Mean 24-h Heart Rate Research Articles

Drug-resistant hypertensive patients responding to multielectrode renal denervation exhibit improved heart rate dynamics and reduced arrhythmia burden

Transluminal renal sympathetic denervation (RDN) reduces blood pressure (BP) in patients with drug-resistant uncontrolled hypertension. We assessed the effect of RDN on heart rate, supraventricular and ventricular ectopic activity and indexes of heart rate variability in 14 patients with drug-resistant uncontrolled hypertension who were all responders to RDN (defined as a reduction in office systolic BP ⩾ 10 mm Hg) at baseline and at 1 and 6 months after the procedure using the multielectrode EnligHTN ablation catheter (St Jude Medical). Office and 24-h systolic and diastolic BP were significantly reduced both at 1 and 6 months after RDN and all patients were office BP responders. There was a trend toward office heart rate reduction (by 6.9 b.p.m., P=0.064) at 1 month and a significant reduction by 10 b.p.m. (P=0.004) at 6 months. Mean 24-h Holter monitoring heart rate was reduced by 6.7 b.p.m. (P=0.022) at 1 month and by 5.3 b.p.m. (P=0.010) at 6 months after RDN. The total number of premature supraventricular and ventricular contractions was significantly decreased and time- and frequency- domain indexes were increased both at 1 and at 6 months after RDN (P<0.05 for both cases). Apart from the substantial BP lowering, RDN results in significant reduction of mean heart rate and arrhythmia burden, restoring autonomic balance in responder patients with drug-resistant uncontrolled hypertension.

156 A single centre experience of Ivabradine and Clonidine for inappropriate sinus tachycardia

<h3>Introduction</h3> Inappropriate sinus tachycardia (IST) is a relatively rare disease that manifests with resting tachycardia, a rapid increase in heart rate (HR) with minimal exertion, a normal ECG and absence of structural heart disease. Treatment options include β-blockade or sinus node modification which are not 100% successful. Newer agents like sinus node inhibitor (Ivabradine) or a centrally acting α-2 sympathomimetic (Clonidine) can be used but there is no success outcome data for either and there is also no evidence that one is better than the other. We present our experience of managing 6 patients with a diagnosis of IST with either Ivabradine or Clonidine or both. <h3>Methods</h3> We identified 6 patients from 2005 to 2009 with a diagnosis of IST (according to accepted international guidelines) who had been treated with either Ivabradine or Clonidine or both. Medical case records were reviewed for each patient. <h3>Results</h3> 5 out of 6 patients were women with a mean age of 27.5 years (range 16–40 years). All patients had been symptomatic for alteast 6 months before presentation to our tertiary centre. 2 patients had associated symptoms of hyperadrenergic surges. Holter monitoring prior to treatment demonstrated sinus tachycardia. Resting pre-treatment mean 24 h HR was 94±10 (range 75–100) and mean HR on minimal exertion was 157±20 (range 130–176). All patients had a structurally normal heart on echocardiogram. Tilt table testing was considered in 3 patients due to their symptoms and it excluded postural orthostatic tachycardia syndrome. Pre-treatment with β-blockers had been unsuccessful in 5/6 patients. The remaining patient had symptomatic asthma and was therefore unable to tolerate β-blockers. Ivabradine was exclusively used in 3 patients and clonidine in 2. 1 patient was started with Ivabradine but later switched over to clonidine as it was ineffective. All 4 patients taking Ivabradine failed to gain symptom relief with no significant reduction in mean 24-h HR parameters. Mean resting HR after 3 months of Ivabradine therapy was 95±9 (range 88–105) and mean HR on exertion was 159±23 (range 128–180). 2/4 patients subsequently had complete sinus node ablation and AAIR pacemaker. In contrast, the 3 patients on clonidine had greater symptom resolution and fall in resting and exercise heart rates at 3 months follow-up. Resting mean HR was 81±3 (range 78–83) and mean HR with exertion was 144±18 (range 132–164). The HR variability pre and post treatment is shown in Abstract 156 figure 1. <h3>Discussion</h3> In our case series of 6 patients, Clonidine was more effective than Ivabradine both in terms of reducing heart rate and treating symptoms for patients with inappropriate sinus tachycardia. Patients with coexisting hyperadrenergic symptoms may benefit the most. A trial of Clonidine can be recommended before considering sinus node ablation. Formal randomised controlled trials are needed to confirm our findings.

