Lecture 10 9/5/24

Question 1

Which diagnoses fall into the supraventricular tachyarrhythmia category?

Answer 1

-premature supraventricular complexes
-supraventricular tachycardia
-atrial fibrillation

Question 2

Which diagnoses fall into the ventricular tachyarrhythmia category?

Answer 2

-premature ventricular complexes
-ventricular tachycardia
-ventricular fibrillation

Question 3

Why are arrhythmias clinically important?

Answer 3

-they can cause clinical signs such as syncope and sudden death
-relentless tachycardia can result in development of myocardial dysfunction

Question 4

What are the main causes of cardiac related sudden death?

Answer 4

-ventricular tachycardia that progresses to ventricular fibrillation
-severe bradycardia

Question 5

What are the general approaches to treating tachyarrhythmias and bradyarrhythmias?

Answer 5

-tachyarrhythmias are treated pharmacologically
-bradyarrhythmias are most often treated trough electronic pacing and occasionally medically

Question 6

What are the two reasons to treat arrhythmias in the short-term?

Answer 6

-if the arrhythmia is associated with clinical signs
-if the patient is at risk of sudden cardiac death and treatment will reduce the risk

Question 7

Why are arrhythmias not always treated?

Answer 7

-anti-arrhythmic agents can worsen arrhythmias in rare cases
-evidence that anti-arrhythmic therapy decreases mortality is lacking

Question 8

What are the classifications for anti-arrhythmic drugs and their mode of action?

Answer 8

-Class 1: sodium blockade
-Class 2: beta blockade
-Class 3: potassium blockade
-Class 4: calcium blockade

Question 9

What are the characteristics of digoxin?

Answer 9

-weak positive inotrope
-vagomimetic effect
-slows AV conduction by impacting the SA node

Question 10

What are the characteristics of Class 1 and 3 drug usage?

Answer 10

-used to suppress abnormal, spontaneous depolarizations
-act on the myocardium

Question 11

What are the characteristics of class 2 and 4 and digoxin drug usage?

Answer 11

-used to slow ventricular response to atrial tachyarrhythmia
-act on conduction system
-block conduction at AV node

Question 12

When is medical therapy indicated for tachycardia?

Answer 12

-persistent tachycardia
-frequent episodes of tachycardia
-frequent “couplets” or “triplets” of premature complexes

Question 13

Which type of diseases are associated with atrial premature complexes?

Answer 13

diseases that cause atrial enlargement

Question 14

Which supraventricular tachyarrhythmia is the most commonly treated?

Answer 14

atrial fibrillation

Question 15

Which agents used to treat SVTA diseases slow AV nodal conduction?

Answer 15

-calcium channel antagonists
-beta-adrenergic antagonists
-digoxin

Question 16

Which agents used to treat SVTA diseases increase atrial refractory period?

Answer 16

-procainamide
-class 3 agents
-class 1c agents

Question 17

What are vagal maneuvers?

Answer 17

pressure/massage applied to the ocular globes or carotid sinuses to initiate a reflex that results in vagal discharge with a principal effect on the conduction system

Question 18

What response is possible when vagal maneuvers are performed on a patient with sinus tachycardia?

Answer 18

gradual slowing

Question 19

What response is possible when vagal maneuvers are performed on a patient with “accessory pathway” tachycardia?

Answer 19

abrupt termination

Question 20

What response is possible when vagal maneuvers are performed on a patient with atrial tachycardia?

Answer 20

AV block

Question 21

When urgently treating supraventricular tachycardia, what are the mainstays of therapy?

Answer 21

-vagal maneuvers
-diltiazem
-esmolol

Question 22

When chronically treating supraventricular tachycardia, what are the mainstays of therapy?

Answer 22

-digoxin
-diltiazem
-atenolol

Question 23

Which disease is associated with atrial distention?

Answer 23

atrial fibrillation

Question 24

What are the two therapeutic strategies for treating atrial fibrillation?

Answer 24

-rate control: patient remains in AFib and drugs are used to slow ventricular response rate
-rhythm control: pharmacologic or electrical conversion to sinus rhythm

Question 25

When is rate control used to treat AFib?

Answer 25

-when AFib complicates structural heart disease
-when AFib is idiopathic

Question 26

When is rhythm control used to treat AFib?

Answer 26

in some cases where AFib is idiopathic

Question 27

What is the main course of therapy for treating ventricular tachyarrhythmias related to extra-cardiac disease?

Answer 27

addressing the non-cardiac, predisposing factors

Question 28

When is pharmacologic therapy indicated in VTA treatment?

Answer 28

-when associated with clinical signs
-when rate is rapid

Question 29

What is the treatment hierarchy for VTA?

Answer 29

-lidocaine
-procainamide
-injectable amiodarone
-beta blockade
-DC countershock under GA

Question 30

Which drugs are used in the chronic management of VTA?

Answer 30

-sotalol
-mexiletine
-amiodarone
-combinations of medications

Question 31

What are the two etiologic categories of 2nd degree AV block?

Answer 31

-type 1: functional and related to elevated vagal tone
-type 2: intrinsic AV node/AV bundle disease

Question 32

When does AV block become an important indication for cardiac pacing?

Answer 32

when the patient has high grade 2nd degree or 3rd degree AV block (3:1 AV conduction ratio or greater)

Question 33

What is the treatment for sick sinus syndrome?

Answer 33

cardiac pacing