Cardiac arrhythmia, specifically paroxysmal supraventricular tachycardia (SVT), accounts for
a substantial proportion of emergency medical services resources utilization. Restoring a
normal sinus rhythm (reconversion) should be done quickly and effectively. Reconversion
requires increasing the atrioventricular node's refractoriness, which can be achieved by
vagal maneuvers, pharmacological agents, or electrical cardioversion.
The Valsalva Maneuver (VM) is a commonly used non-invasive reconversion method. It increases
myocardial refractoriness by increasing intrathoracic pressure for a brief period, thus
stimulating baroreceptor activity in the aortic arch and carotid bodies, resulting in
increased parasympathetic (vagus nerve) tone. The effectiveness of conventional vagal
maneuvers in terminating SVT, when correctly performed, shows a considerable variation
ranging from 19.4% to 54.3%. To improve the effectiveness of the Valsalva Maneuver, the
Modified Valsalva Maneuver (MVM) was introduced. While the standard VM is performed when the
patient is in a sitting position (45°-90°), the modified VM involves having the patient sit
up straight and perform a forced expiration for about 15 seconds, after which the patient is
brought into a supine position with the legs raised (45°) for another 15 seconds. This
modification should increase relaxation, phase venous return, and vagal stimulation. A recent
meta-analysis demonstrated a significantly higher success rate for reconversion to sinus
rhythm when using the MVM compared to the standard VM in patients with an SVT (Odds Ratio =
4.36; 95 percent c.i. 3.30 to 5.76; P < .001). More adverse events were reported in the MVM
group, although this difference is not significant (Risk Ratio = 1.48; 95 percent c.i. 0.91
to 2.42; P = .11). The available evidence suggests that medication use was lower in the MVM
group than in the standard VM group. However, medication use could not be generalized across
the different studies. None of the included studies in this review showed a significant
difference in length of stay in the emergency department (ED). Hence, the gain of
implementing MVM is a higher rate of success with non-invasive reconversion methods. While
the available evidence is highly suggestive of supporting the use of the MVM compared to the
standard VM in the treatment of adult patients with SVT, implementation seems difficult.
Current evaluations, such as the 'gold-standard' randomised controlled trial (RCT) design,
rarely adequately or even explicitly address the context-specific drivers behind
implementation outcomes and their relationship to the underlying programme theory, making it
difficult to interpret their findings in light of other programmes in different settings. As
a result, few evaluation strategies are widely accepted as appropriate. The net benefit of
interventions and understanding how variable outcomes are achieved remains empirically
uncertain. Therefore, it is essential to develop comprehensive, rigorous, and practical
methods to evaluate people-centred quality improvement programmes, inform the selection of
effective and efficient interventions, and facilitate improvement and scaling-up. In
evaluating such complex interventions, the Medical Research Council (MRC) argues for the
importance of process evaluation in conjunction with outcome evaluation to account for
variability in implementation. The MRC's process evaluation framework guides evaluators to
understand the implementation processes (what is implemented and how), mechanisms of
intervention (how the delivery of the intervention produces change) and contextual factors
that affect implementation and outcomes.
Research question This study aimed to evaluate a quality improvement program to improve the
non-invasive care for patients with paroxysmal supraventricular tachycardia in the emergency
department.