Exam 15 - Heart33,34,35 - Basic Ep Pacing Icd

Front 1

AP of a cardiac cell:

Phase 0
-Rapid upstroke depolarization with an influx of ... ions into the cell

Phase 1
-Early rapid repolarization with transient onward movement of ... ions

Phase 2
-Plateau Phase: Continued Influx of ... & slow Influx of ...

Phase 3
-Repolarization: ... outflow

Phase 4
-... Phase

Back 1

sodium
potassium
Sodium
Calcium
Potassium
Resting

Front 2

what phases does the effective refractory period occur during?

During ERP an impulse of any strength cannot initiate depolarization because the impulse follows the initial depolarization too closely. The ... channels are inactive and can not be opened no matter how much the membrane is stimulated to depolarize.

Back 2

phases 0, 1, 2 and early phase 3
Na+

Front 3

what phases does the relative refractory period occur during?

-A strong impulse can cause depolarization, possibly with aberrancy
-A stimulus during certain areas of the RRP may cause life-threatening arrhythmias. When this occurs, it is known as the “R on T phenomenon.”

Back 3

late phase 3 and early phase 4

Front 4

Triggered activity:

Early afterdepolarizations, which occur in Phase 3 of the action potential, are responsible for pause-dependent triggered activity. Early after-depolarization may be caused by:
a. Low ... blood levels (many due to diuretics that are given)
b. Slow heart rate
c. Drug toxicity (ex. quinidine causing the ... type of VT)

Late afterdepolarizations, which occur in late Phase 3 or Phase 4 of the action potential, are responsible for catechol-dependent triggered activity. Delayed after-depolarization may be caused by:
a. Premature beats
b. Increased ... blood levels
c. Increased adrenaline levels
d. Digitalis toxicity

Back 4

potassium
Torsades de Pointes
calcium

Front 5

What is the most common mechanism for tachyarrhythmias?

Back 5

reentry

Front 6

Reentry:

To put it briefly:
- The tissue that forms the block and pathways for a reentry circuit is called the ...
- A premature impulse (such as a Premature Ventricular Contraction, or PVC) serves as a ...
- ...+ ... results in reentry

*Note: A ... may develop due to scar tissue from various forms of heart disease.

Back 6

substrate
trigger
Substrate + Trigger
substrate

Front 7

Mechanisms of rhythm disturbances: underlying mechanisms:

...:
-abnormal automaticity
-triggered activity

...:
-slow or blocked conduction
-reentry

Back 7

impulse formation
impulse conduction

Front 8

With sinus arrest, is there a relationship between the pause and the basic cycle length?

Back 8

no

Front 9

... occurs when the SA node has alternating periods of firing too slowly (< 60 BPM) and too fast (>100 BPM).

It often manifests itself in periods of atrial tachycardia, flutter, or fibrillation. Cessation of the tachycardia is often followed by long pauses from the SA node.

Back 9

Brady/Tachy syndrome

Front 10

with SA exit block, is there a relationship between the pattern and the basic cycle length?

Back 10

Yes

Front 11

... occurs when the SA node fires, but the impulse does not conduct to the pathways that cause the atrium to contract.
-there is a relationship between the pattern and the basic cycle length (because the sinus node continues to fire regularly), of approximately two, but less commonly three or four times the normal P-P interval.

Back 11

SA exit block

Front 12

... can be described as a prolongation of the PR interval, the interval from the onset of the P-wave to the onset of the QRS complex.

First-degree AV block is defined by a PR interval greater than ... seconds. First-degree AV block can be thought of as a delay in AV conduction, but each atrial signal is conducted to the ventricles (1:1 ratio).

Back 12

AV block
0.20 (200 ms)

Front 13

... - Progressive prolongation of the PR interval until there is failure to conduct and a ventricular beat is dropped
-This is usually a normal phenomenon in response to tachycardia.
-the ... node is most commonly the site of this type of block.

Back 13

Second-degree AV block – Mobitz I (aka Wenckebach block)
AV

Front 14

... refers to intermittent dropped beats preceded by constant PR intervals. To differentiate Mobitz I from Mobitz II, note the PR interval in the beats preceding and following the dropped beat. If a difference between these two PR intervals is more than 0.02 seconds (20 ms), then it is Mobitz .... If the difference is less than 0.02 seconds, then it is Mobitz ....
The infranodal (...) tissue is most commonly the site of this type of block.

