Cardiac

Rapid Review

• Mechanism of Action: Transient AV nodal blocker; works on adenosine receptors to slow cardiac conduction.
• Indications: cardioversion of stable, narrow complex tachycardia. 
• Contraindications: Reentrant SVTs, 2nd/3rd degree AV block, sick sinus syndrome, allergy
• Dosage: 6 mg IV (rapidly); may give 12 mg IV two more times if unsuccessful
• Onset: 20-30 seconds
• Duration: 60-90 seconds
• Adverse Reactions: hypotension (if given too slow), bradyarrhythmia, bronchoconstriction
• Special Considerations: May be given via stopcock w/ immediate secondary flush, or as a single push mixed with saline.

Pearls

• Do not use adenosine for patients with wide-complex tachycardias or suspected  Wolf-Parkinson White syndrome, as this may result in worsening arrythmias.
• For undifferentiated tachydysrhythmias, adenosine can be useful diagnostically by briefly slowing down the rhythm enough to be interpreted. Make sure you’re ready to print the EKG when it does!

Deep Dive

• Single Syringe Adenosine for SVT? (REBEL EM)

Rapid Review

• Mechanism of Action: Class III antiarrhythmic. Inhibits potassium channels; causing prolonged refractory periods, decreased automaticity, and slowed SA/AV node conduction which helps suppress and prevent dysrhythmias. Also has sodium channel blocking (class I), beta blocking (class II), and calcium channel blocking (class IV) properties.
• Indications: Wide complex tachyarrhythmias, pulseless V-fib/V-Tach
• Contraindications: allergy to drug, iodine or shellfish allergy, pregnancy
• Dosage:
  • V-fib/pulseless V-Tach: 300 mg IV bolus, followed by 150 mg at next pulse check if needed. 
  • Stable wide-complex tachycardia: 150 mg IV over 10 minutes, followed by infusion of 1 mg/min over 6 hrs. Then 0.5 mg/min drip over next 18 hours.
• Onset: 1 – 30 minutes
• Duration: 1- 3 hours
• Adverse Reactions: Bradycardia, hypotension, prolonged QT, thyrotoxicosis.
• Special Considerations: Between 5 – 20% of patients treated with amiodarone will develop thyrotoxicosis due to amiodarone’s iodine content. May also have long term use side effects, such as pulmonary fibrosis, elevated hepatic enzymes, and CHF. It has an incredibly long half-life (up to 58 days).

Pearls

• Between 5 – 20% of patients treated with amiodarone will develop thyrotoxicosis due to amiodarone’s iodine content. May also have long term use side effects, such as pulmonary fibrosis, elevated hepatic enzymes, and CHF
• To avoid hypotension following IV administration, push the medication slowly (over 10-15 minutes in patients with a pulse)

Deep Dive

• Is Amiodarone Dead? (REBEL EM)

Rapid Review

• Mechanism of Action: Antiplatelet/NSAID; irreversible cyclooxygenase inhibitor, preventing prostaglandin synthesis and platelet aggregation. Makes platelets “slippery”. 
• Indications: Used for prevention and treatment of acute coronary syndrome
• Contraindications: allergy to class/drug; syndrome of asthma, rhinitis, and nasal polyps (“Samter’s Triad), hx of peptic ulcers.
• Dosage: 81 mg daily for prevention; 324 mg for acute episode
• Half-life: 20 – 60 minutes. However, because platelets cannot generate new COX, antiplatelet effects last for duration of the platelet (10 days)
• Adverse Reactions: aspirin toxicity (if over 10 grams consumed), GI ulcer, bronchospasm
• Special Considerations: Avoid use in children, particularly those with viral syndrome, due to the risk of Reye syndrome.

Pearls

• Aspirin is the treatment of choice for pericarditis in patients with ischemic heart disease compared to other NSAIDs. 
• Due to the rare, but serious risk of Reye syndrome, do not give aspirin to pediatric patients suffering or recovering from viral infections. 

Deep Dive

• Aspirin (Drugs.com)

Rapid Review

• Mechanism of Action: Antilipemic agent; HMG-CoA inhibitor. Lowers total LDL, cholesterol, and serum triglyceride levels.
• Indications: Hyperlipidemia. May be used in the ED for acute myocardial infarction to reduce mortality.
• Contraindications: hypersensitivity, liver disease, pregnancy
• Dosage: 10 – 80mg PO daily; depending on desired intensity.
• Half-life: 14 hours
• Adverse Reactions: abdominal pain, myalgia, hepatotoxicity, rhabdomyolysis
• Special Considerations: N/A

Pearls

• Although ED-specific data is sparse, initiating high dose Atorvastatin (80 mg) for ACS prior to PCI is a low risk intervention (with potentially high reward) that is supported by AHA guidelines.
• There is a risk of rhabdomyolysis in patients taking atorvastatin, especially if they have underlying renal disease.

