Sinus & Atrial Rhythms

Question 0

A P-wave that is uniformly rounded would most likely be coming from the ________ node, but a P-wave that is notched, flattened, or diphasic, would be called would be called an _______ P-wave.

Answer 0

1) Sinus

2) Atrial

Question 1

What are the 5 types of Atrial Arryhthmias discussed in Walraven?

Answer 1

1) Wandering Pacemaker
2) Premature Atrial Complex (an ectopic beat)
3) Atrial Tachycardia
4) Atrial Flutter
5) Atrial Fibrillation

Question 2

What is the pathophysiology causing a wandering pacemaker?

Answer 2

A wandering pacemaker is caused when the pacemaker role switches from beat to beat from the SA node to the Atria and back again (sometimes it can wander to the AV junction as well).

Question 3

What are the rules for a Wandering Pacemaker with regards to the following:

1) Regularity
2) Rate
3) P Wave
4) PRI
5) QRS

Answer 3

1) Regularity - Slightly irregular (as the the pacemaker roles wanders between sites)
2) Rate - Normal (60-100)
3) P Wave - Changes with each complex as the pacemaker role changes between sites.
4) PRI - Varies as the the pacemaker site changes but will still be less than 0.20 seconds (may even be less than 0.12 secs)
5) QRS - Normal (less than 0.12 secs)

Question 4

What is the difference between an ectopic beat caused by irritability and an ectopic beat caused by an escape mechanism? How can you distinguish between the two?

Answer 4

1) Irritable Ectopic Beat - Caused when a a site somewhere along the conduction system becomes irritable and overrides the SA node for a single beat.
2) Escape Ectopic Beat - A beat initiated somewhere outside the SA node because the SA node failed to fire.

*You can tell the difference between the two because and irritable ectopic beat will come early in the cardiac cycle, while an escape beat will late in the cardiac cycle and preceded by a prolonged R-R interval.

Question 5

What are the rules for PACs with regards to the following:

1) Regularity
2) Rate
3) P Wave
4) PRI
5) QRS

Answer 5

1) Regularity - Depends on the underlying rhythm, regularity will be interrupted by the PAC.
2) Rate - Depends on the underlying rhythm
3) P Wave - P Wave of early beat differs from the sinus P Waves. Can be flattened or notched or lost inside the preceding T Wave.
4) PRI - 0.12 to 0.20 secs but may exceed 0.20 secs
5) QRS - Normal (less than 0.12 secs)

Question 6

Identify the pathophysiology behind Atrial Tachycardia (AT).

Answer 6

AT is caused by a single focus in the Atria that fires rapidly to override the SA node and thus assumes peacemaking responsibility for the entire rhythm.

Question 7

What are the rules for Atrial Tachycardia with regards to the following:

1) Regularity
2) Rate
3) P Wave
4) PRI
5) QRS

Answer 7

1) Regularity - Regular
2) Rate - 150 to 250
3) P Wave - Peaked, flattened, notched or diphasic, and can be lost in T Wave because the rate is so fast.
4) PRI - Normal (0.12 to 0.20 secs)
5) QRS - Normal (less than 0.12 secs)

Question 8

Identify the pathophysiology behind Atrial Flutter?

Answer 8

Atrial Flutter happens when an area in the atrium initiates an impulse that is conducted in a repetitive, cyclic pattern, creating a series of flutter waves (with sawtooth appearance) at a rate between 150 and 250 bpm.

Question 9

Explain why there is usually more than one P Wave (Sawtooth) between each QRS complex on and Atrial Flutter strip.

Answer 9

To protect the ventricles from receiving too many impulses, the AV node blocks some of the impulses from being conducted through to the ventricles. Rose that do get through are conducted normally.

Question 10

What are the rules for Atrial Flutter with regards to the following:

1) Regularity
2) Rate
3) P Wave
4) PRI
5) QRS

Answer 10

What are the rules for Atrial Flutter with regards to the following:

1) Regularity - Atrial rhythm is regular; ventricular rhythm is usually regular but can be irregular if there is a variable block.
2) Rate - Atrial rate 250 to 350 bpm; ventricular rate varies
3) P Wave - Characteristic sawtooth pattern
4) PRI - Unable to determine
5) QRS - Normal (less than 0.12 secs)

Question 11

What are the two most characteristic features of Atrial Fibrillation?

