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Chronic Illness > Dysrhythmias > Flashcards

Dysrhythmias Flashcards

1
Q

Where is the PR interval?

A

from the beginning of the P wave to the beginning of the Q wave– 0.12-0.2 seconds

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2
Q

Where is the QRS complex?

A

from the beginning of the Q wve to the end of the S wave– less than 0.12 seconds

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3
Q

Where is the QT interval?

A

measure from the beginning of the Q wave to the end of the T wave– 0.34-0.43 seconds (if HR is 60-100)

-prolonged QT intervals is a risk for sudden death

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4
Q

What is the R-R interval?

A

the measure between R waves– 0.6-1 second

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5
Q

What are the 5 things that you ask yourself when interpreting an ECG?

A

1) is the rhythm regular or irregular?
2) what is the rate?
3) is there a P wave for every QRS complex?
4) are the QRS complexes normal or wide?
5) is there an elevation in ST segments?

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6
Q

Which type of MI can not be diagnosed with an ECG?

A

non-ST elevation MI (NSTEMI) because there is no change to the ECG

–a STEMI (MI with ST elevation) signals a more serious MI with full thickness infarction and treatment can be guided by this finding alone (but troponin will still be done)

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7
Q

Define pericarditis

A

inflammation of the pericardium (sac surrounding the heart)

– most common cause is a viral infection, but it is also seen in pts with autoimmune conditions like SLE or RA, or after an MI

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8
Q

What are the manifestations of pericarditis?

A

-fever
-pleuritic chest pain (meaning it is worse on inspiration and improved upon sitting up/forward)
-pericardial friction rub (superficial scratchy or squeaking sound best heard on left sternal border)
-widespread ST-segment elevation
-evidence of pericardial effusion (build up of extra fluid around the heart)

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9
Q

Define pericardial effusion

A

build up of extra fluid around the heart– seen in pericarditis

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10
Q

What is the treatment for pericarditis?

A

-NSAIDS (Ex. ibuprofen or ASA) and colchicine
-corticosteroids

these meds help with inflammation, which is what pericarditis is

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11
Q

What affects does hyperkalemia have on heart rhythm?

A

-produces peaked T waves– exaggerated due to the increased excitability

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12
Q

What affect does hypokalemia have on heart rhythm?

A

-produces a shallow T wave and an extra U wave not usually seen

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12
Q

How does a potassium imbalance affect the heart?

A

-affects the resting membrane potential (RMP) making nerves either more (hyperkalemia) or less (hypokalemia) excitable

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13
Q

What treatment is used to treat hyperkalemia?

A

-IV calcium is used to offset the difference between the RMP and the threshold potential in the case of hyperkalemia– this does NOT lower the K+ levels, so treatment for this is still needed
-if life threatening arrhythmias is present, IV calcium is the priority but will not be used for everyone (like if the hyperkalemia is mild with only subtle ECG changes)

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14
Q

What treatment is used to treat hypokalemia?

A

-K+ supplement
-if a pt is on a loop diuretic causing hypokalemia, they usually are put on a supplement but may also have a potassium sparing diuretic added to reduce K+ wasting

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15
Q

How do you assess if a rhythm is regular on an ECG?

A

-compare the distances between R-R intervals
-when wanting to be precise, a pair of calipers will be used
-for less precise, you can right tallies on a strip of paper at the R-R interval and then compare to the next interval

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16
Q

How many seconds is on a strip?

A

6

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17
Q

How do you get an estimate of rate from an ECG?

A

-count the number of large squares between R-R interval (ex. 5)
-divide 300 by the number (5)

300/5= 60bpm

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18
Q

Define sinus arrhythmia

A

-a normal physiological phenomenon, most commonly seen in young, healthy people
-the HR varies due to reflex changes in vagal tone during the different stages of the respiratory cycle
-inspiration increases the HR by decreasing vagal tone

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19
Q

Define sinus tachycardia

A

-sinus node firing at >100bpm
-associated with psychological/physiological stressors as a compensatory mechanism or d/t various drugs

20
Q

What is the clinical significance of sinus tachycardia?

A

-will result in increased myocardial oxygen demand, decreased supply, and decreased ventricle filling time

21
Q

What is the immediate actions and treatments done for sinus tachycardia?

A

-ensure pt is safe and has IV access, apply O2 as per policy
-in stable pts, treat the underlying cause (such as fluids, treating pain, fever, etc)
-beta blockers may be used

22
Q

Define sinus bradycardia

A

-sinus node fires at a rate of <60bpm
-can also be the result of drugs (beta blockers), hypothermia, Valsalva maneuver, hypothyroidism, hypercalcemia, or injury to SA node (inferior MI)

23
Q

What is the clinical significance of sinus bradycardia?

A

-may result in decreased BP and decreased CO, which can lead to symptoms

24
Q

What are the immediate actions and treatments for sinus bradycardia?

A

-asymptomatic is not normally treated
-ensure pt is safe and has IV access
-atropine IV (anticholinergic)– will increase SA node firing
-long term tx may include pacemaker insertion

25
Q

When is sinus bradycardia normal?

A

-sleeping patients
-conditioned athletes
-as a result of some medications

26
Q

What are the symptoms of symptomatic sinus brady?

A

hypotension– dizziness, nausea, syncope, and SOBOE (shortness of breath on expiration?)