Ambulatory blood pressure monitoring, 2D-echo and clinical variables relating to cardiac events in ischaemic cardiomyopathy following cardioverter-defibrillator implantation

Evaluation of ambulatory blood pressure monitoring (ABPM), two-dimensional (2D) echo and clinical variables in predicting cardiac death and acute decompensated heart failure in patients with ischaemic cardiomyopathy and receiving a cardioverter-defibrillator implantation. We studied 180 consecutive patients (169 men) on an out-patient basis, with systolic dysfunction (ejection fraction ≤35%) and previous myocardial infarction. All received a cardioverter defibrillator (ICD) (116 dual chamber, 36 monocameral and 28 biventricular), for primary prevention of sudden death and standard medical therapy for heart failure. Mean follow-up was 11.7 months. Two-dimensional echo was performed just before ICD implantation, ABPM and haematological samples 2 weeks later. Age, ejection fraction, creatinine, haemoglobin concentration, mean 24-h systolic blood pressure, mean 24-h diastolic blood pressure, mean 24-h heart rate, brain natriuretic peptide, QRS duration, % paced beats, ventricular scar, biventricular pacing, sex and diabetes were considered. Cox proportional hazards regression analysis was used to explore the relationship between events. ROC curves were built for each independent variable. Events occurred in 47 patients (26%); 7 deaths for refractory heart failure and 40 hospitalizations for acute decompensated heart failure. Low mean 24-h systolic blood pressure [hazard ratio 0.96, 95% confidence interval (CI) 0.93-0.99, P = 0.02], high creatinine (hazard ratio 1.61, 95% CI 1.06-2.47, P = 0.01), low haemoglobin concentration (hazard ratio 0.81, 95% CI 0.65-0.99, P = 0.04) and older age (hazard ratio 1.04, 95% CI 1.01-1.08, P = 0.02) were independent predictors of events. Ambulatory systolic blood pressure, haemoglobin, creatinine and age can stratify risk of death and acute decompensated heart failure in patients with ischaemic cardiomyopathy and ICD in whom 2D-echo ejection fraction is not predictive.

Cardiovascular Safety of QVA149, a Combination of Indacaterol and NVA237, in COPD Patients

ABSTRACTThis study assessed the cardiovascular safety of QVA149, an inhaled, once daily, bronchodilator combination containing two 24-hour bronchodilators, the long-acting β2-agonist indacaterol and the long-acting muscarinic antagonist glycopyrronium (NVA237). In this randomised, double-blind, placebo-controlled, parallel-group study, 257 patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) were randomised to receive QVA149 (indacaterol/NVA237) 600/100 μg, 300/100 μg or 150/100 μg, indacaterol 300 μg or placebo, once daily for 14 days. The primary endpoint was change from baseline in 24-h mean heart rate versus placebo on Day 14. 255 patients were included in the safety analysis (mean age 63.8 years, 76.5% male, post-bronchodilator forced expiratory volume in one second [FEV1] 53.2% predicted, FEV1/FVC [forced vital capacity] 50.0%, mean 24-h heart rate 79.6 bpm). There were no clinically significant differences in the 24-h mean heart rate on Day 14 between the three doses of QVA149 and placebo or indacaterol. The confidence intervals of these treatment differences (contrasts) were within the pre-specified equivalence limit (-5 to 5 bpm). No clinically relevant differences in QTc interval (Fridericia's) were observed between groups on Days 1, 7 and 14. Once-daily QVA149 was well tolerated in COPD patients with a cardiovascular safety profile and overall adverse event rates similar to placebo.

