Chapter 32: Arrythmias Flashcards
(140 cards)
1
Q
What is the cardiac conduction system?
A
The electrical signaling system that coordinates heartbeat and causes atria and ventricles to contract.
2
Q
What is an arrhythmia?
A
An abnormal heart rhythm which can cause bradycardia or tachycardia.
3
Q
What can patients feel during an arrhythmia?
A
The heart is beating very fast (fluttering) or abnormally (skipping a beat)
4
Q
List three symptoms of arrhythmia.
A
- Dizziness
- Shortness of breath
- Fatigue
5
Q
What is used for to confirm diagnosis of arrhythmias?
A
Electrocardiogram (ECG)
6
Q
What is a Holter monitor?
A
It is an ambulatory ECG device that records thr electrical activity of the heart continuoisly for 24-48 hours
7
Q
What is the Holter monitor can detect?
A
Intermittent arrhythmias
8
Q
What begins the electrical impulse in the heart?
A
The SA node
9
Q
What is the heart’s natural pacemaker?
A
The SA node
10
Q
What is considered a normal heart rate?
A
60-100 BPM
BPM stands for beats per minute.
11
Q
What does the cardiac action potential refer to?
A
The movement of ions through channels in the myocytes that cause electrical impulses in the cardiac conduction pathway.
12
Q
What is the role of action potentials in the heart?
A
They provide the electricity needed to power the cardiac conduction pathway.
13
Q
What is unique about the cells in the SA node?
A
They have automaticity and can initiate their own action potential.
14
Q
What occurs during Phase 0 of the cardiac action potential?
A
Rapid ventricular depolarization occurs in response to an influx of sodium (Na), leading to ventricular contraction.
15
Q
What is represented by the QRS complex on the ECG?
A
Ventricular contraction
16
Q
What happens during Phase 1 of the cardiac action potential?
A
Early rapid repolarization occurs as Na channels close.
17
Q
Describe Phase 2 of the cardiac action potential.
A
A plateau occurs in response to an influx of calcium (Ca) and efflux of potassium (K).
18
Q
What is the significance of Phase 3 in the cardiac action potential?
A
Rapid ventricular repolarization occurs due to an efflux of K, causing ventricular relaxation.
19
Q
What does the T wave on the ECG represent?
A
Ventricular relaxation that occurs during Phase 3.
20
Q
Fill in the blank: Class la, lb & lc antiarrhythmics primarily work in Phase ____ and Block ___ .
A
0
Na influx
21
Q
Fill in the blank: Class III antiarrhythmics primarily work in Phase ____ and block ____.
A
3
K Efflux
22
Q
What are arrhythmias?
A
Abnormalities of the heart or its conduction system that alter the cardiac action potential.
23
Q
What is the most common cause of arrhythmias?
A
Myocardial ischemia or infarction.
24
Q
What non-cardiac conditions can trigger arrhythmias?
A
- Electrolyte imbalances
- Elevated sympathetic states like hyperthyroidism & infection
- Drugs
25
Which electrolytes are particularly important in relation to arrhythmias?
* Potassium
* Magnesium
* Sodium
* Calcium
26
How are arrhythmias classified?
supraventricular and ventricular.
27
What is the most common type of arrhythmia?
Atrial fibrillation (AF).
28
What type of arrhythmia is Afib?
supraventricular (above the AV node)
29
What are common types of ventricular arrhythmias?
* Premature ventricular contractions (PVCs)
* Ventricular tachycardia (VT)
* Ventricular fibrillation
30
What are PVCs also known as?
Skipped heartbeats.
31
What can a series of PVCs that results in a heart rate > 100 BPM be called?
Ventricular tachycardia (VT).
32
What should be initiated in case of pulseless VT?
Advanced cardiac life support (ACLS).
33
What can untreated VT degenerate into?
Ventricular fibrillation.
34
How does the heart rate affect the QT interval?
The QT interval is longer when the heart rate is slower
35
What is used to correct the QT interval when heart rate is > 60 BPM?
QT interval corrected for heart rate (QTc)
36
When is a QTc interval considered prolonged?
When it is > 440 - 460 milliseconds (msec)
37
At what QTc interval is the risk of Torsade de Pointes (TdP) more worrisome?
When it is > 500 msec
38
What is Torsade de Pointes (TdP)?
A particularly lethal ventricular tachyarrhythmia that can cause sudden cardiac death
39
What are some risk factors for drug-induced QT prolongation?
