Approach to Suspected Dysrhythmia Flashcards

1
Q

Most arrhythmias can be classified as one of the 4 following:

A
  1. Disorders of impulse formation or automaticity
  2. Abnormalities of impulse conduction
  3. Reentry
  4. Triggered activity
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2
Q

cardiac dysrhythmias are divided into 3 groups:

A
  1. Premature / Ectopic / Escape beats or rhythms
  2. Bradyarrhythmias
  3. Tachyarrhythmias
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3
Q

Susceptibility to arrhythmias may result from many causes such as:

A
  1. Genetic abnormalities
  2. Acquired structural HD
  3. Lyte abnormalities
  4. Hormonal imbalances (thyrotoxicosis, hypercatecholaminergic states)
  5. Hypoxia
  6. Drugs (QT interval prolongation; changes in automaticity, conduction, and refractoriness)
  7. Myocardial ischemia
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4
Q

When assessing a patient with palpitations, the goal is to determine whether the symptoms represent:

A
  1. an arrhythmia that is minor and transient
  2. significant CVD
  3. a cardiac manifestation of systemic dz, such as thyrotoxicosis
  4. a benign somatic s amplified by underlying psychosocial characteristics of pt
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5
Q

Factors that increase risk of serious cardiovascular cause of palpitations

A
  1. Hx
    - FHx of significant arrhythmias
    - Personal/Fhx syncope or resuscitated sudden death
    - Hx MI (and likely scarred myocardium)
  2. PE
    - Structural HD -dilated or hypertrophic cardiomyopathies
    - Valvular disease (stenotic or regurgitant)
  3. ECG
    - Prolonged QTC
    - Bradycardia
    - 2nd- or 3rd-degree HB
    - Sustained ventricular arrhythmias
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6
Q

common descriptions of palpitations

A
  1. “Flip-flopping” (or “stop and start” or “skipped beats”) = premature contractions
  2. Rapid “fluttering in the chest” = fluttering regular = SVT, sinus tach, VT; irregular = afib
  3. “Pounding in neck” = afib, aflutter, PACs
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7
Q

associated sx with palpitations?

A

CP, SOB
Dizziness, near syncope or syncope

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8
Q

PMHx that could relate to palpitations

A
  1. Chronic conditions
    - CHF, CAD
    - Valvular disease
    - Thyroid disease, Diabetes, CKD
  2. Social history: alc, Illicit drug use
  3. Meds: Stimulants, OTC cold medicine, AADs
  4. FHx: Sudden death or unexplained death, HD
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9
Q

Main dx studies for palpitations

A

12-lead ekg and ambulatory monitoring

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10
Q

May not actually see a dysrhythmia on EKG, but can obtain clues to any possible cardiac disease

A
  • Prolonged QTc
  • Bradycardia, heart block (AV block and BBB)
  • Signs of old MI
  • Atrial or ventricular hypertrophy / enlargement
  • WPW or other pre-excitation syndrome (short PR interval)
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11
Q

types of ambulatory monitoring devices

A
  • Holter monitor
  • Event monitors
  • Real-time monitors
  • Patch recorders
  • Implantable loop recorders
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12
Q

Useful if ambulatory monitor records a worrisome arrhythmia or if serious arrhythmias are strongly suspected despite normal findings on the appropriate ambulatory monitor

A

Invasive electrophysiology testing

Can induce suspected arrhythmia or map source of arrhythmia for possible ablation

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13
Q

other diagnostic studies for palpitations

A

EKG + exercise test: if palpitations w/ physical exertion and with suspected CAD
Echo: if PE/ECG suggests structural abnormalities or decreased ventricular function
Labs: guides therapy or evaluate discovered dysrhythmias; Thyroid, lytes

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14
Q

what’s Cardioversion?

A

Electrical - Uses electrodes/paddles (50-360 J) and causes mass depolarization of tissue = prolonged refractoriness, “resetting” AP / impulse propagation source
Chemical - Ibutilide (Corvert) – rarely used

Preparation / Procedure
* Pads placed or conduction gel applied to paddles
* Everybody must be clear of touching pt
* Requires informed consent, except in unstable emergency / cardiac arrest
* Requires sedation, except in unconscious unstable patient

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15
Q

indications for cardioversion

A
  1. UNSTABLE Tachyarrhythmias – SVT, AF, VT, VF
  2. Afib / flutter
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16
Q

risks/complications w/ cardioversion

A
  • VT/VF - general anesthesia or lack of synchronization between DC shock and QRS complex
  • Thromboembolus - insufficient anticoagulant therapy
  • Arrhythmias: non-sustained VT, atrial arrhythmia, HB, bradycardia, transient LBBB
  • Myocardial necrosis, myocardial dysfunction
  • Transient hypotension
  • Pulmonary edema
  • burn
17
Q

what is Catheter ablation

A
  • Invasive procedure used to permanently interrupt reentrant circuits
  • Catheters threaded into heart via peripheral arteries and veins
  • Circuit disruption caused by radiofrequency or cryotherapy
  • Reentrant pathways mapped and then ablated
18
Q

Catheter ablation has become the primary modality of therapy for many symptomatic supraventricular arrhythmias, including:

A
  1. AV nodal reentrant tachycardia
  2. Paroxysmal atrial tachycardia
  3. Atrial flutter
19
Q

how is Afib ablation more complex?

A

Involves complete electrical isolation of the pulmonary veins (which are often the sites of initiation of atrial fibrillation) or placing linear lesions within atria to prevent propagation throughout the atrial chamber

20
Q

rare in ablation, but what are the possible complications?

A
  • major vascular damage durint cath insertion
  • perforation = pericardial tamponade
  • damaged AV node = permanent cardiac pacing
  • If afib ablation = atrioesophageal fistula - FATAL!
21
Q

pacemarkers are indicated for?

A

bradyarrhythmias, and do not shock (cardiovert/defibrillate) tachyarrhythmias

  • Symptomatic bradycardia
  • High-grade AV Block
  • Sinus pauses or afib pauses with sx
  • No reversible causes identified – this is important
22
Q

ICDs (Implantable cardioverter-defibrillators) are indicated to ?

A

prevent SCD, and ALL include pacemakers

  1. Primary prevention of Sudden Cardiac Arrest (VT/VF)
    - EF < 35% or other at-risk (Long QT, Brugada, Hypertrophic Cardiomyopathy)
  2. Secondary prevention of Sudden Cardiac Arrest (VT/VF)
23
Q

which is smaller, pacemaker or ICD?

A

pacemaker

24
Q

pacemakers/ICD may have from one to three leads

A

Right Atrium (RA)
Right Ventricle (RV)
Left Ventricle (LV)

25
Q

Pacemakers/ICD are identified by how many leads or chambers and type of device:

A
  • Single chamber pacemaker - RV lead
  • Dual Chamber ICD - RA and RV leads
  • Bi-Ventricular ICD (CRT-D) - RV and LV leads +/- RA lead
26
Q

pt ed about pacemaker/ICD

A
  • Pacing should not be detectable by pt
  • ICD shocks are substantial!!!
  • The devices are METAL and are affected by MAGNETS - will set off metal detectors; MRIs CI (newer devices are MRI-safe now)
  • “pacer spikes” on EKG/telemetry
  • F/U w/ cardiologist, electrophysiologist, or surgeon who implanted device
  • Home wireless monitoring has improved safety