EKG

Narrow Complex Tachycardia

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Narrow Complex Tachycardia, Supraventricular Tachycardia, Paroxysmal Supraventricular Tachycardia, PSVT

  • Definition
  1. Rapid heart rhythms originating in the atrium or atrioventricular node
  2. Transmit via the bundle of His and result in rapid ventricular response
  • Epidemiology
  1. Prevalence: 2-3 per 1000 persons (U.S.)
  2. Age (mean): 45 years old
  3. Gender: Women represent 62% of cases
  • Causes
  • Narrow Complex Tachycardia (Mnemonic: 5H 5T PS)
  1. Similar list to Reversible Causes of Cardiopulmonary Arrest (5H5T)
  2. Hypoxemia
  3. Hypovolemia
  4. Hyperthermia
  5. Hyperkalemia
  6. Hypokalemia
  7. Tamponade (Cardiac Tamponade)
  8. Tension Pneumothorax
  9. Toxins, medications and drugs
    1. Caffeine
    2. Tobacco
    3. Alcohol
    4. Pseudophedrine (or other Sympathomimetics)
  10. Thrombus
    1. Myocardial Infarction
    2. Pulmonary Embolism
  11. Pain or Stress
  12. Structural abnormalities (especially in children)
    1. Hypertrophic Cardiomyopathy
    2. Congenital Heart Disease
  • Types
  • Narrow Complex Tachycardia
  1. Sinus Tachycardia
  2. Supraventricular Tachycardia
    1. Atrioventricular Nodal Reentry (AVNRT)
      1. Signal down the slow AV nodal pathway and retrograde up the fast AV nodal pathway
      2. In 10% of cases, the signal reentry route is reversed
    2. Atrioventricular Reciprocating Tachycardia (AVRT)
      1. Includes Wolff-Parkinson-White Syndrome (characterized by delta wave)
      2. Accessory pathway outside the AV node
        1. Orthodromic (narrow complex): Signal down the AV node and up the accessory path
        2. Antidromic (wide complex): Signal down the accessory path and up the AV node
    3. Atrial Tachycardia (AT)
      1. Abnormal focus of atrial automaticity (outside the SA node)
      2. Unlike AVNRT and AVRT, no accessory pathway is involved
  3. Other Atrial Tachycardias with rapid ventricular response
    1. Atrial Fibrillation
    2. Atrial Flutter
  • Differential Diagnosis
  • Adults - Narrow Complex Tachycardia (key question is 'regular or irregular')
  1. Sinus Tachycardia (regular)
  2. Irregular Supraventricular Tachycardia (may also present as wide complex if aberrancy)
    1. Atrial Fibrillation
  3. Regular Supraventricular Tachycardia
    1. Atrial Flutter
    2. Atrioventricular Nodal Reentry (AVNRT): 60% of SVT cases (esp. women)
    3. Atrioventricular Reciprocating Tachycardia (AVRT): 30% of SVT cases
    4. Atrial Tachycardia (AT): 10% of SVT cases
  • Differential Diagnosis
  • Children - Narrow Complex Tachycardia
  1. Common
    1. Orthodromic Atrioventricular Reciprocating Tachycardia (Orthodromic AVRT, or ORT)
      1. Most common in children (typical, narrow complex SVT)
    2. Atrioventricular Nodal Reentry (AVNRT)
      1. Second most common SVT in children (but rare in young children)
  2. Uncommon
    1. Ectopic Atrial Tachycardia
      1. Similar to sinus rhythm except for altered P Wave appearance and more rapid rate
    2. Atrial Flutter (uncommon in children outside the newborn period)
    3. Atrial Fibrillation (very rare in children)
  3. Congenital Heart Disease history
    1. CHD predisposes patients to scarring with risk of reentrant pathways
    2. Intra-atrial reentrant Tachycardia (IART)
      1. Appears similar to Atrial Flutter
      2. Typically treated with rate control on Diltiazem (if over age 2-5 years), followed by cardioversion
  • History
  1. Timing
    1. Rapid onset and resolution
      1. Supraventricular Tachycardia
    2. Slow onset and resolution
      1. Sinus Tachycardia
  2. Precipitating factors
    1. Caffeine or stimulants, stress
      1. Supraventricular Tachycardia or Sinus Tachycardia
    2. Cardiovascular disease or onset with activity
      1. Ventricular Tachycardia
  • Symptoms
  • Episodic
  1. Anxiety
  2. Chest pressure
  3. Dyspnea
  4. Fatigue
  5. Light headed
  6. Palpitations
  1. Sinus Tachycardia
    1. P Waves present and normal
      1. At higher rates P Wave may be hidden in T Wave
      2. Look for high frequency notching within the T Wave to suggest a hidden P Wave
    2. Variable R-R with constant PR interval
    3. Heart Rate varies with activity
    4. Rate lower than PSVT
      1. Infants < 220 (may approach this with fever)
      2. Children < 180
      3. Adults < 160
  2. Supraventricular Tachycardia
    1. P Waves absent or abnormal
    2. Fixed Heart Rate (constant R-R)
    3. Abrupt rate change
    4. Rate higher than Sinus Tachycardia (especially if Heart Rate twice normal for age or higher)
      1. Infants > 220
      2. Children > 180
      3. Adults > 160
  • Management
  • Stable Patients
  1. New emphasis on use of one Antiarrhythmic
    1. Contrast to prior Antiarrhythmic soups
    2. Pro-arrhythmic effects increase with poly-drugs
  2. Supraventricular Tachycardia Management in the Adult
  3. Supraventricular Tachycardia Management in the Child
  • Management
  • Unstable Patients
  1. Uncertain diagnosis or management
  2. Recurrent Supraventricular Tachycardia refractory to medications
  3. High risk profession or activity (e.g. truck driver, airline pilot, rock climbing, Scuba Diving)
  4. Ablation considered over medication (patient preference)
  5. Wolff-Parkinson-White Syndrome (characterized by delta wave)
  6. Structural heart disease (e.g. Hypertrophic Cardiomyopathy)
  7. Syncope associated with Supraventricular Tachycardia
  8. Wide complex on EKG