Arrhythmias
When the rhythm goes wrong — the Vaughan-Williams classes and atrial fibrillation.
Antiarrhythmics Part 1: The Vaughan-Williams Classes & Sodium-Channel Blockers
There's a dark irony at the heart of rhythm drugs: the very medicines meant to fix a dangerous heartbeat can CAUSE a fatal one. A famous trial gave patients a drug that beautifully suppressed their extra beats — and quietly killed more of them than placebo. That lesson haunts every antiarrhythmic. Start with the map that organizes them all, then meet the sodium-channel blockers where the story begins.
Antiarrhythmics Part 2: Potassium Blockers, Beta & Calcium Blockers
One antiarrhythmic is so effective it can calm almost any rhythm — and so toxic it slowly stains the skin blue, scars the lungs, and derails the thyroid. Amiodarone is the strange miracle-and-menace of heart-rhythm drugs, and it doesn't even respect the classification system. Around it sit the reliable, safer workhorses: the beta blockers and calcium blockers that simply slow the heart's gatekeeper node.
Atrial Fibrillation & SVT: Adenosine, Rate vs Rhythm
A young woman's heart suddenly races to 180 beats a minute. The doctor pushes a drug that makes her heart briefly STOP on the monitor — a flat line for a few terrifying seconds — and then it restarts in a normal rhythm. That drug, adenosine, lasts only seconds and is blocked by your morning coffee. Then there's atrial fibrillation, the world's commonest arrhythmia, where the real danger isn't the racing heart at all — it's a stroke.
