Antiarrhythmics Classification (Vaughan Williams)

Epomedicine, May 27, 2024May 27, 2024

Understand the conducting system of heart, cardiac action potential and pacemaker action potential.

Physiology of Conducting System of Heart

Mnemonic to remember Vaughan Williams classification for anti-arrhythmic – Some Block Potassium Channel DAAM!

Mnemonic	Class	Mechanism of action	Comments	Example	Use
Some	IA	Sodium channel blocker (moderate) Intermediate action	Moderate ↓ phase 0 slope ↑ EFR & AP duration Additional class III action	Quinidine, Procainamide, Disopyramide	Ventricular arrhythmias, WPW (procainamide)
	IB	Sodium channel blocker (weak) Fast action	Small ↓ phase 0 slope ↓ EFR & AP duration	Lidocaine, Mexiletine	VT
	IC	Sodium channel blocker (strong) Slow action	Pronounced ↓ phase 0 slope = EFR & AP duration	Flecainide, Propafenone	Paroxysmal AF, recurrent SVT
Block	II	Beta blocker	↓ phase 4 slope in nodes (pacemaker potential) Prolong AV node repolarization	Atenolol, Bisoprolol, Carvedilol, Esmolol, Metoprolol, Propranolol, Sotalol	Recurrent tachyarrhythmias
Potassium	III	Potassium channel blocker	Delay phase 3 (repolarization)	Amiodarone (also class I, II & IV action), Sotalol (also class II action), Dofetilide, Ibutilide	Atrial fibrillation & flutter, Ventricular tachycardia
Channel	IV	Calcium channel blocker	Prolongs phase 2 ↓ slope phase 0 & 4 in node (pacemaker potential) Prolong AV node repolarization	Verapamil, Diltiazem	Paroxysmal SVT, AF with RVR
DAAM	V/Others	Direct nodal inhibition		Digoxin Atropine Adenosine Magensium sulphate	SVT (Adenosine), Torsades de pointes (Magnesium), Rate control in AF (Digoxin)

PGMEE, MRCS, USMLE, MBBS, MD/MS

Dermatomes : Mnemonic

Sep 18, 2021Sep 18, 2021

Note: C1 doesn’t have a sensory branch For the purpose of making learning easier, we divide the remaining dermatomal segments into 4 groups which will be accompanied by analogies and mnemonics. C2-C4 These supply the “hooded cape” region. C2: hood region abutting the trigeminal distribution C3: upper neck C4: lower…

PGMEE, MRCS, USMLE, MBBS, MD/MS

Venous Drainage of Heart : Mnemonic

Jun 12, 2023Jun 12, 2023

Mnemonic: CAT 1. Coronary sinus (50%): Drains blood from left side of heart → Thebesian valve → Right Atrium 2. Anterior cardiac veins (20%): Drain blood from right side of heart → Right Atrium 3. Thebesian veins/Venae cordis minimi (30%): Drain deoxygenated blood from endocardium and myocardium → Respective chamber…

PGMEE, MRCS, USMLE, MBBS, MD/MS

Pediatric History Taking – Structured format and Guide

May 19, 2019Oct 27, 2020

Identification (ID): Name Age/Date of Birth Sex Informant ( Reliability) Parent’s name, age, address, education, religion Chief Complaints (CC): Symptoms X Duration in Chronological order History of Presenting Illness (HPI): Symptoms: Location, quality, quantity, aggravating and alleviating factors Time course: Onset, duration, frequency, change over time Rx/Intervention: Medications, medical help…

Related Posts

Leave a Reply Cancel reply