Residual heart rate variability measures can better differentiate patients with acute myocardial infarction from patients with patent coronary artery.

Purpose: It has been shown that the power spectral density (PSD) of heart rate variability (HRV) can be decomposed into a power-law function and a residual PSD (rPSD) with a more prominent high-frequency component than that in traditional PSD. This study investigated whether the residual HRV (rHRV) measures can better discriminate patients with acute myocardial infarction (AMI) from patients with patent coronary artery (PCA) than traditional HRV measures.

Materials And Methods: The rHRV and HRV measures of 48 patients with AMI and 69 patients with PCA were compared.

The use of heart rate variability measures as indicators of autonomic nervous modulation must be careful in patients after orthotopic heart transplantation.

The precise relation between heart rate variability (HRV) and autonomic re-innervation has not been established explicitly in patients after orthotopic heart transplantation (OHT), but can be inferred from the fact that the HRV is reduced immediately after OHT and may increase gradually with time. The aim of this study was to investigate the residual HRV in patients about 1-2 years after OHT, as compared with patients after coronary artery bypass graft (CABG) surgery. Thirteen patients who had received OHT and 14 patients who had received CABG surgery were recruited.

Poincaré plot analysis of autocorrelation function of RR intervals in patients with acute myocardial infarction.

The Poincaré plot of RR intervals (RRI) is obtained by plotting RRIn+1 against RRIn. The Pearson correlation coefficient (ρRRI), slope (SRRI), Y-intercept (YRRI), standard deviation of instantaneous beat-to-beat RRI variability (SD1RR), and standard deviation of continuous long-term RRI variability (SD2RR) can be defined to characterize the plot. Similarly, the Poincaré plot of autocorrelation function (ACF) of RRI can be obtained by plotting ACFk+1 against ACFk.

A comparative study of pulse rate variability and heart rate variability in healthy subjects.

Both heart rate variability (HRV) and pulse rate variability (PRV) are noninvasive means for the assessment of autonomic nervous control of the heart. However, it is not settled whether or not the PRV obtained from either hand can be the surrogate of HRV. The HRV measures obtained from electrocardiographic signals and the PRV measures obtained from the pulse waves recorded from the index fingers of both hands were compared in normal subjects by using linear regression analysis and Bland and Altman method.

Foot reflexology can increase vagal modulation, decrease sympathetic modulation, and lower blood pressure in healthy subjects and patients with coronary artery disease.

Objective: Complementary and alternative medicine (CAM) has long been used by people to postpone the aging process and to reverse disease progression. Reflexology is a CAM method that involves massage to reflex areas in the feet and hands. This study investigated the effect of foot reflexology (FR) on the autonomic nervous modulation in patients with coronary artery disease (CAD) by using heart rate variability analysis.

Power spectral analysis of plethysmographic pulse waveform in pregnant women.

Objective: To investigate the effect of pregnancy on the pulse wave of the mother.

Patients And Methods: Pulse waveforms recorded via a pulse oximeter from the left index finger of non-pregnant women and pregnant women in the three trimesters of pregnancy were Fourier transformed into power spectra. Spectral indices of the power spectra of pulse waveform were obtained and compared among non-pregnant women and pregnant women in the three trimesters of pregnancy.

The effect of ice water ingestion on autonomic modulation in healthy subjects.

Objective: Drinking ice water is a common daily activity. The safety of ice water ingestion has been questioned due to its possible deleterious effect on heart rate or cardiac rhythm, especially in patients with acute myocardial infarction. Thus, we investigated the heart rate variability (HRV) before and after ice water ingestion in normal subjects to delineate the possible effect of ice water ingestion on autonomic nervous modulation.

A multicenter study of the association of serum uric acid, serum creatinine, and diuretic use in hypertensive patients.

Background: Individuals with hypertension and hyperuricemia have an increased risk of coronary artery disease and cerebral vascular disease as compared to patients with normal uric acid levels. Our aim is to determine the prevalence of hyperuricemia in hypertensive patients in Taiwan, and whether serum uric acid (SUA) is associated with changes in renal function in patients with hypertension.

