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Cardiology USMLE Step 3 > Section 5: Rhythm Disorders > Flashcards

Section 5: Rhythm Disorders Flashcards

1
Q

Clinical presentation of atrial fibrillation

A
  • Palpitations
  • An irregular pulse

in a person with a history of hypertension, ischemia, or cardiomyopathy

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 2668). . Kindle Edition.

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2
Q

Diagnostic testing for A-fib

A
  • EKG
  • Telemetry monitoring (inpatient)
  • Holter monitoring (outpatient)

Holter monitoring is a continuous, ambulatory cardiac rhythm monitoring for 24 hours or longer

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2669-2672). . Kindle Edition.

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3
Q

Atrial Fibrillation

For the CCS, apart from EKG what other daignostic tests should be done

A
  • Echocardiography: Looking for clots, valve function, and left atrial size
  • Thyroid function testing: T4 and TSH levels
  • Electrolytes: Potassium, magnesium, and calcium levels
  • Troponin or CK-MB levels: These may be appropriate to test in some acute-onset cases

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 2681). . Kindle Edition.

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4
Q

Rx of hemodynamically unstable patients with A-fib

How is hemodynamic instability defined in this context?

A
  • Immediate synchronized electrical cardioversion

Unstable patients should be cardioverted with the first screen, without waiting for TEE or anticoagulation with heparin or warfarin

  • Hemodynamic instability is defined as:
    1. A systolic blood pressure < 90
    2. Congestive failure
    3. Confusion related to hemodynamic instability
    4. Chest pain.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2683-2686). . Kindle Edition.

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5
Q

Rx of hemodynamically stable patients with A-fib

A
  • Stable patients should have their ventricular heart rate slowed if it is > 100– 110 per minute.
  • Rate control medications are:
    • beta blockers (metoprolol, esmolol)
    • calcium channel blockers (diltiazem)
    • digoxin

In the medications, such as metoprolol, diltiazem, or digoxin, combined with anticoagulation is equal or better than cardioversion with electricity or medications.

CHADS (CHF, hypertension, age > 75, diabetes, or stroke/ TIA) is a scoring system to indicate the need for warfarin or dabigatran. A score of 2 or more means warfarin, dabigatran, or rivaroxaban. A score of 0 or 1 means aspirin. CHADS C = CHF H = Hypertension A = Age > 75 D = Diabetes S = Stroke or TIA CHADS score of 0 – 1 needs aspirin. At 2 or more, use warfarin, dabigatran, or rivaroxaban.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2699-2707). . Kindle Edition.

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6
Q

What is the CHADS scoring system in A-fib management?

A
  • CHADS (CHF, hypertension, age > 75, diabetes, or stroke/ TIA) is a scoring system to indicate the need for warfarin or dabigatran
  • A score of 2 or more means warfarin, dabigatran, or rivaroxaban
  • A score of 0 or 1 means aspirin. CHADS
    • C = CHF
    • H = Hypertension
    • A = Age > 75
    • D = Diabetes
    • S = Stroke or TIA

CHADS score of 0 – 1 needs aspirin. At 2 or more, use warfarin, dabigatran, or rivaroxaban

Stroke/ TIA = 2 points

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2708-2709). . Kindle Edition.

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7
Q

What is the difference between A-fib and atrial flutter?

A

The rhythm is irregular in A-fib but regular in A-flutter. Management is the same.

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8
Q

In A-fib or A-flutter, which rate reducing medication is indicated in:

  • Ischemic heart disease
  • Migraines
  • Graves disease
  • Pheochromocytoma
A

Beta Blockers (Metoprolol)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2714-2726). . Kindle Edition.

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9
Q

In A-fib or A-flutter, which rate reducing medication is indicated in:

  • Asthma
  • Migraine
A

Calcium Channel Blockers (Diltiazem)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2714-2726). . Kindle Edition.

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10
Q

In A-fib or A-flutter, which rate reducing medication is indicated in:

  • Borderline hypotension
A
  • Digoxin

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2714-2726). . Kindle Edition

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11
Q

Multifocal Atrial Tachycardia (MAT)

This condition presents like an atrial arrhythmia in association with ———.

EKG features of MAT

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2728-2729). . Kindle Edition

A
  • COPD/ emphysema
  • EKG will show polymorphic P waves, revealing different atrial foci for the QRS complexes
  • As the name implies, patients with MAT have tachycardia (heart rate > 100)
  • MAT manifests as an irregular chaotic rhythm on EKG
  • Do not use beta blockers

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2729-2733). . Kindle Edition.

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12
Q

Clinical presentation of Supraventricular Tachycardia (SVT)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2734-2735). . Kindle Edition.

A

SVT presents with palpitations and tachycardia and occasionally syncope. It is not associated with ischemic heart disease. SVT has a regular rhythm with a ventricular rate of 160– 180.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2736-2737). . Kindle Edition.

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13
Q

Diagnostic tests for SVT

A

EKG

If the EKG does not show SVT, order Holter monitor or telemetry to increase the sensitivity of detection

On CCS, all cases of dysrhythmia should undergo transthoracic echocardiography (TTE) after the initial set of orders.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2738-2743). . Kindle Edition.

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14
Q

Rx for SVT

  • Best initial management for unstable patients
  • Best initial management for stable patients
  • Best long-term management
A
  • Synchronized cardioversion
  • Vagal maneuvers (carotid sinus massage, ice immersion of the face, Valsalva)
    • Next best step in management if vagal maneuvers do not work: Intravenous adenosine (Note: This is the most frequently asked SVT question.)
  • Radiofrequency catheter ablation

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2746-2748). . Kindle Edition.

