Tachyarrhythmias Flashcards
What is a normal heart rate range?
What qualifies as tachycardia?
What qualifies as bradycardia?
Normal: 60-100 bpm
Tachycardia: greater than 100 bpm
Bradycardia: less than 60 bpm
What are the inherent pacing rates of automaticiy for the following foci?
SA node
Atria
AV node/junction
Ventricle
- SA node rate
- 60-100 bpm
- Atria automaticity rate
- 60-80 bpm
- AV node/junction rate
- 40-60 bpm
- Ventricular rate
- 20-40 bpm
What are the steps to evaluating a normal EKG?
- Rate
- find QRS that aligns with dark line on ECG, then cound “300, 150, 100, 70…”
- Look to see if there are P waves in front of QRS
- are they upright?
- How far are they from the QRS
- Are there T waves?
- how far are they from the Q?
- are they upright?
- Look to see if rhythm looks regular
- Check out the axises

What are the characteristics that define tachyarrhythmias?
- Identified by location where foci originate
- sinus node (SA) vs atrial ventricular (AV) node
- supraentricular vs ventricular
- most are propagated through reentry pathways
What is the difference between anatomical and functional reentry circuits?
- Anatomic
- by-pass tracts (accessory pathways)
- pathways you have been born with and are not necessarily present in everyone
- they can bypass the normal conduction pathway & create a circle pathway on their own
- Functional
- microcircuits in areas of the heart
- w/ Afib, there is a lot of small foci throughout the atria & the form their own circular pathway
What is the dominant mechanism for supraentricular tachycardis & ventricular tachycardia?
What does it require?
Reentry
Requires bifurcating pathways of different velocities adn refractory periods
OR
accessory pathway
Describe what is happening in this image

- A
- Normal conduction pathway
- A: long, fast pathway
- refractory to come up to normal is slower
- B: short, shlow pathway
- going back to normal is faster
- the impulses that split at the top will meet down at the distal common pathway to continue its course
- sometimes it can go back up retrograde
- when the retrograde pathway meets the slow pathway, they usually cancel each other out & you don’t have any problems
- B
- if there is a block in the fast pathway that interrupted the course
- the slow pathway made it to the bottom first and was able to go up through the faster pathway & get back up before it was fully refractory, starting the reentry circuit

Supraventricular tachycardia is what type of tachycardia?
How common is it?
How are they classified?
What is the most common site of origin?
- narrow complex tachycardia
- most common of in all age groups
- classification depends on
- site of origin, nature of arrhythmia or mechanism
- Origin (most commonly above bundle of His):
- SA node, atrium, AV node and proimal bundle of His
- automaticity, triggered or reentrant mechanism
- some wide complex tachycardias can be supraventricular
- Origin (most commonly above bundle of His):
- site of origin, nature of arrhythmia or mechanism
What are the type of supraventricular tachycardia?
- sinus tachycardia
- AV node reentrant tachycardia (AVNRT)
- AV reentrant tachycardia (AVRT)
- SA nodal reentrant tachycardia (SANRT)
- junctional tachycardia
- atrial fibrillation
- atrial flutter
- multifocal atrial tachycardia (MAT)
What are the risk factors for supraventricular tachycardia?
- Sympathomimetic use
- caffein overdos, alcohol us, tocabo use
- beta adrenergic medications used in asthma or COPD
- Illicit drugs such as methamphetamines and cocaine
- ADHD medications
- other medications or supplements that can increase heart rate
- OTC cold medications containing phenylephrine or pesudophedrine
- Fat burners or pre-work out supplements
- phentermine for weight loss
- digoxin toxicity
- Underlying medical conditions
- hyperthyroidism, catecholamine producing tumors, previous MI
- Stress, emotional upheaval or tiredness less commonly
- congenital or acquired reentrant pathway, icreased automaticity
What is the clinical presentation of supraventricular tachycardia?
What is the first thing you need to differentiate?
- Need to differentiate stable from unstable
- may be asymptomatic & incidental finding on ECG or exam
- most commonly atrial fibrillation
- Sudden onset of palpitations is most common complaint
- shortness of breath (mild to severe)
- chest pain
- dizziness
- syncope
- diaphoresis
- acute heart failure
What is the initial workup for a patient presenting with supraventricular tachycardia?
ECG
Identify the differential diagnosis for each of the provided scenarios

