LAP — the ventricular rhythm drugs · Lidocaine · Amiodarone · Procainamide
NG-062CARDIO PHARMADHD-friendly visual edition
Page 2 handled the top of the heart. This page is the bottom — and the bottom is where people die. Any rhythm that starts with a V is VERY deadly, because the ventricles are the pump: no ventricular squeeze means no cardiac output, and no cardiac output means no oxygen to the brain. Lidocaine, Amiodarone and Procainamide are the three drugs aimed downstairs — but every one of them comes AFTER electricity.
🦵 LAP = in your lapLidocaine · Amiodarone · Procainamide — all aimed at the ventricles: V-Tach & V-Fib.
🚨 V = VERY deadlyVentricles = cardiac OUTput. Low cardiac OUTput = low oxygen OUT to the body.
🧠 “Cain” CALMS the ventriclesLidocaine and procainamide both calm ventricular tissue. Amiodarone is the heavy artillery.
⚡ Shock before drugPulseless V-Tach or V-Fib → CPR + defibrillate. The drug goes in after the shock, never instead of it.
🗺️
THE LAP MAP
STEP 1 · WHY DOWNSTAIRS IS DEADLY
Understand one thing on this page and make it this: the ventricles are the pump.
🤖 Sparky is back — and she is worried about the bottom of the heart
🧠 ABCD sits on TOP of the heart. LAP sits in your LAP. Two mnemonics, two floors of the same building. If the rhythm name starts with A (atrial) go upstairs; if it starts with V (ventricular) go downstairs.
🚨 Why “V” means VERY deadly — follow the oxygen
🧠 “OUTput = oxygen OUT.” The atria only top up the ventricles (about a fifth of the filling). Lose the atria and you feel bad. Lose the ventricles and you are dead in minutes.
🚨 The two rhythms these drugs exist for
V-Tach: wide, bizarre, regular, fast, no P waves. It has two completely different treatments depending on one assessment.
V-Fib: no organized QRS at all — a chaotic quiver. There is never a pulse in V-Fib. CPR and defibrillation, immediately.
🧠 “Wide = ventricular. Chaotic = fibrillation.” Wide and organized is V-Tach; wide and disorganized is V-Fib. See NG-090 for all nine strips side by side.
⚠️ PVCs — the warning shot before the real thing
A PVC is one early, wide, bizarre beat from the ventricle. Every other beat being a PVC is bigeminy.
Look for the cause first: low K⁺, low Mg²⁺, hypoxia, caffeine/stimulants, ischemia, digoxin toxicity.
Worrying patterns: more than 6 per minute, runs of 3 or more (that is V-Tach), multifocal (different shapes), or a PVC landing on the T wave (R-on-T → torsades / V-Fib).
Occasional PVCs in a healthy, asymptomatic client are usually benign — assess the client.
🧠 “Check the batteries before you call the electrician.” Potassium and magnesium first — you cannot drug your way out of an electrolyte problem.
💊
L · A · P
STEP 2 · THE THREE DRUGS
Same target, three different personalities — and only one of them is gentle.
LLIDOCAINE — “Cain” calms the ventricles
Answer first: a Class Ib sodium channel blocker (see NG-019) that binds preferentially to ischemic, depolarized ventricular tissue — the exact cells misfiring after an MI.
Given for:V-Tach and V-Fib — the ventricular rhythms. It is an accepted ACLS antidysrhythmic for shock-refractory pulseless V-Tach / V-Fib.
How: IV bolus then a continuous infusion on an IV pump, with the client on continuous ECG. Dosing is weight-based and protocol-driven — follow the order and your facility's ACLS protocol.
Never give the lidocaine formulation that contains epinephrine intravenously — that bottle is for local anesthesia only.
Cleared by the liver — doses are lowered in liver disease, heart failure and older adults, because the drug accumulates.
❌ It does nothing for A-fib, A-flutter or SVT. Wrong floor of the building.
🧠 “LidoCAINE CALMS the ventricles — and it only speaks to sick cells.” Class Ib clings to injured, depolarized tissue, so it quiets the infarct zone and leaves healthy muscle mostly alone.
🔬 Why lidocaine goes where the damage is — a cut through the ventricular wall
🧠 “Lidocaine is a bouncer who only grabs the person causing trouble.” Healthy myocardium barely notices it; the injured, over-firing cells get shut down.
AAMIODARONE — the one that works on everything
Answer first: the broadest antidysrhythmic there is. It is Vaughan-Williams Class III (potassium channel blocker) but it also has Class I, II and IV activity — which is exactly why it works on so much and damages so much.