Back 14

Mobitz Type II Second-Degree AV block
I
II
His bundle

Front 15

... is also referred to as complete heart block. It is characterized by a complete dissociation between P-waves and QRS complexes. The QRS complexes are not caused by conduction of the P-waves through the AV node to the ventricles.
In this type of block, the QRS is initiated at a site below the AV node (such as in the His bundle or the Purkinje fibers). This “escape rhythm” is normally 40–60 BPM if initiated by the His bundle (a junctional rhythm) and <40 BPM if initiated by the Purkinje fibers.

Back 15

Third-Degree AV block

Front 16

...:

-A complete or incomplete block in at least two conduction system pathways below the AV Node
-Marked by a widened QRS

Back 16

Bifascicular block

Front 17

To review: Bradyarrhythmias can be classified according to the underlying cause of the disorder:

Impulse ... disorders include sinus bradycardia, sinus arrest (or sinus pause), and brady/tachy syndrome.

Impulse ... disorders include exit block, AV block and Bifascicular/Trifascicular block.

Back 17

generation
conduction

Front 18

terms describing Tachycardias:

... tachycardias originate from an ectopic focus and exhibit a sudden onset and an abrupt cessation, usually with a rate significantly faster than NSR.

... tachycardias are those that last 30 seconds or more, or require intervention for termination.

... tachycardias last at least 6 beats, or less than 30 seconds. The tachycardia spontaneously terminates and requires no intervention.

... tachycardias are characterized by occurring periodically, but occurrences are separated by periods of no tachycardia longer than the periods of tachycardia.

Back 18

Paroxysmal
Sustained
Non-sustained
Recurrent

Front 19

more terms:

... tachycardias have long periods of tachycardia interrupted by short periods of NSR. (VT storm)

... tachycardias originate from a single focus for the most part. The complexes all look similar and the coupling intervals are equal.

... tachycardias originate from multiple foci. The complexes appear different from one another, and the coupling intervals are unequal.

...Tachycardias are tachycardia rhythms that originate above the ventricles for the most part(such as A fib/flutter & AVNRT).

Back 19

Incessant
Monomorphic
Polymorphic
SVT, Supraventricular

Front 20

In ... Tachycardia, the EKG deflection will show a normal P and R-wave depolarization, with a rapid tachycardic rate

-rates range between 100-180 BPM
- The underlying Mechanism is Abnormal Automaticity (Hyper-Automaticity)

Back 20

Sinus

Front 21

... Tachycardia is also an SVT. It is characterized by fast electrical impulses with an ectopic focus originating somewhere in the atrium.
-defined as a series of 3 more consecutive atrial premature beats occurring at a rate of >100 BPM.

Back 21

Atrial

Front 22

...:

Origin: Atrium (outside the Sinus Node)
Mechanism: Abnormal Automaticity
Characteristics: An abnormal P-wave occurring earlier than expected, followed by compensatory pause

often seen in smokers

Back 22

Premature atrial contraction (PAC)

Front 23

...:

Origin: Ventricles
Mechanism: Abnormal Automaticity
Characteristics: A broad complex occurring earlier than expected, followed by a compensatory pause

Back 23

Premature ventricular contractions (PVCs)

Front 24

Ventricular Premature beats that form patterns are classified according to the number of normal ventricular beats that occur between premature beats.
... – PVC every other beat;
... – PVC every third beat; or
... - PVC every fourth beat.

Back 24

Bigeminy
Trigeminy
Quadrigeminy

Front 25

...:

Origin: Varies within the Ventricle
Mechanism: Abnormal Automaticity
Characteristics: Each premature beat changes axis; implies a different focus origin for each beat

Back 25

Multifocal PVC

Front 26

... occurs when the AV nodal rate accelerates to a rate faster than that of the sinus node and takes over the rhythm.

A junctional, or nodal, rhythm is also known to take over a rhythm when the SA node fails to fire. In that instance, however, it is not accelerated.

