Relationship of tachycardia with high blood pressure and metabolic abnormalities: a study with mixture analysis in three populations

Effect of hypertriglyceridemia on left ventricular global longitudinal strain in patients with coronary heart disease in Jilin Province, China: a cross-sectional study

Aims

Using speckle tracking technology to investigate the effect of hypertriglyceridemia on the global longitudinal strain(GLS) of the left ventricle in patients with coronary heart disease in the early stage, and to explore the value of myocardial strain in early identification of cardiac dysfunction in patients with coronary heart disease in the pre-heart failure stage.

Methods

A cross-sectional study of 138 participants was conducted in Jilin Province, China. Basic clinical, biochemical, and echocardiographic data were obtained for all patients. Myocardial strain parameters were compared between the hypertriglyceridemia and normal triglyceride level groups and the effect of hypertriglyceridemia on early left ventricular global longitudinal strain impairment in coronary heart disease patients was evaluated.

Results

The overall longitudinal strain of the left ventricle was smaller in the hypertriglyceridemia group than in the normal triglyceride group. After the multivariate Logistic regression model adjusting for the influence of confounding factors, the results remained stable.

Conclusions

The risk of impairment of global longitudinal strain of the left ventricle in patients with coronary heart disease is positively correlated with triglyceride levels, and hypertriglyceridemia maybe an independent risk factor affecting early cardiac dysfunction in the pre-heart failure stage of patients with coronary heart disease.

Conventional and Bidirectional Genetic Evidence on Resting Heart Rate and Cardiometabolic Traits

CONTEXT

Observational studies have suggested that higher resting heart rate (RHR) may be associated with increased cardiometabolic risk. However, causal associations are not fully understood.

OBJECTIVE

We aimed to examine the direction, strength, and causality of the associations of RHR with cardiometabolic traits.

METHODS

We assessed the strength of associations between measured RHR and cardiometabolic traits in 506 211 and 372 452 participants from China Kadoorie Biobank (CKB) and UK Biobank (UKB). Mendelian randomization (MR) analyses were used to make causal inferences in 99 228 and 371 508 participants from CKB and UKB, respectively.

RESULTS

We identified significant directionally concordant observational associations between RHR and higher total cholesterol, triglycerides (TG), low-density lipoprotein, C-reactive protein (CRP), glucose, body mass index, waist-hip ratio (WHR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) after the Bonferroni correction. MR analyses showed that 10 beat/min higher genetically predicted RHR was trans-ethnically associated with a higher DBP (beta 2.059 [95% CI 1.544, 2.574] mmHg in CKB; 2.037 [1.845, 2.229] mmHg in UKB), higher CRP (0.180 [0.057, 0.303] log mg/L in CKB; 0.154 [0.134, 0.174] log mg/L in UKB), higher TG (0.052 [-0.009, 0.113] log mmol/L in CKB; 0.020 [0.010, 0.030] log mmol/L in UKB) and higher WHR (0.218 [-0.033, 0.469] % in CKB; 0.225 [0.111, 0.339] % in UKB). In the opposite direction, higher genetically predicted SBP, TG, glucose, and WHR, and lower high-density lipoprotein, were associated with elevated RHR.

CONCLUSION

Our large-scale analyses provide causal evidence for associations between RHR and cardiometabolic traits, highlighting the importance of monitoring heat rate as a means of alleviating the adverse effects of metabolic disorders.

Randomized, Placebo-controlled, Dose-escalation, Double-blind Study of Dasiglucagon Effects on QTc in Healthy Volunteers

Background

Dasiglucagon is a novel glucagon analog that is stable in aqueous formulation and approved for use in severe hypoglycemia. Concentration QTc analyses are critical for assessing risk of drug-induced QTc prolongation and potential for fatal cardiac arrhythmias such as torsades de pointes.

Objective

The aim of this study was to determine whether dasiglucagon treatment resulted in any clinically relevant effect on cardiac repolarization in healthy volunteers.

Methods

This double-blind, placebo-controlled, dose-escalation Phase I trial was conducted at a single center in Germany between November 2018 and June 2019. Sixty healthy volunteers aged 18 to 45 years were randomized within dose cohorts to receive intravenous dasiglucagon, intravenous placebo, or subcutaneous dasiglucagon. In the intravenous administration cohorts, doses ranged from 0.03 mg to 1.5 mg. The subcutaneous administration cohort received the approved 0.6 mg dose. In the intravenous administration cohorts, serial electrocardiograms were extracted from continuous Holter monitors at prespecified time points beginning the day before dosing and through 24 hours postdose. Heart rate, PR interval, and QRS duration were evaluated. Concentration-QT analyses corrected by Fridericia's formula (QTcF) were performed using both a linear mixed-effects and a maximum estimated effect (E_max) model.

Results

At the doses studied, dasiglucagon did not have any clinically relevant effect on heart rate, PR interval, or QRS duration. A minor prolongation of the QTcF interval was observed without any clear dose or concentration dependency. Both the linear and E_max models predicted mean and 90% CIs of placebo-corrected change in QTcF remained below 10 ms (the threshold of regulatory concern), although the linear model did not fit the data well at low dasiglucagon plasma concentrations. In the E_max model, the E_max of dasiglucagon was 3.6 ms (90% CI, 1.23–5.95 ms), and the amount to produce half the effect of E_max) was 426.0 pmol/L (90% CI, −48.8 to 900.71 pmol/L). The treatment effect-specific intercept was −0.44 ms (90% CI, −2.37 to 1.49 ms). The most frequently observed treatment-emergent adverse events reported in the trial were gastrointestinal disorders such as nausea and vomiting.

Conclusions

Dasiglucagon does not cause clinically relevant QTc prolongation in concentrations up to ≈30,000 pmol/L, a level 5-fold higher than the highest observed plasma concentrations in clinical trials investigating use of the approved 0.6 mg SC dose. ClinicalTrials.gov Identifier: NCT03735225; EudraCT identifier: 2018-002025-32. (Curr Ther Res Clin Exp. 2022; 83:XXX–XXX)

Associations between sinus tachycardia and adverse cardiovascular outcomes and mortality in cancer patients

Background

Sinus tachycardia in cancer reflects a significant multi-system organ stressor and disease, with sparse literature describing its clinical significance. We assessed cardiovascular (CV) and mortality prognostic implications of sinus tachycardia in cancer patients.

Methods

We conducted a case-control study of 622 cancer patients at a U.S. urban medical center from 2008 to 2016. Cases had ECG-confirmed sinus tachycardia [heart rate (HR) ≥100 bpm] in ≥3 different clinic visits within 1 year of cancer diagnosis excluding a history of pulmonary embolism, thyroid dysfunction, left ventricular ejection fraction <50%, atrial fibrillation/flutter, HR >180 bpm. Adverse CV outcomes (ACVO) were heart failure with preserved ejection fraction (HFpEF), HF with reduced EF (HFrEF), hospital admissions for HF exacerbation (AHFE), acute coronary syndrome (ACS). Regression analyses were conducted to examine the effect of sinus tachycardia on overall ACVO and survival.

Results

There were 51 cases, age and sex-matched with 571 controls (mean age 70±10, 60.5% women, 76.4% Caucasian). In multivariate analysis over a 10-year follow-up period, sinus tachycardia (HR ≥100 vs. <100 bpm) was an independent predictor of overall ACVO (OR 2.8, 95% CI: 1.4–5.5; P=0.006). There was increased incidence of HFrEF (OR 3.3, 95% CI: 1.6–6.5; P=0.004) and AHFE (OR 6.3, 95% CI: 1.6–28; P=0.023), but not HFpEF or ACS (P>0.05) compared with controls. Sinus tachycardia was a significant predictor of overall mortality after adjusting for significant covariates (HR 2.9, 95% CI 1.8–5; P<0.001).