Methods: We studied 2145 hypertensive patients receiving medical treatment, assessed the prevalence of hyperuricemia, and determined the independent risk factors for SUA.

Detrended fluctuation analysis of short-term heart rate variability in late pregnant women.

Spectral analysis of heart rate variability using short or long time series is a common method in the assessment of autonomic nervous activity. Nonlinear method such as detrended fluctuation analysis was proposed and proved to be useful for the possible non-stationary and nonlinear characteristics in the time series of heart period. In this study, we investigated the detrended fluctuation analysis and conventional heart rate variability measures in 16 late pregnant women before and 3 months after delivery and in 16 healthy controls.

Comparison of effect of 5 recumbent positions on autonomic nervous modulation in patients with coronary artery disease.

Background: This study compared the effect of 5 recumbent positions on cardiac autonomic nervous modulation in patients with coronary artery disease (CAD).

Methods And Results: Spectral heart rate variability analysis was performed on 33 CAD patients and 17 patients with patent coronary arteries in random order in 5 positions; namely, supine, right lateral decubitus, left lateral decubitus, left prone and right prone positions. In the right lateral decubitus position, the vagal modulation was the highest and the sympathetic modulation was the lowest among the 5 recumbent positions in the control group.

Abdominal obesity is associated with autonomic nervous derangement in healthy Asian obese subjects.

Background & Aims: Subjects with obesity had autonomic nervous abnormalities. This study investigated autonomic nervous modulation in subjects with obesity and its association with the indices of obesity, especially the body mass index and waist circumference, by heart rate variability analysis.

Methods: Forty-seven adults with a body mass index (in kg/m(2)) greater than 28 were recruited as the obese group and 30 subjects with a body mass index less than 23 were recruited as the control group.

Effect of disease activity and position on autonomic nervous modulation in patients with systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) are known to have lower heart rate variability and impaired vagal modulation, and right lateral position has been shown to lead to a higher vagal modulation than supine position in healthy subjects and patients with cardiovascular diseases. This study evaluated the effect of disease activity and different recumbent positions on cardiac autonomic nervous modulation by heart rate variability analysis in patients with SLE. Thirty-five female patients with SLE and 33 female controls were enrolled in this study.

Hypoxemia and autonomic nervous dysfunction in patients with chronic obstructive pulmonary disease.

Objective: Hypoxemia is known to be associated with abnormal heart rate variability (HRV) that can reflect the severity of the illness and may have prognostic value in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to examine the relationship between the derangements in cardiac autonomic nervous function and the oxygenation status or degree of airflow obstruction in COPD patients by using HRV analysis.

Methods: Thirty clinically stable COPD patients and 18 age-matched normal subjects were included in this study.

Increase in the vagal modulation by acupuncture at neiguan point in the healthy subjects.

Acupuncture at the Neiguan (P6) point has been shown to lessen nausea and vomiting which are related to vagal modulation. This study investigated whether acupuncture at the P6 point could improve vagal modulation by using heart rate variability analysis. We compared the heart rate variability measures of 39 subjects receiving acupuncture at the P6 point, 38 subjects receiving sham acupuncture, and 34 subjects receiving no treatment at all.

Characterization and quantification of the return map of RR intervals by Pearson coefficient in patients with acute myocardial infarction.

The return map is the plot that displays the relationship between a point and its consecutive point in a time series. This study tried to characterize and quantify the return map of RR intervals (RRI) in subjects with patent coronary arteriogram and in patients with acute myocardial infarction (AMI) by using some parameters of linear regression between RRI(n+1) and RRI(n), and compared the newly introduced parameters with the time- and frequency-domain indices of heart rate variability (HRV) obtained from the same RRI. Three quantitative measures were introduced to quantify the return map of RRI: the Pearson coefficient, slope and Y-intercept of linear regression between RRI(n+1) and RRI(n).