Cardiac Rhythm Disturbances Flashcards

1
Q

Instability as related to cardiac rhythm d turbances means that the dysrhythmia is

A

(1) impairing perfusion and threatening vital organ function

( 2) has the potential to deteriorate into cardiac arrest

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2
Q

most common bradycardia

A
  1. sinus bradycardia
  2. junctional rhythm

less commonly, idioventricular rhythm

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3
Q

Atrial fibrillation or flutter with slow ventricular response are uncommon; these rhythms are usually seen in patients

A

experiencing significant conduction system disease,

ssick sinus syndrome

suffering from excessive AV node blocking medications.

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4
Q

If the patient is unstable, the vast majority of AV blocks

A

third-degree heart block

followed much less frequently by second-degree AV block

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5
Q

If the patient is stable, most frequently seen

A
  1. second-degree type I AV block

third-degree AV block is less common

second-degree type II AV block is quite rare.

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6
Q

Atropine MOA

A

enhances the automaticity of the sinoatrial (SA) node and p tiates conduction through the AV node by direct vagolytic activity.

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7
Q

β-Adrenergic agents MOA

A

chronotropic and inotropic cardiac activity,

as well as enhancing electrical conduction within the AV node and infranodal system,

thus their potential to produce ischemia and ectopy

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8
Q

Glucagon

A

inotropic and chronotropic cardiac activity independent of the β-adrenergic receptors.

Glucagon is primarily used for bradycardias due to cardiotoxicity from β-blocker or calcium channel–blocker overdose.

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9
Q

most appropriate pacing method for the acutely symptomatic patient

A

Transcutaneous pacing

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10
Q

Atropine

A

0.5- to 1.0-milligram IV push; may repeat every 3–5 min until desired heart rate is achieved or to total dose of 3 milligrams

Most effective for bradydysrhythmias due to sinus and higher AV nodal disease

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11
Q

Dopamine

A

IV infusion at rate 2–20 micrograms/kg/min; titrate to desired heart rate

May precipitate myocardial ischemia and ectopy

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12
Q

Epinephrine

A

IV infusion at rate 2–10 micrograms/min; titrate to desired heart rate

May precipitate myocardial ischemia and ectopy

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13
Q

Glucagon

A

3–10 milligrams IV infused over 1–2 min, followed by an IV continuous infusion of 1–5 milligrams/h

Used for cardiotoxicity associated with β-blocker and calcium channel–blocker overdose
Limited human data are available supporting its use Nausea and vomiting are often limiting side effects Tachyphylaxis may develop during infusion

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14
Q

Adenosine

A

6-milligram rapid IV push;
if after 1–2 min the dysrhythmia persists,
repeat rapid IV push with 12 milligrams;
may repeat once more if dysrhythmia persists

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node

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15
Q

Verapamil

A

5–10 milligrams IV bolus over 2–3 min;
if after 15 min the dysrhythmia persists,
may repeat with dose of 10 milligrams

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node and reducing ventricular rate in atrial fibrillation or flutter

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16
Q

Diltiazem

A

15–20 milligrams IV bolus over 2 min,
followed by IV infusion at 5–10 milligrams/h;
a repeat bolus of 20–30 milligrams may be given after 15 min if inadequate response to initial bolus

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node and reducing ventricular rate in atrial fibrillation or flutter

17
Q

Esmolol

A

500 micrograms/kg IV bolus over 1 min, followed by IV infusion starting at 50 micrograms/kg/min; titrate infusion to desired heart rate

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node and reducing ventricular rate in atrial fibrillation or flutter

18
Q

Metoprolol

A

2.5–5 milligrams IV every 2–5 min; maximum total dose 15 milligrams IV over 10–15 min

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node and reducing ventricular rate in atrial fibrillation or flutter

19
Q

Metoprolol

A

2.5–5 milligrams IV every 2–5 min; maximum total dose 15 milligrams IV over 10–15 min

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node and reducing ventricular rate in atrial fibrillation or flutter

20
Q

Propranolol

A

1–3 milligrams IV over 1 min; may repeat every 2–5 min up to a total of 5 milligrams

Effective in terminating narrow QRS complex reentrant tachydysrhythmias involving the AV node and reducing ventricular rate in atrial fibrillation or flutter

21
Q

Procainamide

A

Initial: 20–50 milligrams/min
100 milligrams every 5 min until arrhythmia is suppressed, hypotension occurs, or the QRS complex is prolonged by 50% from its original duration
(maximum dose:17 milligrams/kg)
Maintenance infusion rate: 1–4 milligrams/min

Used in wide-complex tachydysrhythmias and new-onset atrial fibrillation
Median time to conversion of new-onset atrial fibrillation about 1 h
Caution in patients with AMI and LV dysfunction Infuse initial dose at rate of 20 milligrams/min to reduce adverse effects

22
Q

Amiodarone

A

Stable patient: 150 milligrams in 100 mL of D5W over 10 min,
followed by infusion at 1 milligram/min for 6 h
If breakthrough arrhythmia occurs, may give repeat 150-milligram boluses over 10 min
Maximum total daily dose is 2.2 grams

Ventricular fibrillation or pulseless ventricular tachycardia: 300 milligrams IV bolus; may repeat with additional dose of 150 milligrams IV bolus

Used in wide-complex tachydysrhythmias and new-onset atrial fibrillation
Preferred in setting of AMI or LV dysfunction Contraindicated in pregnancy

23
Q

Lidocaine

A

Loading dose: 50–100 milligrams over 2–3 min.
May repeat in 5 min (up to 300 milligrams in any 1-h period) Maintenance: 1–4 milligrams/min (start low in patients with liver dysfunction or CHF)

Third-line agent for ventricular tachycardia and ventricular fibrillation

24
Q

Magnesium sulfate

A

2 grams IV over 2 min, followed by infusion of 1–2 grams/h

Used in torsades de pointes with long QT interval

25
Q

Ibutilide

A

Weight <60 kg: 10 micrograms/kg IV over 10 min Weight >60 kg: 1 milligram IV over 10 min

Used for conversion of new-onset atrial fibrillation or flutter Median time to conversion 20–30 min