Researchers in Poland explored cardiovascular autonomic dysfunction in patients with myasthenia gravis (MG) by utilizing various testing methods and published their results in the Journal of Clinical Medicine. They included 38 patients with MG whose cardiovascular autonomic testing results were compared with those of 30 age- and gender-matched controls.
The study recorded participants’ cardiovascular parameters, baroreflex sensitivity (BRS), spectral indices of short-term heart rate (HRV), and systolic blood pressure variability (SBPV). Researchers also assessed cardiac autonomic function during the response to standing (tilt) and deep breathing tests (expiration/inspiration ratio-E/I).
They found that patients with MG, as compared to controls, had altered SBPV at rest, significantly reduced heart rate response to the deep breathing test, increased sympathovagal balance after tilt, and lower values of BRS and hemodynamic parameters, which include a cardiac index, index contractility, left ventricular work index, at rest and during tilt.
The study also noted that disease severity was an independent predictor of diminished vagal tone (E/I ratio) and increased sympathetic response to tilt (delta LF/HF-RRI) as measured with HRV. There was no significant difference in heart rate and blood pressure responses to the tilt test between the 2 groups, nor between disease duration and autonomic parameters.
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The study highlights the importance of evaluating patients with MG for symptoms of cardiac autonomic dysfunction. Cardiac autonomic dysfunction in patients with MG can be life threatening, and this study provides valuable insight into cardiovascular parameters that can potentially influence morbidity and mortality in MG.
Zawadka-Kunikowska M, Rzepiński Ł, Tafil-Klawe M, Klawe JJ, Zalewski P, Słomko J. Association of cardiac autonomic responses with clinical outcomes of myasthenia gravis: short-term analysis of the heart-rate and blood pressure variability. J Clin Med. 2022;11(13):3697. doi:10.3390/jcm11133697