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Background New methods based on nonlinear theory have been developed to give more insight into complex heart rate (HR) dynamics. This study was designed to test the hypothesis that altered HR dynamics, as analyzed with complexity and fractal measures, may precede the spontaneous onset of paroxysmal atrial fibrillation (PAF). Secondly, the difference in the temporal change of these measurements between the different types of atrial fibrillation (AF) was assessed. Methods and Results From 105 Holter tapes in which PAF was recorded, 44 PAF (≥5 min) episodes in 33 patients (22 men, 58±12 years), preceded by sinus rhythm for more than 1 h, were selected and submitted to timeand frequency-domain HR variability analyses, along with detrended fluctuation analysis, approximate entropy (ApEn) and sample entropy (SampEn). The 60 min before the onset of AF were divided into 6 10-min periods and studied using repeated measures ANOVA. PAF episodes were divided into 3 subgroups: an increased HF component and decreased L/H ratio (vagal type, n=20); increased L/H ratio and decreased HF component (sympathetic type, n=14); and non-related type (n=10). None of the time-or frequency-domain parameters showed any significant change before AF in any type of AF. The 1 showed a tendency to decrease before the onset of AF and the change in 1 was divergent according to the AF type. The ApEn decreased before the onset of AF (1.005±0.046, 60-50 min before AF to 0.894±0.052, 10-0 min before AF; p=0.032). The SampEn also decreased progressively before the start of AF (1.165± 0.085, 60-50 min before AF to 0.887±0.077, 10-0 min before AF, p=0.003). The decrease in both the ApEn and SampEn was irrespective of the AF type. Conclusions A reduction in the ApEn and SampEn, which reflects the nonlinear complexity of HR variability, is a hallmark of altered HR dynamics preceding the spontaneous onset of AF. (Circ J 2006; 70: 94 -99)

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To compare the change in lipoprotein metabolism with aging, we analyzed the lipid and protein compositions of individual lipoprotein fractions. Healthy and nonobese elderly participants (elderly group, n = 26) had a serum lipid profile within the normal range, although slightly higher than in young participants (control group, n = 18). However, the elderly group had a twofold higher serum uric acid level and triglyceride (TG):high-density lipoprotein cholesterol ratio. The elderly group had less antioxidant ability and elevated TG content in high-density lipoprotein (HDL) with enhanced cholesteryl ester transfer activity. An elevated level of advanced glycated end products in lipoproteins and fragmentation of apoA-I were present in the elderly group, with detected lower apoA-I level and more multimerized apoA-I in HDL. The protein levels of apoA-I, apoC-III, and serum amyloid A in lipoprotein-deficient serum were increased in the elderly group.

The results of this study show that although women have a higher in-hospital mortality than men, female gender itself is not an independent risk factor for in-hospital mortality.