Podcast
Questions and Answers
Which class of antiarrhythmic drugs primarily blocks potassium channels?
Which class of antiarrhythmic drugs primarily blocks potassium channels?
What is a primary characteristic of Class IB antiarrhythmic drugs?
What is a primary characteristic of Class IB antiarrhythmic drugs?
Which of the following antiarrhythmic drug classes is rarely used and markedly inhibits sodium channels?
Which of the following antiarrhythmic drug classes is rarely used and markedly inhibits sodium channels?
Which class of antiarrhythmic drugs is most commonly used for treating supraventricular rhythms involving the AV node?
Which class of antiarrhythmic drugs is most commonly used for treating supraventricular rhythms involving the AV node?
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Which antiarrhythmic drug is known to have multiple mechanisms of action, classifying it as miscellaneous?
Which antiarrhythmic drug is known to have multiple mechanisms of action, classifying it as miscellaneous?
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What condition is characterized by a slow, irregular heart rate with pronounced sinus arrhythmia?
What condition is characterized by a slow, irregular heart rate with pronounced sinus arrhythmia?
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Which arrhythmia is indicated by a heart rate exceeding 160-180 bpm?
Which arrhythmia is indicated by a heart rate exceeding 160-180 bpm?
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What should be done for a patient with more than 30 ectopic complexes per minute?
What should be done for a patient with more than 30 ectopic complexes per minute?
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Which arrhythmia involves an irregular, fast heart rate due to ectopic atrial activity?
Which arrhythmia involves an irregular, fast heart rate due to ectopic atrial activity?
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In the context of high-grade 2nd degree heart block, what is commonly measured during assessment?
In the context of high-grade 2nd degree heart block, what is commonly measured during assessment?
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What indicates an increased risk of sudden cardiac death in certain breeds, such as Dobermans and Boxers?
What indicates an increased risk of sudden cardiac death in certain breeds, such as Dobermans and Boxers?
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What does the R-on-T phenomenon refer to in cardiac assessment?
What does the R-on-T phenomenon refer to in cardiac assessment?
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Which of the following conditions is classified as a fast, irregular heart rate?
Which of the following conditions is classified as a fast, irregular heart rate?
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Study Notes
Auscultation of Heart Rate and Rhythm
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Slow heart rate (Bradycardia): Can be regular or irregular.
- Causes: Sinus bradycardia, complete heart block, sick sinus syndrome, atrial standstill with escape rhythm, high-grade 2nd degree heart block.
- Treatment (If indicated): Atropine 0.04 mg/kg IV.
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Fast heart rate (Tachycardia): Can be regular or irregular.
- Causes: Sinus tachycardia, intermittent supraventricular premature complexes (SVPCs), paroxysmal supraventricular tachycardia (SVT), sustained SVT (excluding atrial fibrillation), intermittent ventricular premature complexes (VPCs), paroxysmal ventricular tachycardia (VT), sustained VT.
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Treatment (If indicated): Treat arrhythmia if:
- More than 30 ectopic complexes per minute
- Paroxysms or sustained VT >130 bpm
- Paroxysms or sustained SVT >160-180 bpm
- Multiform VPCs
- SV or V arrhythmias in the presence of myocardial failure
- Breeds at risk for sudden death (Dobermans, Boxers)
- Clinical signs of hypotension
- VPCs close to the T wave of the preceding complex (R-on-T phenomenon)
- Consider underlying causes of ectopic rhythms.
Antiarrhythmic Drugs
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Class IA: Block sodium channels.
- Examples: Quinidine, procainamide
- Use: Supraventricular and ventricular rhythms.
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Class IB: Block sodium channels.
- Examples: Lidocaine, mexiletine, tocainide
- Use: Ventricular rhythms. Have affinity for diseased or ischemic muscle tissue.
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Class IC: Block sodium channels.
- Examples: Flecainide, propafenone
- Use: Markedly inhibit Na2+ channels; rarely used.
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Class II: Block beta receptors.
- Examples: Atenolol, propanolol, metoprolol, sotalol
- Use: Supraventricular rhythms (atrial fibrillation) by affecting the AV node. Some effects on ventricular rhythms.
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Class III: Block potassium repolarizing channels.
- Examples: Amiodarone, sotalol, bretylium
- Use: Broad-spectrum class, effective for supraventricular and ventricular rhythms.
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Class IV: Block calcium channels.
- Examples: Diltiazem, verapamil
- Use: Supraventricular rhythms by affecting the AV node (atrial fibrillation).
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Description
This quiz covers the essential aspects of auscultation related to heart rate and rhythm, including bradycardia and tachycardia, their causes, and potential treatments. Test your knowledge on various cardiac arrhythmias and their management strategies.