Given for: V-Tach and V-Fib (including shock-refractory pulseless arrest), and also A-fib and A-flutter. Traditionally taught as the second LAP drug, but current ACLS lists amiodarone first for shock-refractory V-Fib / pulseless V-Tach, with lidocaine as the alternative — follow your ACLS algorithm and facility protocol.
IV: continuous ECG and BP monitoring — hypotension and bradycardia are the immediate risks. Slow the infusion rate for hypotension; use an infusion pump and a filter per policy. Prolonged peripheral infusion causes phlebitis — a central line is preferred.
Half-life is measured in weeks, so side effects persist long after the drug is stopped.
⚠️ It raises digoxin and warfarin levels — expect dose reductions and watch the INR and the digoxin level (see page 3).
🧠 “Amiodarone is the antibiotic-of-last-resort of cardiology.” Broad-spectrum, effective, and something goes wrong in nearly every organ if you use it long enough.
PPROCAINAMIDE — “Cain” again, but on its way out
Answer first:Class Ia. It calms the ventricles like lidocaine, but it is used far less often now — the source infographic flags it as not commonly tested. Know the name and the two red flags.
🦋 Drug-induced lupus-like syndrome — joint pain, muscle aches, a butterfly-shaped facial rash, fever, pleuritic chest pain, positive ANA. Reversible when the drug stops.
🩸 Blood dyscrasias — agranulocytosis and thrombocytopenia. Monitor the CBC; report fever, sore throat, bruising or bleeding.
📐 Prolongs the QT → torsades risk, and widens the QRS. The infusion is stopped for a QRS that widens by more than about half, for hypotension, when the dysrhythmia is suppressed, or at the maximum dose.
📉 Hypotension with rapid infusion — it must go in on a pump with continuous ECG and BP.
🧠 “PROCAINamide gives you a PORCELAIN face.” The lupus butterfly rash across the cheeks — one image, one drug, one answer.
🧠 “L = Lids (the brain). A = All of you. P = Porcelain face.” Three drugs, three unmistakable pictures.
🚨
WATCH FOR
STEP 3 · TOXICITY
These drugs are given to people who are already unstable. The toxicity signs are subtle until they are not.
🧠 LIDOCAINE TOXICITY — neuro checks are the PRIORITY
🧠 “Lidocaine talks to your LIDS.”Lips tingle · In the ears ringing · Dizzy & drowsy · Seizures. The mouth and the ears warn you before the brain does.
🚨 AMIODARONE — five organs, one drug
🧠 “AMIODARONE ruins your LUNGS, THYROID, LIVER, EYES and SKIN.” Picture a blue-gray client with a dry cough sitting in the eye doctor's chair. Five organs, one image.
🧪 The labs and tests that go with these drugs
Test
Why
K⁺3.5–5.0 mEq/L
Low K⁺ makes the ventricles irritable and makes every antidysrhythmic less effective
Mg²⁺1.3–2.1 mEq/L
Low Mg²⁺ → torsades. Magnesium is the treatment for torsades
QTc on 12-lead
Amiodarone and procainamide stretch it; >500 ms is the classic hold-and-call threshold
LFTs · TSH · CXR · PFTs · eye exam
Amiodarone baseline and periodic surveillance
CBC · ANA
Procainamide — blood dyscrasias and the lupus-like syndrome
Renal function
Dosing and clearance; also drives K⁺ and Mg²⁺ swings
Adult reference ranges — always use your facility's lab values.
🧠 “Batteries, then wires.” Correct K⁺ and Mg²⁺ (the batteries) before blaming the drug (the wires).
🌀 Torsades de pointes — the complication these drugs can CAUSE
Answer first: the treatment is IV magnesium sulfate. Magnesium Mellows out the heart.
Causes: post-MI, hypoxia, low magnesium, low potassium, and QT-prolonging drugs — including amiodarone and procainamide themselves.
Looks like: polymorphic V-Tach whose amplitude twists and waxes and wanes around the baseline — the "Tornado Pointes" strip.
If it becomes pulseless, it is treated as V-Fib: CPR + defibrillation.
🧠 “Tornado Pointes → Mag it.” A twisting tornado on the monitor gets magnesium. Nothing else in this chapter gets magnesium.
⏱️ Why the shock cannot wait for the drug
Coarse V-Fib responds to defibrillation. Left alone it becomes fine V-Fib and then asystole, and the odds fall with every passing minute. High-quality CPR and early defibrillation are the only two interventions proven to change the outcome.
Antidysrhythmics improve the chance of return of circulation — they are given after the shock and after epinephrine, and they do not replace either one.
🧠 “Shock · CPR · Epi · then the LAP drug.” If a test option offers a drug before a shock in pulseless V-Fib, it is wrong.
