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Questions and Answers
Which class of antiarrhythmics decrease heart contractility by causing a blockade of calcium channels in the SA and AV nodes?
What is the primary indication for Amiodarone?
What is the mechanism of action for Class I antiarrhythmics?
Which of the following is a major risk associated with Class 1A sodium channel blockers?
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What is the mechanism of action for Adenosine?
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What is the effect of Amiodarone on the QT interval?
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What is the mechanism of action for Anticoagulants?
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Which of the following is a Class III antiarrhythmic?
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What is the standard form of heparin?
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What is the MOA of heparin?
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What are the two main uses of heparin?
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Can heparin be taken orally?
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What is the reason to avoid heparin via the IM route?
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What is the reversal agent for heparin toxicity?
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What is Heparin-induced Thrombocytopenia (HIT)?
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What is the class of drugs that promotes the lysis of fibrin and the dissolution of thrombi?
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What is the MOA of thrombolytics?
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What is the difference between anticoagulants and thrombolytics?
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In a patient with Long QT syndrome, which medication should be avoided?
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What is the sensation felt by a patient experiencing Torsedes De Pointes?
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Which of the following antiarrhythmic classes does NOT decrease heart contractility?
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What is the primary mechanism of action of beta blockers?
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Which of the following antiplatelet drugs is a prototype?
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What is the mechanism of action of thrombolytics?
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Which of the following is NOT a risk associated with Class 1A sodium channel blockers?
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What is the primary effect of Adenosine on the heart?
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What is the primary function of anticoagulants?
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Which of the following is a side effect of beta blockers?
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What is the mechanism of action of Class II antiarrhythmics?
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Which of the following is a route of administration for heparin?
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What is the primary indication for Class III antiarrhythmics?
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What is a common side effect of amiodarone?
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What is the mechanism of action of thrombolytics?
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What is the primary indication for thrombolytics?
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What is the reversal agent for heparin toxicity?
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What is Heparin-induced Thrombocytopenia (HIT)?
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Study Notes
Medications for Long QT Syndrome
- In an acute setting, magnesium sulfate is given to patients with Long QT syndrome.
Antiarrhythmic Drugs and QT Prolongation
- Class I (Sodium channel blockers, e.g., Quinidine) and Class III (Potassium Channel Blockers, e.g., Amiodarone) antiarrhythmic drugs increase the risk of QT prolongation.
- Other medications associated with increased risk of QT prolongation include antipsychotics, antidepressants, and antibiotics.
Torsedes De Pointes
- A patient experiencing Torsedes De Pointes feels skipped beats, palpitations, racing heart, and chest discomfort/pain/pressure.
- QT prolongation occurs when repolarization takes longer than depolarization, causing the heart to relax and then receive another beat during that relaxation period.
Antiarrhythmic Drug Classes
- Class I: Sodium channel blockers (e.g., Quinidine) decrease heart contractility by blocking sodium channels in the SA node and AV node.
- Class II: Beta blockers (e.g., Propranolol) decrease heart contractility by blocking beta receptors in the SA node and AV node.
- Class III: Potassium Channel Blockers (e.g., Amiodarone) decrease heart contractility by blocking potassium channels in the SA node and AV node.
- Class IV: Calcium Channel Blockers (e.g., Verapamil) decrease heart contractility by blocking calcium channels in the SA node and AV node.
- Class V: Others (e.g., Adenosine) decrease heart contractility by blocking various channels in the SA node and AV node.
Beta Blockers
- Beta blockers belong to Class II antiarrhythmics.
- Mechanism of action: decrease the automaticity of the SA node and slow conduction through the AV node, helping to control tachyarrythmias.
- Clinical uses: antihypertension, heart failure, angina, myocardial infarction, arrhythmias.
- Types:
- Non-selective (e.g., Propranolol): cause bradycardia, hypotension, and broncospasms.
- Beta 1 selective (e.g., Metopralol, Atenelol): slow down heart rate, preferred for patients with respiratory issues.
- Non-selective with additional actions (e.g., Carvedilol, Labetalol): also block alpha 1, helping with hypertension.
Class III Antiarrhythmic: Amiodarone
- Prototype drug for Class III antiarrhythmics.
- Mechanism of action: blocks potassium channels, preventing efflux of potassium from the cell, leading to delayed repolarization of the cardiac cell membrane.
- Uses: primarily indicated for ventricular arrhythmias.
- Side effects: pulmonary toxicity, thyroid dysfunction, hepatotoxicity, optic neuropathy, blue-gray skin color changes, hypotension, bradycardia, and QT prolongation.
- Can accumulate in tissues due to its lipophilic nature, leading to toxicity.
- Crosses the blood-brain barrier.
Anticoagulants
- Mechanism of action: disrupt the coagulation cascade, ultimately suppressing the production of fibrin.
- Do not break up existing clots, but rather prevent the development of future clots.
- Classes:
- Heparin and its derivatives (e.g., Enoxaparin)
- Warfarin
- Direct Oral Anticoagulants (DOACs): Dabigatran, Rivaroxaban, Apixaban
Antiplatelet Drugs
- Mechanism of action: inhibit platelet aggregation, preventing platelets from clumping together to form clots.
- Prototype drugs: Aspirin, Clopidogrel, Ticagrelor
Thrombolytics
- Mechanism of action: promote the lysis (breaking) of fibrin and the dissolution of thrombi.
