Loss of fractal heart rate dynamics in depressive hemodialysis patients.

Objective: To assess the relationship between depression, reduced heart rate (HR) variability, and altered HR dynamics among patients with end-stage renal disease who are receiving hemodialysis (HD) therapy.

Methods: We analyzed the 24-hour electrocardiograms of 119 outpatients receiving chronic HD. HR variability was quantified with the standard deviation of normal-to-normal R-R intervals, the triangular index, and the powers of the high- (HF), low- (LF), very-low (VLF), and ultra-low frequency (ULF) components.

Myocardial radial strain in early diastole is useful for assessing left ventricular early diastolic function: comparison with invasive parameters.

Background: Peak myocardial systolic strain determined using myocardial strain imaging is a useful index of left ventricular (LV) myocardial systolic function. We investigated the relationship between peak myocardial radial strain during early diastole and LV early diastolic function.

Methods: A total of 85 patients without localized LV wall-motion abnormality underwent myocardial strain imaging and diagnostic cardiac catheterization.

Lack of inertia force of late systolic aortic flow is a cause of left ventricular isolated diastolic dysfunction in patients with coronary artery disease.

Objectives: We investigated whether a lack of inertia force of late systolic aortic flow and/or apical asynergy provoke early diastolic dysfunction in patients with coronary artery disease (CAD).

Background: Left ventricular (LV) isolated diastolic dysfunction is a well-recognized cause of heart failure.

Methods: We evaluated LV apical wall motion and obtained left ventricular ejection fraction (LVEF) by left ventriculography in 101 patients who underwent cardiac catheterization to assess CAD.

Both HDL3 and HDL2 exert a powerful anti-oxidative and protective effect against acceleration of oxidative modification of LDL by ascorbic acid.

The objective of the present study was to establish whether high-density lipoprotein 3 (HDL3) or high-density lipoprotein 2 (HDL2) might show an anti-oxidative effect on the acceleration of the oxidative modification of low-density lipoprotein (LDL) by ascorbic acid from measurement of the agarose gel electrophoretic mobility of LDL. LDL was incubated without adding transitional-metal ions for 48 or 96 h in phosphate-buffered saline (PBS) alone, with ascorbic acid (20 microg/mL), or with both ascorbic acid (20 microg/mL) and HDL3 (200 microg protein/mL). The LDL autoxidation occurred in PBS alone.

Usefulness of plasma brain-type natriuretic peptide level to differentiate left ventricular diastolic dysfunction from preserved diastolic function in patients with systolic dysfunction.

The extent of left ventricular (LV) diastolic dysfunction is related to the finding that some patients with cardiomegaly due to LV systolic dysfunction have good exercise tolerance, although others have limited tolerance. A brain-type natriuretic peptide level of >/=104 pg/ml reliably enables the detection of relatively worse LV diastolic function in patients with systolic dysfunction, and this value may provide clinically useful information for the management of patients with cardiomegaly.

Tl-201 washout rate in remote normal regions in patients with prior myocardial infarction and left ventricular remodeling.

Background: Myocardial characteristics of remote normal regions in patients with myocardial infarction (MI) and left ventricular (LV) remodeling have not been fully elucidated. Thus, we investigated this issue from the viewpoint of myocardial Tl-201 dynamics.

Methods And Results: In 14 patients with prior anterior MI, 10 with inferior MI, and 14 age-matched patients with atypical chest pain served as controls; exercise stress Tl-201 SPECT and cardiac catheterization were performed.

1/f scaling in heart rate requires antagonistic autonomic control.

We present systematic evidence for the origins of 1/f -type temporal scaling in human heart rate. The heart rate is regulated by the activity of two branches of the autonomic nervous system: the parasympathetic (PNS) and the sympathetic (SNS) nervous systems. We examine alterations in the scaling property when the balance between PNS and SNS activity is modified, and find that the relative PNS suppression by congestive heart failure results in a substantial increase in the Hurst exponent H towards random-walk scaling 1/ f(2) and a similar breakdown is observed with relative SNS suppression by primary autonomic failure.

Critical scale invariance in a healthy human heart rate.

We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.

Two cases with renal infarction diagnosed in the early course using contrast-enhanced CT.

We experienced two cases of renal infarction with atrial fibrillation who presented with acute abdominal pain. On initial urinalysis, both patients showed no hematuria, but the plasma lactate dehydrogenase level was markedly elevated with little or no rise in plasma transaminases. Their diagnosis was confirmed by contrast-enhanced CT of the abdomen on the second and third days of the crisis.

Prognostic value of nonlinear heart rate dynamics in hemodialysis patients with coronary artery disease.

Background: Although altered nonlinear heart rate dynamics predicts death in patients with coronary artery disease (CAD), its prognostic value in chronic hemodialysis patients with CAD is unknown.

Methods: We analyzed 24-hour electrocardiogram for nonlinear heart rate dynamics and heart rate variability in a retrospective cohort of 81 chronic hemodialysis patients with CAD.

Results: During a follow-up period of 31 +/- 20 months, 19 cardiac and 8 noncardiac deaths were observed.

Prognostic value of heart rate variability in patients with end-stage renal disease on chronic haemodialysis.

Background: Although decreased heart rate variability (HRV) is an independent predictor of death in various populations, its prognostic value in patients with end-stage renal disease on chronic haemodialysis is unknown.

Methods: We prospectively studied 120 chronic haemodialysis patients (age 61+/-11 years; males 51%; diabetics 38%; duration of haemodialysis therapy 50+/-114 months) who underwent 24 h electrocardiography at baseline for analysis of time- and frequency-domain HRV.

Results: All HRV measures in the patients were significantly reduced compared with those obtained from 62 age-matched healthy subjects.

Circadian rhythm of atrioventricular conduction predicts long-term survival in patients with chronic atrial fibrillation.

The R-R interval of the electrocardiogram during atrial fibrillation (AF) appears absolutely irregular. However, the Poincaré plot of the R-R interval reveals a sector shape of distribution that is unique to AF. Furthermore, the height of lower envelope (LE1.