Conclusions

Independent of typical factors that affect cardiovascular disease, sinus tachycardia around the time of cancer treatment is associated with increased ACVO and mortality in cancer patients at 10 years of follow-up.

Chronic stimulation of group II metabotropic glutamate receptors in the medulla oblongata attenuates hypertension development in spontaneously hypertensive rats

Baroreflex dysfunction is partly implicated in hypertension and one responsible region is the dorsal medulla oblongata including the nucleus tractus solitarius (NTS). NTS neurons receive and project glutamatergic inputs to subsequently regulate blood pressure, while G-protein-coupled metabotropic glutamate receptors (mGluRs) play a modulatory role for glutamatergic transmission in baroreflex pathways. Stimulating group II mGluR subtype 2 and 3 (mGluR2/3) in the brainstem can decrease blood pressure and sympathetic nervous activity. Here, we hypothesized that the chronic stimulation of mGluR2/3 in the dorsal medulla oblongata can alleviate hypertensive development via the modulation of autonomic nervous activity in young, spontaneously hypertensive rats (SHRs). Compared with that in the sham control group, chronic LY379268 application (mGluR2/3 agonist; 0.40 μg/day) to the dorsal medulla oblongata for 6 weeks reduced the progression of hypertension in 6-week-old SHRs as indicated by the 40 mmHg reduction in systolic blood pressure and promoted their parasympathetic nervous activity as evidenced by the heart rate variability. No differences in blood catecholamine levels or any echocardiographic indices were found between the two groups. The improvement of reflex bradycardia, a baroreflex function, appeared after chronic LY379268 application. The mRNA expression level of mGluR2, but not mGluR3, in the dorsal medulla oblongata was substantially reduced in SHRs compared to that of the control strain. In conclusion, mGluR2/3 signaling might be responsible for hypertension development in SHRs, and modulating mGluR2/3 expression/stimulation in the dorsal brainstem could be a novel therapeutic strategy for hypertension via increasing the parasympathetic activity.

Resting Heart Rate as a Cardiovascular Risk Factor in Hypertensive Patients: An Update

A large body of evidence has shown that resting heart rate (RHR) holds important prognostic information in several clinical conditions. In the majority of the general population studies, a graded association between RHR and mortality from all causes, cardiovascular (CV) disease, ischemic heart disease, and stroke has been observed. These associations appeared even stronger and more consistent in hypertensive patients. Studies performed with 24-hour ambulatory recording have shown that an elevated nighttime heart rate may confer an additional risk on top of office RHR. The mechanisms by which tachycardia alone or in association with sympathetic overactivity induces CV damage are well understood. Fast RHR is a strong predictor of future hypertension, metabolic disturbances, obesity, and diabetes. Several experimental lines of research point to high RHR as a main risk factor for the development of atherosclerosis, large artery stiffness, and CV disease. Elevated RHR is a common feature in patients with hypertension. Thus, there is a large segment of the hypertensive population that would benefit from a treatment able to decrease RHR. Improvement of unhealthy lifestyle should be the first goal in the management of the hypertensive patient with elevated RHR. Most clinical guidelines now recommend the use of combination therapies even in the initial treatment of hypertension. Although no results of clinical trials specifically designed to investigate the effect of RHR lowering in human beings without CV diseases are available, in hypertensive patients with high RHR a combination therapy including a cardiac slowing drug at optimized dose seems a sensible strategy. Tachycardia can be considered both as a marker of sympathetic overactivity and as a risk factor for cardiovascular events. In this sketch, the main cardiovascular and metabolic effects of increased sympathetic tone underlying high heart rate are shown. The link between tachycardia and cardiovascular events can be explained also by the direct hemodynamic action of heart rate on the arteries and the left ventricular (LV) wall.

The HARVEST. Looking for optimal management of young people with stage 1 hypertension

In the last few decades there has been much debate about the management of low-risk stage 1 hypertension in youth. In this article, we review the main findings of the HARVEST cohort accrued over 30 years, highlighting the contribution of this study to the existing literature. Tachycardia and sympathetic overdrive were closely intertwined in our HARVEST participants, promoting the development of sustained hypertension, metabolic abnormalities, and increased susceptibility to vascular complications. Short-term blood pressure variability in this age group had a prognostic power even greater than that of average 24h blood pressure. In the HARVEST participants, changes in left ventricular anatomy and contractility were the earliest signs of hypertensive cardiac involvement, whereas left ventricular filling was only marginally affected. Our results highlighted the role of glomerular hyperfiltration in determining microalbuminuria and renal damage in the early stage of hypertension. The genetic approach provided an important contribution to risk stratification and patient management. The HARVEST confirmed the importance of maintaining a good lifestyle for preventing the onset of hypertension, diabetes and cardiovascular events. Isolated systolic hypertension in the first decades of life appeared as a heterogeneous condition. To establish whether antihypertensive drug treatment should be started in this condition the clinician should consider the individual cardiovascular risk profile, the level of office mean BP and central BP. Despite recent progress in our knowledge, systolic hypertension still represents a challenging issue for the clinician. Hopefully, the HARVEST will continue to contribute data that help to fill the present gaps in evidence.

Mercury in the human adrenal medulla could contribute to increased plasma noradrenaline in aging

Plasma noradrenaline levels increase with aging, and this could contribute to the sympathetic overactivity that is associated with essential hypertension and the metabolic syndrome. The underlying cause of this rise in noradrenaline is unknown, but a clue may be that mercury increases noradrenaline output from the adrenal medulla of experimental animals. We therefore determined the proportion of people from 2 to 104 years of age who had mercury in their adrenal medulla. Mercury was detected in paraffin sections of autopsied adrenal glands using two methods of elemental bioimaging, autometallography and laser ablation-inductively coupled plasma-mass spectrometry. Mercury first appeared in cells of the adrenal medulla in the 21–40 years group, where it was present in 52% of samples, and increased progressively in frequency in older age groups, until it was detected in 90% of samples from people aged over 80 years. In conclusion, the proportion of people having mercury in their adrenal medulla increases with aging. Mercury could alter the metabolism of catecholamines in the adrenal medulla that leads to the raised levels of plasma noradrenaline in aging. This retrospective autopsy study was not able to provide a definitive link between adrenal mercury, noradrenaline levels and hypertension, but future functional human and experimental studies could provide further evidence for these associations.

Sex-Specific Epidemiology of Heart Failure Risk and Mortality in Europe: Results From the BiomarCaRE Consortium

OBJECTIVES

This study investigates differences between women and men in heart failure (HF) risk and mortality.

BACKGROUND

Sex differences in HF epidemiology are insufficiently understood.

METHODS

In 78,657 individuals (median 49.5 years of age; age range 24.1 to 98.7 years; 51.7% women) from community-based European studies (FINRISK, DanMONICA, Moli-sani, Northern Sweden) of the BiomarCaRE (Biomarker for Cardiovascular Risk Assessment in Europe) consortium, the association between incident HF and mortality, the relationship of cardiovascular risk factors, prevalent cardiovascular diseases, biomarkers (C-reactive protein [CRP]; N-terminal pro-B-type natriuretic peptide [NT-proBNP]) with incident HF, and their attributable risks were tested in women vs. men.

RESULTS

Over a median follow-up of 12.7 years, fewer HF cases were observed in women (n = 2,399 [5.9%]) than in men (n = 2,771 [7.3%]). HF incidence increased markedly after 60 years of age, initially with a more rapid increase in men, whereas incidence in women exceeded that of men after 85 years of age. HF onset substantially increased mortality risk in both sexes. Multivariable-adjusted Cox models showed the following sex differences for the association with incident HF: systolic blood pressure hazard ratio (HR) according to SD in women of 1.09 (95% confidence interval [CI]: 1.05 to 1.14) versus HR of 1.19 (95% CI: 1.14 to 1.24) in men; heart rate HR of 0.98 (95% CI: 0.93 to 1.03) in women versus HR of 1.09 (95% CI: 1.04 to 1.13) in men; CRP HR of 1.10 (95% CI: 1.00 to 1.20) in women versus HR of 1.32 (95% CI: 1.24 to 1.41) in men; and NT-proBNP HR of 1.54 (95% CI: 1.37 to 1.74) in women versus HR of 1.89 (95% CI: 1.75 to 2.05) in men. Population-attributable risk of all risk factors combined was 59.0% in women and 62.9% in men.