* Higher doses
* Multiple QT-prolonging drugs
* Reduced drug clearance
* Electrolyte abnormalities
* Other cardiac conditions
* Female gender
40
What electrolyte abnormalities can increase the risk of QT prolongation?
* Low potassium (hypokalemia)
* Low magnesium (hypomagnesemia)
* Low calcium (hypocalcemia)
41
What is an example of a medication with maximum dose recommendations to minimize QT prolongation risk?
Citalopram/Escitalopram
42
Which class of antiarrhythmics can prolong the QT interval?
Class la, Ic, and III
43
Name 5 anti-infective that can prolong the QT interval.
* Hydroxychloroquine
* Azole antifungals
* Macrolides
* Quinolones
* Lefamulin
44
Which SSRIs are associated with the highest risk of QT prolongation?
* Citalopram
* Escitalopram
45
What antiemetics prolong QT interval?
* 5-HT3 receptor antagonists (e.g., ondansetron)
* Droperidole
* Metoclopramide
* Promethazine
46
Name a first-generation antipsychotic that can prolong the QT interval.
* Haloperidol
* Chlorpromazine
* Thioridazine
47
Which Second gen antipsychotic hast the highest risk of QT prolongation?
Ziprasidone
48
What type of oncology medications can prolong the QT interval?
* Androgen deprivation therapy (e.g., leuprolide)
* Tyrosine kinase inhibitors (e.g., nilotinib)
* Arsenic trioxide
49
What should be checked to identify reversible causes before administering antiarrhythmic drugs?
Electrolytes & A toxicology screen
50
What potential risks are associated with antiarrhythmic drugs?
Inducing proarrhythmia or worsening an existing arrhythmia
51
How can the risk of additive proarrhythmia be minimized?
By correcting electrolyte abnormalities prior to and throughout antiarrhythmic use
52
What is the Vaughan Williams classification system used for?
It splits antiarrhythmic drugs into categories based on their dominant electrophysiological effect or mechanism of action.
53
What is the MOA of amiodarone as an antiarrhythmic?
It is a class III antiarrhythmic (K channel blocker) that also blocks Na and Ca channels and adrenergic receptors.
54
What is the half-life of amiodarone?
40 - 60 days.
55
How does amiodarone affect thyroid function?
Its iodine content can impact thyroid function.
56
Despite its toxicities, why is amiodarone commonly prescribed?
It is a preferred antiarrhythmic in patients with heart failure.
57
List the four classes of the Vaughan Williams classification.
* Class I: Sodium Channel Blockers
* Class II: Beta-blockers
* Class III: Potassium Channel Blockers
* Class IV: Non-dihydropyridine Calcium Channel Blockers
58
List antiarrhythmic medications in class Ia,
Ib, and Ic.
## Footnote
Double Quarter Pounder, Lettuce, Mayo, Fries Please!
* Ia: Disopyramide, Quinidine, Procainamide
* Ib: Lidocaine, Mexiletine
* Ic: Flecainide, Propafenone
59
What are Class II antiarrhythmic medications?
## Footnote
Because
Beta belockers
60
What types of drugs are included in Class III of the Vaughan Williams classification?
## Footnote
Dieting During Stress Is Always
* Dronedarone
* Dofetilide
* Sotalol
* Ibutilide
* Amiodarone
61
What are the two examples of Class IV non-dihydropyridine calcium channel blockers?
## Footnote
Very Difficult
* Verapamil
* Diltiazem
62
What is the brand name of Amiodarone?
Nexterone, Pacerone
63
What are the boxed warnings associated with Amiodarone?
* Pulmonary toxicity
* Hepatotoxicity
* Life-threatening arrhythmias
64
What are the contraindications for using Amiodarone?
* Iodine hypersensitivity
65
What warnings are associated with Amiodarone?
* Hyper- and hypothyroidism (hypo is more common)
* visual impairment (Optic neuropathy, corneal microdeposits)
* Photosensitivity (blue-gray skin discoloration)
* Neurotoxicity
66
Is Amiodarone safe to use during pregnancy?
Avoid in pregnancy (teratogenic)
67
What are common side effects of Amiodarone?
* Hypotension
* Bradycardia
* Photosensitivity
68
What should be monitored while on Amiodarone?
