Archive for the ‘Heart’ Category - Part 4

Postural Response of Low-Frequency Component of Heart Rate Variability: Prognostic Value of Reduced HF

The relationships between autonomic neural activities and HRV also could be influenced by medications and respiratory parameters. An increase in breathing frequency and a decrease in tidal volume reduce the HF without changing the mean cardiac vagal tone. Indeed, in earlier clinical studies with ambulatory monitoring, the HRV measures showing the strongest predictive power were […]

Postural Response of Low-Frequency Component of Heart Rate Variability: Discussion

Major Findings This study demonstrated that the postural response of HRV assessed under well-controlled conditions predicts the risk for cardiac death during long-term follow-up in patients with CAD. We observed that an increased postural response of the LF predicts an increased risk for cardiac death during 8-year follow-up of patients with CAD. The prognostic association […]

Postural Response of Low-Frequency Component of Heart Rate Variability: Survival Analysis

Univariate Cox regression analysis of baseline clinical features revealed that age, previous myocardial infarction, reduced ejection fraction, and the number of diseased coronary arteries were associated with increased risks for cardiac death and that age was associated with noncardiac death (Table 3). Although no significant association with a risk for death was detected for heart […]

Postural Response of Low-Frequency Component of Heart Rate Variability: Results

Follow-up Results During a mean follow-up period of 99 ± 23 months (follow-up range, 14 to 131 months), 25 patients (10%) died. Thirteen patients died from cardiac causes (acute myocardial infarction, 9 patients; sudden cardiac death, 4 patients), and 12 died from noncardiac causes (fatal stroke, 6 patients; malignancies, 3 patients; renal failure, 1 patient; […]

Postural Response of Low-Frequency Component of Heart Rate Variability: Statistical Analysis

Power spectral density was computed by a 256-point fast-Fourier transformation, was corrected for loss of variance resulting from the sampling and filtering processes described earlier, and was integrated by > 0.04 to 0.15 Hz, 0.20 to 0.30 Hz, and 0.00 to 0.50 Hz, respectively, for obtaining the LF, the HF, and the total power. The […]

Postural Response of Low-Frequency Component of Heart Rate Variability: HUTT and Analysis of HRV

The protocol of HUTT and the method of HRV analysis at baseline have been reported previously. Briefly, patients were asked to avoid cigarette smoking and beverages containing caffeine after 8:00 pm the day preceding the HUTT. The test was performed in an air-conditioned room (temperature range, 23°C to 24°C) between 2:30 and 3:30 pm and […]

Postural Response of Low-Frequency Component of Heart Rate Variability: Control Subjects

After discharge from the hospital, all patients were observed and medically treated by cardiologists in the Nagoya City University Hospital or by their family doctors. In 1999, the medical records were reviewed for cardiovascular events, intervention therapies, and medications. Furthermore, after obtaining written informed consent, the patients or their families were interviewed by telephone about […]

Postural Response of Low-Frequency Component of Heart Rate Variability: Materials and Methods

Patients We studied retrospectively a cohort of 250 consecutive patients (181 men and 69 women) who were admitted to the Nagoya City University Hospital for elective cardiac catheterization and coronary angiography between November 1987 and February 1991. During the hospital admission, we had assessed short-term HRV during HUTT during previous studies on the relationships between […]

Postural Response of Low-Frequency Component of Heart Rate Variability

Decreased heart rate variability (HRV) is associated with an adverse prognosis in patients with coronary artery disease (CAD). This association has been ascribed to the harmful effects of cardiac vagal dysfunction and/or the resulting relative sympathetic overactivity. However, with few exceptions, most earlier studies that reported the prognostic value of HRV have been based on […]

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