CONCLUSIONS

Women had a lower risk for HF than men. Sex differences were seen for systolic blood pressure, heart rate, CRP, and NT-proBNP, with a lower HF risk in women.

Genetic and environmental factors on heart rate, mean arterial pressure and carotid intima-media thickness: A longitudinal twin study

BACKGROUND

Heart rate (HR), mean arterial pressure (MAP) and carotid intima-media thickness (cIMT) are moderately heritable cardiovascular traits, but the environmental effects on the longitudinal change of their heritability have never been investigated.

METHODS

368 Italian and Hungarian twins (107 monozygotic, 77 dizygotic) underwent oscillometric measurement and B-mode sonography of bilateral carotid arteries in 2009/2010 and 2014. Within- -individual/cross-study wave, cross-twin/within-study wave and cross-twin/cross-study wave correlations were estimated, and bivariate Cholesky models were fitted to decompose the total variance at each wave and covariance between study waves into additive genetic, shared and unique environmental components.

RESULTS

For each trait, a moderate longitudinal stability was observed, with within-individual/crosswave correlations of 0.42 (95% CI: 0.33-0.51) for HR, 0.34 (95% CI: 0.24-0.43) for MAP, and 0.23 (95% CI: 0.12-0.33) for cIMT. Cross-twin/cross-wave correlations in monozygotic pairs were all significant and substantially higher than the corresponding dizygotic correlations. Genetic continuity was the main source of longitudinal stability, with across-time genetic correlations of 0.52 (95% CI: 0.29-0.71) for HR, 0.56 (95% CI: 0.31-0.81) for MAP, and 0.36 (95% CI: 0.07-0.64) for cIMT. Overlapping genetic factors explained respectively 57%, 77%, and 68% of the longitudinal covariance of the HR, MAP and cIMT traits.

CONCLUSIONS

Genetic factors have a substantial role in the longitudinal change of HR, MAP and cIMT; however, the influence of unique environmental factors remains relevant. Further studies should better elucidate whether epigenetic mechanisms have a role in influencing the stability of the investigated traits over time.

Heart rate, mortality, and the relation with clinical and subclinical cardiovascular diseases: results from the Gutenberg Health Study

BACKGROUND

Higher, but also lower resting heart rate (HR), has been associated with increased cardiovascular events and mortality. Little is known about the interplay between HR, cardiovascular risk factors, concomitant diseases, vascular (endothelial) function, neurohormonal biomarkers, and all-cause mortality in the general population. Thus, we aimed to investigate these relationships in a population-based cohort.

METHODS

15,010 individuals (aged 35-74 at enrolment in 2007-2012) from the Gutenberg Health Study were analyzed. Multivariable regression modeling was used to assess the relation between the variables and conditional density plots were generated for cardiovascular risk factors, diseases, and mortality to show their dependence on HR.

RESULTS

There were 714 deaths in the total sample at 7.67 ± 1.68 years of follow-up. The prevalence of diabetes mellitus, arterial hypertension, coronary and peripheral artery disease, chronic heart failure, and previous myocardial infarction exhibited a J-shaped association with HR. Mortality showed a similar relation with a nadir of 64 beats per minute (bpm) in the total sample. Each 10 bpm HR reduction in HR < 64 subjects was independently associated with increased mortality (Hazard Ratio 1.36; 95% confidence interval 1.06-1.75). This increased risk was also present in HR > 64 subjects (Hazard Ratio 1.29; 95% confidence interval 1.19-1.41 per 10 bpm increase in HR). Results found for vascular and neurohormonal biomarkers exhibited a differential picture in subjects with a HR below and above the nadir.

DISCUSSION

These results indicate that in addition to a higher HR, a lower HR is associated with increased mortality.

Tachycardia: The hidden cardiovascular risk factor in uncomplicated arterial hypertension

Early detection and management of elevated blood pressure is crucial in reducing the burden of cardiovascular disease (CVD). The importance of an absolute risk assessment and patient risk stratification has been highlighted in the European hypertension guidelines since 2003. Amongst numerous risk factors influencing patient prognosis, elevated heart rate (HR) has been indicated as important predictor of future risk of hypertension, coronary heart disease, sudden cardiac death, heart failure, CVD, stroke, total cancer and mortality. Given that resting HR can be easily determined in clinical practice and modified by lifestyle changes as well as beta-blocker therapy, it seems reasonable that lowering resting HR should be a potential target to reduce disease burden and premature mortality. However, there is a lack of outcome studies of HR lowering in tachycardia-related hypertension. This review outlines the underlying mechanisms of early course hypertension pathophysiology with the critical role of the sympathetic nervous system activation, the prognostic significance of fast HR and the mechanistic rationale for the use of non-pharmacological approaches and/or highly long-acting cardioselective beta-blockers with some consideration given to betaxolol properties.

Resting heart rate and relation to disease and longevity: past, present and future

Assessment of heart rate has been used for millennia as a marker of health. Several studies have indicated that low resting heart rate (RHR) is associated with health and longevity, and conversely, a high resting heart to be associated with disease and adverse events. Longitudinal studies have shown a clear association between increase in heart rate over time and adverse events. RHR is a fundamental clinical characteristic and several trials have assessed the effectiveness of heart rate lowering medication, for instance beta-blockers and selective sinus node inhibition. Advances in technology have provided new insights into genetic factors related to RHR as well as insights into whether elevated RHR is a risk factor or risk marker. Recent animal research has suggested that heart rate lowering with sinus node inhibition is associated with increased lifespan. Furthermore, genome-wide association studies in the general population using Mendelian randomization have demonstrated a causal link between heart rate at rest and longevity. Furthermore, the development in personal digital devices such as mobile phones, fitness trackers and eHealth applications has made heart rate information and knowledge in this field as important as ever for the public as well as the clinicians. It should therefore be expected that clinicians and health care providers will be met by relevant questions and need of advice regarding heart rate information from patients and the public. The present review provides an overview of the current knowledge in the field of heart rate and health.

The effect of obesity and components of metabolic syndrome on leptin levels in Saudi women

BACKGROUND

Leptin levels are reported to be increased with excessive body fat and is a potential determinant of obesity and its complications. Our Objective is to evaluate the relationship between leptin levels and BMI, waist circumference and metabolic syndrome components in normal and obese females classified according to their BMI.

SUBJECTS AND METHODS

A total of 136 female subjects aged between 20 and 60 years were recruited for the current study. Anthropometric measures included body mass index and waist circumference. The blood samples were used for estimation of plasma fasting blood glucose and serum was used for estimation of triglycerides, total cholesterol, low and high density lipoproteins, and total leptin.

RESULTS

Correlation between glucose and lipids profile with waist circumference among the whole study group (obese and non-obese) is reflecting that a strong positive correlation between BMI and blood glucose, serum TGs, cholesterol and LDL, a negative correlation was reported between BMI and serum HDL. Mean of leptin concentrations in two groups were found to be 5.77 ng/ml (±1.00) in non-obese and 28.89 ng/ml (±4.91) in the obese with metabolic syndrome. Leptin had a positive correlations with triglycerides (r = 0.84, p < 0.001), total cholesterol (r = 0.77, p < 0.001), LDL (r = 0.83, p < 0.001), waist circumference (r = 0.86, p < 0.001) and BMI (r = 0.72, p < 0.001) in the test group. a negative correlation was reported between BMI and serum HDL (r = -0.48, p < 0.001).

CONCLUSION

Leptin levels were high in Saudi women with high BMI and waist circumference. There was a significant correlation between leptin levels and Obesity.