- Narrow
- Regular
- Sinus tachycardia
- physiologic sinus tachycardia
- inappropriate sinus tachycardia
- AVNRT
- AVRT
- Focal AT
- Atrial flutter
- Junctional tachycardia
- SANRT
- rarely ventricular tachycardia
- Sinus tachycardia
- Irregular
- AF
- Multifocal AT (or sinus tachycardia with frequent atrial ectopy(
- Focal AT with variable AV block
- Atrial flutter with variable AV block
- Regular
- Wide
- Regular
- Monomorphic VT
- Any SVT with aberrant conduction, ventricular pacing, preexcitation, certain antiarrhythmic medications, or significant electrolyte abnormalities
- antidromic ARVT with antegrade AV conduction via accessory pathway (WPW syndrome)
- Irregular
- AF, atrial flutter, or focal AT with aberrant conduction
- AF, atrial flutter or focal AT with antegrade conduction via accessory pathway (WPW syndrome)
- Polymorphic VT (including torsade de pointes)
- Ventricular fibrillation
- Antidromic AVRT due to nodoventricular/nodofascicular accessory pathway with variable VA conduction
- Regular

What is the next work up step following the EKG?
If there are no abnormalities?
If there are?
What labs are you ordering?
- If no abnormalities / symptoms are intermittent can proceed to further work-up outpatient
- If abnormality found on EKG
- abnormal rhythm shoudl be treated & further work-up postponed until patient is stable
- Labs
- electrolytes
- thyroid functin
- anemia if suspect substance abuse (CBC)
- urine drug screen
Describe the appropriate cardiac monitors to precribe for out-patient work up
- Cardiac Monitors
-
Holter monitor
- continuous ECG monitors
- Not patient activated
- but patients should write down when they have symptoms
- Short duration of use (24-48hrs up to 2 weeks)
- for use of daily or every other day symptoms
- Event monitors
- patient activation recording
- if symptom happens at night, you may miss a recording
- longer duration of monitoring sometimes up to 1 month
- patient activation recording
- Mobile Cardiac Telemetry
- Both patient activation and set parameter auto-trigger (HR, length of a pause, etc.)
- Can be used for longer monitoring (30+ days)
- Loop Recorder
- implanted under the skin (usually over the heart)
- can be work 2-3 years
-
Holter monitor
Describe the possible out-patient work up procedures that can be used in addition to cardiac monitoring
- Echocardiogram
- rule out any structureal abnormalities and assess myocardial wall function/ejection fraction
- Exercise Testing to induce exertional arrhythmias or underlying CAD
- Electrophysical Study (EPS)
- invasive, multipolar electrode catheter based study of area suspected to contain the reentry pathway to evaluate for or induce arrhythmia at time of study
- complications: myocardial perforation with cardiac tamponade, pseudoaneurysms at arterial access site adn provocation of nonclinical arrhythmias
- invasive, multipolar electrode catheter based study of area suspected to contain the reentry pathway to evaluate for or induce arrhythmia at time of study
- Direct cardiac mapping
- potentials recorded directly from the heart are spatially depicted as functin of time in an integrated manner
What is the treatment for active, current supraventricular tachycardia?
- In stable patients, you can do a vagal maneuver, carotid massage or cold water/ice on face
- in older people must ensure no carotid artery disease prior to carotid massage
- Adenosine can also be used if initial maneuvers are unsuccessful (into large vein)
- 6mg x1 and may repeat at 12 mg x2
- If adenosine does not work can use IV beta-blockers or non-dihydropyridine CCB (verapamil, diltiazem)
- Class III or Clas IC drugs can be used as alternatives
- Caution in WPW as can precipitate VF (choose procainamide or amiodarone)
- If continued arrhythmia or patient become unstable, immediate direct current cardioversion with sedation required
What is the treatment for chronic intermittent supreventricular tachycardias?
- Chronic pharmacological suppression in mild, less frequent cases “pill in the pocket”
- oral beta-blockers, non-dihydropyridine calcium channel blockers, class IC antiarrhythmic drug flecainide typically used
- Cryoablation or radiofrequence catheter ablation in recurrent, severe cases is definitive treatment
Describe the characteristics of Sinus Tachycardia
Rate?
ECG findings?
Causes?
Clinical presentation?
Treatment?
- Rate: 100-180 bpm
- P-wave before every QRS with stable PR interval
- Causes vary but include
- excessive caffein use
- Illicit drug use
- Normal resonse to exercise
- pulmonary emboli
- hyperthyroidism
- stress/andiety disorders
- pheochromocytoma
- sepsis
- Presentation
- gradual onset & termination
- In patients with underlying coronary artery disease (CAD) can precipitate chest pain
- Treatment
- typically aimed at cessation of of offending agends or target underlying disease
- beta-blockers or nondihydropyridine calcium channel blockers may be used to decrease heart rate
- Ivabradine has been usefulin patients with inappropriate or refractory sinus tachycardia