Origin: AV Node or Junctional Tissue
Mechanism: Abnormal Automaticity

Back 26

Accelerated Idio-Junctional Rhythm (or Idio-Nodal Rhythm)

Front 27

... is a form of ectopic or automatic ventricular arrhythmia. It is characterized by a ventricular rate that is faster than the underlying sinus rate, yet slower than traditional VT. Because the rate is faster than the sinus rate, it dominates and takes over the rhythm.
Origin: Ventricle
Mechanism: Abnormal Automaticity (Hyper-Automaticity)

Back 27

Accelerated Idioventricular Rhythm (AIVR)

Front 28

...:

Origin: Right & Left Atrium
Mechanism: Reentry
Characteristics: Rapid, regular p-waves

Back 28

Atrial flutter

Front 29

...:

Origin: Right and/or left atrium
Mechanism: Multiple wavelets of reentry
Rate: 400 BPM
Characteristics: Random, chaotic rhythm; atria quiver; associated with irregular ventricular rhythm

Back 29

Atrial fibrillation

Front 30

Atrial fibrillation can also result from the rapid discharge of impulses from one or many ectopic (non-sinus) sites in the atria. The ectopic cells (called foci) depolarize independently of the sinus node and disrupt the normal sinus rhythm.

... firing takes place at multiple atrial ectopic sites. The cells produce many depolarization waves that activate different areas of the atrial myocardium at different times. AF occurs because the myocardial cells do not contract and relax rhythmically, in normal synchronization with the sinus node.

Back 30

Multifocal

Front 31

look at slide 98

Back 31

ok

Front 32

...:

An SVT caused by the existence of an extra pathway from the atria to the ventricles

Extra pathway + AV Node = reentry

2 Types
-...
*A to V through node, then enters accessory pathway to loop
*Produces narrow complex SVT
-...
A to V through accessory pathway, then enters node to loop
-Produces wide-complex SVT

Back 32

AVRT (AV reciprocating tachycardia)
Orthodromic
Antidromic

Front 33

What is the most common form of AVRT?
-MC is orthodromic
-Delta waves are seen

Back 33

Wolf-Parkinson-White (WPW) Syndrome

Front 34

...:

Origin: AV Node
Mechanism: Reentry
Rate: 150 - 230 BPM, faster in teenagers
Characteristics: Normal QRS with absent P-waves; most common SVT in adults

Back 34

AVNRT (AV nodal reentry tachycardia)

Front 35

... ( twists of points) is a distinctive VT in which the QRS complexes change in morphology from positive to negative and appear to twist around an imaginary base line. The changing patterns are due to a movement in the reentrant mechanism.
It is associated with prolonged repolarization, may be acquired or congenital and may be a very deadly form of VT. Events leading to this are:
-Hypokalemia
- Prolongation of the action potential duration
- Early afterdepolarizations
- Critically slow conduction that contributes to reentry

Back 35

Torsades de Pointes (TdP)

Front 36

...:

Origin: Ventricle
Mechanism: Multiple Wavelets of reentry
Characteristics: Irregular with no discrete QRS

Back 36

Ventricular Fibrillation

Front 37

Neurocardiogenic Syncope is when a neurological disorder causes the inhibition of an electrical impulse. The brain keeps the impulse from being formed.

-... is a disease of the carotid sinus, a dilated portion of the carotid artery that has pressure-sensitive receptors that regulate heart rate and blood pressure. It is an extreme reflex response to carotid sinus stimulation and usually results in bradycardia and/or vasodilation. It can be induced by, among other things, a tight collar, shaving, head turning, exercise, and, of course, carotid sinus massage.
-... is a neurally mediated transient loss of consciousness and can be triggered by prolonged standing, fear, mental anguish, physical pain or anticipation of trauma or pain. The most common symptoms are dizziness, blurred vision, weakness, nausea, sweating, and abdominal discomfort.

Back 37

Hypersensitive Carotid Sinus Syndrome (CSS)
Vasovagal syncope

Front 38

The Reveal® Plus ... is an implantable patient- and automatically-activated monitoring system that records subcutaneous ECG and is indicated for:
- Patients with clinical syndromes or situations at increased risk of cardiac arrhythmias
- Patients who experience transient symptoms that may suggest a cardiac arrhythmia

Back 38

Insertable Loop Recorder (IRL)