nitrates.
• Coronary Angiography: Definitive. Spasm can be provoked with ergonovine or acetylcholine.
• Holter Monitoring: Detects transient ST-elevation during episodes.

💊 Management (Principles overlap with ACS)

• Sublingual Nitrates: GTN for acute symptom relief.
• Calcium Channel Blockers: (diltiazem, verapamil, amlodipine) are the cornerstone for prevention.
• Long-acting Nitrates: Reduce recurrence of spasm.
• 🚫 Beta-blockers: Avoid — worsen vasospasm.
• Lifestyle & Risk: 🚭 Smoking cessation, lipid control, avoid triggers (cold, stress, vasoconstrictor drugs such as cocaine or triptans).
• Statins: If coexistent atherosclerosis.

🇬🇧 Clinical Pearls (UK Context)

• Prinzmetal angina can mimic STEMI → treat initially as ACS until spasm confirmed.
• Ensure follow-up with cardiology and consider vasospastic angina when ST-elevation rapidly resolves with GTN.
• Smoking is the strongest modifiable risk factor — emphasise cessation.