anti arrythmatics

Answer 1

DISOPYRAMIDE
Mechanism: Na⁺ channel blocker – binds open/activated Na⁺ channels in cardiac myocytes → ↓ Na⁺ influx during Phase 0 → prolonged AP duration

Uses: Ventricular dysrhythmias, prevention of paroxysmal AF/flutter, recurrent arrhythmias

Side Effects: GIT upset, dry mouth, nausea, constipation, hypotension, QT prolongation, urinary retention, vision issues

Key Warning: Negative inotrope → ↓ intracellular Ca²⁺ → ↓ contractility → contraindicated in heart failure

Answer 2

Mechanism: Na⁺ channel blocker – slows Phase 0 → ↓ rate of depolarization and contraction

Use: Ventricular arrhythmias (especially post-MI)

Side Effects: Hypotension, cardiac arrest, blurred vision, dizziness, drowsiness, nausea, vomitin

Answer 3

FLECAINIDE / PROPAFENONE (Class 1c Antiarrhythmics)
Mechanism: Blocks fast Na⁺ channels → slows conduction velocity (minimal effect on repolarization)
Use: “Pill-in-the-pocket” for paroxysmal AF, recurrent tachyarrhythmias
Side Effects: Arrhythmias, asthenia (weakness), dizziness, dyspnoea, oedema, vision disturbances

Answer 4

🃏 ATENOLOL, BISOPROLOL, PROPRANOLOL, NADOLOL (Class II – Beta Blockers)
Mechanism: Block β1 (and sometimes β2) receptors → ↓ HR, contractility, BP; ↓ SNS activity
Uses:

Paroxysmal AF (prevent recurrence)

Hypertension (↓ CO and BP)

Angina (↓ cardiac workload)

Post-MI (secondary prevention)

Propranolol: also for anxiety
Side Effects: Bradycardia, fatigue, dizziness, GI upset, depression, cold extremities, sleep disturbance
Warnings:

Can cause bronchospasm → avoid in asthma/COPD

May affect glucose → hypo/hyperglycemia

Answer 5

AMIODARONE (Class III – Potassium Channel Blocker)
Mechanism: Prolongs Phase 3 (repolarization) → extends refractory period
Uses:

WPW syndrome

Supraventricular & ventricular tachyarrhythmias
Side Effects:

Arrhythmias, liver, pulmonary, and thyroid disorders

QT prolongation, bronchospasm, hypotension, headache
Note: Inhibits peripheral T4 → T3 conversion → may cause hypothyroidism

Answer 6

SOTALOL (Class III – Potassium Channel Blocker)
Mechanism:

Non-selective β-blocker with K⁺ channel blocking → prolongs repolarization (↑ AP duration)
Uses:

Paroxysmal supraventricular dysrhythmias

Ventricular ectopics & tachyarrhythmias
Side Effects:

Anxiety, chest pain, dyspepsia, palpitations, sexual dysfunction, torsades de pointes, QT prolongation (↑ risk in females)
Note: Requires ECG monitoring due to QT risk

Answer 7

VERAPAMIL / DILTIAZEM / AMLODIPINE (Class IV – Calcium Channel Blockers)
Mechanism:

Block L-type Ca²⁺ channels → reduce Phase 2 Ca²⁺ influx → ↓ HR & contractility, ↑ myocardial perfusion
Uses:

Prevent supraventricular tachycardia recurrence

Control ventricular rate in AF (not in WPW)
Side Effects:

Dizziness, flushing, headache, nausea, peripheral oedema, palpitations, drowsiness, vomiting

Answer 8

DIGOXIN (Cardiac Glycoside)
Mechanism:

↑ myocardial contractility (positive inotrope)

↓ AV node conduction (↑ vagal tone)
Uses:

AF/flutter (rate control)

Heart failure (in sinus rhythm)
Side Effects:

Arrhythmias, visual disturbances, dizziness, GI upset, skin rash
Monitoring:

Serum digoxin, renal function, potassium levels essential