Relationship between occlusal force and endothelial function in community-dwelling elderly women: A pilot study.

OBJECTIVE: In this study, age, endothelial function as flow-mediated dilation (FMD), occlusal force, grip strength, and advanced glycation end products (AGEs) were obtained. AGEs were measured as indicators of aging, while grip strength was measured as an indicator of muscle strength. This study aimed to explain the relationship between occlusal force and endothelial function and determine whether occlusal force can be a new indicator in community preventative care projects. MATERIALS AND METHODS: In 38 community-dwelling women (age, 76.7 ± 5.7 years), the occlusal force and grip strength were measured, the endothelial function was evaluated by FMD, and AGEs were obtained. The relationship between occlusal force, measurement items, and factors were investigated independently related to endothelial function. RESULTS: There were significant correlations between occlusal force and grip strength (r = .54, p < .01). The degree of FMD was significantly associated with occlusal force (r = .60, p < .01) and grip strength (r = .35, p < .05) or increase in AGEs (r = -.37, p < .05). Multiple regression analysis revealed that occlusal force was significantly associated with the degree of FMD (p < .01). CONCLUSION: Occlusal force can be an important indicator of endothelial function in the community-dwelling elderly. This study may help understand the general health of the elderly in communities.

Effects of pre-bedtime blue-light exposure on ratio of deep sleep in healthy young men.

This study aimed to investigate the effects of pre-bedtime blue-light exposure on ratio of deep sleep and sleep quality. In this study, 11 healthy young men were exposed to three conditions for 1 h before bedtime: 1) incandescent light, 2) blue-light, or 3) blue light-blocking glasses on. The following morning, subjective sleep quality was measured using the Oguri-Shirakawa-Azumi Sleep Inventory. Sleep time, ratio of sleep, ratio of deep sleep, and body movements during sleep were measured using a mat sleep-scan (sleep scan, SL- 504; TANITA Corp., Japan) and an ambulatory portable sleep study system (LS-140; Fukuda Denshi Co. Ltd., Japan). Ratio of deep sleep was significantly decreased in the blue-light exposure group compared to the groups with incandescent light and blue light-blocking glasses (p < 0.01), There were no differences noted in sleep time or body movements among the three groups. These results suggest that blue-light exposure to affects sleep quality by reducing the ratio of deep sleep.

Effects of maneuver of hair-washing motion and gender on oxygen uptake and ventilation in healthy people.

It is known that patients with chronic obstructive pulmonary disease experience dyspnea during unsupported arm exercise (UAE). We examined the respiratory variables in during a hair-washing motion for healthy young people requiring the UAE to find the effects across gender, motion, and speed. In this study, 33 healthy young people were enrolled. Participants performed the following four types of hair-washing motions: both hands with fast speed, both hands with slow speed, one hand with fast speed, and one hand with slow speed. The respiratory variables such as oxygen uptake ([Formula: see text]O2), carbon dioxide output ([Formula: see text]CO2), and respiratory rate (RR), or minute ventilation ([Formula: see text]E) were measured. Regarding [Formula: see text]O2, [Formula: see text]CO2, and RR during the rest period and in each motion, [Formula: see text]O2 and [Formula: see text]CO2 in males were significantly greater than those in females. RR in the female participants had greater value than that in males. Among the maneuvers, [Formula: see text]O2, [Formula: see text]CO2 or [Formula: see text]E during a hair-washing motion with both hands were greater than those during hair-washing motion with one hand. [Formula: see text]O2, [Formula: see text]CO2, RR, or [Formula: see text]E during a hair-washing motion with both hands fast speed was greater than those during a hair-washing motion with slow speed. In conclusion, this study showed the effects owing to the differences in motion maneuvers and gender during UAE in healthy young people. These suggest a need to consider motion maneuver or gender when teaching motion methods of activities of daily living on the patients.

Dynamic and not static change in ventricular repolarization is a substrate of ventricular arrhythmia on chronic ischemic myocardium.

OBJECTIVE: The restitution mechanism has been the focus of attention as the possible mechanism behind ventricular fibrillation (VF). However, its contribution in chronic ischemic heart has not been established. METHODS: We investigated chronic ischemic dogs with occlusion of left anterior descending artery. Sixty unipolar electrograms were simultaneously recorded from an entire cardiac surface. Activation-recovery intervals (ARIs) and QRST deflection area (AQRST) were measured during constant atrial pacing. The ischemic dogs were divided into two groups, five dogs in VF(+) group or seven dogs in VF(-) group, according to VF occurrence by programmed electrical stimulation. RESULTS: When investigating ARI dispersions on an epicardium, there was no difference between VF(+) and VF(-) groups. The relationship between ARIs and diastolic intervals was quantified as an electrical restitution curve. The slopes of the ARI restitution curve for the anterior left ventricle in VF(+) dogs were significantly steeper than those of VF(-) dogs. The amplitude of AQRST alternans were significantly greater in VF(+) dogs than VF(-) dogs. CONCLUSIONS: Combined observation of steep restitution slopes and increased electrical alternans supported the restitution mechanism as being involved in the arrhythmia. Dynamic restitution properties and not static single-beat ARI dispersion may play an important role in the VF arrhythmia in the chronic ischemic heart.

Lower ankle-brachial index is associated with poor sleep quality in patients with essential hypertension.