Answer 11

1) No discernible P Waves

2) Grossly irregular rhythm

Question 12

What are the rules for Atrial Fibrillation with regards to the following:

1) Regularity
2) Rate
3) P Wave
4) PRI
5) QRS

Answer 12

1) Regularity - Grossly irregular
2) Rate - Atrial rate greater than 350 bpm; ventricular rate varies greatly.
3) P Wave - not discernible; atrial activity is referred to as fibrillatory waves (f waves).
4) PRI - Unable to measure
5) QRS - Normal (less than 0.12 secs)

Question 13

Is the ventricular rhythm regular or irregular in Atrial Flutter?

Answer 13

This depends on how the AV node is blocking the impulses. If the atrial impulses are being conducted in a regular pattern (i.e., 2:1 or 4:1), the ventricular rhythm would be regular. But if the conduction ration varied (i.e., 2:1 then 3:1then 4:1), the ventricular rhythm would be irregular.

Question 14

Explain the following terms:

1) Atrial Fibrillation with Controlled Ventricular Response
2) Rapid Ventricular Response (Atrial Fibrillation Uncontrolled)

Answer 14

1) Atrial Fibrillation with Controlled Ventricular Response - Afib with a ventricular rate of 100 bpm or less.
2) Rapid Ventricular Response (Atrial Fibrillation Uncontrolled) - Afib with a ventricular rate greater than 100.

Question 15

What are some of the common causes of PACs?

Answer 15

1) Caffeine
2) Alcohol
3) Nicotine
4) Stretched Atrial Myocardium (i.e., Hypervolemia )
5) Hypokalemia
6) Hypoxemia
7) Early indicator of CHF and PEs

Question 16

What are some of the common causes of Atrial Flutter?

Answer 16

1) CAD
2) Hypertension
3) Mitral Valve Disease
4) Hyperthyroidism
5) Chronic Lung Disease
6) Cor Pulmonale (right ventricular failure)
7) Cardiomyopathy

Question 17

What is the medical management for a patient with Atrial Flutter?

Answer 17

If the PT is unstable, urgent electrical Cardioversion is indicated. If the patient is stable, the QRS is narrow, and RR is regular, Adenosine (6mg) may be rapidly administered via IV to slow the conduction through the AV node, if ineffective, 12mg may be administered via rapid IV bolus.
If Adenosine fails to convert the rhythm, cardioversion is indicated.

Question 18

What is the medical management for a patient with Atrial Fibrillation?

Answer 18

Electrical cardioversion is indicated for an unstable patient unless the patient has been in A-fib > 48hrs, this is because they are at greater risk for embolization.
IV Adenosine is indicated for the stable patient in A-fib < 48hrs.

Question 19

Describe Wolf-Parkinson’s Syndrome.

Answer 19

WPW Syndrome is caused by the presence of an abnormal accessory electrical conduction pathway between the atria and the ventricles. Impulses traveling down this abnormal pathway may stimulate the ventricles to contract prematurely, resulting in a SVT. WPW Syndrome has a characteristic delta wave that makes the QRS wider than usual.

Question 20

Why should medications that block AV conduction be avoided for patients in A-fib who also have a wide QRS and irregular ventricular rhythm?

Answer 20

Because an accessory pathway might be present (as in WPW Syndrome) and these meds will actually increase the ventricular rate thought that accessory pathway.

Question 21

What are some examples of meds that slow the conduction of impulses through the AV node and are indicated for A-flutter and A-fib?

Answer 21

1) Adenosine
2) Diltiazem
3) Verapamil
4) Digoxin

Question 22

Warfarin is medicated for patients who have A-fib along with which other comorbidities?

Answer 22

1) > 75 yrs old
2) Hypertension
3) Heart Failure
4) Hx of stroke

Question 23

What Tx option is available to A-fib patients who are unresponsive to meds?

Answer 23

Ablation therapy or pacemaker implantation

Question 24

Describe the difference between Coarse A-fib and Fine A-fib.

Answer 24

Course A-fib has a bumpy baseline, while fine A-fib has a fine, almost smooth, discernible baseline.

Question 25

Which electrolyte is responsible for depolarization? Repolarization?

Answer 25

1) Depolarization - Sodium

2) Repolarization - Potassium

Question 26

What is the clinical significance of Hypokalemia in heart patients?

Answer 26

Hypokalemia can lead to irritability and excitation (the opposite of polarized/resting)

Question 27

What is the clinical significance of Calcium and Magnesium on heart patients?.

Answer 27

1) Calcium - Responsible for cardiac contractility, vascular tone and blood clotting.
2) Magnesium - Activates enzymes involved in the breakdown of ATP for energy, which is responsible for neuromuscular function and myocardial contraction/irritability.

