Bradycardias and Ventricular Arrhythmias

Question 1

bradyarrhythmia HR

Answer 1

< 60 bpm

Question 2

patients are usually symptomatic at what heartrate

Answer 2

< 50 bpm

Question 3

bradyarrhythmia may result from

Answer 3

sinus node dysfunction due to underlying structural heart disease or aging

Question 4

risk factors for bradyarrhythmia

Answer 4

age, hypothyroidism, drugs, other toxins, cardiac disease, sleep apnea, electrolyte imbalances, hypothermia, hypoglycemia

Question 5

sick sinus syndrome

Answer 5

symptomatic sinus bradycardia and/or periods of sinus arrest

Question 6

tachy-brady syndrome

Answer 6

alternating tachyarrhythmias and bradyarrhythmias

Question 7

long term treatment of sick sinus syndrome

Answer 7

permanent ventricular pacemaker

• improves symptoms
• decreases incidence of paroxysmal AF and embolism

Question 8

AV block definition

Answer 8

conduction delay or block can occur in any are of the AV system

Question 9

av block occurs in patients

Answer 9

without underlying structural heart disease (trained athletes)

Question 10

1st degree av block

Answer 10

prolonged PR interval ( > 0.2 seconds)

1:1 AV conduction (usually AVN)

Question 11

2nd degree av block

Mobitz I

Answer 11

progressive PR prolongation until QRS is dropped

< 1:1 AV conduction (AVN)

Question 12

2nd degree av block

Mobitz II

Answer 12

random non-conducted beats (absence of QRS)

< 1:1 AV conduction (below AVN)

Question 13

3rd degree av block

Answer 13

AV dissociation

Absence of AV conduction (AVN or below)

Question 14

Mobitz II or 3rd degree block + signs of poor perfusion

Answer 14

• initiate transcutaneous pacing immediately
• atropine 0.5 mg IV
• epi, dopamine, if atropine failes

Question 15

3rd degree block can lead to

Answer 15

sudden cardiac arrest and death

Question 16

first step in treating HR < 50 bpm

Answer 16

identify and treat underlying cause

• maintain airway
• oxygen if hypoxemic
• cardiac monitor
• IV access
• ECG

Question 17

persistent bradyarrhythmia can cause

Answer 17

hypotension, acutely altered mental status, signs of shock, ischemic chest discomfort, or acute heart failure

Question 18

treatment you give is bradyarrhythmia is causing problems

Answer 18

Atropine IV dose

- 0.5 mg bolus, repeat every 3-5 minutes (max is 3 mg)

Question 19

if atropine doesn’t work, what’s next

Answer 19

transcutaneous pacing, dopamine infusion, or epinephrine infusion

Question 20

dopamine infusion

Answer 20

usual infusion rate is 2-20 mcg/kg per minute. titrate to patient response and taper slowly

Question 21

epinephrine infusion

Answer 21

2-10 mcg per minute infusion. titrate to patient response

Question 22

most common ventricular arrhythmias

Answer 22

premature ventricular complexes (PVC), ventricular tachycardia (VT), ventricular fibrillation (VF)

Question 23

symptoms of ventricular arrhythmias

Answer 23

• sometimes asymptomatic
• mild palpitations with PVCs, chest pain, dyspnea, and syncope
• VT progressing to life threatening hemodynamic collapse with VF necessitating CPR

Question 24

PVC occurs in patients

Answer 24

with or without structural heart disease

Question 25

causes of pvc

Answer 25

may be caused by abnormal automaticity, triggered activity, or reentrant mechanisms

Question 26

PVCs + period of MI

Answer 26

risk factor for death independent of LV dysfunction, atherosclerosis

Question 27

simple PVCs

Answer 27

infrequent, all waves look alike

Question 28

complex PVCs

Answer 28

> 5 PVCs/min, couplets, R-on-T beats, multiform waves, associated with higher mortality

Question 29

treatment for symptomatic PVCs with underlying heart disease

Answer 29

initiate BB

Question 30

Define VT

Answer 30

more than 3 consecutive PVCs at rate greater than 100 bpm

Question 31

causes of wide QRS VT that are reversible | 5 H's

Answer 31

hypoxemia, hypovolemia, hydrogen ions (acidosis), hypo/hyperkalemia, hypothermia

Question 32

causes of wide QRS VT that are reversible | 5 T's

Answer 32

tension pneumothorax, tamponade (cardiac), toxins, thrombosis (pulmonary), thrombosis (cardiac)

Question 33

most important treatment of VT/VF

Answer 33

synchronized DCC

Question 34

drugs used in VF/VT

Answer 34

epinephrine and amiodarone

Question 35

epi in cardiac arrest

Answer 35

dose = 1 mg IV push every 3-5 minutes | may repeat with every cycle

Question 36

amiodarone in cardiac arrest

Answer 36

dose = 300 mg first cycle, 150 mg second cycle

Question 37

route of administrations in ACLS

Answer 37

IV, IO | if you can't get either of those, Endotracheal (ET)

Question 38

IV roa in ACLS

Answer 38

quick IV push followed by normal saline flush (20 mL) to distribute drug throughout the body

Question 39

IO access in ACLS

Answer 39

intraosseous if IV access not available

Question 40

ET access in ACLS

Answer 40

drugs are dosed 2-2.5 times the IV dose diluted in 10 mL normal saline

Question 41

drugs that can be used in ET roa

Answer 41

``` Naloxone Atropine Vasopressin Epinephrine Lidocaine ```

Question 42

most effective agent after vf/vt occurrence

Answer 42

amiodarone

Question 43

non drug therapies for after vf/vt occurrence

Answer 43

- catheter ablation - implantable cardioverter-defibrillator (ICD) - leads implanted trans venously

Question 44

non drug therapy | tiered therapy approach

Answer 44

1. anti-tachycardia pacing 2. low energy defibrillation 3. painful, high energy defibrillation shock if needed

Question 45

VF

Answer 45

- death rapidly ensues without resuscitation | - common sudden cardiac death cause

Question 46

TdP

Answer 46

rapid form of VT (delayed ventricular repolarization) | considered a deadly rhythm

Question 47

drugs that cause QT prolongation | antiarrhythmic

Answer 47

``` quinidine procainamide disopyramide amiodarone dofetilide sotalol ibutilide ```

Question 48

drugs that cause QT prolongation | psychotropics

Answer 48

TCAs haloperidol/droperidol pimozide atypical antipsychotics

Question 49

drug classes that cause QT prolongation

Answer 49

antiarrhythmic, psychotropics, toxins, antihistamines, antibiotics, methadone, PPI

Question 50

drugs that cause QT prolongation | toxins

Answer 50

organophosphates | arsenic

Question 51

drugs that cause QT prolongation | antibiotics

Answer 51

macrolides (erythromycin and clarithromycin) Bactrim fluoroquinolones antifungals (fluconazole, voriconazole, posaconazole)

Question 52

drugs that cause QT prolongation | misc

Answer 52

``` corticosteroids diuretics quinine chloroquine chloral hydrate cisapride tacrimolus ```

Question 53

pts w baseline QTc interval > 450

Answer 53

should not receive those agents

Question 54

pts w an increase in QTc interval to > 560 msec after drug initiation

Answer 54

decrease dose or discontinue

Question 55

TdP likely to recur after

Answer 55

DCC and restoration of stable rhythm

Question 56

therapy to prevent recurrence of TdP

Answer 56

IV magnesium sulfate | temporary transvenous pacing or pharmacological pacing