Describe the characteristics of Premature Atrial Complexes
Origination?
How common are they?
ECG?
Causes?
Clinical Presentation?
Treatment?
- Origination
- originate froma ny area of the atrium
- Frequency
- most common cause of irregular pulse & palpitations
- common in normal hearts & increase with age
- ECG
- P-wave is typically different from teh p-wave of the dominating rhythm indicating different focus or origin
- P-R interval can often exceed 120 ms
- non-conducted PACs can often be buried in the T-wave if occurrign late int eh cardiac cycle
- P-wave is typically different from teh p-wave of the dominating rhythm indicating different focus or origin
- Cause - may situations
- infection
- inflammation
- MI
- anxiety
- excessive caffeine
- illicit drugs
- Clinical features
- can precipitate the occurrence of SVT
- Treatment
- do not generally require therapy except in symptomatic persons, then beta blocker or calcium channel blocker can be attempted

Describe the characteristics of Atrial Flutter
Rate?
How common are they?
Origination?
ECG?
Causes?
- Rate
- 250-350 bpm
- Frequency
- less common than atrial fibrillation
- Origination
- Reentrant tachycardia in the right atrium
- use 2 similar circuits clockwise (upright waves) or counterclockwise (inverted waves) around the tricuspid annulus
- rates and flutter pattern consistent and predictable
- Reentrant tachycardia in the right atrium
- ECG
- Regulat “saw-tooth” flutter waves without isoelectric wave between flutter waves
- seen best in II, III, aVF, or V1
- Atrial conduction to ventricular conduction
- Regulat “saw-tooth” flutter waves without isoelectric wave between flutter waves
- Causes
- reentry without significant heart disease
- septal defects
- pulmonary emboli
- mitral or tricuspid stenosis and regurgitation
- heart failure
- scaring from previous ablations
- aging
- toxic & metabolic derangements
- thyrotoxicosis, alcoholism, pericarditis

What are things to be aware of during an physical exam on a patient with atrial flutter?
- anxious patient
- may be hypotensive
- rapid flutter waves in the jugular venous pulse
- palpable pulse is typically regular
- EKG consistent with regularly regular sawtooth flutter waves
Treatment/Management for Atrial Flutter?
- Carotid massage or adenosine can slow rate but rarely terminates
- Acute therapy: rate vs. rhythm
- early restoration of sinus rhythm preferred
- IV beta or calcium channel blockers, amiodarone, digoxin
- if pharmacological agents not tolerated, direct cardioversion
- If rhythm initiated by acute event (sepsis, surgery, etc) treatment for up to 1 month
- Therapy for transient, chronic episodes
- long term oral beta-blocker, calcium channel blocker, amiodarone, flecainide, sotalol
- similar to treatment for trial fibrillation
- requires anticoagulation
- definitive treatment is catheter ablation
Describe the characteristics of Atrial Fibrillation
Clinical Presentation?
ECG?
Causes?
Treatment?
- Clinical Presentation
- chaotic atrial rhythm relted to continuous, variable activation of the atria
- recurrent, paroxysmal, perisistent or permanent
- ECG
- irregularly irregular QRS comlplexes on ECT with no distinct P-waves
- rates are variable & can fluctuate widely
- Cause
- higher risk with age & other chronic conditions
- can be heriditary
- Treatment
- similar to atrial flutter
- anticoagulation based on risk for stroke
- CHADS2
- CHA2DS2-VASc


















