22/05/2026
⚡️ PROLONGED QT DRUGS — THE “TORSADES TRAP” 💔⚠️
A prolonged QT interval can trigger Torsades de Pointes (TdP) — a dangerous polymorphic VT that may cause syncope, seizures, or sudden cardiac death 😵💫⚡️
🫀 What is QT prolongation?
QT interval = ventricular depolarization + repolarization
📏 Corrected QT (QTc):
* Men: >440 ms = prolonged
* Women: >460 ms = prolonged
* 🚨 QTc >500 ms = HIGH RISK for TdP
⚠️ Dangerous ECG Clues
✅ Long QT
✅ Giant T/U waves
✅ “Short-long-short” sequence
✅ Polymorphic VT twisting around baseline 🌀
💊 HIGH-YIELD QT PROLONGING DRUGS
❤️ Antiarrhythmics (Most Exam-Famous)
🥇 Class IA
* Quinidine
* Procainamide
* Disopyramide
🥈 Class III
* Amiodarone
* Sotalol
* Dofetilide
* Ibutilide
📌 Sotalol = BIG torsades risk ⚠️
🦠 Antibiotics
🍎 Macrolides
* Azithromycin
* Clarithromycin
* Erythromycin
💥 Fluoroquinolones
* Levofloxacin
* Ciprofloxacin
* Moxifloxacin
🍄 Antifungals
* Fluconazole
* Voriconazole
🧠 Psychiatric Drugs
😵 Antipsychotics
* Haloperidol
* Olanzapine
* Quetiapine
* Ziprasidone
😔 Antidepressants
* Citalopram
* Escitalopram
* Amitriptyline
* Venlafaxine
📌 Haloperidol + IV use = dangerous QT prolongation ⚡️
🤢 Antiemetics
* Ondansetron
* Domperidone
* Droperidol
* Metoclopramide (rarely)
📌 IV ondansetron can prolong QT significantly ⚠️
🧪 Others
* Methadone 💉
* Chloroquine / Hydroxychloroquine
* Tacrolimus
* Lithium
* Co***ne
* Some antihistamines (older generations)
🚨 Risk Factors for Torsades
“THE PERFECT STORM” 🌩️
💊 QT-prolonging drug
➕
🧂 Low K⁺
🧂 Low Mg²⁺
🧂 Low Ca²⁺
➕
❤️ Bradycardia
➕
👩 Female s*x
➕
🫀 Structural heart disease
= ⚡️ TORSADES DE POINTES ⚡️
🧠 EXAM PEARLS
💥 “Erythromycin + hypokalemia”
➡️ Think torsades
💥 “Syncope after starting antipsychotic”
➡️ Check QT interval
💥 “Polymorphic VT with prolonged QT”
➡️ Diagnosis = Torsades de Pointes
🚑 Torsades Treatment
If unstable:
⚡️ Immediate DC cardioversion
Stable torsades:
💉 IV Magnesium Sulfate
—even if magnesium level is normal!
Also:
✅ Stop offending drug
✅ Correct K⁺/Mg²⁺
✅ Treat bradycardia
✅ Overdrive pacing if recurrent
🔥 SUPER MEMORY HACK
“ABCDE” of QT Drugs 💡
🅰️ Antiarrhythmics
🅱️ Biotics (macrolides, quinolones)
🅲️ Psych meds (“Crazy meds”)
🅳️ Domperidone / Droperidol
🅴️ Electrolyte problems worsen everything
⚡ Classic ECG Association
Long QT ➜ Early Afterdepolarizations ➜ Torsades 🌀
