🧠 STEP 10 — Student Memory Support
🃏 1️⃣ High-Yield Flashcards
What are the three major mechanisms of arrhythmia?
Abnormal automaticity, triggered activity and re-entry.
What ECG pattern is characteristic of atrial fibrillation?
Absent discrete P waves with irregularly irregular R–R intervals.
Why does atrial fibrillation increase stroke risk?
Loss of atrial contraction causes blood stasis, especially in the left atrial appendage, leading to thrombus formation.
What ECG finding defines first-degree AV block?
PR interval greater than 200 milliseconds with every P wave conducted.
What is the ECG pattern of Mobitz type I AV block?
Progressive PR prolongation followed by a dropped QRS complex.
What is the ECG pattern of Mobitz type II AV block?
Constant PR intervals with sudden non-conducted P waves.
What finding indicates complete heart block?
AV dissociation, with independent P waves and QRS complexes.
How should a regular broad-complex tachycardia in structural heart disease be considered?
Ventricular tachycardia until proved otherwise.
What is torsades de pointes?
Polymorphic ventricular tachycardia associated with a prolonged QT interval.
Which antiarrhythmic class blocks fast sodium channels?
Class I antiarrhythmic drugs.
What is the main electrophysiological action of beta-blockers?
They reduce phase 4 nodal depolarization and slow AV nodal conduction.
What is the major action of class III antiarrhythmic drugs?
Potassium-channel blockade causing prolonged phase 3 repolarization and refractoriness.
What is the major serious adverse effect of amiodarone?
Pulmonary toxicity, including pneumonitis and fibrosis.
Why is flecainide avoided in significant structural or ischemic heart disease?
It may cause dangerous ventricular proarrhythmia.
What clinical pattern should raise suspicion of myocarditis?
Recent viral illness followed by chest pain, heart failure, arrhythmia or conduction block.
What are the characteristic clinical features of acute pericarditis?
Sharp pleuritic positional chest pain, pericardial friction rub and diffuse ECG changes.
Which ECG changes support acute pericarditis?
Widespread concave ST elevation with PR depression.
What converts a pericardial effusion into cardiac tamponade?
Raised intrapericardial pressure causing impaired ventricular filling and reduced cardiac output.
🧠 2️⃣ Mnemonics
Mnemonic Title: Antiarrhythmic Classes
Mnemonic Word: Some Block Potassium Channels
Meaning:
- S — Sodium-channel blockers: Class I
- B — Beta-blockers: Class II
- P — Potassium-channel blockers: Class III
- C — Calcium-channel blockers: Class IV
Mnemonic Title: Atrial Fibrillation Management
Mnemonic Word: S-R-R-C
Meaning:
- S — Stability assessment
- R — Rate control
- R — Rhythm control
- C — Clot/stroke prevention
Mnemonic Title: Pericarditis Diagnostic Features
Mnemonic Word: P-R-E-E
Meaning:
- P — Positional chest pain
- R — Pericardial rub
- E — ECG changes
- E — Effusion
Diagnosis is supported when at least two features are present.
Mnemonic Title: Tamponade Warning Features
Mnemonic Word: H-J-M
Meaning:
- H — Hypotension
- J — Raised JVP
- M — Muffled heart sounds
📋 3️⃣ Memory Tables
Table 1 — Commonly Confused AV Blocks
| AV block | PR interval | Dropped QRS | Key clue |
|---|---|---|---|
| First degree | Prolonged and fixed | No | Every P wave conducted |
| Mobitz I | Progressively lengthens | Yes | Wenckebach pattern |
| Mobitz II | Fixed | Yes | Sudden dropped beat |
| Complete block | No fixed relationship | Variable | AV dissociation |
Table 2 — Pericarditis, Myocarditis and Tamponade
| Condition | Main process | Key clue | Main danger |
| Pericarditis | Pericardial inflammation | Positional pain + friction rub | Effusion/recurrence |
| Myocarditis | Myocyte inflammation | Troponin rise + ventricular dysfunction | HF, VT, heart block |
| Tamponade | Impaired filling from pressure | Hypotension + raised JVP + echo collapse | Obstructive shock |
⚡ 4️⃣ Rapid Revision Points
Must Remember
- Atrial fibrillation produces absent P waves and an irregularly irregular rhythm.
- Stroke prevention must be assessed separately from rate control in atrial fibrillation.
- Mobitz II is more dangerous than Mobitz I because it may progress to complete heart block.
- Pulseless VT and VF require defibrillation and CPR.
- Unstable tachyarrhythmia with a pulse requires synchronized cardioversion.
- Class I drugs block sodium channels; Class III drugs prolong repolarization.
- Flecainide should be avoided in significant structural or ischemic heart disease.
- Amiodarone may cause pulmonary, thyroid and hepatic toxicity.
- Adenosine is given as a rapid IV bolus for regular AV node-dependent narrow-complex tachycardia.
- Myocarditis may present with heart failure, arrhythmia or conduction block after infection.
- Colchicine reduces recurrence in acute pericarditis.
- Cardiac tamponade requires urgent pericardial drainage.
🩺 5️⃣ Clinical Memory Hooks
Clinical Hook 1:
Irregularly irregular pulse + absent P waves → Atrial fibrillation
Clinical Hook 2:
Previous MI + regular broad-complex tachycardia → Scar-related ventricular tachycardia
Clinical Hook 3:
Polymorphic VT + prolonged QT → Torsades de pointes → IV magnesium
Clinical Hook 4:
Recent viral illness + heart failure or heart block → Myocarditis
Clinical Hook 5:
Positional chest pain + friction rub + diffuse ST elevation → Acute pericarditis
⭐ 6️⃣ Starred High-Yield Exam Points
⭐ High-Yield Points:
- ⭐ Absent P waves with irregularly irregular R–R intervals strongly indicates atrial fibrillation.
- ⭐ Broad-complex tachycardia in structural heart disease should be treated as VT until proved otherwise.
- ⭐ Pulseless VT/VF requires immediate defibrillation and CPR.
- ⭐ Torsades de pointes is treated with IV magnesium and removal of the QT-prolonging cause.
- ⭐ Flecainide is contraindicated in significant structural or ischemic heart disease.
- ⭐ Amiodarone can cause serious pulmonary toxicity.
- ⭐ High-grade AV block or sustained VT in myocarditis requires urgent specialist care.
- ⭐ Cardiac tamponade is diagnosed by hemodynamic compromise and requires urgent drainage.