The Problem of Highlighting Benign Nonsustained Supraventricular Tachycardias on Heart Rhythm Monitoring Reports

Dear Readers,

The term paroxysmal supraventricular tachycardia (PSVT) has been used to refer to arrhythmias such as atrioventricular (AV) nodal reentrant tachycardia (AVNRT), AV reentrant tachycardia (AVRT) using an accessory pathway, and atrial tachycardia (AT). The diagnostic term PSVT is used to differentiate these rhythms from other forms of supraventricular tachycardia (SVT) such as sinus tachycardia, atrial fibrillation (AF), and atrial flutter. Although some of these other SVTs such as AF are also paroxysmal, using the term PSVT has come to imply that the patient has an arrhythmia that can be treated with vagal maneuvers, terminated with adenosine, prevented with beta-blockers, and is amenable to catheter ablation. The safety and efficacy of catheter ablation for the treatment of PSVT has been well established—the message that patients with recurrent episodes of PSVT, especially when refractory to medical therapy, should be considered for ablation has been heard by the medical community.

Patients with PSVT typically present with recurrent episodes of rapid, regular, paroxysmal palpitations that can last for minutes to hours. They are most commonly diagnosed with PSVT when they present to the emergency department with sustained tachycardia that is documented on a 12-lead electrocardiogram (ECG). When patients are treated with intravenous adenosine for termination, a 12-lead rhythm strip is also used sometimes to document the termination.

As cardiac rhythm recording devices have become ubiquitous and more convenient, many more patients with palpitations are now able to effectively correlate their symptoms with their rhythm, especially for patients with brief episodes. Many of these patients have struggled for years to get an ECG performed before arrhythmia termination. For patients with very infrequent symptoms, handheld devices or smart watches can be used to catch the arrhythmia. These recording devices, however, have led to the documentation of brief arrhythmias that have minimal or no clinical significance. As an example, patients with palpitations can now wear a heart monitor for up to 2 weeks. These patients will almost certainly have some premature atrial and ventricular beats, asymptomatic AV nodal Wenckebach when sleeping, and short runs of AT. Often, these findings have nothing to do with the patient’s symptoms. Therefore, it is critical that the ordering physician or nurse carefully review the results of the monitor with the patient to correlate any reported symptoms in the diary with the recorded rhythms and determine if any of the abnormalities are clinically significant.

When patients wear a monitor and even a very brief episode of AT is recorded, they are often diagnosed with PSVT. Many of these patients are then referred to an electrophysiologist. At times, patients arrive to their appointment expecting that an ablation procedure is indicated to treat their palpitations, even though these arrhythmias are usually not the source of their symptoms. Even when they are the source, they are very rarely amenable to ablation.

One factor that aggravates the problem of short episodes of AT being referred unnecessarily to cardiologists and electrophysiologists is the final report format of the Holter or event recorder. For many heart rhythm monitoring devices, the final report is intended to emphasize critical arrhythmias such as long pauses, heart block, ventricular tachycardia, and AF, which are highlighted on the cover of the report. Unfortunately, any SVT lasting more than 3 beats is also highlighted (Figure).

It is not clear why 4-beat runs of AT are so prominently displayed on Holter monitor reports, but it has definitely led to an overemphasis of these arrhythmias, meaningless diagnoses of SVT, and unnecessary referrals to specialists. Brief runs of AT are almost always benign and rarely require further evaluation, but doctors and nurses ordering these reports react to what is highlighted in these final reports.

These reports need to change. At the very least, highlighting episodes of AT lasting <30 seconds should be discontinued. Although changing the format of Holter and event reports may require companies to obtain approval by the United States Food and Drug Administration, placing importance on nonsustained AT in the final reports will continue to result in confusion and misdiagnosis of PSVT, resulting in unnecessary health care resource utilization.

Disclosures: Dr Knight reports that he has served as a consultant, speaker, investigator, and/or has received EP fellowship grant support from Abbott, AtriCure, Baylis Medical, Biosense Webster, Biotronik, Boston Scientific, CVRx, Medtronic, Philips, and Sanofi. He has no equity or ownership in any of these companies.