Background: The Valsalva Maneuver (VM) is the first-line treatment for paroxysmal supra-ventricular tachycardia, but a recent, novel, and efficient tool to restore sinus rhythm has been described, i.e., the Reverse Valsalva (RV). This study aims to compare changes in cardiovascular hemodynamics and autonomic system activity (ANS) based on heart rate variability (HRV) analysis during both maneuvers.
Methods: Fifteen healthy participants performed the VM and RV maneuvers three times in a sitting position for durations of 15 s and 10 s, respectively. Blood pressure (BP) and heart rate (HR) were continuously monitored before, during and after the tests. Autonomic system activity was evaluated using frequency-domain analysis of HRV.
Results: The decrease in HR from baseline to the lowest values, expressed as a ratio, was similar during both maneuvers (0.81 during the RV vs. 0.79 during the VM, p = 0.27). However, the final lowest HR in response to the RV was higher than that in response to the VM, 70/min vs. 59/min (p <0.001). The activation of the autonomic nervous system during the most bradycardic phase of the RV (phase II) and VM (phase IV) showed that the total power of HRV was less prominent during the RV than during the VM (p <0.012), with similar levels of parasympathetic activation. Conclusions: Our results showed less HR slowdown during the RV than during the VM. The changes in HRV parameters during both procedures in particular phases of the RV and VM suggest that the auto-nomic nervous system is activated alternately, so these tests can be used complementarily in a clinical setting with different results.

Microvascular angina (MVA) is a condition characterized by the presence of angina-like chest pain, a positive response to exercise stress tests, and no significant stenosis of coronary arteries in coronary angiography, with absence of any other specific cardiac diseases. The etiology of this syndrome is still not known and it is probably multifactorial. Coronary microvascular dysfunction is proposed as the main pathophysiological mechanism in the development of MVA. Altered somatic and visceral pain perception and autonomic imbalance, in addition to myocardial ischemia, has been observed in subjects with MVA, involving dynamic variations in the vasomotor tone of coronary microcirculation with consequent tran-sient ischemic episodes. Other theories suggest that MVA may be a result of a chronic inflammatory state in the body that can negatively influence the endothelium or a local imbalance of factors regulating its function. This article presents the latest information about the epidemiology, diagnostics, etiopathogen-esis, prognosis, and treatment of patients with MVA.