Question 28

What is the significance of Phosphorous on heart patients?

Answer 28

Phosphorous is essential for ADP/ATP, which are esponsible for energy inside the cell.
Hypophosphatemia can cause muscular weakness, including respiratory and cardiac arrest.

Question 29

What does the QT interval represent and what’s the normal range?

Answer 29

The QT interval represents the total time for ventricular depolarization and repolarization, and is measured form the beginning of the QRS complex to the end of the T-wave.
The normal range is 0.36 to 0.44 seconds.

Question 30

What does the TP segment represent, how is it measured and which 2 significant events happen during this segment?

Answer 30

The TP segment represents diastole. It is measured from the end of the T-wave to the beginning of the P-wave. Two significant events that happen during diastole are:

1) Ventricular Diastolic Filling
2) Coronary Artery Filling

Question 31

What are the mentioned med classes that can prolong the QT interval?

Answer 31

1) Asthma inhalers - Albutrol and Salmeterol
2) Antihistamines - Benadryl
3) Antiarrhytmics - Quinidine
4) Antipsychotics - Amitryptyline and Perphanazine

Question 32

Name 6 common causes of Sinus Bradycardia.

Answer 32

1) Damage to SA Node (i.e., inferior wall MI)
2) Parasympathetic stimulation (i.e., Vagal stimulation)
3) Hypoxemia (i.e., during suction)
4) Athletic hearts
5) Pacemaker failure
6) Meds (i.e., Beta-blockers)

Question 33

Explain the difference between PVCs and Bradycardia with ventricular escape beats.

Answer 33

1) Premature Ventricular Contractions - When the ventricles contract first, before the atria have optimally filled up. The heart beat is initiated by the Purkinje Fibers.
2) Bradycardia with Ventricular Escape Beats - Happens when the ventricles initiate a heart beat because the SA node’s rate is too slow.

Question 34

Which class of medication is indicated for patients experiencing Bradycardia with Ventricular Escape Beats?

Answer 34

Atropine - Stimulates the SNS

Question 35

(T/F) During sinus arrhythmias, the heart rate increases with inspiration and decreases with expiration.

Answer 35

True

Question 36

Define Paroxysmal Atrial Tachycardia.

Answer 36

PAT is an acute onset of Atrial Tachycardia

Question 37

What are the 3 mentioned clinical significances of PAT?

Answer 37

1) Coronary arteries are unable to fill due to short diastolic time
2) Shortened ejection time with decreased cardiac output may progress to heart failure, shock or death.
3) Increased HR causes increased MVO2, especially with MI

Question 38

What is MVO2 and how is it calculated?

Answer 38

MVO2 - Myocardial Volume Oxygen Consumption

MVO2 = SBP x HR

Question 39

Describe Ablative Therapy used to treat Atrial Tachycardia.

Answer 39

A special catheter is placed against the area of the heart responsible for the problem. Radio-frequency energy is then passed to the tip of the catheter, so that it heats up and destroys the target area. Considered a non-surgical procedure.

Question 40

What is the standard Tx for the following types of patients experiencing Atrial Tachycardia:

1) Stable PT
2) Symptomatic PT
3) Life-threatening/Unstable PT

Answer 40

1) Stable PT - Vagotonic maneuvers (Valsalva maneuver, carotid sinus massage, dig, pacemaker override.
2) Symptomatic PT - Adenosine (may cause brief arrest), Verapamil (titrate and give slowly).
3) Life-threatening/Unstable PT - Synchronized cardioversion.

Question 41

What’s the difference between controlled and uncontrolled Atrial Fibrillation?.

Answer 41

1) Controlled - Atrial Fibrillation with a ventricular rate of 100 or less.
2) Uncontrolled - Atrial Fibrillation with a ventricular rate greater than 100.

Question 42

How does a patient with Atrial Fibrillation usually present?

Answer 42

Weak, SOB, and syncope is usually common. All are as a result of lack of cardiac output.

Question 43

What are the 5 mentioned treatments for acute atrial fibrillation?

Answer 43

1) Diltiazem (CCB) - IV bolus then drip
2) Procainamide or Ibutilide drip (Antiarrhytmics)
3) Cardioversion
4) Ablative Therapy
5) Anticoagulants - To prevent clots and resulting CVA

Question 44

What are the 4 mentioned Txs for Chronic Atrial Fibrillation?

Answer 44

1) Diltiazem (CCB) - oral
2) Procainamide or Amiodorone (Antiarrhytmics) - Oral
3) Digoxin
4) Anticoagulants