* ECG
* BP
* HR
* Electrolytes
* LFTs every 6 months
* Thyroid function (TSH and free T4) every 3-6 months
* Regular eye exams
69
What is a unique requirement for intravenous infusions of Amiodarone lasting more than 2 hours?
Require a non-PVC container (e.g., polyolefin or glass)
70
What is the preferred type of line for administering Amiodarone?
Central line preferable
71
What size filter should be used for Amiodarone during IV administration?
0.22 micron filter
72
With which substance is Amiodarone incompatible?
Heparin (flush line with saline)
73
What is a key interaction of Amiodarone with Sofosbuvir?
Amiodarone and Sofosbuvir should not be used together due to enhanced bradycardic effect
74
Which CYP450 enzymes does Amiodarone inhibit?
Amiodarone is a weak inhibitor of CYP450 2C9, 2D6, 3A4 and P-gp
75
What is the maximum recommended dose of Simvastatin & Lovastatin when using Amiodarone?
* Do not exceed 20 mg/day of Simvastatin
* Do not exceed 40 mg/day of Lovastatin
76
What is the recommended adjustment for Warfarin dose when starting amiodarone?
Decrease Warfarin dose by 30-50%
77
What should be done to the digoxin dose when starting amiodarone?
Decrease digoxin dose by 50%
78
What are the main mechanisms of action for other antiarrhythmics?
Other antiarrhythmics primarily work by blocking sodium or potassium channels
79
List two antiarrhythmics recommended in ACLS algorithms for cardiac arrest.
* Lidocaine
* Adenosine
80
What should Quinidine be taken with to avoid gastrointestinal upset?
Take with food or milk
## Footnote
\
81
What are the potential side effects of Disopyramide?
* Anticholinergic effects (e.g., dry mouth, constipation, urinary retention)
82
What are the warnings associated with Quinidine?
* Proarrhythmic
* Hepatotoxicity
* Hemolysis risk
83
What is a notable side effect of Quinidine that may indicate toxicity?
* Cinchonism
* Drug-induced lupus erythematosus
* Diarrhea
* stomach cramping
84
What are the symptoms of Cinchonism?
Symptoms include tinnitus, hearing loss, blurred vision, headache, and delirium.
85
What is the active metabolite of Procainamide?
N-acetyl procainamide (NAPA)
86
How is NAPA cleared?
NAPA is renally cleared and requires dosing adjustments based on renal function.
87
What are the boxed warnings associated with Procainamide?
* Agranulocytosis
* Drug-induced lupus erythematosus (DILE)
* Antinuclear antibody (ANA)
88
What are the therapeutic levels of Procainamide?
Procainamide: 4-10 mcg/mL
89
What is the drug of choice for Wolff-Parkinson-White syndrome?
Procainamide
90
What are Class Ib drugs primarily used for?
Ventricular arrhythmias only
91
What is IV Lidocaine used for?
Refractory VT/Cardiac arrest
92
What are the boxed warnings for Flecainide?
Proarrhythmic effects, especially in AF
93
What are the contraindications for Flecainide?
heart failure or myocardial infarction.
94
What is the brand name for Propafenone?
Rythmol SR
95
List some contraindications for Propafenone.
Structural heart disease (e.g., heart failure, myocardial infarction)
96
What are some common side effects of Propafenone?
* Taste disturbance (metallic)
* Dizziness
* Visual disturbances
* Nausea/Vomiting
97
What is a major boxed warning for Dronedarone?
Contraindicated in patients with decompensated heart failure or permanent atrial fibrillation due to risk of death, stroke, and heart failure
98
List some contraindications for Dronedarone.
* Concurrent use of erythromycin
* Strong CYP3A4 inhibitors
* QT-prolonging drugs
99
What are some warnings associated with Dronedarone?
* Hepatic failure
* Pulmonary toxicity
100
What are some common side effects of Dronedarone?
* Proarrhythmic
* Diarrhea
* Bradycardia
* Asthenia
101
What is a key note regarding Dronedarone compared to Amiodarone?
Dronedarone does not contain iodine and has little effect on thyroid function
102
What must be monitored when initiating Dofetilide?
Continuous ECG monitoring and assessment of CrCl for a minimum of 3 days
103
What are some potential side effects of Dofetilide?
Ventricular tachycardias (e.g., TdP)
104
Which 2 antiarrhythmic drug are preferred in HF?
* Amiodarone
* Dofetilide
105
What is the CrCl cut-off for sotalol and what action should be done?
