BradycardiaAtropineDopamine infusionEpinephrine infusion

AtropineMechanism of Action

Inhibits the actions of acetycholine on structures

innervated by postganglionic sites

(smooth/cardiac muscle, SA/AV nodes)

AtropineIndications

First drug for symptomatic sinus bradycardiaMay be beneficial in AV block or asystoleSecond drug in asystole or slow PEAOrganophosphate poisoning; large dose may be

neededPrecautions

MI and hypoxia – atropine increases oxygen demandAvoid in hypothermiaNot effective for 2nd type II or new 3rd degree block

(may slow the rhythm)Doses < 0.5 mg may cause a paradoxical slowing

AtropineAsystole or slow (<60)PEA

1 mg IV/IO pushRepeat every 3 to 5 minutes (if rhythm persists) to

max. of 3 mg.Bradycardia

0.5 mg IV every 3-5 minutes as needed; max. of 3 mg.

Use shorter dosing interval and higher doses in severe clinical situations

Endotracheal Administration2-3 mg diluted in 10 mL water or NS

Organophosphate PoisoningLarge doses (2-4 mg or higher) may be necessary

Don’t delay pacing for severely symptomatic (unstable) patients.

Don’t delay pacing for severely symptomatic (unstable) patients.

DopamineMechanism of Action

Stimulates adrenergic receptors; dose

dependent.

DopamineIndications

Second-line drug for symptomatic bradycardiaHypotension with signs and symptoms of shock

PrecautionsCorrect hypovolemia with volume before initializingUse caution with cardiogenic shock and associated CHFMay cause tachydysrhythmias; excessive

vasoconstrictionDon’t mix with sodium bicarbonate

IV AdministrationInfusion at 5-20 mcg/kg/min.Titrate to patient response; taper slowly

EpinephrineMechanism of Action

Stimulates adrenergic receptors and is not dose dependent like dopamine.

EpinephrineIndications

Cardiac arrest VF; VT; asystole; PEA

Symptomatic bradycardia After atropine; alternative to dopamine

Severe hypotension When atropine and pacing fail; hypotension

accompanying bradycardia; phosphodiesterase enzyme inhibitors

Anaphylaxis; severe allergic reactions Combine with large fluid volume; corticosteroids;

antihistamines

EpinephrinePrecautions

May increase myocardial ischemia, angina, and oxygen demand

High doses do not improve survival; may be detrimental

Higher doses may be needed for poison/drug induced shock

DosingCardiac arrest 1 mg (1:10,000) IV/IO every 3-5 min.High dose up to 0.2 mg/kg for specific drug OD’sInfusion of 2-10 mcg/min.Endotracheal of 2-2.5 times normal doseSQ/IM 0.3-0.5 mg

TachycardiaAdenosineDiltiazemMetoprololAmiodaroneLidocaineMagnesium Sulfate

AdenosineMechanism of Action

Slows impulse formation in the SA node; slows

conduction time through AV node; depresses left ventricular function and

restores NSR.

AdenosineIndications

1st drug for stable, narrow complex, regular SVT

May consider for unstable SVT while preparing for cardioversion

Wide-complex tachycardia thought to be, or determined to be reentry SVT

Does not convert atrial fibrillation, atrial flutter, or VT

Diagnostic maneuver; stable narrow-complex SVT

AdenosineContraindications/Precautions

Poison/drug induced tachycardia is contraindicated2nd and 3rd degree block is contraindicatedTransient side effects; flushing, CP, asystole,

brady, ectopyLess effective with theophylline or caffeineIf used for VT may cause worsening of clinical

conditionTransient periods of sinus brady or ventricular

ectopy common after termination of SVTSafe in pregnancy

AdenosinePlace supine or mild reverse Trendelenburg6 mg rapidly followed by 20 mL flushMay repeat at 12 mg every 1-2 minutes if

unsuccessful

DiltiazemMechanism of Action

Inhibits calcium movement across cell membranes of

cardiac and smooth muscle. Causes vasodilation, decreses heart rate and contractility,

slows SA and AV conduction.

