Before We Start
When the ventricles go rogue — four drugs that bring them back
The ventricles are the heart's main pumping chambers. When they start firing chaotically — too fast, from the wrong place, or in a disorganized quiver — blood stops flowing effectively. The patient may be pulseless or near-pulseless. This is a life-threatening emergency.
PALS gives you four antiarrhythmic drugs used for ventricular arrhythmias. These appear on NCLEX, in ACLS certification, and at the bedside of any cardiac patient.
💡 The Two Dangerous Ventricular Rhythms
V-tach: Ventricles fire rapidly (above 100 bpm, often 150–250) from an ectopic focus. Wide, bizarre QRS complexes. With a pulse = urgent. Without a pulse = treat like V-fib.
V-fib: Ventricles quiver randomly — no coordinated contraction, no pulse, no output. Chaotic, irregular waveforms on ECG. This is cardiac arrest. Immediate defibrillation is the priority — drugs support defibrillation.
The Mnemonic
PALS — four drugs for ventricular arrhythmias
P — Procainamide
Class IA antiarrhythmic — slows conduction throughout the heart
Procainamide blocks sodium channels, slowing depolarization and stabilizing irritable ventricular tissue.
When used: Stable V-tach with a pulse. Wide-complex tachycardia of uncertain origin. Not first-line in cardiac arrest — amiodarone has largely replaced it in codes.
How given: Slow IV infusion (20–50 mg/min) — never a fast bolus, causes severe hypotension.
Stop the infusion if: QRS widens more than 50% from baseline, hypotension develops, or arrhythmia terminates. Widening QRS = cardiac toxicity.
Side effects: Hypotension, QRS widening, QT prolongation (Torsades risk), lupus-like syndrome with long-term use.
💊 Procainamide has largely been replaced by amiodarone in many protocols, but remains an option for stable V-tach. Know it for NCLEX — it appears in arrhythmia management questions, particularly for wide-complex tachycardia.
A — Amiodarone
The workhorse antiarrhythmic — used in V-fib and V-tach codes
Amiodarone is a Class III antiarrhythmic that blocks potassium channels, prolonging the action potential and refractory period. It also has sodium channel, calcium channel, alpha, and beta blocking properties — its broad mechanism makes it effective against a wide range of arrhythmias.
ACLS dose for V-fib/pulseless V-tach: 300mg IV push in code. Can follow with 150mg IV push once if V-fib persists.
Dose for stable V-tach: 150mg IV over 10 minutes, then 1mg/min × 6 hours, then 0.5mg/min × 18 hours.
Long-term toxicity (high-yield NCLEX):
• Pulmonary fibrosis — most dangerous, can be fatal
• Thyroid dysfunction — hypo or hyperthyroidism (drug contains iodine)
• Liver toxicity
• Corneal microdeposits — bluish-gray vision
• Photosensitivity — blue-gray skin discoloration with sun exposure
• QT prolongation — Torsades risk
💊 Amiodarone monitoring: patients on long-term amiodarone need pulmonary function tests, thyroid function tests, liver function tests, eye exams, and ECGs periodically. The monitoring burden is high — this drug touches almost every organ system.
L — Lidocaine
Class IB antiarrhythmic — stabilizes ventricles, especially ischemic tissue
Lidocaine blocks sodium channels specifically in ischemic (damaged) cardiac tissue — the tissue most likely to generate dangerous ectopic beats. Normal cardiac tissue is relatively unaffected at therapeutic doses.
When used: V-fib/pulseless V-tach when amiodarone is not available — acceptable ACLS alternative. Post-resuscitation to prevent V-fib recurrence.
ACLS dose: 1–1.5 mg/kg IV bolus. Can follow with 0.5–0.75 mg/kg every 5–10 minutes. Maximum 3 mg/kg.
Lidocaine toxicity — SAMS:
• Slurred speech
• Altered CNS (confusion, drowsiness)
• Muscle twitching
• Seizures
At very high doses, lidocaine causes the ventricular arrhythmias it treats. Stop the infusion immediately if SAMS appear.
💊 Lidocaine is also the most common local anesthetic — the same drug used by dentists. The IV cardiac dose is the same molecule at higher systemic concentrations. That is why toxicity monitoring matters — a local anesthetic in the wrong dose becomes a cardiac toxin.
S — Sotalol
Beta blocker + antiarrhythmic — dual mechanism drug
Sotalol has both Class II (beta-blocking) and Class III (potassium channel blocking) properties. Effective for ventricular arrhythmias AND atrial arrhythmias, particularly atrial fibrillation rhythm control.
When used: Maintenance therapy for sustained ventricular arrhythmias. A-fib rhythm control — keeping the heart in sinus rhythm after cardioversion.
