Heller Ch. 5

Question 1

What does a supraventricular arrhythmia look like on ECG?

Answer 1

Frequent QRS complexes

Merged P and T waves

Question 2

What is the duration of supraventricular tachycardia?

Answer 2

Abrupt onset
Lasts minutes–>hours
Abrupt stop

Question 3

What are three causes of supraventricular tachycardia?

Answer 3

Ectopic focus
Reentry phenomenon
Atrial flutter

Question 4

What is an ectopic focus?

Answer 4

An irritated atrial region takes over the pacemaker function

Question 5

What is reentry phenomenon?

Answer 5

A single wave of excitation doesn’t die, but continuously travels around some abnormal conduction loop

Question 6

What might cause reentry phenomenon?

Answer 6

Abnormal repolarization and altered refractory periods in local areas of the myocardium

Question 7

What would atrial flutter look like on an ECG?

Answer 7

A fixed ratio of P wave to QRS complexes

More P waves than QRS complexes

Question 8

Why doesn’t the AV node fire every time the SA node fire during atrial flutter?

Answer 8

Atrial flutter SA firing is too fast, the AV node is still in the refractory period

Question 9

What is a conduction block?

Answer 9

Impaired conduction through tissue

Question 10

Where does a conduction block occur?

Answer 10

AV node

Question 11

What does a first-degree conduction block look like on an ECG?

Answer 11

Long PR interval (>0.2s)

Question 12

Is a first-degree conduction block usually bad?

Answer 12

No, but may deteriorate to an actual interruption of conduction

Question 13

What is a second-degree look like on an ECG?

Answer 13

Multiple P waves per QRS complex

Question 14

Why can’t all of the P waves result in a QRS complex?

Answer 14

Impulses are blocked by cells still being in refractory period

Question 15

What aggravates a second-degree block?

Answer 15

High atrial rates

Slower than normal conduction through the AV nodal region

Question 16

What happens in third-degree conduction block?

Answer 16

No impulses are transmitted through the AV node

SA and AV node are not synchronized and some area near the AV node assumes pacemaker role

Question 17

What does a third-degree conduction block look like on an ECG?

Answer 17

P waves and QRS complexes occur randomly

QRS complexes are less frequent

Question 18

What happens in atrial fibrillation?

Answer 18

Atrial cells are not synchronized–>no P wave

Question 19

What do the ventricles do during A fib?

Answer 19

Contract randomly

Question 20

Is the problem with A fib that there is a low SV?

Answer 20

No, atrial contraction has little to do with ventricular filling

Question 21

What is the problem with A fib?

Answer 21

Clots can form in the atria

Question 22

What should be given to people with A fib to avoid problems?

Answer 22

Anticoagulants

Question 23

Where do bundle branch blocks (hemiblocks) occur?

Answer 23

Either of the Purkinje branches as a result of MI

Question 24

Are hemiblocks bad?

Answer 24

They are usually inconsequential

Question 25

What does a hemiblock look like on an ECG?

Answer 25

A wider QRS complex (>0.12s) | Ventricular depolarization is less synchronized

Question 26

What causes Premature Ventricular Contractions (PVCs)?

Answer 26

An ectopic focus in the ventricle

Question 27

What is the effect of PVCs?

Answer 27

Contraction with a small stroke volume...followed by a missed beat...followed by a contraction with a large stroke volume

Question 28

What do PVCs look like on and ECG?

Answer 28

Large-amplitude, long-duration QRS complexes

Question 29

Are PVCs dangerous?

Answer 29

The occasional PVC is not | Frequent PVCs are a sign of possible myocardial or perfusion problems

Question 30

What causes ventricular tachycardia?

Answer 30

A ventricular ectopic focus

Question 31

Is ventricular fibrillation serious?

Answer 31

Yes Rapid rate-->insufficient filling Not synchronized-->less effective contraction

Question 32

What can ventricular tachycardia usually precede?

Answer 32

Ventricular fibrillation

Question 33

What happens as a result of delayed ventricular myocyte repolarization?

Answer 33

Prolonged QT intervals

Question 34

What causes prolonged QT intervals?

Answer 34

Ion channels during plateau phase (genetic? electrolyte disturbances? Pharm agents?)

Question 35

When is a QT interval considered long?

Answer 35

When it is >50% of the cycle

Question 36

What is the concern with a prolonged QT interval?

Answer 36

Prolongs vulnerable period during which extra stimuli can evoke tachycardia (torsades de pointes) or fibrillation

Question 37

What happens in ventricular fibrillation?

Answer 37

Various areas of the ventricle are excited and contract asynchronously

Question 38

When is ventricular fibrillation most likely to occur?

Answer 38

When excitation occurs while cell is still in T wave | Causes circus pathway

Question 39

What does cardiac conversion (PADs) do?

Answer 39

Depolarizes all heart cells simultaneously...attempt to synchronize cells

Question 40

What happens with aortic stenosis?

Answer 40

Systolic murmur | Increased resistance-->hypertrophy

Question 41

What is the problem with aortic stenosis?

Answer 41

Increased workload on left ventricle

Question 42

What happens with mitral stenosis?

Answer 42

Can cause atrial hypertrophy

Question 43

What is the problem with mitral stenosis?

Answer 43

Pulmonary congestion-->elevated pulmonary capillary pressure-->shortness of breath

Question 44

What causes a low diastolic pressure and large pulse pressure and a diastolic murmur?

Answer 44

Aortic insufficiency

Question 45

What is the problem with aortic insufficiency?

Answer 45

Reduction in forward flow out to the tissues | High volume workload of the left ventricle

Question 46

What has a systolic murmur and can lead to shortness of breath?

Answer 46

Mitral regurgitation...also has similar consequences as aortic insufficiency

Question 47

How do AV valve stenosis/insufficiency cause edema?

Answer 47

Atrial pressure puts more pressure on upstream capillary beds-->tissue edema

Question 48

What causes hypertrophy and wall thickening?

Answer 48

Stenotic valves

Question 49

What causes dilated chambers w/o wall thickening?

Answer 49

Insufficient valves