CHAPTER 17: SUPRAVENTRICULAR TACHYARRHYTHMIAS

I. Physiologic sinus tachycardia

 Defining feature: normal sinus mechanism precipitated by exertion, stress, concurrent illness (Table 17-2)

II. Pathologic supraventricular tachycardia

 A. Tachycardia originating from the atrium

Defining feature: tachycardia may continue despite beats that fail to conduct to the ventricles, indicating that the AV node is not participating in the tachycardia circuit

 1. Inappropriate sinus tachycardia

Defining feature: tachycardia from the normal sinus node area that occurs without an identifiable precipitating factor as a result of dysfunctional autonomic regulation

 2. Focal atrial tachycardia

Defining feature: Regular atrial tachycardia with defined p wave; may be sustained, nonsustained, paroxysmal, or incessant. Frequent sites of origin occur along the valve annuli of left or right atrium, pulmonary veins, coronary sinus musculature, superior vena cava

 3. Atrial flutter – macroreentrant atrial tachycardia

Defining feature: organized reentry creates organized atrial activity, commonly seen as sawtooth flutter waves at rates typically faster than 200 beats/min

  a. Common atrial flutter

   i. Right atrial reentry parallel to the tricuspid annulus and dependent on conduction through the isthmus between the inferior vena cava and tricuspid annulus

    1. Counterclockwise (as viewed from the ventricular aspect)

    2. Clockwise

  b. Atypical atrial flutter

   i. Usually due to reentry in left or right atrium associated with scars usually from prior surgery or catheter ablation for atrial fibrillation, but may be idiopathic

 4. Atrial fibrillation

Defining feature: chaotic rapid atrial electrical activity with variable ventricular rate; the most common sustained cardiac arrhythmia in older adults

 5. Multifocal atrial tachycardia

Defining feature: multiple discrete p waves often seen in patients with pulmonary disease during acute exacerbations of pulmonary insufficiency

 B. AV nodal reentry tachycardia

Defining feature: paroxsymal regular tachycardia with P waves visible at the end of the QRS complex or not visible at all; the most common paroxysmal sustained tachycardia in healthy young adults; more common in women

 C. Tachycardias associated with accessory atrioventricular pathways

  a. Orthodromic AV reentry tachycardia

Defining feature: paroxysmal sustained tachycardia similar to AV nodal reentry; during sinus rhythm, evidence of ventricular preexcitation may be present (Wolff-Parkinson-White syndrome) or absent (concealed accessory pathway)

  b. Preexcited tachycardia

Defining feature: wide QRS tachycardia with QRS morphology similar to VT

  1. Antidromic AV reentry – regular paroxysmal tachycardia

  2. Atrial fibrillation with preexcitation–irregular wide complex, or intermittently wide complex tachycardia, some with dangerously rapid rates faster than 250/min

  3. Atrial tachycardia or flutter with preexcitation