SVT

Question 1

What does true heart rate depend on?

Answer 1

AV node conduction and subsequent ventricular contraction

Question 2

Most common therapies in SVT.

Answer 2

Meds that slow AV conduction

• adenosine
• Beta Blockers
• CCB (diltiazem, verapamil)
• digoxin

Question 3

What are the 3 electrical etiologies for SVT?

Answer 3

1. Increased Automaticity
2. Re-entry
3. Triggered Activity

Question 4

What are the 3 anatomical locations for etiologies of SVT?

Answer 4

1. SA node
2. Atria
3. AV node or Junction

Question 5

Treatment for physiological sinus tachycardia.

Answer 5

Usually a secondary cause (emotion, exercise, fear, infection). Treatment involves the treating the underlying cause.

Question 6

Treatment for inappropriate Sinus Tachycardia.

Answer 6

Usually electrical or neuronal cause.

-Treat with beta blockers or ablation of irritated foci

Question 7

Difference between Re-entry Sinus tachycardia and the other two types.

Answer 7

Re-entry ST is paroxysmal, the other two are gradual onset.

Question 8

Most common type of Paroxysmal SVT.

Answer 8

AV node Reciprocating Tachycardia (AVNRT): caused by re-entry

Question 9

Name and describe the two types of AVNRT.

Answer 9

Typical: slow pathway conducts impulse from atria to ventricles, short RP interval

Atypical: fast pathway conducts signal from ventricles to atria, long RP interval

Question 10

Tx for AVNRT

Answer 10

If Stable: vagal maneuvers, adenosine, ablation (long term).

If unstable: defibrillator (DC cardioversion)

Question 11

Tx for junctional tachyarrhythmias.

Answer 11

Beta blockers, ablation

Question 12

Non-paroxysmal Junctional tachycardia is a benign condition, why is it medically relevant?

Answer 12

Can be a marker for a more serious underlying condition: digoxin toxicity, COPD, hypokalemia, hypoxia etc.

Question 13

What is AV Re-entry tachycardia?

Answer 13

Re-entry that uses Extra-Nodal Pathways

-Can create delta waves or absolutely no PR segment. P waves terminates and immediately the QRS begins

Question 14

What type of AVRT is considered Wolff-Parkinson-White syndrome?

Answer 14

Pre-excitation (delta wave) of QRS along with Tachycardia (>100bpm)

Question 15

What are the two types of pathway conductions in AVRT?

Answer 15

Orthodromic: signal travels down the AV node pathway then back up the extra nodal tissue.

Antidromic: signal travels down the extra nodal tissue then back up the AV node tissue

Question 16

Treatment for WPW.

Answer 16

Ablation of the extranodal tissue

Question 17

Main medication used to treat general AVRT.

Answer 17

Procainamide

Question 18

How is focal atrial tachycardia differentiated from flutter or fibrillation?

Answer 18

The baseline between the T wave and P wave is isoelectric

Question 19

Two causes for Focal Atrial Tachycardia and treatments for each.

Answer 19

Re-entry: ablation

Foci Irritation: meds

Question 20

How is Multifocal Atrial Tachycardia diagnosed on EKG and what are common conditions associated with it?

Answer 20

EKG: multiple P wave shapes

Associated with pulmonary disease, metabolic disease, electrolyte imbalance

Question 21

Tx for Multifocal Atrial Tachycardia

Answer 21

Calcium Channel Blockers

Question 22

Most common cause of atrial flutter.

Answer 22

Cavotriscupid Isthmus: piece of conducting tissue by the IVC and tricuspid valve that allow re-entry into the atria for multiple fast depolarizations

Question 23

What is an important long term treatment for atrial flutter?

Answer 23

Anticoagulants: clots tend to form due to blood stasis in the atria, they can embolize and go to the lungs