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  • Supraventricular Arrhythmias

    Jennifer Salotto, MD

    Trauma, Acute Care Surgery, & Surgical Critical Care Fellow

    SCC Lecture Series

    January 2015

  • Objectives:

    Review anatomy and physiology of cardiac conduction system.

    Define supraventricular arrhythmia.

    Describe the initial approach to a patient with an arrhythmia.

    Discuss diagnosis and treatment options for patients with atrial fibrillation, atrial flutter, and supraventricular tachycardia.

  • Cardiac arrhythmias

    Caused by a derangement in electrical impulse initiation, conduction, or both

    Classified as:

    Brady (100bpm)

    Tachyarrythmias categorized by location of origin of irregular impulse:

    Above the AV node (supraventricular)

    Below the AV node (ventricular)

  • Cardiac Conduction System.

    SA node= pacemaker

    Generates cardiac impulse, automaticity

    Jxn SVC and RA

    RCA in 60%

  • Cardiac Conduction System.

    SA node -> atria

    ->atrioventricular node

    AV node controls

    atrial impulse tx to

    ventricles, thus

    regulating speed of

    atrial and ventricular contractions

  • Cardiac Conduction System.

    AV node to

    intraventricular septum

    via bundle of His

    R, L BB

    Purkinje fibers

    Activate ventricles

  • Cardiac Conduction System.

    Heavy innervation from sympathetic and parasympathetic nervous system determines heart rate and speed of contraction

    Sympathetic:Epinephrine, NE act on adrenergic receptors.Faster conduction,Increased impulse generation.

    Parasympathetic:Vagus nerve releasesacetylcholine, whichacts on muscarinicreceptors.Slows sinus nodeimpulse generationand conductionthru AV node.

  • Factors promoting arrhythmias in surgical pts:

    Iatrogenic Factors: Patient Factors:

    volume overload

    direct manipulation of the heart

    intravascular catheters


    cardiopulmonary bypass

    Underlying structural abnormalities




    Electrolyte imbalances

    Excess sympathetic tone

  • What is supraventricular arrhythmia?

    Abnormal impulse arises above bundle of His

    Require atrial or AV nodal tissue to initiate & maintain,d.aWw&psig=AFQjCNEn9NaDxRaMUAbGENr0e35cEIkrdw&ust=1420659441706519,d.aWw&psig=AFQjCNEn9NaDxRaMUAbGENr0e35cEIkrdw&ust=1420659441706519

  • Supraventricular arrhythmias

    Atrial tachycardia

    Atrial fibrillation

    Atrial flutter

    Supraventricular tachycardia

    AV nodal re-entrant (60%)

    Atrioventricular reentry, accessory pathway (30%)

  • Initial evaluation

    Vital Signs: stable vs. unstable

    History & Physical Exam


    Other diagnostic modalities

  • Stable vs. Unstable

    The urgency of therapy depends on hemodynamic stability.

    If unstable address ABCs first

    and brady: call for external pacers

    and wide QRS: call for defibrillator

    All patients:

    Consider underlying ischemia or heart failure

    Telemetry and pulse oximetry

  • Stable vs. Unstable

    The hemodynamic impact of an arrhythmia depends on:

    the ventricular response

    preservation of cardiac output

    degree of underlying structural or ischemic disease

  • History

    Family or personal history of arrhythmia, ischemic disease, valvular disease

    Assess recent medications


    Chest pain, SOB, palpitations, presyncope, syncope

    Above may occur w/ any arrhythmia

  • Physical Exam



    Pulses, IVs


    Regular or irregular? Murmur?



  • Look at the monitor.

    Supraventricular arrhythmia:

    Rapid, narrow QRS complex (

  • Diagnosis

    Progress from simple to invasive testing.

    EKG is the first line in diagnosis.

    Early in evaluation , address underlying abnormalities which may be triggers:

    Ischemia (EKG)

    Hypercarbia (ABG)

    Proarrhythmic drugs

    Electrolytes (BMP)

    Malpositioned catheter (CXR)

  • Electrocardiogram

    Conduction velocityThrough AV Node

  • EKG and Supraventricular Arrhythmia Assess QRS: wide vs. narrow

    Wide: ventricular arrhythmia, but also SVA w/ bundle block or accessory pathway

    Look for presence of P waves

    No p waves- suspect A fib.


    300 bpm suggests atrial flutter

    More P waves than QRS: AV block

    SA node firing but signal not conducting


  • Other diagnostic modalities


    Evaluates for functional and structural abnormalities


    Thyroid function tests

    EP Studies:

  • Supraventricular arrhythmias

    Atrial tachycardia

    Atrial fibrillation

    Atrial flutter


    AV nodal re-entrant (60%)

    Atrioventricular reentry, accessory pathway (30%)

  • SVA: Atrial Fibrillation

    MC post-op arrhythmia

    Impulse above bundle of His -> disorganized atrial activity, dyssynchrony of contraction between atrium and ventricle

    Loss of atrial kick and reduced CO

    No reserve = unstable

    Stasis leads to thromboembolic even