BACKGROUND: The ankle-brachial index (ABI), ratio of leg blood pressure to arm blood pressure is used extensively as a screening test for stratification of cardiovascular risk. The problems in sleep disturbed nocturnal fall in blood pressure and may relate to development of hypertension. However, the role of sleep quality on ankle-brachial index remains unclear. METHODS AND RESULTS: This study examined 101 patients with essential hypertension. We analyzed the association with ABI on age, sex, body height, body weight, body mass index, waist circumference, blood pressure, HDL-cholesterol, LDL-cholesterol, HbA1c, sleep quality evaluated by Pittsburgh Sleep Quality Index (PSQI), smoking habits, alcohol habits. The ABI is associated with the following seven parameters; body height (r = 0.36, p < 0.001), body weight (r = 0.30, p < 0.005), systolic BP (r = -0.23, p < 0.05), HbA1c (r = -0.24, p < 0.05), PSQI score (rho = -0.31, p < 0.005), alcohol intake (rho = 0.23, p < 0.05) and sex (F = 6.65, p < 0.05). By a multiple linear regression analysis with ABI as the dependent variable after forcing the seven parameters above into the model, body height, HbA1c and PSQI score were significantly associated with ABI (R (2) for the model = 25%, p < 0.001). CONCLUSION: Poor sleep quality was independently associated with lower ABI in patients with essential hypertension. The results may provide new insight related to the interaction between sleep quality and blood pressure.

Severity in myocardial dysfunction contributed to long-term fluctuation of heart rate, rather than short-term fluctuations.

BACKGROUND: It is known that heart rate shows complex behavior, long-term fluctuation of heart rate, and short-term fluctuations in heart failure. Analyzing these properties and examining the relationship to the disease, severity may increase the understanding of the background of heart rate variability (HRV). METHODS: In 61 patients (mean age 65 +/- 9 years, 32 ischemic heart disease, 29 cardiomyopathy), with myocardial dysfunction, 24-hour ambulatory electrocardiography was performed. After the construction of the time series of R-R intervals, 15 HRV parameters were measured, including mean heart rate, standard deviation of N-N intervals (SDNN), ratio of low frequency/high frequency power (LF/HF), HRV triangular index (TI), and ratio of length/width at the 90% level of all scattered points. RESULTS: By using the multiple regression analysis, we tested which HRV parameter (HR, SDNN, LF/HF, TI, or length/width) independently correlated with left ventricular ejection fraction (EF) or left ventricular diastolic dimension (EDD). The results demonstrated that TI and SDNN independently correlated with EF (multiple R = 0.59). Moreover, TI and SDNN independently correlated with EDD (multiple R = 0.45). CONCLUSION: TI and SDNN were indicators of the disease severity in myocardial dysfunction, while LF/HF, indicators of autonomic tone, did not have such an ability. It was of interest that the disease severity contributed to long-term fluctuations (TI, SDNN) of heart rate, rather than short-term fluctuations (LF/HF).

Restitution properties and occurrence of ventricular arrhythmia in LQT2 type of long QT syndrome.

INTRODUCTION: The aim of this study was to clarify the ventricular tachyarrhythmia mechanism induced by the I(Kr)-blocking agent E4031, simulating the LQT2 form. Electrophysiologic properties were examined in 13 canines before and after administration of E4031. METHOD AND RESULTS: Thirty-six needle electrodes were inserted into the anterior left ventricular wall. From each needle, local unipolar electrograms were obtained from four intramural sites. Activation time (AT) and activation-recovery interval (ARI) were measured. To evaluate the susceptibility to ventricular arrhythmia, intramural ARI dispersions and the restitution relationship between ARI and diastolic interval were calculated. After E4031 administration, ARI prolonged uniformly in each myocardial layer. However, ARI dispersion was not augmented compared with control. The slope of the ARI restitution curve after E4031 was significantly steeper than control. A steep slope may result from augmented ARI alternans. In 11 of the 13 canines, ventricular tachyarrhythmia was induced by programmed stimulation after E4031, whereas no arrhythmia was induced by the same protocol in control. CONCLUSION: Steepness of electrical restitution may play a major role in arrhythmogenicity in LQT2 hearts.

Regional prolongation of ARI and altered restitution properties cause ventricular arrhythmia in heart failure.

The mechanism of arrhythmogenicity in heart failure remains poorly understood. We examined the relationship between electrical abnormalities and ventricular arrhythmia by using experimental heart failure models. Sixty unipolar electrograms were recorded from the entire cardiac surface in control dogs (n = 13) and pacing-induced heart failure dogs (n = 16). In failing hearts, activation time (AT) was delayed at the apex, and AT dispersion increased in failing hearts. Activation-recovery intervals (ARI) were prolonged mainly at the apex and ARI dispersion was significantly augmented. The slope of the ARI restitution curve, interaction of diastolic interval, and ARI in failing hearts was significantly steeper than in control hearts. Ventricular fibrillation (VF) was easily induced by programmed stimulation in failing hearts, whereas no arrhythmia occurred in control hearts. Computer simulation studies could reproduce the experimental results. Altering the ARI restitution to the steep slope causes VF in a model heart. It is suggested that electrical remodeling, especially steepness of electrical restitution, may play a role in arrhythmogenicity in failing hearts.

Improvement of ventricular arrhythmia by octreotide treatment in acromegalic cardiomyopathy.

We report a case of acromegalic cardiomyopathy in a 46-year-old Japanese man with pituitary adenoma. Increased secretion of growth hormone and insulin-like growth factor I were detected. He had left ventricular hypertrophy, impaired cardiac function, and frequent ventricular premature complexes. After 2-month treatment with octreotide, a long-acting somatostatin analogue, levels of both hormones were decreased. At the same time, left ventricular hypertrophy (intraventricular septal thickness: 22.5 to 17.8 mm), cardiac function (ejection fraction: 38 to 50%), and frequency of ventricular premature complexes (17,249 to 2,882 beats a day) were improved. Transsphenoidal surgery was then safely performed. Treatment with octreotide is thought to have some effect on improvement of ventricular arrhythmia in acromegalic heart.