Head Down Deep Breathing for Cardioversion of Paroxysmal Supraventricular Tachycardia

The use of vagal manoeuvres in narrow complex tachyarrhythmias in primary care

Supraventricular tachydysrhythmias (SVTs) are a common presenting complaint, with a national prevalence of 3/1000 persons. While most commonly stable, prolonged paroxysms can deteriorate into haemodynamically unstable subtypes or ventricular dysrhythmias. Early recognition with appropriate management is critical to reducing the morbidity associated with this condition. The American Heart Association holds that vagal manoeuvres are a first-line therapy in the management algorithm of stable SVTs. However, they state that no clear recommendations can be made around which manoeuvre to use, highlighting that future research should examine the efficacy and safety profiles of the various manoeuvres. In the South African primary care setting, clinicians must be at the forefront of pragmatic management strategies in the face of resource limitations, such as the unavailability of adenosine - a second-line therapy when vagal manoeuvres fail. In this article, we begin with a case study and review the literature around vagal manoeuvres.

Randomised Controlled Trial Assessing Head Down Deep Breathing Method Versus Modified Valsalva Manoeuvre for Treatment of Supraventricular Tachycardia in the Emergency Department

INTRODUCTION

Supraventricular tachycardia (SVT) is commonly encountered in the emergency department (ED). Vagal manoeuvres are internationally recommended therapy in stable patients. The head down deep breathing (HDDB) technique was previously described as an acceptable vagal manoeuvre, but there are no studies comparing its efficacy to other vagal manoeuvres. Our objective in this study was to compare the rates of successful cardioversion with HDDB and the commonly practiced, modified Valsalva manoeuvre (VM).

METHODS

We conducted a randomised controlled trial at an acute hospital ED. Patients presenting with SVT were randomly assigned to HDDB or modified VM in a 1:1 ratio. A block randomisation sequence was prepared by an independent biostatistician, and then serially numbered, opaque, sealed envelopes were opened just before the intervention. Patients and caregivers were not blinded. Primary outcome was cardioversion to sinus rhythm. Secondary outcome(s) included adverse effects/complications of each technique.

RESULTS

A total of 41 patients were randomised between 1 August, 2018-1 February, 2020 (20 HDDB and 21 modified VM). Amongst the 41 patients, three spontaneously cardioverted to sinus rhythm before receiving the allocated treatment and were excluded. Cardioversion was achieved in six patients (31.6%) and seven patients (36.8%) with HDDB and modified VM, respectively (odds ratio 1.26, 95% confidence interval, 0.33, 4.84, P = 0.733). Seventeen (89.5%) patients in the HDDB group and 14 (73.7%) from the modified VM group did not encounter any adverse effects. No major adverse cardiovascular events were recorded.

CONCLUSION

Both the head down deep breathing technique and the modified Valsalva manoeuvre appear safe and effective in cardioverting patients with SVT in the ED.