DiltiazemIndications

Controlling ventricular rate in a-fib or flutterAfter adenosine to treat refractory reentry SVT if

adequate blood pressureContraindications/Precautions

Do not use with wide-complex rhythmsDo not use with poison/drug induced tachycardiaAvoid in WPWAvoid in AV nodal blocksBlood pressure may drop from peripheral

vasodilation

DiltiazemRate control

15-20 mg (0.25 mg/kg) IV over 2 minutesAfter 15 min. another 20-25 mg (0.35 mg/kg)

IV over 2 minutes, if neededMaintenance Infusion

5-15 mg/hour; titrated to physiologically appropriate heart rate

MetoprololMechanism of Action

Selectively blocks beta-1 receptors, slowing sinus heart rate, decreasing

cardiac output, and decreasing BP.

MetoprololIndications

Administer to all patients with suspected MI or unstable angina, absent contraindications

Second-line agent for SVT refractory to adenosine

To reduce myocardial ischemia in MI patients with elevated heart rate and/or blood pressure

Emergency antihypertensive therapy for acute hemorrhagic or ischemic stroke

MetoprololContraindications/Precautions

Hemodynamically unstable patients should not receive Signs of heart failure Low cardiac output Increased risk for cardiogenic shock

Relative contraindications: 1st, 2nd, 3rd degree blocks; active asthma; reactive airway disease; severe bradycardia; hypotension < 100 mmHg

Concurrent administration of calcium channel blockers can cause serious hypotension

Monitor cardiac and pulmonary status throughout

AmiodaroneMechanism of Action

Prolongs myocardial cell action potential duration and refractory period by

direct action on all cardiac tissue; decreases AV and SA

conduction rates.

AmiodaroneIndications

Life threatening dysrhythmias VF/pulseless VT unresponsive to shock, CPR, and

vasopressor Recurrent hemodynamically unstable VT Seek expert opinion for other uses

Contraindications/PrecautionsBradycardia2nd and 3rd degree blockDo not administer with meds that prolong QT

interval (procainamide)

AmiodaroneVF/VT – 300 mg IV/IO in 20-30 mL NS. Can

follow with ONE dose of 150 mg in 3-5 minutes, if needed.

Life threatening dysrhythmias150 mg over 10 minutes. May repeat every 10

minutes as needed.

LidocaineMechanism of Action

Decreases depolarization, automaticity, and

excitability of ventricle during diastole by direct

action, reversing ventricular dysrhythmias.

LidocaineIndications

Alternative to amiodarone in VF/VT arrestStable monomorphic VTMalignant PVC’sCan be used if Torsades is suspected

Contraindications/PrecautionsProphylactic use in AMI is contraindicatedReduce maintenance dose in liver impaired

patientsDiscontinue infusion if toxicity develops

LidocaineCardiac Arrest

Initial dose is 1-1.5 mg/kgRefractory VF 0.5-0.75 mg/kg in 5-10 min. Max 3

mg/kgEndotracheal dose 2-4 mg/kg

Perfusing Dysrhythmia0.5-0.75 mg/kg up 1-1.5 mg/kg dosing range.

Repeat if necessary at lower range to total dose of 3 mg/kg

Maintenance Infusion1-4 mg/min

Magnesium SulfateMechanism of Action

Increases magnesium levels in cases where prolonged

QT interval is thought to be secondary to

hypomagnesemia.

Magnesium SulfateIndications

Torsades is suspected in cardiac arrestLfe-threatening ventricular dysrhythmias in

digitalis ODPrecautions

Fall in BP with rapid administrationUse caution in renal failure

DosingArrest 1-2 g over 5-20 min.Torsades w/ pulse 1-2 g over 5-60 min.

VasopressinMechanism of Action

Causes vasoconstriction with reduced blood flow, increasing core perfusion

during cardiac arrest.

VasopressinIndications

Alternative to epinephrine in adult refractory VF/VT

Alternative to epinephrine in asystole or PEAContraindications/Precautions

Potent peripheral vasoconstrictor (increased demand upon resuscitation)

DosingSingle dose of 40 u that replaces either the 1st or

2nd dose of epinephrine. Epinephrine can be resumed 3-5 minutes after

Can be used endotracheally; no suggested dose