Continuous positive airway pressure treatment for obstructive sleep apnoea reduces resting heart rate but does not affect dysrhythmias: a randomised controlled trial

Obstructive sleep apnoea (OSA) is associated with cardiovascular morbidity and may precipitate cardiac dysrhythmias. Uncontrolled reports suggest that continuous positive airway pressure (CPAP) may reduce dysrhythmia frequency and resting heart rate. We undertook a randomised controlled trial of therapeutic CPAP and compared with a subtherapeutic control which included an exploration of changes in dysrhythmia frequency and heart rate. Values are expressed as mean (SD). Eighty-three men [49.5 (9.6) years] with moderate-severe OSA [Oxygen Desaturation Index, 41.2 (24.3) dips per hour] underwent 3-channel 24-h electrocardiograms during normal daily activities, before and after 1 month of therapeutic (n = 43) or subtherapeutic (n = 40) CPAP. Recordings were manually analysed for mean heart rate, pauses, bradycardias, supraventricular and ventricular dysrhythmias. The two groups were well matched for age, body mass index, OSA severity, cardiovascular risk factors and history. Supraventricular ectopics and ventricular ectopics were frequently found in 95.2% and 85.5% of patients, respectively. Less common were sinus pauses (42.2%), episodes of bradycardia (12%) and ventricular tachycardias (4.8%). Compared with subtherapeutic control, CPAP reduced mean 24-h heart rate from 83.0 (11.5) to 79.7 (9.8) (P < 0.002) in the CPAP group compared with a non-significant rise (P = 0.18) from 79.0 (10.4) to 79.9 (10.4) in the subtherapeutic group; this was also the case for the day period analysed separately. There was no significant change in the frequencies of dysrhythmias after CPAP. Four weeks of CPAP therapy reduces mean 24-h heart rate possibly due to reduced sympathetic activation but did not result in a significant decrease in dysrhythmia frequency.

Recombinant Human Thyrotropin Enhances Endothelial-Mediated Vasodilation of Conduit Arteries

Endothelial cells possess receptors to TSH. Their role is largely unknown. The objective of the study was to determine whether elevated serum TSH levels, as occur in hypothyroidism, affect endothelial function of large arteries and vascular risk biomarkers. Thirty-four consecutively recruited patients, who had undergone thyroidectomy for thyroid carcinoma, were studied in connection with one of the monitoring procedures based on recombinant human (rh) TSH administration. Flow-mediated dilation (FMD) of the brachial artery and serum vascular risk markers were measured at baseline and for 5 d after the administration of rhTSH (0.9 mg im on d 1 and 2). Holter electrocardiogram and echocardiography were performed on d 2. rhTSH caused a rapid increase in flow-mediated dilation from the basal value of 10.2 to 15.6% at 6 h (P < 0.0000001), to 16.1% on d 2 (P < 0.0000001), and to 14.9% on d 6 (P = 0.0015). The results were identical when the analysis was made in a subgroup of 19 patients free of vascular risk conditions. Vascular cell adhesion molecule-1, TNFalpha, IL-6, and high sensitive C-reactive protein were unaffected by rhTSH, whereas homocysteine was decreased. Arterial blood pressure, mean 24-h heart rate, and left ventricular function were unaffected by rhTSH. rhTSH causes marked and persistent activation of the endothelial mediated vasodilation, independent of systemic hemodynamic changes.

Office and out of office heart rate measurements: which clinical value?

Office and out of office heart rate measurements: which clinical value?

Early signs of left ventricular dysfunction in adolescents with Type 1 diabetes mellitus: The importance of impaired circadian modulation of blood pressure and heart rate