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15
Q

Clinical presentation of Wolff-Parkinson-White Syndrome (WPW)

A
  • WPW presents as SVT that can alternate with ventricular tachycardia (VT)
  • The other main clue to the diagnosis is worsening of SVT after the use of calcium blockers or digoxin.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2749-2752). . Kindle Edition.

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16
Q

Diagnostic test fo WPW syndrome

A
  • WPW is diagnosed with finding a delta wave on the EKG
  • The most accurate test is electrophysiologic studies

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2753-2755). . Kindle Edition.

17
Q

Rx of WPW syndrome:

  • Best initial therapy
  • Best long term therapy
A
  • Best initial therapy if the patient is described as being in SVT or VT from WPW: Procainamide
  • Best long-term therapy: Radiofrequency catheter ablation

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2757-2759). . Kindle Edition.

18
Q

Clinical presentation of ventricular tachycardia

A
  • Palpitation
  • Syncope
  • Chest pain
  • Sudden death

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2760-2761). . Kindle Edition.

19
Q

Diagnostic tests for VT

  • Best initial test
  • Most accurate test
A
  • EKG
    • if EKG does not detect VT, then telemetry monitoring should be ordered.
  • Electrophysiologic studies.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2763-2765). . Kindle Edition

20
Q

Rx for persistent VT

  • Hemodynamically stable
  • Hemodynamically unstable
A
  • Hemodynamically stable
    • Amiodarone
    • Lidocaine
    • Procainamide
    • Magnesium

Use the mnemonic PALM

  • Hemodynamically unstable
    • Synchronized cardioversion
21
Q

What is Torsade de pointes?

How is it managed?

A
  • Torsade de pointes is ventricular tachycardia with an undulating amplitude.
  • Magnesium should always be given in addition to medical or electrical therapy.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2777-2779). . Kindle Edition.

22
Q

How does Ventricular Fibrillation (V-Fib) V-fib presents?

A

Ventricular Fibrillation (V-Fib) V-fib presents as sudden death.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2780-2781). . Kindle Edition.

23
Q

Diagnostic testine of V-fib

24
Q

Treatment of V-fib

A

Treatment of V-fib is always with unsynchronized cardioversion first.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2785-2786). . Kindle Edition.

25
Q

How is unsynchronized cardioversion (defibrillation) is administered?

A
  1. Continue CPR
  2. Reattempt defibrillation
  3. Administer IV epinephrine or vasopressin
  4. Reattempt defibrillation
  5. Administer IV amiodarone or lidocaine
  6. Reattempt defibrillation
  7. Repeat several cycles of CPR between each shock

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2795-2802). . Kindle Edition.

26
Q

What are the 3 criteria used in the management of syncope

A
  1. Was the loss of consciousness sudden or gradual?
  2. Was the regaining of consciousness sudden or gradual?
  3. Finding on cardiac exam
27
Q

Syncope:

List the causes of sudden loss of consciousness

A
  • Cardiac etiology
  • Neurologic (seizures)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2810-2811). . Kindle Edition.

28
Q

Syncope:

List the causes of gradual loss of consciousness

A
  • Toxic-metabolic problems
  • Hypoglycemia
  • Drug toxicity/ intoxication
  • Anemia
  • Hypoxia

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2812-2817). . Kindle Edition.

29
Q

Syncope:

List the causes of sudden regaining of consciousness

A
  • Cardiac etiology
  • Rhythm disorder versus structural disease

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2822-2824). . Kindle Edition.

30
Q

Syncope:

List the causes of gradual regaining of consciousness

A

Neurologic (seizures)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 2825). . Kindle Edition.

31
Q

Syncope:

List causes of syncope with normal cardiac exam

A

Ventricular arrhythmia

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 2830). . Kindle Edition.

32
Q

Syncope:

List causes of syncope with abnormal cardiac exam

A
  • Structural heart disease:
    • Aortic stenosis
    • HOCM
    • Mitral stenosis
    • Mitral valve prolapse (rare)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2832-2836). . Kindle Edition.

33
Q

Diagnostic tests for Syncope:

  • Initial tests
  • Specific tests
A
  • Initial tests:
    • Cardiac and neurological examination
    • EKG
    • Chemistries (glucose)
    • Oximeter
    • CBC
    • Cardiac enzymes (CK-MB, troponin)
  • Specific tests:
    • If a murmur is present, order an echocardiogram
    • If the neurological exam is focal or there is a history of head trauma due to syncope, order head CT
    • If a headache is described, order head CT
    • If a seizure is described or suspected, order head CT and EEG.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2842-2849). . Kindle Edition.

34
Q

True or False:

Carotid Dopplers are not useful in syncope

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 2850). . Kindle Edition.

A

True. Carotid Dopplers are not useful in syncope. A patient cannot pass out from a carotid embolus.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 2850). . Kindle Edition.

35
Q

Further diagnostic tests for syncope if the EKG is not revealing

A
  • Holter monitor on outpatients
  • Telemetry monitoring for inpatients
  • Repeat check of CK-MB and troponin levels 4 hours later
  • Urine and blood toxicology screens
  • Tilt table testing to diagnose neurocardiogenic (vasovagal) syncope
  • Electrophysiological testing
  • The Holter monitor is a 24- to 72-hour continuous ambulatory EKG. This is routine for most patients with syncope requiring admission

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2856-2865). . Kindle Edition

36
Q

Rx of syncope

A
  • Treatment of syncope is based on the etiology. The majority of cases never get a specific diagnosis.
  • The most important thing to do in syncope is to exclude a cardiac etiology, such as an arrhythmia.
  • The majority (> 80 percent) of mortality from syncope involves a cardiac etiology.
  • If a ventricular dysrhythmia is diagnosed as the etiology of syncope, an implantable cardioverter/ defibrillator is indicated.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 2868-2872). . Kindle Edition.

Cardiology USMLE Step 3 (12 decks)

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