27
Q

Define supraventricular dysrhythmias

A

-a problem within the atria, the AV node, or the bundle of His
-characterized by the absence of normal P waves and are typically associated with fast heart rates
-QRS complexes are usually normal in appearance

Ex. Afib, atrial flutter and supraventricular tachycardia

28
Q

Define supraventricular tachycardia

A

-also called SVT and atrial tachycardia
-irritated areas on atria take over as pacemaker– impulses are caught in a “re-entry loop”
-associated with underlying cardiac disease, SNS stimulation
-most often paroxysmal (periodic and resolving)– pt has “runs” of SVT in between normal rhythm

29
Q

What is the clinical significance of supraventricular tachycardia?

A

-if prolonged, may cause myocardial ischemia, decrease ventricle (decreased CO)

30
Q

What immediate actions and treatments should be done for supraventricular tachycardia?

A

-if stable, valsalva maneuver or carotid massage, CCMs, BBs, adenosine
-if unstable, synchronized cardioversion

31
Q

Describe the modified valsalva maneuver used in treatment for SVT

A

While in the semi-fowler position the patient is instructed to blow forcefully into a 10 mL
syringe to move the plunger for about 15 sec then is lowered into the supine position and
passive leg raises are performed for another 15 sec

32
Q

Describe the medications used for treatment of SVT

A

Medications: calcium channel and beta blockers as well as adenosine to slow conduction at the AV
node.
▪ adenosine causes bronchoconstriction, so may be contraindicated in pts with asthma/COPD

33
Q

Define Afib

A

-atrial fibrillation
-Rapid and irregular depolarizations from multiple ectopic areas of the atria
-irregular & rapid ventricular response
-Usually occurs d/t injured or stretched atrial tissue (MI, HF, pericarditis) or d/t
stimulants or electrolyte imbalances

34
Q

What is the clinical significance of afib?

A
  • May be asymptomatic but can also result in ↓CO
  • Chronic afib significantly increases the risk of embolic stroke
35
Q

What immediate actions and treatments are used for afib?

A
  • If present for <48h, antiarrhythmic drugs (amiodarone) or cardioversion → NSR
  • If chronic- anticoagulation and rate control (ventricular response <100bpm)

will be based on symptoms and HR

36
Q

What does the ECG look like for afib?

A

-irregular
-p waves are chaotic
-v rate 75-150

37
Q

What does the ECG look like for SVT?

A

-regular
-p waves are “hidden” in the t waves
-rate of around 230

38
Q

What should be done before cardioversion?

A

-assess for risk of embolization and treat with anticoagulants if needed prior to cardioversion– the longer the afib is present the more likely that a clot will be dislodged

39
Q

Describe atrial flutter

A
  • Impulse is generated from a single place in the right atrium (not SA node) that fires rapidly
  • Not as common as afib, can occur d/t MI, HF, pericarditis, or d/t stimulants or electrolyte
    imbalances
40
Q

What is the clinical significance of atrial flutter?

A
  • May be asymptomatic but can also result in ↓CO
  • Chronic aflutter significantly increases the risk of embolic stroke
41
Q

What immediate actions and treatments are done for atrial flutter?

A

similar approach as afib

  • If present for <48h, antiarrhythmic drugs or cardioversion → NSR
  • If chronic- anticoagulation and rate control (ventricular response <100bpm)

based on symptoms and HR

42
Q

Describe an atrial flutter ECG

A

-regular (can be irregular)
-4:1 ratio
-p waves look like a saw tooth
-A rate about 270-300
-V rate about 70

43
Q

Describe a ventricular dysrhythmia

A

Premature ventricular contractions (PVCs)
* Impulse originating in the ventricles (a premature QRS with no associated P wave)
* Single instances are normal and associated with stimulants (caffeine, alcohol, nicotine).
Also d/t fever, exercise, MI, and electrolyte imbalances

If an impulse originates below the AV node and bundle of His it is considered a ventricular
dysrhythmia. This may be a benign “add on” rhythm such as with occasional PVCs, or a life-
threatening rhythm such as V-tach and V-fib

44
Q

What is the clinical significance of ventricular dysrhythmia?

A
  • Single or couplets can cause feeling of palpitations (but often asymptomatic)
  • Multiple PVCs in a row can decrease CO
45
Q

What are the immediate actions and treatments for ventricular dysrhythmia?

A
  • Remove/treat the cause (if symptomatic)
  • Amiodarone used to prevent runs of V-tach
46
Q

Describe ventricular dysrhythmia on an ECG

A

A PVC is a premature occurrence of a QRS complex.
* HR varies according to intrinsic rate and number of PVCs.
* Although the rhythm may be irregular because of premature beats, if the underlying rhythm is
sinus, it is considered “a sinus rhythm with PVCs”.
* The P wave is rarely visible and is usually lost in the QRS complex of the PVC. Retrograde
conduction may occur, and the P wave may be seen following the ectopic beat.
* The PR interval is not measurable.
* The QRS complex is wide and distorted in shape, lasting longer than 0.12 second. The T wave
is generally large and opposite in direction to the major direction of the QRS complex

47
Q

What is a PVC?

A

-premature ventricular contraction (premature QRS complex)
-impulse originating below the AV node and bundle of His
-ventricular dysrhythmia
-p wave rarely visible and usually lost in the QRS complex
-PR interval not measurable
-QRS is wide and distorted
-often asymptomatic but can feel like palpations and cause dizziness

48
Q

What electrolyte imbalances can cause PVCs?

A

-hypokalemia
-hyperkalemia
-hypomagnesemia
-hypocalcemia

Chronic Illness (3 decks)

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