Reliability of heart rate as neuroadrenergic marker in the metabolic syndrome

BACKGROUND

Metabolic syndrome is characterized by a pronounced sympathetic overactivity as documented by the marked increase in muscle sympathetic nerve traffic (MSNA) as well as in plasma norepinephrine values reported in this condition. Whether and to what extent heart rate (HR) reflects the abovementioned adrenergic alterations in metabolic syndrome remains largely undefined. It is also undefined the validity of the abovementioned adrenergic markers in reflecting the main features of the metabolic syndrome.

METHODS

In 65 metabolic syndrome patients, aged 56.5 ± 1.3 years (mean ± SEM), we measured over a 30-min resting period blood pressure, HR (ECG), venous plasma norepinephrine (HPLC) and MSNA (microneurography). We also evaluated anthropometric and metabolic variables including HOMA index, correlating them with the adrenergic markers. The same measurements were also made in 48 age-matched healthy controls.

RESULTS

HR was significantly greater in the metabolic syndrome patients than in controls (74.6 ± 1.5 versus 67.5 ± 1.5 bpm, P < 0.001) and significantly and directly correlated with the elevated norepinephrine and MSNA values (r = 0.25 and 0.33, P < 0.05 and 0.01, respectively). MSNA was significantly and directly related to blood pressure (r = 0.27 and 0.31 SBP and DBP, respectively, P < 0.05 for both), BMI (r = 0.36, P < 0.01), waist circumference (r = 0.34, P < 0.01), waist-to-hip ratio (r = 0.49, P < 0.01) and plasma insulin (r = 0.57, P < 0.01). In contrast, no significant correlation was detectable between HR or norepinephrine and the abovementioned anthropometric and metabolic variables.

CONCLUSION

Our data show that in the metabolic syndrome not only peripheral but also cardiac sympathetic drive is markedly potentiated and HR can be regarded as a marker of adrenergic overdrive characterizing this clinical condition. The reliability of HR (and of plasma norepinephrine) as sympathetic marker appears to be limited, however, this variable being unable to reflect, at variance from MSNA, the main metabolic and anthropometric abnormalities characterizing the metabolic syndrome.

Independent association of resting energy expenditure with blood pressure: confirmation in populations of the African diaspora

BACKGROUND

Obesity is a major risk factor for hypertension, however, the physiologic mechanisms linking increased adiposity to elevations in blood pressure are not well described. An increase in resting energy expenditure (REE) is an obligatory consequence of obesity. Previous survey research has demonstrated that REE is an independent predictor of blood pressure, and eliminates the co-linear association of body mass index. This observation has received little attention and there have been no attempts to provide a causal explanation.

METHODS

At baseline in an international comparative study on obesity, 289 participants aged 25-44 were recruited from communities in the US, the Seychelles, Ghana and South Africa and had REE measured with indirect calorimetry. All participants were thought to be free of major illness.

RESULTS

In multivariate regression models, both systolic and diastolic blood pressure were positively associated with REE (p < 0.01), while body mass index and fat mass were negatively correlated with systolic blood pressure (p < 0.01, and p < 0.05 respectively), but not diastolic blood pressure.

CONCLUSIONS

These data confirm previous reports and suggest that a common physiologic abnormality links REE and blood pressure. Elevated catecholamines, a putative metabolic characteristic of obesity, is a possible candidate to explain this association. The direct role of excess adipose tissue is open to question.

Resting heart rate and impaired glucose regulation in middle-aged and elderly Chinese people: a cross-sectional analysis

Background

Elevated resting heart rate (RHR) has been reported to be associated with metabolic syndrome and type 2 diabetes. The aim of this study was to explore whether a positive relationship exists between RHR and impaired glucose regulation (IGR) among middle-aged and older Chinese individuals.

Methods

We conducted a cross-sectional analysis that included a total of 9898 subjects (3194 men and 6704 women) in a Chinese population. The RHRs were derived from ECG recordings, and the subjects were stratified based on RHR quartiles.

Results

RHR levels were significantly higher in the subjects with isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (i-IGT), IFG + IGT and diabetes than in those with normal glucose regulation. When multivariate logistic regression analyses were performed, the odds ratios were substantially higher for the subjects with IGR (odds ratio 2.19, 95% confidence interval 1.85–2.58) in the fourth RHR quartile compared with those in the first quartile after adjustment for potential confounding covariates, and the corresponding OR for the combined IGR and type 2 diabetes group was 2.56 (95% CI 2.20–2.98, p < 0.001). Multiple regression analyses demonstrated that RHR was significantly associated with fasting plasma glucose, 2-h OGTT plasma glucose and A1c.

Conclusions

Our cross-sectional findings provide evidence that high RHR is associated with existing IGR among middle-aged and older Chinese individuals.

Hypertension in Patients with Cardiac Transplantation

Hypertension is a common complication among post cardiac transplant recipients affecting more than 95% of patients. Increased blood pressure poses a significant cardiovascular morbidity and mortality in these patients; it should be identified quickly and needs to be managed appropriately. Understanding the pathophysiology and contributing factors to this disease in these complex and unique patients is the key to appropriate treatment selection.

Management of the hypertensive patient with elevated heart rate: Statement of the Second Consensus Conference endorsed by the European Society of Hypertension

In June 2015, a panel of experts gathered in a consensus conference to plan updating recommendations on the management of the hypertensive patient with elevated heart rate (HR), previously released in 2006. The issues examined during that meeting and further discussed by the participants during the following months involved the assessment of HR, the relevance of HR as a cardiovascular risk factor, the definition of tachycardia and the treatment of the hypertensive patient with high HR. For the measurement of resting HR the panel experts recommended that scientific investigations focusing on HR should report information on length of resting period before measurement, information about temperature and environment, method of measurement, duration of measurement, number of readings, time interval between measurements, body position and type of observer. According to the panellists there is convincing evidence that HR is an important risk factor for cardiovascular disease and they suggest to routinely include HR measurement in the assessment of the hypertensive patient. Regarding the definition of tachycardia, the panellists acknowledged that in the absence of convincing data any threshold used to define tachycardia is arbitrary. Similarly, as there are no outcome studies of HR lowering in tachycardia hypertension, the panellists could not make practical therapeutic suggestions for the management of such patients. However, the experts remarked that absence of evidence does not mean evidence against the importance of tachycardia as a risk factor for cardiovascular disease and that long-term exposure to a potentially important risk factor may impair the patient's prognosis. The main aims of the present document are to alert researchers and physicians about the importance of measuring HR in hypertensive patients, and to stimulate research to clarify unresolved issues.

Glucocorticoid-induced fetal origins of adult hypertension: Association with epigenetic events

Hypertension is a predominant risk factor for cardiovascular diseases and a major health care burden. Accumulating epidemiological and experimental evidence suggest that adult-onset hypertension may have its origins during early development. Upon exposure to glucocorticoids, the fetus develops hypertension, and the offspring may be programmed to continue the hypertensive trajectory into adulthood. Elevated oxidative stress and deranged nitric oxide system are not only hallmarks of adult hypertension but are also observed earlier in life. Endothelial dysfunction and remodeling of the vasculature, which are robustly associated with increased incidence of hypertension, are likely to have been pre-programmed during fetal life. Apparently, genomic, non-genomic, and epigenomic factors play a significant role in the development of hypertension, including glucocorticoid-driven effects on blood pressure. In this review, we discuss the involvement of the aforementioned participants in the pathophysiology of hypertension and suggest therapeutic opportunities for targeting epigenome modifiers, potentially for personalized medicine.

The Association of Resting Heart Rate and Incident Hypertension: The Henry Ford Hospital Exercise Testing (FIT) Project

BACKGROUND

Given that sympathetic tone is associated with hypertension, we sought to determine whether resting heart rate (RHR), as a surrogate for cardiac autonomic function, was associated with incident hypertension.