Deep Dive

• ACS? Start My Statins! (EP Monthly)

Rapid Review

• Mechanism of Action: Antiplatelet; irreversibly binds to P2Y12 adenosine diphosphate receptors, thus reducing platelet activation and aggregation
• Indications: Used to decrease risk of MI/Stroke. In acute settings, it may be used prior to percutaneous coronary intervention in AMI. 
• Contraindications: active bleeding, allergy to drug/class
• Dosage: 75mg PO daily for prevention; 300 mg PO for acute ischemic event
• Onset: 2 hours
• Duration: 5 days
• Adverse Reactions: bleeding, pruritus, hypersensitivity reaction
• Special Considerations: N/A

Pearls

• If you’re giving aspirin for ACS, you should give clopidogrel as well in order to achieve a therapeutic effect in time for possible PCI.
• The antiplatelet function of clopidogrel can last up to 5 days. Consider this in patients who come in with active bleeding or those who may need surgery. 

Deep Dive

• A Case of Identity Part Two (EMNerd)

Rapid Review

• Mechanism of Action: Calcium channel blocker (non-dihydropyridine); class IV antiarrhythmic that inhibits calcium influx, thus slowing AV nodal conduction and causing vasodilation of the coronary vessels.
• Indications: Rate control for Atrial fibrillation/Atrial flutter; conversion of PSVT to sinus rhythm.
• Contraindications: Allergy to drug/class, wide-complex tachycardia, severe hypotension. Use caution if patient is on beta-blockers. 
• Dosage: Generally 0.25mg/kg (max 20mg) bolus over 2 minutes as loading dose; followed by infusion of 5-15 mg/hr
• Onset: 2-3 minutes (IV)
• Duration: 1-3 hours (IV); half life of 3-5 hours
• Adverse Reactions: Hypotension, bradycardia
• Special Considerations: N/A

Pearls

• Diltiazem has been shown to be slightly more effective than metoprolol as a rate control agent for atrial fibrillation w/ RVR. However, diltiazem should not be given in patients who are concomitantly presenting with acute decompensated heart failure, as this can cause a profound hypotension. 
• Use caution when administering diltiazem in patients who have already received beta-blocking agents (ex. metoprolol). 

Deep Dive

• Diltiazem vs. Metoprolol in the Management of Atrial Fibrillation or Flutter w/ Rapid Ventricular Rate in the Emergency Department (JEM)

Rapid Review

• Mechanism of Action: Vasopressor; beta 1 agonist > beta 2 agonist. Exerts both ionotropic and chronotropic effects depending on dose.
• Indications: Cardiogenic shock, septic shock
• Contraindications: Allergy, acute MI, severe hypertension, arrhythmias
• Dosage: 2-20 mcg/kg/min IV
• Onset: Immediate
• Duration: 2 minutes
• Adverse Reactions: Dysrhythmias, tachycardia, anxiety, tremors

Pearls

• Dobutamine is the preferred agent for cardiogenic shock in the ED. The second line agent, milrinone, is equally efficacious but has a slower onset.  
• Since dobutamine exerts it’s effects primarily on the contractility of the myocardium and thus increases oxygen demand, patients should be monitored for signs/symptoms of demand ischemia.

Deep Dive

• Dobutamine (PubMed)

Rapid Review

• Mechanism of Action: Vasopressor; sympathomimetic catecholamine that binds to beta 1, beta 2, and alpha 1 receptors. Increases HR, myocardial contractility, vasoconstriction, and bronchodilation.
• Indications: Anaphylaxis, cardiac arrest, severe asthma, hypotension
• Contraindications: Allergy to drug/class
• Dosage:
  • Anaphylaxis or Asthma: 0.3-0.5 mg of 1:1000 IM
  • Cardiac Arrest: 1 mg 1:10,000 IV push
  • Hypotension: 1-10 mcg/min IV
• Onset: Immediate
• Duration: < 5 minutes
• Adverse Reactions: Dysrhythmias, myocardial ischemia, tachycardia

Pearls

• “Push Dose” IV epinephrine may be useful in a pinch, but there is a high risk of life-threatening medication errors when mixing and administering this formulation.
• Although epinephrine auto-injectors are frequently dosed at 0.3 mg IM, epinephrine is frequently underdosed in anaphylaxis. If the patient is > 50 kg, Go with 0.5 mg instead! 