- Prototype drug: tPA alteplase
- Uses: break up existing clots.
Heparin
- Standard form: unfractionated heparin.
- Lower molecular form: Enoxaparin.
- Mechanism of action: activates antithrombin, which inactivates clotting factors Xa and thrombin, preventing the conversion of fibrinogen to fibrin.
- Routes of administration: subQ, IV.
- Not absorbed through the digestive system, so cannot be taken orally.
- Should be avoided via the IM route to prevent hematoma formation.
- Uses: prophylactic (prevents clots from forming in those with risk of clots, such as Afib) and prevents current clots from getting bigger (those with DVT).
- Side effects: bleeding, bloody stool, vomiting that looks like coffee grounds, petechiae.
- Reversal agent: Protamine Sulfate.
- Can cause Heparin-induced Thrombocytopenia (HIT), an immune response against heparin.
Medications for Long QT Syndrome
- In an acute setting, magnesium sulfate is given to patients with Long QT syndrome.
Antiarrhythmic Drugs and QT Prolongation
- Class I (Sodium channel blockers, e.g., Quinidine) and Class III (Potassium Channel Blockers, e.g., Amiodarone) antiarrhythmic drugs increase the risk of QT prolongation.
- Other medications associated with increased risk of QT prolongation include antipsychotics, antidepressants, and antibiotics.
Torsedes De Pointes
- A patient experiencing Torsedes De Pointes feels skipped beats, palpitations, racing heart, and chest discomfort/pain/pressure.
- QT prolongation occurs when repolarization takes longer than depolarization, causing the heart to relax and then receive another beat during that relaxation period.
Antiarrhythmic Drug Classes
- Class I: Sodium channel blockers (e.g., Quinidine) decrease heart contractility by blocking sodium channels in the SA node and AV node.
- Class II: Beta blockers (e.g., Propranolol) decrease heart contractility by blocking beta receptors in the SA node and AV node.
- Class III: Potassium Channel Blockers (e.g., Amiodarone) decrease heart contractility by blocking potassium channels in the SA node and AV node.
- Class IV: Calcium Channel Blockers (e.g., Verapamil) decrease heart contractility by blocking calcium channels in the SA node and AV node.
- Class V: Others (e.g., Adenosine) decrease heart contractility by blocking various channels in the SA node and AV node.
Beta Blockers
- Beta blockers belong to Class II antiarrhythmics.
- Mechanism of action: decrease the automaticity of the SA node and slow conduction through the AV node, helping to control tachyarrythmias.
- Clinical uses: antihypertension, heart failure, angina, myocardial infarction, arrhythmias.
- Types:
- Non-selective (e.g., Propranolol): cause bradycardia, hypotension, and broncospasms.
- Beta 1 selective (e.g., Metopralol, Atenelol): slow down heart rate, preferred for patients with respiratory issues.
- Non-selective with additional actions (e.g., Carvedilol, Labetalol): also block alpha 1, helping with hypertension.
Class III Antiarrhythmic: Amiodarone
- Prototype drug for Class III antiarrhythmics.
- Mechanism of action: blocks potassium channels, preventing efflux of potassium from the cell, leading to delayed repolarization of the cardiac cell membrane.
- Uses: primarily indicated for ventricular arrhythmias.
- Side effects: pulmonary toxicity, thyroid dysfunction, hepatotoxicity, optic neuropathy, blue-gray skin color changes, hypotension, bradycardia, and QT prolongation.
- Can accumulate in tissues due to its lipophilic nature, leading to toxicity.
- Crosses the blood-brain barrier.
Anticoagulants
- Mechanism of action: disrupt the coagulation cascade, ultimately suppressing the production of fibrin.
- Do not break up existing clots, but rather prevent the development of future clots.
- Classes:
- Heparin and its derivatives (e.g., Enoxaparin)
- Warfarin
- Direct Oral Anticoagulants (DOACs): Dabigatran, Rivaroxaban, Apixaban
Antiplatelet Drugs
- Mechanism of action: inhibit platelet aggregation, preventing platelets from clumping together to form clots.
- Prototype drugs: Aspirin, Clopidogrel, Ticagrelor
Thrombolytics
- Mechanism of action: promote the lysis (breaking) of fibrin and the dissolution of thrombi.
- Prototype drug: tPA alteplase
- Uses: break up existing clots.
Heparin
- Standard form: unfractionated heparin.
- Lower molecular form: Enoxaparin.
- Mechanism of action: activates antithrombin, which inactivates clotting factors Xa and thrombin, preventing the conversion of fibrinogen to fibrin.
- Routes of administration: subQ, IV.
- Not absorbed through the digestive system, so cannot be taken orally.
- Should be avoided via the IM route to prevent hematoma formation.
- Uses: prophylactic (prevents clots from forming in those with risk of clots, such as Afib) and prevents current clots from getting bigger (those with DVT).
- Side effects: bleeding, bloody stool, vomiting that looks like coffee grounds, petechiae.
- Reversal agent: Protamine Sulfate.
- Can cause Heparin-induced Thrombocytopenia (HIT), an immune response against heparin.
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Description
Test your knowledge on Long QT syndrome and its association with antiarrythmic drugs. Learn which medications increase the risk of QT prolongation and how to manage acute settings.