Diabetic cardiomyopathy is a well-defined complication of diabetes that occurs in the absence of ischemic heart disease or hypertension. Moreover impaired circadian blood pressure (BP) variation has been associated with autonomic dysfunction. The aim of our study was to evaluate diurnal BP fluctuations and autonomic function and their association with left ventricular function in adolescents with Type 1 diabetes mellitus (T1DM). In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/-SD) age of 17.3 (+/-4.1) yr and a mean (+/-SD) diabetes duration of 8.5 (+/-3.3) yr, 24-h ambulatory BP was recorded. Moreover 24-h heart rate (HR) monitoring was performed. Myocardial structural parameters were studied by echocardiogram. Left ventricular end-diastolic (EDDLV) and end-systolic diameters (ESDLV) were estimated and left ventricular mass index (LVMI) was calculated using the Devereux formula. The patients were divided into 2 groups according to the absence of decrease (non-dippers) or the decrease (dippers) of nocturnal diastolic BP (DBP). The non-dippers showed, in comparison with the dippers, reduced mean 24-h HR (79.6 vs 84.0 beats/min, p=0.05) and reduced mean day-time HR (81.3 vs 86.0 beats/min, p=0.05). The nondippers also presented greater ESDLV (28.7 vs 25.9 mm, p=0.001) and EDDLV (47.8 vs 45.1 mm, p=0.040), and LVMI (90.2 vs 78.3 g/m2, p=0.044), in comparison with the dippers. During stepwise multiple regression, the most important variables affecting LVMI were mean HR (day): (b=-0.40, p=0.001), high frequency domain variable of HR variability (b=0.38, p=0.016) and glycosylated hemoglobin (b=0.67, p=0.001). In conclusion, we found that a group of normotensive diabetic adolescents with impaired nocturnal BP reduction, also had autonomic dysfunction, together with impaired left ventricular function. These findings suggest that there is a close relationship between autonomic function and left ventricular remodeling in patients with T1DM, which may be attributed to altered diurnal BP profile, autonomic neuropathy and poor glycemic control.

Differences between diabetic and non-diabetic hypertensive patients with first acute non-ST elevation myocardial infarction and predictors of in-hospital complications

This investigation was undertaken to compare diabetic and non-diabetic hypertensive patients with a first acute non-ST segment elevation myocardial infarction (NSTEMI) and to assess the impact of clinical and laboratory parameters on the occurrence of in-hospital complications. The study population comprised 112 consecutive male hypertensive patients with their first NSTEMI, who were divided into two groups according to the presence of type 2 diabetes mellitus. All patients underwent echocardiography and 24-h electrocardiographic (ECG) and blood pressure monitoring within 48 h from admission. Diabetic hypertensive patients had significantly higher mean daytime, night-time, 24-h systolic blood pressure and heart rate and hypertensive peaks (P < 0.01), more episodes of asymptomatic ST segment depression (P < 0.05), which were also more severe and prolonged (P < 0.01), and more episodes of non-sustained ventricular tachycardia (P = 0.01). Diabetic patients showed a greater left ventricular mass index (LVMI) and a lower left ventricular ejection fraction (LVEF) (P < 0.01). In-hospital adverse clinical events were more frequent in diabetic hypertensives compared to non-diabetics (40.3% versus 18.1%, P = 0.01). In particular, heart failure occurred during hospitalization in 33.3% versus 14.5% (P = 0.02). The difference in transient cerebral ischaemic attacks did not reach statistical significance (7.0% versus 1.8%, P = 0.18). Multivariate Cox proportional hazards analysis showed that the only independent predictors for the occurrence of in-hospital adverse clinical events in diabetic patients were: 24-h systolic blood pressure variability [relative risk (RR) = 1.013, 95% confidence interval (CI) = 1.001-1.025, P = 0.03]; mean 24-h heart rate (RR = 7.05, 95% CI = 1.35-35.9, P = 0.02) and the LVMI (RR = 1.9, 95% CI = 1.121-3.785, P = 0.02). This study indicates that in-hospital complications, including heart failure and transient cerebral ischaemia, occur frequently during the acute phase of a first NSTEMI in patients with both diabetes and hypertension. The coexistence of diabetes and hypertension doubles the risk of complications with respect to hypertension alone. In addition, adverse events may appear despite an initial uncomplicated clinical presentation, which can be predicted by the early assessment of heart rate and blood pressure behaviour and by the echocardiographic assessment of left ventricular mass.

