Heart rate variability and red cell distribution width in patients with systolic left heart failure

Heart rate variability and hematological parameters in pregnant women

Background

There are few researches on hematological parameters (hemoglobin, red cell distribution width [RDW], white blood cells [WBCs], mean platelets volume [MPV], and heart rate variability [HRV]). There are no published data on this concept (HRV and hematological parameters) during pregnancy.

Methods

A cross‐sectional study was conducted at Saad Abul Ela hospital in Khartoum, Sudan during the period of July to August 2018. Pregnant women with singleton, a live baby, were enrolled in this study. Clinical history and examination were performed. HRV (autonomic modulation) was assessed using time and frequency domain HRV indices.

Results

One hundred and five pregnant women were enrolled. The median (quartile) of the age, parity, and gestational age was 30.0 (25.0‐35.0) years, 1.0 (0‐3.0), and 38.0 (32.0‐39.0) weeks, respectively. While there were positive correlations between hemoglobin and low frequency (LF), RDW and high frequency (HF), WBCs and HF Norm, WBCs and LF/HF, MPV and HF Norm, LF Norm and LF/HF, there was no significant correlation between the hematological (hemoglobin, WBCs, RDW, and MPV) and HRV parameters. Linear regression analysis showed no significant association between age, parity, gestational age, body mass index, hemoglobin, RDW, and HRV variables. The Log₁₀ WBCs were negatively associated with Log₁₀ HF (ms²/Hz). MPV was positively associated with LF Norm and negatively associated with HF Norm.

Conclusion

The study failed to show significant associations between age, parity, gestational age, hemoglobin, RDW, and HRV variables. The WBCs were negatively associated with HF. MPV was positively associated with LF Norm, and it was negatively associated with HF Norm.

Red Blood Cell Distribution Width is Independently Correlated With Diurnal QTc Variation in Patients With Coronary Heart Disease

To investigate the relationship between red blood cell distribution width (RDW) and diurnal corrected QT (QTc) variation in patients with coronary heart disease. This retrospective study included 203 patients who underwent coronary angiography between February 2013 and June 2014. RDW values and dynamic electrocardiography (Holter) results were collected to investigate the relationship between RDW and diurnal QTc variation. Patients were separated into three groups (A, B, and C) by binning their RDW values in an ascending order. RDW values, coronary artery scores and diurnal QTc variations were significantly different among these groups (P < 0.05). While coronary artery scores gradually rose with increased RDW, diurnal QTc variation decreased. Pearson's correlation analysis was applied to control for confounding factors, and multiple correlation analysis showed that coronary artery score was positively correlated with RDW (r = 0.130, P = 0.020), while it was not correlated with the diurnal QTc variation (r = -0.226, P = 0.681). RDW was negatively correlated with diurnal QTc variation (r = -0.197, P = 0.035). RDW is independently associated with diurnal QTc variation in patients with coronary heart disease.

Association between red cell distribution width and the risk of heart events in patients with coronary artery disease

Red cell distribution width (RDW) has been found to be a novel prognostic biomarker in patients with coronary artery disease (CAD); however, the association between RDW and the risk of heart events in patients with CAD is yet to be fully elucidated. Thus, the aim of the present study was to determine whether an elevated RDW was associated with the Framingham risk score (FRS) in patients with CAD. Data were retrospectively collected from Affiliated Dongyang Hospital of Wenzhou Medical University (Dongyang, China). The patients had undergone a coronary angiography and their clinical data were integrated. The patients (male, 260; female, 132) were divided into two groups based on the results of the coronary angiography, namely the CAD (n=283) and control groups (n=109). The FRS was calculated for all the subjects, and complete blood count testing with biochemical measurements was performed. The mean RDW level was 13.7±1.8% in the CAD group and 13.1±1.0% in the control group, while the mean FRS was 9.0±4.9 in the CAD group and 6.4±3.9 in the control group. The RDW and FRS were significantly higher in the CAD group compared with the control group (P<0.001). No statistically significant differences were observed between the groups with regard to the hematocrit, mean corpuscular volume, platelets, glucose, urea, albumin, aspartate aminotransferase, total cholesterol, triglycerides (TG), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and N-terminal pro-brain natriuretic peptide (P>0.05). The RDW was shown to significantly correlate with the red blood cell (RBC) count (r=-0.133, P=0.029), hemoglobin level (r=-0.207, P=0.001) and TG level (r=0.226, P<0.001) within the laboratory parameters, as well as the FRS (r=0.206, P<0.001). In the stepwise multivariate linear regression, which included the RBC count, hemoglobin level, TG level and RDW, the FRS was predicted by hemoglobin (r²=0.034, P=0.001), TG (r²=0.059, P<0.001) and RDW (r²=0.030, P=0.003) parameters. Therefore, a novel association was revealed between higher levels of RDW and an elevated FRS in patients with CAD, which raises the possibility that a simple marker, RDW, may be associated with an increased risk of heart events in CAD patients.

