In the absence of significant pathophysiological finding, abnormal neural control of the atria is considered to be one of the mechanisms of atrial fibrillation. In this study sympatho-vagal balance at sinus node of 35 patients (19 M, 57±12 years) with recurrent paroxysmal atrial fibrillation (P) was assessed by measuring the changes induced by passive tilt on spectral profile of RR interval series. Power spectral densities were estimated by applying an autoregressive model. 28 age-matched (12 M, 52±13 years) healthy volunteers were considered as control (C). In both P and C the mean cycle length was reduced by tilt (P: 924.8±118.9 ms vs. 799.7±119.2 ms, p<0.0001, C: 938.12±179.8 ms vs. 775.8±146.0 ms, p=0.001). While in C low-high frequency power ratio (LF/HF) increased after tilt from 2.5±2 to 10.3±7 (p<0.0001), no significant changes were found in the overall P patients (from 5.5±14 to 8.6±11). In a sub-group of P patients (14/35) LF/HF power ratio decreased from 8.7±9 to 3.4±3, (p=0.05). This sub-group of P patients was characterized in basal condition by a reduced variability. (SD: 25.5±9 ms vs. 38.7±16 ms, p=0.01) and a higher LF/HF ratio than C (8.7±9 vs. 2.5±2, p=0.02). Spectral analysis allow to select a subgroup (40%) of P patients showing an anomalous response to sympathetic stimulation and alterated basal tone. Thus, disorder in autonomic control is documented in a fraction of P patients, which may have an implication on the occurrence and symptomatology of paroxysmal atrial fibrillation
Abnormal neural control in paroxysmal atrial fibrillation assessed by spectral analysis of RR intervals during passive tilt
Nollo, Giandomenico;Ravelli, Flavia;
1999-01-01
Abstract
In the absence of significant pathophysiological finding, abnormal neural control of the atria is considered to be one of the mechanisms of atrial fibrillation. In this study sympatho-vagal balance at sinus node of 35 patients (19 M, 57±12 years) with recurrent paroxysmal atrial fibrillation (P) was assessed by measuring the changes induced by passive tilt on spectral profile of RR interval series. Power spectral densities were estimated by applying an autoregressive model. 28 age-matched (12 M, 52±13 years) healthy volunteers were considered as control (C). In both P and C the mean cycle length was reduced by tilt (P: 924.8±118.9 ms vs. 799.7±119.2 ms, p<0.0001, C: 938.12±179.8 ms vs. 775.8±146.0 ms, p=0.001). While in C low-high frequency power ratio (LF/HF) increased after tilt from 2.5±2 to 10.3±7 (p<0.0001), no significant changes were found in the overall P patients (from 5.5±14 to 8.6±11). In a sub-group of P patients (14/35) LF/HF power ratio decreased from 8.7±9 to 3.4±3, (p=0.05). This sub-group of P patients was characterized in basal condition by a reduced variability. (SD: 25.5±9 ms vs. 38.7±16 ms, p=0.01) and a higher LF/HF ratio than C (8.7±9 vs. 2.5±2, p=0.02). Spectral analysis allow to select a subgroup (40%) of P patients showing an anomalous response to sympathetic stimulation and alterated basal tone. Thus, disorder in autonomic control is documented in a fraction of P patients, which may have an implication on the occurrence and symptomatology of paroxysmal atrial fibrillationI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