Deep Dive

• Epinephrine (PubMed)

Rapid Review

• Mechanism of Action: Short acting beta blocker; antagonizes beta 1 receptors in the myocytes.
• Indications: Aortic dissection, hypertensive emergency refractory V-fib
• Contraindications: Allergy to drug/class, cardiogenic shock, 2nd-3rd degree AV block
• Dosage: Generally 500 mcg/kg loading dose, followed by infusion of 50-300 mcg/kg/min
• Onset: Within 60 seconds
• Duration: 9 minutes
• Adverse Reactions: Hypotension, dizziness, peripheral ischemia, infusion site reaction
• Special Considerations: Avoid giving together with calcium channel blockers

Pearls

• Esmolol is very effective in rapidly controlling heart rate, which is important for conditions like aortic dissection. However, for hypertensive crises, blood pressure is more effectively controlled by agents like nicardipine or clevidipine. 
• Given it’s acidic pH, esmolol can cause significant tissue damage if extravasated. 

Deep Dive

• Esmolol in Refractory Ventricular Fibrillation (CORE EM)

Rapid Review

• Mechanism of Action: Beta blocker; antagonism of alpha 1, beta1, and beta 2 receptors
• Indications: Hypertensive crisis, intracranial hemorrhage
• Contraindications: Asthma, bradycardia, hypotension, cardiogenic shock
• Dosage:
  • Bolus dose: 20-80 mg IV q10 minutes PRN
  • Infusion: 1-8 mg/min titrated to effect
• Onset: 2-5 minutes (IV)
• Duration: 4 hours (IV)
• Adverse Reactions: Orthostatic hypotension, sweating, flushing

Pearls

• Because labetalol predominantly only works on beta receptors, avoid giving labetalol for a hypertension secondary to sympathomimetic agents (methamphetamine, cocaine) due to the risk of unopposed peripheral vasoconstriction.
• Labetaol may be useful if your only trying to drop BP by a modest amount (ex. 10-30 mm), however, it is generally less effective than more titratable agents such as nicardipine or clevidipine.

Deep Dive

• Labetalol (PubMed)

Rapid Review

• Mechanism of Action: Local anesthetic/antiarrhythmic; As a local anesthetic it acts on sodium ion channels on the internal surface of the nerve cell membranes to prevent nerve depolarization, thus blocking pain signals. In cardiac myocytes, lidocaine slows the action potential during phase 0.
• Indications: Local anesthesia for injury reduction/repair
• Contraindications: Known hypersensitivity, wolf-parkinson-white syndrome, dysrhythmias secondary to local anesthetic toxicity
• Dosage:
  • Local anesthetic: 5 mg/kg (max 300mg)
  • Antiarrhythmic: 1-1.5 mg/kg IV loading dose, followed by infusion of 2 mg/min
• Onset: 1-2 minutes
• Duration: 10-20 minutes (IV), 30-90 min 
• Adverse Reactions: CNS toxicity, urticaria, venous inflammation, bronchospasm

Pearls

• Lidocaine has historically been used as RSI pretreatment to decrease sympathetic stimulation, which was thought to be beneficial to TBI patients and those with obstructive airway disease. However, given a lack of evidence, it is no longer recommended for RSI
• Both lidocaine and amiodarone have fairly similar efficacies for the treatment of V-Tac/V-Fib, but lidocaine may be more effective for arrhythmias secondary to tricyclic antidepressants or sodium channel blockade overdoses.

Deep Dive

Rapid Review

• Mechanism of Action: Beta blocker; cardio-selective beta-1 receptor inhibitor with minimal or no effects on beta-2 receptors. Decreases cardiac output via negative inotropic and chronotropic effects.
• Indications: Atrial fibrillation (rate control), hypertension, heart failure, acute MI, migraine
• Contraindications: Sick sinus syndrome, 2nd-3rd degree heart block, hypersensitivity 
• Dosage:
  • Atrial fibrillation: 2.5 – 5 mg IV over 2 minutes (up to 3 doses). Transition to PO afterwards.
  • Acute MI: 5 mg IV q 2 minutes (up to 3 doses)
• Onset: Peaks at 20 minutes (after 10 minute IV infusion)
• Duration: 5-8 hours
• Adverse Reactions: Bradycardia, heart failure, bronchospasm, fatigue, dizziness

Pearls

• Avoid using metoprolol in patients who were recently treated with other non-dihydropyridine calcium channel blockers, such as diltiazem.
• Metoprolol is a reasonable treatment for atrial fibrillation w/ RVR, though diltiazem has been shown to be slightly more effective.  