Red blood cell distribution width: A simple parameter with multiple clinical applications

The red blood cell distribution width (RDW) is a simple and inexpensive parameter, which reflects the degree of heterogeneity of erythrocyte volume (conventionally known as anisocytosis), and is traditionally used in laboratory hematology for differential diagnosis of anemias. Nonetheless, recent evidence attests that anisocytosis is commonplace in human disorders such as cardiovascular disease, venous thromboembolism, cancer, diabetes, community-acquired pneumonia, chronic obstructive pulmonary disease, liver and kidney failure, as well as in other acute or chronic conditions. Despite some demographic and analytical issues related to the routine assessment that may impair its clinical usefulness, an increased RDW has a high negative predictive value for diagnosing a variety of disorders, but also conveys important information for short- and long-term prognosis. Even more importantly, the value of RDW is now being regarded as a strong and independent risk factor for death in the general population. Although it has not been definitely established whether an increased value of RDW is a risk factor or should only be considered an epiphenomenon of an underlying biological and metabolic imbalance, it seems reasonable to suggest that the assessment of this parameter should be broadened far beyond the differential diagnosis of anemias. An increased RDW mirrors a profound deregulation of erythrocyte homeostasis involving both impaired erythropoiesis and abnormal red blood cell survival, which may be attributed to a variety of underlying metabolic abnormalities such as shortening of telomere length, oxidative stress, inflammation, poor nutritional status, dyslipidemia, hypertension, erythrocyte fragmentation and alteration of erythropoietin function. As such, the aim of this article is to provide general information about RDW and its routine assessment, to review the most relevant implications in health and disease and give some insights about its potential clinical applications.

Red cell distribution width, haemoglobin A1c and incidence of diabetes mellitus

OBJECTIVE

Hyperglycaemia has multiple effects on the red blood cell (RBC), including glycation of haemoglobin, reduced deformability and reduced lifespan. Red cell distribution width (RDW) is a measure of the heterogeneity of erythrocyte volumes. The aim of this study was to explore the relationships between RDW and glucose, haemoglobin A1c (HbA1c) and incidence of diabetes mellitus (DM).

DESIGN, SETTING AND SUBJECTS

RDW and mean corpuscular volume were measured in 26 709 non-diabetic participants (aged 45-73 years) from the population-based Malmö Diet and Cancer cohort. HbA1c and fasting venous blood glucose levels were measured in 4845 subjects.

MAIN OUTCOME MEASURE

Incidence of DM (n = 2944) over 14 years of follow-up was studied by linkage with national and local DM registers.

RESULTS

Individuals with low RDW had significantly higher risk of developing DM [adjusted hazard ratio (HR) 1.48, 95% confidence interval (CI) 1.29-1.70, for 1st vs. 4th quartile], especially in subjects with impaired fasting glucose (n = 416) (HR 2.15, 95% CI 1.12-4.14). Low RDW was also associated with significantly higher waist circumference and glucose, insulin and triglyceride concentrations. By contrast, RDW was significantly and positively associated with HbA1c, corresponding an increase in HbA1c of 0.10% per 1 SD increase in RDW.

CONCLUSION

Low RDW is associated with increased incidence of DM independently of other risk factors. We propose that low RDW could be a surrogate marker of reduced RBC survival, with lower HbA1c due to shorter duration of glucose exposure. RDW is a biomarker that could improve risk assessment for individuals at risk of developing DM.

Red cell distribution width in relation to incidence of coronary events and case fatality rates: a population-based cohort study

AIMS

High red cell distribution width (RDW) is a strong prognostic factor in patients with cardiovascular disease. We investigated the association between RDW and incidence of acute coronary events (CEs) and fatal outcome in subjects who subsequently experienced a first CE.

METHODS AND RESULTS

RDW was measured in 26 820 subjects (aged 45-73 years, 61.6% women), without history of myocardial infarction or stroke, who participated in the Malmö Diet and Cancer study during 1991-1996. Cox proportional hazards model was used to analyse the association between RDW and CE. During a mean follow-up of 14 years, 1995 subjects had a first CE, of which 415 subjects died on the same day as the CE (fatal on day 1), another 86 died within 28 days (fatal in 28 days) and 1494 were non-fatal (survived >28 days). After adjustment for risk factors, baseline RDW was significantly associated with incidence of fatal CE (HR 1.82, CI 1.35 to 2.44) but not with non-fatal CE (HR 0.96, CI 0.82 to 1.12). Among all subjects with a CE during follow-up, the proportion who died on day 1 was 13.7%, 18.2%, 22.5% and 26.7%, respectively, for first, second, third and fourth quartiles of RDW.

CONCLUSIONS

In this population-based study of subjects without history of CE or stroke, high RDW was associated with increased incidence of fatal CE. No relationship was observed for incidence of non-fatal CE.

Red blood cell distribution width is associated with incidence of atrial fibrillation

OBJECTIVES

Red blood cell distribution width (RDW), a measure of variation in erythrocyte volume, has been associated with several cardiovascular disorders, but the relationship with atrial fibrillation (AF) remains unclear. We investigated the association between RDW and incidence of first hospitalization due to AF in a population-based cohort.

DESIGN

Red blood cell distribution width was measured in 27,124 subjects from the general population (age 45-73 years, 62% women) with no history of AF, heart failure, myocardial infarction or stroke. The association between baseline RDW and incidence of AF identified from the Swedish Hospital Discharge Register was evaluated.

RESULTS

During a mean follow-up of 13.6 years, 1894 subjects (53% men) were hospitalized with a diagnosis of AF. After adjustment for potential confounding factors, including cardiovascular disease risk factors, nutrient intake (iron, vitamin B12 and folate) and several haematological parameters (haemoglobin concentration, mean corpuscular volume and corpuscular haemoglobin content), the hazard ratio (HR) for incidence of AF was 1.33 [95% confidence interval (CI) 1.16-1.53] for the fourth versus first quartile of RDW (P for trend <0.001). The results were essentially unchanged when subjects with incident myocardial infarction or hospitalizations because of heart failure were censored from the analysis (HR 1.30, 95% CI 1.13-1.51; P for trend = 0.001).

CONCLUSION

Red blood cell distribution width was associated with incidence of AF independently of several cardiovascular, nutritional and haematological factors in this study of middle-aged subjects from the general population.