Critical concern — QT prolongation: Sotalol significantly prolongs the QT interval. A prolonged QT is the substrate for Torsades de Pointes — a dangerous polymorphic V-tach that can degenerate into V-fib.
Before starting sotalol, always check:
• Baseline QT interval (below 450ms men, below 470ms women)
• Potassium and magnesium — hypokalemia and hypomagnesemia worsen QT prolongation
• Other QT-prolonging drugs (additive risk)
Sotalol is always initiated in-hospital with telemetry monitoring for the first 3 days.
💊 "Sotalol starts in the hospital." Unlike most oral antiarrhythmics that can be started outpatient, sotalol requires inpatient telemetry because of the QT and Torsades risk. If NCLEX asks which drug requires inpatient initiation with telemetry — sotalol is the answer.
🏥 Clinical Scenario — V-Fib Code, PALS Drugs in Action
Mr. Johansson, 67 years old, step-down unit, 2 days post-anterior MI. At 3:18am the telemetry alarm fires — V-fib. You enter the room. Unresponsive, pulseless, not breathing.
CPR
Code called, CPR started immediately. Compressions at 100–120/min, depth 2–2.4 inches, full recoil, minimal interruptions. Defibrillator pads applied. Two-minute CPR cycle completed.
Shock
Rhythm check — V-fib confirmed. 200J shock delivered. CPR immediately resumed. Epinephrine 1mg IV given. Rhythm check at 2 minutes: still V-fib. Second shock delivered.
A
Amiodarone 300mg IV push given during CPR after second shock. Rationale: first antiarrhythmic in the ACLS V-fib algorithm. Stabilizes the myocardium and increases likelihood the next shock achieves sustained conversion.
Convert
Third shock delivered. Sinus rhythm at rate 68. Pulse present. BP 102/64. Patient begins to move. Post-resuscitation care: amiodarone infusion 1mg/min started, 12-lead ECG, ICU transfer, targeted temperature management considered.
📌 NCLEX Application
Code drug selection: "After two defibrillations and epinephrine for V-fib, which antiarrhythmic does the nurse prepare?" → Amiodarone 300mg IV push.
Amiodarone toxicity: "A patient on long-term amiodarone reports progressive shortness of breath and dry cough. Which complication does the nurse suspect?" → Pulmonary toxicity (pulmonary fibrosis) — the most serious long-term adverse effect.
QT prolongation: "Before sotalol, which lab does the nurse assess?" → Serum potassium and magnesium — hypokalemia and hypomagnesemia worsen QT prolongation and increase Torsades risk.
Lidocaine toxicity: "A patient on a lidocaine infusion develops slurred speech and muscle twitching. Priority action?" → Stop the infusion immediately. These are SAMS — seizures can follow.
⚠️ The Trap — Amiodarone Is Safe Long-Term
Amiodarone is the go-to antiarrhythmic — it works for so many rhythms, it is in ACLS, it is everywhere. This creates the incorrect assumption that it is safe for long-term use.
The reality: Amiodarone has one of the worst long-term toxicity profiles of any cardiac drug. With chronic use it can cause pulmonary fibrosis (irreversible, potentially fatal), thyroid failure or thyrotoxicosis, liver failure, permanent skin discoloration, and corneal deposits affecting vision.
The nursing role: Ensure the patient gets monitoring — PFTs, TFTs, LFTs, eye exams, ECGs, chest X-rays — at prescribed intervals. Educate: use sunscreen, report ANY new shortness of breath or vision changes immediately. Amiodarone pulmonary toxicity presenting as "just a cough" that gets ignored ends lives.
NCLEX angle: Patient teaching for long-term amiodarone: use sunscreen (photosensitivity), report SOB immediately (pulmonary toxicity), keep all follow-up appointments, report vision changes.
✓ Quick Self-Test
Answer before checking:
1. What does PALS stand for in this mnemonic?
2. In ACLS for V-fib, which PALS drug is given first after failed defibrillation?
3. What are the signs of lidocaine toxicity (SAMS)?
4. Why does sotalol require inpatient initiation on telemetry?
5. A patient on long-term amiodarone reports worsening shortness of breath over 3 months. What does the nurse suspect and what action is taken?
Answers:
1. Procainamide · Amiodarone · Lidocaine · Sotalol.
2. Amiodarone 300mg IV push. Lidocaine is an acceptable alternative if amiodarone unavailable.
3. Slurred speech, Altered CNS, Muscle twitching, Seizures. Stop the infusion immediately if any appear.
4. Sotalol significantly prolongs QT interval, creating risk for Torsades de Pointes. Highest risk is the first 3 days of therapy — telemetry monitoring required during initiation.
5. Suspect amiodarone-induced pulmonary fibrosis. Notify provider immediately. Anticipate CXR and PFTs. Drug may need to be discontinued — this complication can be irreversible.