METHODS

We analyzed 21,873 individuals without a history of hypertension who underwent a clinically indicated exercise stress test. Baseline RHR was assessed prior to testing and was categorized as <70, 70-85, and >85 beats-per-minute (bpm). Incident hypertension was defined by subsequent diagnosis codes for new-onset hypertension from three or more encounters. We tested for effect modification by age (<60 vs. ≥60 years), sex, race, and history of coronary heart disease (CHD).

RESULTS

Mean (±SD) age was 49 (±12) years, 55% were men and 21% were Black. Compared to the lowest RHR (<70 bpm) category, patients in the highest category (>85 bpm) were younger, more likely to be female, heavier, diabetic, and achieve lower metabolic equivalents (METS). Over a median of 4 years follow-up, there were 8,179 cases of incident hypertension. Compared to RHR <70 bpm, persons with RHR >85 bpm had increased risk of hypertension after adjustment for CHD risk factors, baseline blood pressure (BP), and METS (hazard ratio = 1.15 (95% confidence interval 1.08-1.23)). Age was an effect modifier (interaction P = 0.02), whereas sex, race, and CHD were not. In age-stratified analyses the relationship remained significant only in those younger than 60 years.

CONCLUSION

Elevated RHR is an independent risk factor for incident hypertension, particularly in younger persons. Whether lifestyle modification or other strategies to reduce RHR can prevent incident hypertension in high-risk individuals warrants further study.

Resting heart rate is an independent predictor of all-cause mortality in the middle aged general population

BACKGROUND

High resting heart rate (RHR) predicts cardiovascular outcomes in patients with vascular disease and heart failure. We evaluated the prognostic value of RHR in a large contemporary population-based, prospective cohort of individuals without known coronary artery disease.

METHODS AND RESULTS

Resting heart rate (RHR) was determined in 4091 individuals (mean age 59.2 ± 7.7; 53 % women) from the Heinz Nixdorf RECALL study, of whom, 3348 were free of heart rate lowering medication. During 10.5 years of follow-up (median), 159 (3.9 %) individuals developed a coronary event and 398 (9.7 %) died of any cause. Persons without any event (n = 3603) had similar heart rates as persons with coronary events (69.5 ± 11 versus 69.9 ± 11 bpm, p = 0.51) but lower heart rates than persons who died (72.3 ± 13 bpm, p < 0.0001). In individuals without heart rate lowering medication, an increase in heart rate by 5 bpm was associated with an increased hazard ratio (HR) for all-cause mortality of 13 % in unadjusted analysis and also upon adjustment for traditional cardiovascular risk factors, including coronary artery calcification [full model: HR (95 % CI) 1.13 (1.07-1.20), p < 0.0001], but not for coronary events [HR 1.02 (0.94-1.11), p = 0.60]. In individuals without heart rate lowering medication, the HR (full model) for heart rate ≥70 versus <70 bpm with regard to all-cause mortality and coronary events was 1.68 (1.30-2.18), p < 0.0001, and 1.20 (0.82-1.77), p = 0.35. Analysis of the entire cohort revealed a continuous relationship of heart rate with all-cause mortality [HR for lowest to highest heart rate quartile 1.64 (1.22-2.22), p = 0.001, full model] but not with coronary events [HR 1.04 (0.65-1.66), p = 0.86].

CONCLUSIONS

In the general population without known coronary artery disease and heart rate lowering medication, elevated RHR is an independent risk marker for all-cause mortality but not for coronary events.

Heart Rate, Life Expectancy and the Cardiovascular System: Therapeutic Considerations

It has long been known that life span is inversely related to resting heart rate in most organisms. This association between heart rate and survival has been attributed to the metabolic rate, which is greater in smaller animals and is directly associated with heart rate. Studies have shown that heart rate is related to survival in apparently healthy individuals and in patients with different underlying cardiovascular diseases. A decrease in heart rate due to therapeutic interventions may result in an increase in survival. However, there are many factors regulating heart rate, and it is quite plausible that these may independently affect life expectancy. Nonetheless, a fast heart rate itself affects the cardiovascular system in multiple ways (it increases ventricular work, myocardial oxygen consumption, endothelial stress, aortic/arterial stiffness, decreases myocardial oxygen supply, other) which, in turn, may affect survival. In this brief review, the effects of heart rate on the heart, arterial system and survival will be discussed.

Plasma Renin Activity and Resting Heart Rate in a Population of Community-Dwelling Japanese: The Tanushimaru Study

BACKGROUND

Heart rate is a strong predictor of mortality and development of obesity and diabetes. The renin-angiotensin-aldosterone system plays an important role in blood pressure control and volume homeostasis. Although many studies have indicated the association between aldosterone and hypertension or insulin resistance, epidemiological evidence of the association of heart rate with plasma renin activity (PRA) remains scant. Therefore, we investigated whether heart rate is associated with PRA.

METHODS

A total of 1,943 subjects were enrolled, who underwent a health examination in Tanushimaru in 2009. Plasma renin and aldosterone concentrations were measured by radioimmunoassay. PRA and the homeostasis model assessment (HOMA) were used by natural-log transformed. Resting heart rate was measured using electrocardiography.

RESULTS

We divided the subjects into four groups by heart rate (<60/min, 60-69/min, 70-79/min, ≥80/ min), and analyzed an association between PRA and heart rate by analysis of covariance after adjustments for age and sex. The adjusted mean PRA and HOMA index showed a significant trend (P < 0.01) as higher heart rate, although there was no significant trend between aldosterone and heart rate (P = 0.26). In multiple linear regression analysis adjusted for age, sex, systolic blood pressure, HOMA index, and hypertensive medication, PRA was positively and strongly associated with elevated heart rate (P < 0.01).

CONCLUSIONS

This epidemiological study demonstrated that PRA, but not aldosterone, is significantly and positively associated with higher resting heart rate in a general population.

Association beween resting heart rate, shear and flow-mediated dilation in healthy adults

Preclinical data have demonstrated that heart rate (HR) can directly impact vascular endothelial function, in part, through a shear-stress mechanism. This study sought to explore, in humans, the associations between resting heart rate and both shear and endothelial function assessed by flow-mediated dilation (FMD). The brachial artery FMD test was performed in 31 apparently healthy volunteers. Basal (B) and hyperaemic (H) shear were quantified in the following two ways using data from the FMD test: the traditional cumulative shear area under the curve up to peak dilation (Shearcum) method; and our novel method of shear summation (Shearsum), which accounts for HR by summing each individual cardiac cycle shear up to peak dilation. Data were grouped by tertiles based on resting HR as follows: low (LHR = 43-56 beats min(-1); n = 10); middle (MHR = 58-68 beats min(-1); n = 11); and high (HHR = 69-77 beats min(-1); n = 10). Within the LHR group, both B-Shearcum and H-Shearcum were significantly higher (P < 0.001) than B-Shearsum and H-Shearsum, respectively, whereas in the HHR group B-Shearcum and H-Shearcum were significantly lower (P < 0.001) than B-Shearsum and H-Shearsum, respectively. The FMD in the LHR group (8.8 ± 0.8%) was significantly greater than that in both the MHR group (5.5 ± 0.8%; P = 0.009) and the HHR group (5.9 ± 0.8%; P = 0.024). These findings demonstrate the existence of a relationship between heart rate and both shear and endothelial function in humans. Moreover, these findings have implications for considering heart rate as an important physiological variable when quantifying shear and performing the FMD test.

Protective role of resting heart rate on all-cause and cardiovascular disease mortality

OBJECTIVE

To study the protective role of lower resting heart rate (RHR) in cardiovascular disease (CVD) and all-cause mortality.

