Supraventricular Tachyarrhythmias

Supraventricular Tachyarrhythmias is a topic covered in the Washington Manual of Medical Therapeutics.

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General Principles

  • Supraventricular tachyarrhythmias (SVT) are often recurrent, rarely persistent, and frequently a cause of visits to emergency departments and primary care physician offices.
  • The evaluation of patients with SVT should always begin with prompt assessment of hemodynamic stability and clinical status.
  • The diagnostic and therapeutic discussion that follows is aimed at the hemodynamically stable patient. If a patient is deemed clinically unstable based on clinical signs and symptoms, one should immediately proceed to cardioversion per ACLS guidelines.

Definition

  • Tachyarrhythmias that require atrial or AV nodal tissue or both for their initiation and maintenance are termed SVT.
  • The QRS complex in most SVTs is narrow (QRS <120 ms). However, SVTs can present as a wide-complex tachycardia (QRS ≥120 ms) if they are aberrantly conducted or in an accessory pathway–mediated tachycardia.

Classification

  • SVT is initially classified by ECG in an effort to understand the likely underlying arrhythmia mechanism.
  • A diagnostic approach, based on the ECG, is summarized in Figure 7-1.
    Figure 7-1 Diagnostic approach to tachyarrhythmias.
    Descriptive text is not available for this image

    AF, atrial fibrillation; AFL, atrial flutter; AT, atrial tachycardia; AV, atrioventricular; AVNRT, atrioventricular nodal reentrant tachycardia; AVRT, atrioventricular reentrant tachycardia; EAT, ectopic atrial tachycardia; MAT, multifocal atrial tachycardia; O-AVRT, orthodromic AVRT; PAC, premature atrial complex; SANRT, sinoatrial nodal reentrant tachycardia; ST, sinus tachycardia; SVT, supraventricular tachyarrhythmia; VT, ventricular tachycardia; WPW, Wolff-Parkinson-White.

  • Narrow QRS complex tachyarrhythmias can be divided into those arrhythmias requiring only atrial tissue for initiation and maintenance (atrial tachycardia [AT], AF, and AFL) versus those that require the AV junction for perpetuation (JT, AVNRT, and AVRT).
  • Paroxysmal SVT specifically refers to intermittent SVT other than AF, AFL, and multifocal AT (MAT).

Epidemiology

  • The estimated prevalence of paroxysmal SVT in the normal population is 2.25/1000, with an incidence of 35/100,000 person-years.1
  • In the absence of structural heart disease, SVT most commonly presents between the ages of 12 and 30.1
  • Women are twice as likely to develop SVT as men.1

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General Principles

  • Supraventricular tachyarrhythmias (SVT) are often recurrent, rarely persistent, and frequently a cause of visits to emergency departments and primary care physician offices.
  • The evaluation of patients with SVT should always begin with prompt assessment of hemodynamic stability and clinical status.
  • The diagnostic and therapeutic discussion that follows is aimed at the hemodynamically stable patient. If a patient is deemed clinically unstable based on clinical signs and symptoms, one should immediately proceed to cardioversion per ACLS guidelines.

Definition

  • Tachyarrhythmias that require atrial or AV nodal tissue or both for their initiation and maintenance are termed SVT.
  • The QRS complex in most SVTs is narrow (QRS <120 ms). However, SVTs can present as a wide-complex tachycardia (QRS ≥120 ms) if they are aberrantly conducted or in an accessory pathway–mediated tachycardia.

Classification

  • SVT is initially classified by ECG in an effort to understand the likely underlying arrhythmia mechanism.
  • A diagnostic approach, based on the ECG, is summarized in Figure 7-1.
    Figure 7-1 Diagnostic approach to tachyarrhythmias.
    Descriptive text is not available for this image

    AF, atrial fibrillation; AFL, atrial flutter; AT, atrial tachycardia; AV, atrioventricular; AVNRT, atrioventricular nodal reentrant tachycardia; AVRT, atrioventricular reentrant tachycardia; EAT, ectopic atrial tachycardia; MAT, multifocal atrial tachycardia; O-AVRT, orthodromic AVRT; PAC, premature atrial complex; SANRT, sinoatrial nodal reentrant tachycardia; ST, sinus tachycardia; SVT, supraventricular tachyarrhythmia; VT, ventricular tachycardia; WPW, Wolff-Parkinson-White.

  • Narrow QRS complex tachyarrhythmias can be divided into those arrhythmias requiring only atrial tissue for initiation and maintenance (atrial tachycardia [AT], AF, and AFL) versus those that require the AV junction for perpetuation (JT, AVNRT, and AVRT).
  • Paroxysmal SVT specifically refers to intermittent SVT other than AF, AFL, and multifocal AT (MAT).

Epidemiology

  • The estimated prevalence of paroxysmal SVT in the normal population is 2.25/1000, with an incidence of 35/100,000 person-years.1
  • In the absence of structural heart disease, SVT most commonly presents between the ages of 12 and 30.1
  • Women are twice as likely to develop SVT as men.1

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