Androgen excess is associated with the increased carotid intima-media thickness observed in young women with polycystic ovary syndrome

We evaluated carotid intima-media thickness (CIMT) as an early marker of atherosclerosis, as well as its main determinants among androgen excess, obesity and insulin resistance, in patients with polycystic ovary syndrome (PCOS). We selected 40 PCOS patients and 20 non-hyperandrogenic women who were similar in terms of age and grade of obesity. Complete clinical, metabolic and hormonal profiles and left common CIMT measurements were obtained. Patients with PCOS presented with increased mean CIMT values when compared with controls (F = 8.575; P = 0.005), and this was independent of obesity. Five PCOS patients but no controls had increased CIMT values. CIMT correlated directly with serum total and free testosterone, androstenedione and dehydroepiandrosterone-sulfate levels and mean 24-h heart rate (HR), and inversely with the insulin sensitivity index (ISI), but no correlation was observed with the body mass index (BMI). Multiple stepwise linear regression models showed that in PCOS patients, the main determinants of CIMT were serum total testosterone or androstenedione concentrations, with no influence of ISI or the mean 24-h HR. Compared with control women, PCOS patients present with an increased CIMT, independent of obesity and related directly to androgen excess; this suggests that hyperandrogenism is associated with atherosclerosis and cardiovascular risk in these women.

QT interval prolongation in association with impaired circadian variation of blood pressure and heart rate in adolescents with Type 1 diabetes

The aim of our study was to assess diurnal blood pressure (BP) and heart rate variability and their possible relationship to the duration of the QT interval in adolescents with Type 1 diabetes. In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/- sd) age of 17.3 (+/- 4.1) years and a mean (+/- sd) diabetes duration of 8.5 (+/- 3.3) years, 24-h ambulatory BP was recorded. In addition, 24-h heart rate (HR) monitoring was performed and QT and corrected QT (QTc) intervals were estimated as indices of autonomic function. The patients were divided into two groups according to the absence of a decrease (non-dippers) or the presence of a decrease (dippers) in nocturnal diastolic BP (DBP). In comparison with the dippers, the non-dippers showed reduced mean 24-h HR (79.6 vs. 84.0 beats/min, P = 0.05) and reduced mean daytime HR (81.3 vs. 86.0 beats/min, P = 0.05). The QT interval was prolonged in the non-dippers (366.3 vs. 347.5 ms, P = 0.015), and end systolic (28.7 vs. 25.9 mm, P = 0.004) and end diastolic left ventricular diameters (47.8 vs. 45.5 mm, P = 0.037) were greater. In stepwise multiple regression, HR variables were the most important factors affecting DBP ratio or the duration of the QT interval. In conclusion, normotensive diabetic adolescents with impaired nocturnal BP reduction also have impaired autonomic function tests, in association with prolonged QT interval and increased left ventricular diameters. These findings suggest that diabetic adolescents who have the 'non-dipper' phenomenon may need close follow-up for the possible development of vascular complications, such as cardiac arrhythmias and left-ventricular hypertrophy.

757 Ambulatory blood pressure monitoring and 2D-echo in predicting non arrhythmic cardiac events after ICD implantation for MADIT II criteria. A new prognostic index

Aim:We compared ambulatory blood pressure monitoring (ABPM) and 2D echo to predict cardiac death and heart failure (combined end-point) after implantation of internal cardiac defibrillator (ICD) in 135 consecutive patients, all fulfilling MADIT II criteria; 115 men and 20 females, mean age 66±7, 86 with dual chamber ICD, 20 with cardiac resinchronization therapy (CRT), 29 patients received single chamber ICD. Methods: ABPM was performed 2 weeks after ICD implantation on outpatients basis with Spacelabs 90207. Mostpatients were on medical therapy with betablockers (75%), ace-inhibitors (90%) and diuretics (90%) at the time of ABPM evaluation. ABPM variables considered were: mean 24hour Systolic Blood Pressure (m24hSBP), mean 24hour Diastolic Blood Pressure (m24hDBP), mean 24h Heart Rate (m24hHR), Pulse pressure (PP). 2D-echo was performed before ICD implantation. LVEF was calculated by Simpson rule. Age, Blood Creatinine (BC) and CRT were also considered in statistical analysis. Results: At 1 year follow-up there were 25 cardiac events (18%), 4 cardiac deaths (cardiogenic shock) and 21 hospitalizations for pulmonary oedema or congestive heart failure. Age (p= 0.007), m24hDBP (p=0.02) and BC (p=0.02) were significantly associated with events, but not LVEF (p = 0.6), m24hSBP (p=0.09), m24hHR (p=0.08), PP (p= 0.27) and CRT (p=0.96). Only age (Odds ratio 3.8, p=0.01) and m24hDBP (Odds Ratio 2.3 p=0.04) remained significantly associated with clinical events in multivariate analysis. A prognostic index (PI) was built from these variables (m24hDBP and age) according to the formula: 120− age + m24hDBP. PI was significantly lower in patients with clinical events (107± 9 vs 121± 14, p 108 remained event-free in contrast with 55% of patients with PI ≤108 (p <0.001 by Log-rank test). Multivariate Cox regression analysis (including as covariates PI, age, LVEF, m24hDBP) confirmed that only PI was significantly associated with events (Hazard Ratio 11.4 with 95% confidence interval 2.4-55 with p =0.003). Conclusion:The PI built bym24hDBP and age could be a simple method to stratify the hemodynamic risk in patients with uniformally depressed LVEF (≤ 30% by MADIT II criteria) and ICD. .