PATIENTS AND METHODS

Patients (n=53,322) who received a baseline medical examination between January 1, 1974, and December 31, 2002, were recruited from the Cooper Clinic, Dallas, Texas. They completed a medical questionnaire and underwent clinical evaluation. Patients with CVD or cancer or who had less than 1 year of mortality follow-up were excluded from the study. Relative risks and 95% CIs for all-cause and CVD mortality across RHR categories were estimated using Cox proportional hazards models.

RESULTS

Highest cardiorespiratory fitness with lower mortality was found in individuals with an RHR of less than 60 beats/min. Similarly, patients with a higher RHR (≥80 beats/min) were at greater risk for CVD and all-cause mortality compared with an RHR of less than 60 beats/min. This analysis was followed by stratification of the data by hypertension, where hypertensive individuals with high RHRs (≥80 beats/min) were found to be at greater risk for CVD and all-cause mortality compared with those with hypertension and lower RHRs (<60 beats/min). In addition, unfit individuals with high RHRs had the greatest risk of CVD and all-cause mortality. The unfit with low RHR group had a similar risk for CVD and all-cause mortality as the fit with high RHR group.

CONCLUSION

Lower cardiorespiratory fitness levels and higher RHRs are linked to greater CVD and all-cause mortality.

Oxyntomodulin increases intrinsic heart rate through the glucagon receptor

Two hormones from the gastrointestinal tract, glucagon and oxyntomodulin (OXM), vigorously elevate the intrinsic heart rate (I_HR) of mice. We have previously shown that OXM influences murine heart rate (HR) independent of the glucagon-like peptide 1 (GLP-1) receptor. Here, we demonstrate using radiotelemetry in mice deficient in the glucagon receptor (Gcgr −/−) that both OXM and glucagon require the glucagon receptor for their chronotropic effects on the heart. Furthermore, we found that other hormones associated with hunger and satiety (ghrelin, leptin, and PYY_3-36) had no effect on I_HR, while cholecystokinin moderately elevated the I_HR. Finally, the resting HR of Gcgr −/− mice was higher than in control mice (Gcgr +/+ and Gcgr +/−) at thermal neutral temperature (30°C). Using atropine, we demonstrated that Gcgr −/− mice have diminished parasympathetic (PNS) influence of the heart at this temperature. Gcgr −/− mice displayed a normal bradycardia as compared to controls in response to administration of either methacholine (to activate the muscarinic acetylcholine receptor) or methoxamine (to activate the baroreflex through agonism of the α1 adrenergic receptor agonist) suggesting that vagal pathways are intact in the Gcgr −/− mice. As OXM is an agonist of the GLP-1 receptor and Gcgr with antidiabetic activity, we suggest OXM may be an alternative to glucagon in the treatment of overdose of beta-blockers to elevate HR in clinical conditions.

Association of resting heart rate with carotid and aortic arterial stiffness: multi-ethnic study of atherosclerosis

Resting heart rate is an easily measured, noninvasive vital sign that is associated with cardiovascular disease events. The pathophysiology of this association is not known. We investigated the relationship between resting heart rate and stiffness of the carotid (a peripheral artery) and the aorta (a central artery) in an asymptomatic multi-ethnic population. Resting heart rate was recorded at baseline in the Multi-Ethnic Study of Atherosclerosis (MESA). Distensibility was used as a measure of arterial elasticity, with a lower distensibility indicating an increase in arterial stiffness. Carotid distensibility was measured in 6484 participants (98% of participants) using B-mode ultrasound, and aortic distensibility was measured in 3512 participants (53% of participants) using cardiac MRI. Heart rate was divided into quintiles and we used progressively adjusted models that included terms for physical activity and atrioventricular nodal blocking agents. Mean resting heart rate of participants (mean age, 62 years; 47% men) was 63 bpm (SD, 9.6 bpm). In unadjusted and fully adjusted models, carotid distensibility and aortic distensibility decreased monotonically with increasing resting heart rate (P for trend <0.001 and 0.009, respectively). The relationship was stronger for carotid versus aortic distensibility. Similar results were seen using the resting heart rate taken at the time of MRI scanning. Our results suggest that a higher resting heart rate is associated with an increased arterial stiffness independent of atrioventricular nodal blocker use and physical activity level, with a stronger association for a peripheral (carotid) compared with a central (aorta) artery.

Influence of heart rate at rest for predicting the metabolic syndrome in older Chinese adults

The aim of this study was to examine the relationship between seated resting heart rate and the metabolic syndrome (MetS) among older residents of Guangzhou, South China. A total of 30,519 older participants (≥50 years) from the Guangzhou Biobank Cohort Study were stratified into quartiles based on seated resting heart rate. The associations between each quartile and the MetS were assessed using multivariable logistic regression. A total of 6,907 (22.8 %) individuals were diagnosed as having the MetS, which was significantly associated with increasing heart rate quartiles (P < 0.001). Participants in the uppermost quartile (mean resting heart rate 91 ± 8 beats/min) of this cardiovascular proxy had an almost twofold increased adjusted risk (odds ratio (95 % CI) = 1.94 (1.79, 2.11), P < 0.001) for the MetS, as compared to those in the lowest quartile (mean resting heart rate, 63 ± 4 beats/min). Heart rate, which is an inexpensive and simple clinical measure, was independently associated with the MetS in older Chinese adults. We hope these observations will spur further studies to examine the usefulness of resting heart rate as a means of risk stratification in such populations, for which targeted interventions should be implemented.

Impact of basal heart rate on long-term prognosis of heart transplant patients

Previous studies in patients with heart failure have shown that an elevated basal heart rate (HR) is associated with a poor outcome. Our aim with this study was to investigate if this relationship is also present in heart transplantation (HTx) recipients. From 2003 until 2010, 256 HTx performed in our center were recruited. Patients who required pacemaker, heart-lung transplants, pediatrics, retransplants, and those patients with a survival of less than 1 year were excluded. The final number included in the analysis was 191. Using the HR obtained by EKG during elective admission at 1 year post-HTx and the survival rate, an ROC-curve was performed. The best point under the curve was achieved with 101 beats per minute (bpm), so patients were divided in two groups according to their HR. A comparison between survival curves of both groups was performed (Kaplan-Meier). Subsequently, a multivariate analysis considering HR and other variables with influence on survival according to the literature was carried out. A total of 136 patients were included in the group with HR ≤100 bpm, and 55 in the one with HR >100 bpm. There were no basal differences in both groups except for primary graft failure, which was more frequent in the >100 bpm group (30.9 vs. 17%, P = 0.033). Patients with ≤100 bpm had a better long prognosis (P < 0.001). The multivariate analysis proved that high HR was an independent predictor of mortality. Our study shows that HR should be considered as a prognosis factor in HTx patients.

Blood pressure tracking over the adult life course: patterns and correlates in the Framingham heart study

The extent to which select vascular risk factors differentially influence blood pressure (BP) is incompletely understood. Thus, we used multilevel modeling to analyze serial BP measurements using 21 732 person-observations obtained on Framingham Heart Study participants (mean age, 38 years, 52% women; 4993 unique individuals) over a 28-year period. We related longitudinal tracking of each BP measure (systolic BP, diastolic BP, mean arterial pressure, and pulse pressure) to age, sex, body mass index, smoking, diabetes mellitus, total/high-density lipoprotein cholesterol ratio, and heart rate. In multivariable-adjusted analyses, we observed that older age, male sex, greater body mass index, and higher heart rate were positively associated with increase in all BP measures (P<0.0001). Notably, higher total/high-density lipoprotein cholesterol ratio was associated with greater mean arterial pressure (P<0.01). Conversely, diabetes mellitus and smoking were associated with higher pulse pressure (P<0.01). We also observed effect modification by sex: the increase in pulse pressure with age and body mass index was more pronounced in women compared with men (P<0.0001). All BP measures tracked at higher levels in both men and women with multiple vascular risk factors. Taken together, our longitudinal observations in a large community-based sample demonstrate a greater pulsatile load in women than in men with increasing age. We also observed a differential impact of select vascular risk factors on the individual components of BP, underscoring distinct regulation of these measures over the life course.