Deep Dive

• Metoprolol (PubMed)

Rapid Review

• Mechanism of Action: Dihydropyridine calcium channel blocker; inhibits influx of extracellular calcium ions across myocardial cells and vascular smooth muscle cells, causing coronary vasodilation and decrease in peripheral resistance
• Indications: Hypertension, intracranial hemorrhage
• Contraindications: Hypersensitivity, aortic stenosis
• Dosage: 5 mg/hour IV infusion, increase by 2.5 mg q5 minutes until target BP achieved (Max 15mg/hr). Decrease to 3mg/hr once goal BP achieved. 
• Onset: 5-10 minutes
• Duration: 2-6 hours
• Adverse Reactions: Headache, peripheral edema, hypotension 

Pearls

• Nicardipine is easily titratable, though infusions come in large fluid volumes (ex. 150 mL/hour). For patients with renal failure, heart failure, or hepatic failure, clevidipine is preferred because it can achieve the same blood pressure control w/ less volume. 
• Nicardipine has a fairly long duration of action. Blood pressure may continue to drop even after the infusion has been discontinued. 

Deep Dive

• Nicardipine (Drugs.com)

Rapid Review

• Mechanism of Action: Vasodilator; stimulates cGMP production, causing vasodilation of venous and arterial vasculature, reducing pulmonary vascular resistance. Functions as an analgesic for angina by improving coronary blood flow and reducing ischemia. For CHF exacerbation, it improves preload and promotes redistribution of fluid from the pulmonary system
• Indications: Angina, CHF exacerbation
• Contraindications: Systolic BP < 90. Recent viagra or cialis use.
• Dosage:
  • Angina: 0.3 – 0.6mg SL q5min, max 3 doses in 15 min
  • CHF: 5-200mcg/min (IV), start at 5 mcg/min and increase 10mcg q3-5 minutes until desired effect
• Onset: 1-3 minutes
• Duration: 30 minutes
• Adverse Reactions: Hypotension, headaches
• Special Considerations: N/A

Pearls

• Due to erratic absorption, topical nitroglycerin ointment should be avoided for cardiac patients when possible. However, it has been shown to be effective as an adjunct medication for extravasation injuries caused by vasopressors or hyperosmolar agents.
• Because nitroglycerin is an oxidizing agent, prolonged durations of high doses may cause the patient to develop methemoglobinemia.

Deep Dive

• The Death of MONA in ACS: Nitroglycerin (REBEL EM)

Rapid Review

• Mechanism of Action: Vasodilator; water-soluble salt comprised of ferrous iron complexed with nitric oxide. Produces peripheral vasodilation of both arteries and veins (slightly more selective for veins)
• Indications: Hypertensive crisis, congestive heart failure
• Contraindications:
• Dosage: 0.25 mcg/kg/min IV, titrate slowly by 0.2mcg/min q5 minutes until goal BP achieved. 
• Onset: < 1 minutes
• Duration: 3-5 minutes
• Adverse Reactions: Cyanide toxicity, methemoglobinemia, hypotension

Pearls

• Nitroprusside is a highly effective antihypertensive agent, but should be used with extreme care due to the risk of hypotension, cyanide toxicity, increased ICP, and methemoglobinemia. Because it requires ICU level monitoring, it is often not feasible to use in the emergency department.
• Remember, the the dose limit for nitropusside is 10 mcg/minute for no greater than 10 minutes!

Deep Dive

• Sodium Nitroprusside (PubMed)

Rapid Review

• Mechanism of Action: Vasopressor; similar to epinephrine, but primarily agonistic at alpha 1 and beta 1 receptors, with little-to-no beta 2 or alpha 2 activity
• Indications: Hypotension refractory to IV fluids
• Contraindications: No absolute contraindications. Be cautious using in low-volume states.
• Dosage: Generally 8-12 mcg/min IV, titrate up to effect (max dose 25 mcg). Maintenance dosage 2-4 mcg/min
• Onset: Immediate
• Duration: 1-2 minutes after infusion stops
• Adverse Reactions: Extravasation injury, decreased end-organ perfusion, reflex bradycardia, headache

Pearls

• The balanced activity of norepinephrine across alpha 1 and beta 1 receptors makes it an ideal “go-to” initial vasopressor for undifferentiated shock. 
• Norepinphrine should ideally be administered via a central line due to the risk of extravasation, but can still be given safely via peripheral lines in a pinch.