Long-term effects of low-dose 17β-estradiol plus dydrogesterone on 24-h ambulatory blood pressure in healthy postmenopausal women: A 1-year, randomized, prospective study

The aim of the present 12-month, randomized, prospective controlled study was to investigate the long-term effects of low-dose oral hormone replacement therapy (HRT) on 24-h blood pressure in healthy, normotensive postmenopausal women. A total of 80 postmenopausal women received either 1 mg micronized 17β-estradiol daily, sequentially combined with 10 mg dydrogesterone for 14 days of each 28-day cycle (n = 44), or no treatment (n = 36). Ambulatory blood pressure was recorded for a 24-h period at baseline and after 12 months. After 12 months, mean 24-h systolic ambulatory blood pressure fell significantly in the HRT group (−5.4 mmHg; p < 0.01). The difference between the values in the HRT and control groups after 12 months was significant (p < 0.01). Mean 24-h heart rate also fell significantly with HRT (−4.9 beats/min; p < 0.05), and the value was significantly lower than in the control group (p < 0.05). Mean daytime systolic blood pressure fell significantly in the HRT group (−6.6 mmHg; p < 0.001), and the value was significantly lower than in the control group (p < 0.05). There were no significant changes in blood pressure in the control group. In conclusion, sequential low-dose oral HRT with 17β-estradiol/dydrogesterone caused a significant decrease in 24-h and daytime systolic ambulatory blood pressure in normotensive postmenopausal women.

Long-Term Follow-up of the Circadian Rhythm of Heart Rate and Heart Rate Variability in Healthy Elderly Patients

The long-term age-related changes in circadian rhythm of heart rate variability (HRV), that is, autonomic nervous activity, remain unknown in elderly people. Holter monitoring was conducted twice at an interval of 15 years in 15 healthy elderly patients (age: 70.0 +/- 4.1 years, at first monitoring, female: 10) and assessed the age-related changes in 24-h mean and hourly mean normal sinus R-R interval (mean NN), HRV (high frequency (HF) component, low frequency (LF) component and LF/HF) and the circadian rhythms. As a result, 24-h mean mean NN (0.976 +/- 0.115 vs 0.903 +/- 0.117 (s), p = 0.0019), LF/HF (1.681 +/- 0.731 vs 0.962 +/- 0.442, p = 0.0022), and LF (278.88 +/- 176.43 vs 179.19 +/- 132.33 (ms2), p = 0.0039) significantly decreased 15 years later, although 24-h mean HF (221.20+/-138.89 vs 310.78+/-296.73 (ms2), p = 0.1102) increased slightly. The hourly mean NN closely correlated with hourly HF and LF/HF throughout circadian rhythms both at first and second monitoring. In the morning hours, amplitude rates of all HRV indices increased significantly 15 years later. In elderly people, age-related changes in the 24-h mean heart rate (HR) were conversely dissociated from those of the 24-h mean HRV. However, the close correlation between hourly HR and HRV was preserved, even in very elderly patients. Additionally, the amplitude rates in HRV in the morning increased with age. These age-related changes of HR and HRV might be characteristic of elderly people.

