Atrial Tachycardia Differential Diagnoses

Updated: Nov 16, 2019
  • Author: Bharat K Kantharia, MD, FRCP, FAHA, FACC, FESC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Diagnostic Considerations

The differential diagnosis of atrial tachycardia is the differential diagnosis of supraventricular tachycardia (SVT) and includes the following:

  • Sinus tachycardia

  • Atrial flutter (see the image below)

  • Atrial fibrillation

  • Atrioventricular (AV) junction–dependent reentrant tachycardias (AV nodal reentrant tachycardia and AV reentrant tachycardia using an accessory pathway)

    Atrial tachycardia. This image shows an example of Atrial tachycardia. This image shows an example of rapid atrial tachycardia mimicking atrial flutter. A single radiofrequency application terminates the tachycardia. The first three tracings show surface electrocardiograms, as labeled. AblD and AblP = distal and proximal pair of electrodes of the mapping catheter, respectively; HBED and HBEP = distal and proximal pair of electrodes in the catheter located at His bundle, respectively; HRA = high right atrial catheter; MAP = unipolar electrograms from the tip of the mapping catheter; RVA = catheter located in right ventricular apex.

Note that "non-paroxysmal” junctional tachycardia is not an atrial tachycardia, but it can easily be confused with one. The distinction is made either on the basis of an electrophysiologic study or by a spontaneous tracing showing atrial dissociation, but with a QRS complex that is identical with that observed in sinus rhythm. With the popularity and rise in ingestion of "energy drinks," it is possible that the incidence of non-paroxysmal junctional tachycardia may increase.

Differentiating among these diagnoses requires electrocardiographic (ECG) analysis of the tachycardia for P wave activity. In SVT, the ECG typically has narrow QRS complexes (unless aberrant conduction with typical left or right bundle-branch block occurs or a bystander preexcitation is seen).

Assessment of the relationship of the P waves to the QRS complex (R waves) can help to guide diagnosis. A short RP interval (P wave immediately following the QRS) suggests different causes of the tachycardia than does a long RP interval (interval wave preceding QRS).

In short RP interval SVT, the differential diagnosis includes the following:

  • Typical AV nodal reentrant tachycardia

  • AV reentrant tachycardia using accessory pathways

  • Atrial tachycardia with long first-degree AV block

  • Atrial tachycardia originating from the os of the coronary sinus or junctional tachycardia

To determine the diagnosis requires additional maneuvers, such as vagal stimulation (eg, carotid sinus massage, Valsalva maneuver), or adenosine.

In long RP interval SVT, the differential diagnosis includes the following:

  • Atypical (fast-slow) AV nodal reentrant tachycardia

  • Permanent junctional reciprocating tachycardia (PJRT) due to a slowly conducting retrograde accessory pathway

  • Atrial tachycardia

  • Sinus tachycardia

  • Sinus node reentry

  • Atrial flutter

  • AV reentrant tachycardia

Diagnosis requires assessment of the patient condition, vagal maneuvers, adenosine, and cardioversion—namely, procedures that may not only be diagnostic but also therapeutic.

For multifocal atrial tachycardia (MAT), the differential diagnosis includes atrial fibrillation because both can manifest with an irregular pulse. MAT with aberration or preexisting bundle branch block may be misinterpreted as ventricular tachycardia (VT).

However, if the patient also has new signs or symptoms (eg, chest pain, unexplained dyspnea, inappropriate hypotension) or a recent illness, perform a more extensive workup because atrial tachycardia may not be the primary problem; acute pulmonary embolus, acute noncardiac illness, thyroid disease, or drugs (especially sympathomimetics or bronchodilators) can cause atrial tachycardia. In addition, with frequent or incessant tachycardia, tachycardia-induced cardiomyopathy may develop.

Another tachycardia that mimics atrial tachycardia is inappropriate sinus tachycardia. Strictly speaking, inappropriate sinus tachycardia and postural orthostatic tachycardia syndrome (POTS) are not atrial tachycardias, because their origin is not abnormal. They are sinus tachycardias related to enhanced sinus automaticity, abnormal autonomic function (dysautonomia), or physiologic reflexes

Differential Diagnoses