The complex interaction between overweight, hypertension, and sympathetic overactivity

There is ample evidence in the epidemiological and clinical literature that hypertension and overweight are closely and causally interrelated. Sympathetic nervous system (SNS) overactivity has been well documented in both hypertension and overweight, but it is not clear whether this is a coincidental finding or whether the association reflects a mechanistic role of SNS in these two interrelated clinical conditions. Whereas in this review we focus on the evidence for a primary role of SNS in the development of hypertension and overweight, it is clear that the process can be initiated from other starting points such as primary overeating or sleep apnea. After overweight evolves, hormones secreted by fat cells further accelerate SNS overactivity, weight gain, and blood pressure increase. The main thesis of this article is that regardless of where the process started, the same clinical picture of hypertension, overweight, and SNS overactivity will emerge. There is good evidence that in genetically prone individuals, prolonged SNS stimulation elicits a down regulation of beta-adrenergic receptors. This in turn decreases the ability to dissipate calories and diminishes the beta-adrenoceptor-mediated vasodilatation. We hypothesize that beta-adrenoceptor downregulation is the linchpin in the association of SNS with overweight and hypertension.

Resting heart rate and incident heart failure in apparently healthy men and women in the EPIC-Norfolk study

AIMS

Increasing levels of resting heart rate are associated with increased risk of developing hypertension and cardiovascular disease, and seem to play a role in the progression of heart failure. The shape of the association between resting heart rate and risk of developing heart failure has not been examined in healthy individuals of the general population.

METHODS AND RESULTS

Hazard ratios (HRs) of heart failure comparing categories of resting heart rate [51-60 b.p.m. (reference), 61-70 b.p.m., 71-80 b.p.m., 81-90 b.p.m., and 91-100 b.p.m.] were calculated in apparently healthy men (9805) and women (12 321) aged 39-79 participating in the 'European Prospective Investigation into Cancer and Nutrition' (EPIC) study in Norfolk. During a mean follow-up of 12.9 years, 1356 incident cases of heart failure occurred. In participants without potential heart rate-modifying medication, age- and sex-adjusted incidence rates of heart failure were 3.3, 3.7, 4.0, 5.1, and 5.5 per 1000 person-years for increasing categories of resting heart rate; compared with the reference category, HRs and 95% confidence intervals (CI) for increasing categories of resting heart rate were 1.08 (0.88-1.34), 1.17 (0.94-1.46), 1.39 (1.08-1.79), and 1.42 (1.00-2.03), respectively, in multivariable analysis adjusting for age, sex, body mass index, systolic blood pressure, prevalent diabetes, cholesterol concentration, social class, educational level, smoking, and physical activity. Within the reference range of resting heart rate (50-100 b.p.m.) each 10 b.p.m. increase was associated with an 11% increase in hazard of heart failure in multivariable analysis. The results did not change materially after adjusting for myocardial infarction and coronary heart disease events during follow up (1.12, 1.06-1.18).

CONCLUSION

Resting heart rate shows a graded association with hazard of heart failure in apparently healthy men and women which is not mediated by coronary heart disease. Further study is needed to examine the underlying mechanisms.

Heart rate-lowering efficacy and respiratory safety of ivabradine in patients with obstructive airway disease: a randomized, double-blind, placebo-controlled, crossover study

BACKGROUND

There is substantial evidence that heart rate (HR) is a powerful predictor of mortality in both normal individuals and in patients with cardiovascular disease. The use of β-adrenoceptor antagonists (β-blockers) has confirmed the importance of lowering elevated HR in a patient's prognosis. However, these agents can have undesirable adverse effects (AEs) and due to the risk of bronchoconstriction are contraindicated in patients with obstructive airway disease. A selective bradycardic agent, without such undesirable effects, could be of therapeutic interest. Ivabradine, a new I(f) inhibitor that acts specifically on the sino-atrial node, is a pure HR-lowering agent.

OBJECTIVE

The objective of this study was to assess HR-lowering efficacy and respiratory safety of ivabradine in patients with asthma and chronic obstructive pulmonary disease (COPD).

METHODS

This was a randomized, single-center, double-blind, placebo-controlled, crossover trial. Enrolment began in May 2009, and the last patient completed the study in January 2011. The study was conducted in an ambulatory setting. A total of 40 patients completed the study (20 asthmatic patients and 20 COPD patients). Inclusion criteria were: documented diagnosis of asthma or COPD according to international guidelines, age 18-75 years, and mean HR on Holter ECG recording of ≥60 beats/min. Exclusion criteria included disease exacerbation in a previous month or inability to understand instructions on the study procedures. All patients received ivabradine 7.5 mg twice daily for 5 days and placebo twice daily for 5 days in a crossover manner, in one of the two arms of the study, with at least 2 days of washout between treatments. The main outcome measures included the difference in HR between ivabradine and placebo treatment and change in HR in comparison with baseline. Other evaluated outcomes were differences in the peak expiratory flow rate (PEFR), the daily symptom score, rescue medication consumption, and AEs.

RESULTS

Ivabradine produced significantly lower mean HR than placebo in both groups of patients: asthma 67.4 ± 8.38 versus 82.85 ± 11.19 beats/min (p < 0.001) and COPD 69.75 ± 8.9 versus 81.05 ± 9.75 beats/min (p < 0.001). Similar results were observed for the minimal HR as well as for the maximal noted HR. In comparision with baseline, ivabradine significantly reduced HR in both groups of studied patients (all p < 0.05), whereas placebo did not have such an effect. No significant difference, in either the asthma or the COPD group, was found between ivabradine and placebo in morning and evening peak expiratory flow rate, peak expiratory flow diurnal variability, daily symptom scores, and rescue medication usage (all p > 0.05). Both treatments were well tolerated. The incidence of AEs was low and generally similar in both periods of treatment, except for visual symptoms during treatment with ivabradine, which was reported by 5% of the patients.

CONCLUSION

Our study demonstrated that selective HR reduction with ivabradine is effective in patients with asthma and COPD, with no alteration in respiratory function or symptoms over the duration of the study. Ivabradine offers an interesting alternative, as an HR-lowering agent, in patients with respiratory disease and contraindications to β-blockers.

CLINICAL TRIAL REGISTRATION

Registered at www.clinicaltrials.gov (NCT01365286).

Tobacco and metabolic syndrome

Tobacco is a leading contributor to morbidity and mortality globally. Metabolic syndrome is a constellation of abdominal obesity, atherogenic dyslipidemia, raised blood pressure, insulin resistance (with and without glucose intolerance), pro-inflammatory state, and pro-thrombotic state. Tobacco use is associated with various core components of metabolic syndrome. It has been found to play a causal role in various pathways leading on to development this condition, the current article discusses various facets of this association.

Evening heart rate measured at home is associated with visceral obesity and abnormal fat distribution in patients with hypertension

BACKGROUND

Our aim was to examine the association between heart rate (HR) and visceral obesity and abnormal fat distribution in patients undergoing treatment for hypertension. We also ascertained whether such associations differ depending on the time of day when HR is measured and the venue at which the measurement is carried out (office or home).

METHODS

The study enrolled a total of 390 patients (mean age 63.9 years; 45% men) receiving treatment with antihypertensive drugs other than β blockers or nondihydropyridine Ca-channel blockers. Office blood pressure (BP) and HR as well as home BP and HR, both morning and evening, were measured in all these patients for 14 days. The amount of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were determined using abdominal computed tomography (CT).

RESULTS

Evening HR was positively associated with VAT (r = 0.26) and negatively associated with SAT (r = -0.16); as a consequence, evening HR was closely associated with the VAT/SAT ratio (r = 0.30; all P < 0.01). In contrast, neither office nor morning HR was associated with VAT. The significant association between evening HR and VAT remained unchanged even after adjustment for significant covariates including SAT (P = 0.001). A multiple logistic regression analysis revealed that a 1-s.d. increase (10 beats per minute) in evening HR was significantly associated with visceral obesity (defined as VAT ≥100 cm)(2) (odds ratio (95% confidence interval: 1.7 (1.3-2.3)), P < 0.001), and that this association was independent of body mass index (BMI) and abdominal obesity (waist circumference ≥85 cm for men and ≥90 cm for women).