✅
PRIORITY & TEACHING
STEP 4 · WHAT YOU DO
One ladder for the emergency, one short list for the ward.
✅ The priority ladder for a ventricular rhythm
1
CHECK A PULSE. This single assessment splits the whole algorithm. Wide-complex tachycardia with a pulse ≠ pulseless V-Tach.
▼
2
No pulse → start CPR and DEFIBRILLATE (unsynchronized). V-Fib and pulseless V-Tach are the two shockable rhythms.
Pulse present and stable → now a drug: amiodarone, lidocaine, or procainamide, per the ACLS algorithm and provider order — on a pump, on continuous ECG.
▼
5
Fix the cause. Oxygen, K⁺, Mg²⁺, ischemia, acidosis, drug toxicity. A rhythm that keeps coming back has an unfixed cause.
Say it out loud:“Pulse first. Shock before drug. Cause last but never never.”
🧠 “P-S-D-C” — Pulse · Shock · Drug · Cause. Four letters, correct order, every ventricular question.
✅ While the infusion is running
Continuous ECG — watch QRS width and QTc, not just the rate
Blood pressure frequently — hypotension is the first thing amiodarone and procainamide do
Neuro checks on lidocaine — level of consciousness, speech, tingling, twitching. Use a consistent tool such as the Glasgow Coma Scale so a change is obvious to the next nurse.
IV pump only, never a gravity drip; check the site — amiodarone is a phlebitis risk peripherally
Have the defibrillator at the bedside and pads on the client
Recheck K⁺ and Mg²⁺ and replace them
🧠 “Monitor the strip, the pressure, and the brain.” Three things on a ventricular drip — rhythm, BP, neuro.
🧑🏫 What the client on long-term amiodarone must hear
Report a new dry cough, getting breathless while walking, or any new shortness of breath — immediately.
Expect routine blood work — thyroid, liver — and a yearly eye exam.
Sunscreen and covered skin. Sunburn happens fast; a blue-gray skin tone can develop with long use.
Tell every prescriber and pharmacist you take amiodarone — it interacts with warfarin, digoxin and many antibiotics.
Grapefruit juice raises amiodarone levels — avoid it.
Do not stop it on your own — it stays in your body for weeks either way.
🧠 “Cough, color, checkups.” Three things to report or keep: a new cough, a change in skin color, and every scheduled checkup.
🧠 Lidocaine = LIDSLips tingle · ears rIng · Dizzy/drowsy · Seizures. Neuro checks are the priority.
🫁 Amiodarone = 5 organsLungs · Thyroid · Liver · Eyes · Skin. Plus bradycardia, hypotension and a long QT.
⚡ Pulse → Shock → DrugPulseless V-Tach or V-Fib = defibrillate. Unstable with a pulse = synchronized cardioversion.
🎯 Cover & check — 7 rapid-fire questions
Q1: What does LAP stand for and where do those drugs work?
Lidocaine, Amiodarone, Procainamide — the ventricular rhythm drugs. They work at the bottom of the heart, for V-Tach and V-Fib. ABCD drugs work at the top (page 2).
Q2: Why is any rhythm starting with "V" the priority?
The ventricles generate cardiac output. If they quiver instead of squeezing, stroke volume falls to nearly zero — low cardiac OUTput means low oxygen OUT to the brain and body, and the client dies in minutes.
Q3: A client on a lidocaine drip says her lips feel numb and she hears ringing. What do you do?
Stop the infusion and notify the provider — these are early lidocaine toxicity signs and the next steps are confusion, twitching and seizures. Protect the airway, keep the client on the monitor, do a full neuro assessment, and have seizure precautions in place.
Q4: A client who has taken amiodarone for eight months reports a new dry cough and gets short of breath walking to the bathroom. Priority concern?
Pulmonary toxicity / fibrosis. Report it now; expect a chest X-ray and pulmonary function tests. Also review TSH, LFTs, vision and skin color.
Q5: Which LAP drug causes a lupus-like syndrome, and what would you monitor?
Procainamide. Watch for joint pain, muscle aches, a butterfly facial rash and fever, with a positive ANA. Also monitor the CBC for blood dyscrasias and the ECG for QRS widening and QT prolongation.
Q6: The client is in V-Tach on the monitor. What is your very first action?
Check a pulse (and assess the client). Pulseless V-Tach = CPR and defibrillation. V-Tach with a pulse but unstable = synchronized cardioversion. V-Tach with a pulse and stable = antidysrhythmic drug per the algorithm.
Q7: A strip shows polymorphic V-Tach twisting around the baseline. Treatment?
Torsades de pointes — IV magnesium sulfate, plus correcting potassium and stopping any QT-prolonging drug. If it is pulseless, defibrillate.