A new approach to interpreting the LF/HF ratio: a study in hypertensive patients

Resistant arterial hypertension (RHTN) has been associated with sympathetic hyperactivity, which represents a significant challenge in the management and treatment of arterial hypertension. In the present study, autonomic modulation was analysed in hypertensive, resistant hypertensive, and refractory hypertensive patients, compared to a group of apparently healthy normotensive individuals. Participants with resistant hypertension were included only after the exclusion of secondary hypertension and pseudo-resistance diagnoses. Heart rate variability (HRV) analysis included parameters from the time domain, frequency domain, and nonlinear methods, providing a comprehensive assessment of global autonomic modulation. The results demonstrated a significant reduction in global HRV across all three hypertensive groups, evidenced by decreases in parameters from the time domain, frequency domain and nonlinear methods. Furthermore, a concomitant reduction in the low- and high-frequency components was observed, with the decrease in the high-frequency component being more pronounced. These findings challenge the traditional view of isolated sympathetic hyperactivity in hypertension. Instead, the results reveal a relative predominance of sympathetic function due to the more marked attenuation of parasympathetic activity. These results underscore the need to reinterpret autonomic dysfunction in arterial hypertension, particularly in its more severe forms, as a global loss of autonomic modulation.