Kim - Cardiac Excitation

Question 1

A branch of the anterior intermodal tract that connects the right and left atria

Answer 1

Bachmann bundle

Question 2

Middle tract of atrial fibers

Answer 2

Tract of wenckebach

Question 3

Posterior tract of atrial fibers that connects the SA node to the AV node

Answer 3

Tract of thorel

Question 4

Where does the bundle of His (which is continuous w/ the AV node) give off the left bundle branch

Answer 4

At the top of the interventricular septum

Question 5

Activation of beta-1 adrenergic receptors in the SA node, produces and increase in I-f which ____-

Answer 5

Increases the rate of phase 4 depolarization

Question 6

SA node discharge frequency is _____ when temperature rises

Answer 6

Increased

Question 7

An impulse initiated by a latent pacemaker

Answer 7

Escape beat

Question 8

Junctional escape:

Answer 8

Beats arise from the AV node or proximal bundle of His

Question 9

Ventricular escape

Answer 9

Beats arise from a more distal point in the conduction system

Question 10

SA node suppressed and fires less freq than normal

Site of impulse formation shifted to a latent pacemaker.

Answer 10

Escape beat (series of these is escape rhythm)

Question 11

Types of bradyarrhythmias

Answer 11

Junctional escape rhythm

Ventricular escape rhythm

Question 12

Key feature of bradyarrhythmias

Answer 12

Decreased sinus node automaticity

Question 13

Where do beats arise from in junctional escape

Answer 13

AV node or proximal bundle of HIS

Question 14

Is heart rate faster in junctional escape rhythms or ventricular escape rhythms?

Answer 14

Junctional escape rhythms

AV node faster than distal ventricle

Question 15

Increased sinus node automaticity

Enhanced automaticity of latent pacemakers

Answer 15

Tachyarrhythmias

Question 16

A latent pacemaker develops an intrinsic rate of depolarization that is faster than the SA node

Answer 16

Ectopic beat

Question 17

High catecholamine concentrations can enhance the automaticity of latent pacemakers, and if the resultant rate of depol exceeds that of the sinus node, then ______- will develop

Answer 17

An ectopic rhythm

Question 18

Causes for ectopy

Answer 18

High catecholamine concentrations

Electrolyte disturbances

Drug toxicities

Cardiac tissue injuries in myocardial cells outside of conduction system

Question 19

When do early afterdepolarizations occur?

Answer 19

Phase 2 (plateau)

Or

Phase 3 (rapid depol phase)

Question 20

When are early afterdepolarizations most likely to occur?

Answer 20

During therapy w/ certain drugs

In inherited long-QT syndromes

Question 21

What are early afterdepolarizations the initiating mechanism of ?

Answer 21

Polymorphic ventricular tachycardia

“Torsades de pointes”

Question 22

When is it most common for delayed-afterdepolarizations to occur?

Answer 22

States of high IC [Ca]

Digitalis intoxication

Question 23

Causes of conduction block

Answer 23

Ischemia

Fibrosis

Inflammation

Some drugs

Question 24

A propagating impulse is blocked because it encounters a region of the heart that is electrically inexcitable.

AV block common and major reason for implantation of pacemaker

Answer 24

Conduction block

Question 25

Atrial flutter is a type of ?

Answer 25

Reentry tachycardia resulting from unidirectional blcok

Question 26

Reentry which can occur over any anatomically fixed path

Answer 26

Anatomical reentry

Question 27

Reentry does not require a fixed path

Answer 27

Functional reentry

Polymorphic V tach
(Atrial fibrillation)
(Ventricular fibrillation)