めまい患者の自律神経機能-心電図RR間隔の周波数スペクトル分析による静的,経時的および動的分析ー Autonomic Nervous Function in Patients with Vertigo-Evaluation for Static Function, Variation and Dynamic Change Using Power Spectral Analysis of RR Intervals-
自律神経機能障害が原因と思われるめまい症例94例に対し, 心電図RR間隔の周波数スペクトル分析を用いて, 安静時, 安静時から起立後の経時的な変動ならびに起立負荷時の自律神経機能を測定した. そして, 脈波伝播速度 (PWV) と心電図RR間隔の変動係数 (CV<SUB>RR</SUB>) の自律神経機能の結果と比較した. その結果, 安静時のスペクトル分析の結果はPWV, CV<SUB>RR</SUB>の結果とよく類似していた. また, 特に正常では起立時に亢進すべき交感神経機能がPWV, CV<SUB>RR</SUB>での交感神経亢進・副交感神経低下例では逆に低下していた. すなわち, 安静時よりすでに過度の交感神経亢進状態にあったものが起立刺激によって突然著しく低下したため, めまいが誘発されたものと考えられた.
Power spectral analysis of RR intervals (PSA) of 94 vertiginous patients with associated autonomic nervous dysfunction (AND group), 31 patients with vertebro-basilar insufficiency (VBI group) and 25 controls were analyzed in supine and upright positions. In addition, static function, variation from the supine to the upright position and dynamic change in autonomic nervous function (ANF) from the supine to the upright position were examined. Heart rate was recorded for 120 seconds in the supine and 40 seconds in the upright position. RR intervals for each 20-second period were computed using FFT (Fast Fourier Transformation), and the ratio of low frequency power (0.05-0.15Hz) to high frequency power (0.15-0.4Hz) (L/H) of PSA were analyzed as an index of sympathetic activity. The PSA was examined by the following three parameters; L/H at rest during the 80-second period from 20 to 100 seconds (static function), the L/H variation between each 20-second period from 0 to 160 seconds (variation) and the ratio of L/H to that in the upright position (dynamic change). The results of PSA were compared with those of pulse wave velocity (PWV) and the coefficient of variation of the RR interval (CV<SUB>RR</SUB>), and association between attacks of vertigo and ANF was determined. The results of static function of PSA and the results of PWV and CV<SUB>RR</SUB> were very similar, indicating that both methods are useful for evaluating ANF in vertiginous patients. In the AND group, the variation in sympathetic activity tended to be larger in patients with sympathetic hyperfunction and parasympathetic hypofunction and in the patients with sympathetic hypofunction and parasympathetic hyperfunction resulting from PWV and CV<SUB>RR</SUB>, than in the controls. The dynamic change in patients with sympathetic hyperfunction and parasympathetic hypofunction resulting from PWV and CV<SUB>RR</SUB> was also significantly lower than that in the controls (p<0.01). Some patients in the AND group already showed excessive sympathetic hyperfunction at rest, and changing the position from supine to upright might trigger sympathetic hypofunction, causing an attack of vertigo. The PSA results in the VBI group were similar to those in the controls, suggesting that sympathetic dysfunction did not affect VBI-induced vertigo.
日本耳鼻咽喉科學會會報 100(4), 457-466, 1997-04-20