CONCLUSIONS

In these patients receiving treatment for hypertension, high evening HR was associated with visceral obesity, independent of the presence of subcutaneous fat and BMI. This novel finding could explain why cardiovascular risk is higher in individuals with high HR.

Experimental measurement of dynamic fluid shear stress on the aortic surface of the aortic valve leaflet

Aortic valve (AV) calcification is a highly prevalent disease with serious impact on mortality and morbidity. Although exact causes and mechanisms of AV calcification are unclear, previous studies suggest that mechanical forces play a role. Since calcium deposits occur almost exclusively on the aortic surfaces of AV leaflets, it has been hypothesized that adverse patterns of fluid shear stress on the aortic surface of AV leaflets promote calcification. The current study characterizes AV leaflet aortic surface fluid shear stresses using Laser Doppler velocimetry and an in vitro pulsatile flow loop. The valve model used was a native porcine valve mounted on a suturing ring and preserved using 0.15% glutaraldehyde solution. This valve model was inserted in a mounting chamber with sinus geometries, which is made of clear acrylic to provide optical access for measurements. To understand the effects of hemodynamics on fluid shear stress, shear stress was measured across a range of conditions: varying stroke volumes at the same heart rate and varying heart rates at the same stroke volume. Systolic shear stress magnitude was found to be much higher than diastolic shear stress magnitude due to the stronger flow in the sinuses during systole, reaching up to 20 dyn/cm(2) at mid-systole. Upon increasing stroke volume, fluid shear stresses increased due to stronger sinus fluid motion. Upon increasing heart rate, fluid shear stresses decreased due to reduced systolic duration that restricted the formation of strong sinus flow. Significant changes in the shear stress waveform were observed at 90 beats/min, most likely due to altered leaflet dynamics at this higher heart rate. Overall, this study represents the most well-resolved shear stress measurements to date across a range of conditions on the aortic side of the AV. The data presented can be used for further investigation to understand AV biological response to shear stresses.

Environmental and occupational exposure to lead as a potential risk factor for cardiovascular disease

We have evaluated current knowledge on relations between environmental and occupational exposure to lead with a strong emphasis on cardiovascular disease risk factors, such as the influence of lead compounds on lipid disturbances and arterial blood pressure. In addition, "novel" biochemical and vascular risk factors for cardiovascular diseases were discussed, as well as the combination of lead exposure and genetic predisposition to cardiovascular diseases. Occupationally and educationally, awareness of the unfavourable effects of lead on cardiovascular diseases risk factors should be emphasised. Indeed, accurate identification of the various mechanisms that might account for the effects of lead on the cardiovascular system should be of the highest priority in this field of research.

Blood pressure control and cardiovascular risk profile in hypertensive patients from central and eastern European countries: results of the BP-CARE study

AIMS

Limited information is available on office and ambulatory blood pressure (BP) control as well as on cardiovascular (CV) risk profile in treated hypertensive patients living in central and eastern European countries.

METHODS AND RESULTS

In 2008, a survey on 7860 treated hypertensive patients followed by non-specialist or specialist physicians was carried out in nine central and eastern European countries (Albania, Belarus, Bosnia, Czech Republic, Latvia, Romania, Serbia, Slovakia, and Ukraine). Cardiovascular risk assessment was based on personal history, clinic BP values, as well as target organ damage evaluation. Patients had a mean (±SD) age of 60.1 ± 11 years, and the majority of them (83.5%) were followed by specialists. Average clinic BP was 149.3 ± 17/88.8 ± 11 mmHg. About 70% of patients displayed a very high-risk profile. Electrocardiogram was performed in 99% of patients, echocardiography in 65%, carotid ultrasound in 24%, fundoscopy in 68%, and search for microalbuminuria in 10%. Ambulatory BP monitoring was performed in about one-fifth of the recruited patients. Despite the widespread use of combination treatment (87% of the patients), office BP control (<140/90 mmHg) was achieved in 27.1% only, the corresponding control rate for ambulatory BP (<130/80 mmHg) being 35.7%. Blood pressure control was (i) variable among different countries, (ii) worse for systolic than for diastolic BP, (iii) slightly better in patients followed by specialists than by non-specialists, (iv) unrelated to patients' age, and (v) more unsatisfactory in high-risk hypertensives and in patients with coronary heart disease, stroke, or renal failure.

CONCLUSION

These data provide evidence that in central and eastern European countries office and ambulatory BP control are unsatisfactory, particularly in patients at very high CV risk, and not differ from that seen in Western Europe. They also show that assessment of subclinical organ damage is quite common, except for microalbuminuria, and that combination drug treatment is frequently used.

The haemodynamic response to propranolol in cirrhosis with arterial hypertension: a comparative analysis with normotensive cirrhotic patients

BACKGROUND

Cirrhosis with arterial hypertension is not uncommon. Haemodynamic alterations in these patients and the effects of beta-blocker on hepatic venous pressure gradient (HVPG) and systemic haemodynamics have not been evaluated.

AIMS

To compare the systemic haemodynamic alterations in hypertensive and normotensive cirrhotics, and to investigate the effects of propranolol on these parameters.

METHODS

A retrospective analysis of consecutive hypertensive cirrhotic patients (n = 33) who underwent haemodynamic assessment and paired HVPG measurement was done. Normotensive cirrhotics (n = 50) served as controls.

RESULTS

Hypertensive patients had a significantly higher heart rate, systemic (SVRI), and pulmonary vascular resistance. There was a significant reduction in mean arterial pressure (MAP) in the hypertensive cirrhotic group from 112 (107-130) mmHg to 95 (77-114) mmHg (P < 0.01), but no change in the normotensives. SVRI remained the same in the hypertensive cirrhotic group, but it increased in the normotensives. There was no correlation between MAP reduction and HVPG reduction.

CONCLUSIONS

The frequency of HVPG response with propranolol treatment in hypertensive cirrhotics is similar to normotensive cirrhotics. Propranolol treatment reduces MAP significantly in hypertensive patients with cirrhosis. Treatment with a nonselective beta-blocker is a good strategy for hypertensive cirrhotic patients.

Relationship of body mass index with haemodynamic variables and abnormalities in young adults

We aimed at investigating whether the degree of adiposity is related to haemodynamic variables such as systolic blood pressure (SBP), diastolic blood pressure (DBP) and resting heart rate (HR), and to haemodynamic abnormalities such as hypertension and resting tachycardia. A cross-sectional study was carried out among young students in Ebonyi State University, Nigeria. A total of 710 subjects (350 males and 360 females) aged 20-25 years were recruited for the study. Resting blood pressure and HR of subjects were measured and the body mass index (BMI) was calculated from height and weight measurements. The observed prevalences in this study were as follows: overweight, 20% in males and 26% in females; obesity, 8% in males and 6% in females; hypertension, 17% in males and 14% in females; and resting tachycardia, 22% in males and 24% in females. In both genders, BMI showed significant correlations (P<0.001 or P<0.01 or P<0.05) with SBP, DBP and HR after controlling for age and physical activity status, and SBP indicated the strongest association with BMI. Furthermore, the prevalence of hypertension and tachycardia increased with an increase in BMI level, whereas overweight/obese subjects indicated significantly higher risk of hypertension than did the non-overweight/obese controls. The present findings therefore strengthen the previously reported usefulness of BMI in predicting cardiovascular risks and add to our understanding of the early development of obesity-related cardiovascular abnormalities in young adults and the need to prevent obesity early in life and to avoid its unfavourable life-threatening consequences later in life.