CrCl < 60 mL/min, decrease frequency
106
What boxed warning is associated with Sotalol?
* Initiation and dosage increases should be done in a hospital with continuous ECG monitoring
* Adjust dosing interval based on CrCl
107
What are the warnings associated with Sotalol?
* Proarrhythmias
* Bronchoconstriction
108
What are the side effects of Sotalol?
* Bradycardia
* Palpitations
* Chest pain
* Dizziness
* Fatigue
* Dyspnea
* N/V
109
What is the primary use of Adenosine?
It is used for supraventricular re-entrant tachycardias
110
What occurs during atrial fibrillation (AF)?
Multiple waves of electrical impulses in the atria result in an irregular and usually rapid ventricular response.
111
What can the rapid ventricular rate in AF lead to?
It can reduce cardiac output, leading to hypotension, worsening ischemia, and heart failure.
112
What are some lifestyle modifications recommended for patients at risk for AF?
* Weight loss
* Tobacco cessation
* Minimization of alcohol consumption
* Optimization of blood pressure and blood glucose control
113
What characterizes Paroxysmal AF?
Intermittent AF that terminates within 7 days of onset.
114
What is Persistent AF?
Continuous AF sustained for more than 7 days.
115
What risk increases due to stagnant blood in the atria during AF?
Risk of clot formation.
116
What can happen if a clot formed during AF embolizes?
It can travel to an artery in the brain, potentially causing a stroke.
117
What are the two main strategies for treating AF?
* Rate control
* Rhythm control
118
What is the goal resting heart rate for symptomatic AF patients?
Less than 80 BPM.
119
What is a more lenient goal resting heart rate in asymptomatic patients?
Less than 110 BPM.
120
Which medications are recommended for controlling ventricular rate in AF?
* Beta-blockers
* Non-DHP CCBs
121
What should not be given to patients with heart failure with reduced ejection fraction (HFrEF)?
Non-DHP CCB.
122
What is the primary goal of Rhythm Control?
To restore and maintain normal sinus rhythm (NSR).
123
What types of drugs are used in Rhythm Control?
* Class Ia
* Class Ic
* Class III antiarrhythmic drugs
* Electrical cardioversion
124
What is the preferred strategy for permanent AF regarding rhythm control?
Avoid a rhythm-control strategy with antiarrhythmic drugs due to risk outweighing benefits.
125
What is required for stroke prophylaxis in AF patients?
Anticoagulation may be required to prevent clotting risk.
126
Which medications are preferred for stroke prevention in non-valvular AF?
* DOACs (e.g., apixaban, rivaroxaban)
127
When is warfarin indicated for stroke prevention?
In patients with AF and a mechanical heart valve.
128
What influences the decision about long-term anticoagulation after a rhythm control strategy?
The patient's clot risk.
129
What is the MOA of digoxin?
Inhibits the Na-K-ATPase pump, causing a positive inotropic effect that leads to increased cardiac contractility.
130
How does digoxin affect heart rate?
Exerts a parasympathetic effect, enhancing vagal tone to slow conduction through the AV node, resulting in reduced heart rate
131
What is the typical oral dose of digoxin?
0.125-0.25 mg PO daily
132
What should be done if a patient's CrCl is less than 60 mL/min?
Decrease the dose or frequency; hold in acute renal failure
133
How to convert Digoxin PO to IV?
Dose should also be reduced by 20-25% when converting from oral to IV.
134
What are common side effects of digoxin?
Dizziness, visual/mental disturbances, N/V, diarrhea
135
What symptoms indicate digoxin toxicity?
* N/V,
* loss of appetite,
* abdominal pain,
* blurred/double vision,
* greenish-yellow halos,
* confusion,
* delirium,
* bradycardia,
* life-threatening arrhythmias
136
What is the therapeutic range of digoxin for atrial fibrillation?
0.8-2 ng/mL
137
What types of drugs can interact with digoxin?
P-gp inhibitors, CYP 3A4 inhibitors, beta-blockers, non-DHP CCBs, clonidine, dexmedetomidine
138
What does rhythm control in arrhythmias involve?
Methods for conversion to and maintenance of normal sinus rhythm (NSR)
139
What are the pharmacologic options for cardioversion?
Amiodarone, dofetilide, flecainide, ibutilide, propafenone
140
What is a risk associated with cardioversion?
Thromboembolism