Deep Dive

• Norepinephrine (PubMed)

Rapid Review

• Mechanism of Action: Vasopressor; selective alpha 1 adrenergic agonist causing peripheral vasoconstriction. No beta-adrenergic activity.
• Indications: Hypotension (best in distributive or neurogenic shock), low flow priapism
• Contraindications: Hypersensitivity, severe hypertension, closed angle glaucoma
• Dosage:
  • Hypotension: Start 100-200 mcg/min, then taper down
    • Consider push-dose (50-200 mcg) boluses
  • Low flow priapism: 100-500 mcg injection q 3-5 minutes until resolution
• Onset: 1-3 minutes (IV)
• Duration: 5-20 minutes (IV)
• Adverse Reactions: Reflex bradycardia, hypertension, pulmonary edema, extravasation

Pearls

• Phenyephrine has purely alpha 1 adrenergic activity (peripheral vasoconstriction), making it particularly useful for neurogenic or distributive shock. 
• Phenylephrine may cause a reflex bradycardia/decreased cardiac output following the increase in systemic vascular resistance. Avoid using this medication in patients with heart failure or underlying bradycardia.

Deep Dive

• Phenylephrine (PubMed)

Rapid Review

• Mechanism of Action: Class Ia Antiarrhythmic; binds to fast sodium channels inhibiting recovery after repolarization. Prolongs action potential and reduces the speed of impulse conduction.
• Indications: Ventricular arrhythmias, atrial fibrillation/flutter, WPW syndrome
• Contraindications: Allergy, prolonged QT, myasthenia gravis, 2nd-3rd AV block
• Dosage: Generally 100 mg IV every 5 minutes
• Onset: 10-30 minutes
• Duration: 2.5 – 4.7 hours
• Adverse Reactions: Bradycardia, hypotension, QRS/QT prolongation

Pearls

• The PROCAMIO study in 2017 showed that procainamide is safer and more efficacious than amiodarone for chemical cardioversion of stable ventricular tachycardia.
• Procainamide has historically been used for diagnostic testing of Brugada syndrome (commonly known as the “procainamide challenge”), however this is no longer recommended due to it’s low sensitivity and risk of adverse arrhythmias.

Deep Dive

• Procainamide (PubMed)

Rapid Review

• Mechanism of Action: Non-selective beta blocker; competitively blocks beta-1 and beta-2 adrenergic stimulation in the heart. Results in decrease in heart rate, blood pressure, myocardial contractility, and myocardial oxygen demand.
• Indications: Thyroid storm, hypertension, angina, atrial fibrillation, anxiety
• Contraindications: Bradycardia, COPD/asthma/emphysema
• Dosage:
  • Thyroid storm: 0.5 – 1mg IV over 10 minutes (redose 1-3 mg every few hours) or 60-80 mg PO q4 hours
• Onset: 2-10 minutes (IV), 1-2 hours (PO)
• Duration: Half-life of 3-6 hours in patients with healthy renal systems.
• Adverse Reactions: Bradycardia, abdominal pain, nausea, erectile dysfunction, wheezing

Pearls

• For thyroid storm, propranolol is the preferred agent over other beta-blockers due to its highest activity on decreasing conversion of T4 to T3. It should be given before anti-thyroid medications (ex. Propylthiouracil, methimazole) or iodine solutions.
• When combined with amiodarone, propranolol can be effective in treating electrical storm from an implanted cardiac device w/o acute ischemia. 

Deep Dive

• Propranolol (Drugs.com)

Rapid Review

• Mechanism of Action: Vasopressor; stimulates V1 and V2 receptors, causing vasoconstriction (without inotropic or chronotropic effects), as well as renal water retention.
• Indications: Vasodilatory shock, diabetes insipidus, bleeding esophageal varices
• Contraindications: Hypersensitivity
• Dosage: 0.01 – 0.1 U/min
• Onset: Peak in 15 minutes (IV)
• Duration: Fades within 20 minutes of stopping infusion
• Adverse Reactions: Splanchnic vasoconstriction, uterine contraction, oliguria

Pearls

• Vasopressin is typically used as a second line agent for septic shock after norepinephrine has reached it’s maximum dose. It is frequently given in conjunction with steroids (ex. hydrocortisone), due to it’s beneficial relationship.
• When able, vasopressin should be delivered via central line as opposed to peripheral line due to it’s vesicant properties and risk for extravasation.

Deep Dive

• Vasopressin (PubMed)