Effects of n–3 fatty acids from fish on premature ventricular complexes and heart rate in humans

A large body of evidence suggests that n-3 fatty acids from fish prevent fatal heart disease. They may be an effective and safe alternative to drug treatment for reducing the risk of arrhythmia and sudden cardiac death. We investigated the effect of n-3 fatty acids on heart rate and premature ventricular complexes (PVCs), a common form of arrhythmia that may trigger arrhythmias that are more life-threatening. Patients (n=84) with >or=1440 PVCs/24 h in a previous Holter recording were randomly assigned to receive 1.5 g/d of either n-3 fatty acids or placebo. Two 24-h Holter recordings were made at baseline, and 2 were made after an intervention of approximately 14 wk. Treatment did not significantly affect the number of PVCs. The number decreased in the fish-oil group by 867/24 h more than it decreased in placebo group (95% CI: -3187, 1453). However, the mean 24-h heart rate was significantly affected, decreasing in the fish-oil group by a mean of 2.1 beats/min more than it decreased in the placebo group (95% CI: -3.9, -0.3). Supplementation with 1.5 g n-3 fatty acids/d from fish does not substantially suppress the number of PVCs in a patient population with frequent PVCs. However, n-3 fatty acids decreased heart rate by 2.1 beats/min, a significant decrease that predicts a lower risk of sudden death.

Heart rate variability in soccer players with mitral valve prolapse or benign arrhythmia

Numerous studies have reported increased cardiac vagal activity in well endurance-trained athletes. However, no clear data exist regarding the cardiac autonomic activity in athletes with common cardiovascular findings, such as mild mitral valve prolapse (MVP) and transient benign arrhythmias. Therefore, the purpose of this study was to investigate and compare the cardiac autonomic outflow by heart rate variability (HRV) analysis between soccer players with mild MVP and rhythm disorders and other athletes with transient benign arrhythmias but without any structural cardiac disease. Twenty Greek male soccer players with mild MVP (group A, aged 20.2±4.5 years), 20 players with benign cardiac rhythm and conduction disorders without structural cardiac disease (group B, aged 21.0±3.6 years) and 20 healthy age-matched sedentary men (group C) were examined. All subjects underwent clinical evaluation, resting electrocardiogram for QTc calculation, echocardiography and 24-h ambulatory Holter recordings for HRV analysis. The mean 24-h heart rate, the HRV index and the mean 24-h R-R interval were significantly increased in all athletes compared to controls (p<0.05). Moreover, group A presented significantly decreased HRV index compared to group B by 18.2% (p<0.05). Resting QTc was prolonged only in group B compared to groups A and C by 9.5% and 11.2%, respectively (p<0.05), whereas no significant difference was found between groups A and C. It is concluded that athletes with MVP present limited exercise-induced cardiac vagal predominance compared to those with benign arrhythmias and without any structural cardiac disease.

Effects of valsartan and nifedipine coat-core on systemic arterial stiffness in hypertensive patients

The aim of this study was to compare the effects of long-term antihypertensive treatment on brachial-ankle pulse wave velocity (PWV), a marker of systemic arterial stiffness, between angiotensin II receptor blocker valsartan and long-acting calcium channel blocker nifedipine coat-core. Forty-one patients (54 +/- 3 years of age, 20 men and 21 women) with essential hypertension (155 +/- 3/95 +/- 3 mm Hg) were randomly allocated to the treatment with valsartan (80 mg once daily) or nifedipine coat-core (20 mg once daily). Brachial-ankle PWV and 24-h ambulatory blood pressures (BP) were measured before and 3 months after treatment. Baseline data did not differ between the valsartan and nifedipine groups. The PWV also was similar between the groups (1669 +/- 65 v 1622 +/- 64 cm/sec). Three months of treatment similarly reduced resting systolic and diastolic BP (nifedipine, -18.4 +/- 4.2/-11.9 +/- 2.7 mm Hg; valsartan, - 17.4 +/- 3.3/-9.8 +/- 2.1 mm Hg, all P < .001). The PWV was significantly reduced compared with baseline values in the valsartan group (-195 +/- 42 cm/sec, P < 0.001) but not in the nifedipine group (-69 +/- 40 cm/sec, NS). The 24-h mean heart rate increased in the nifedipine group but remained unchanged in the valsartan group, although BP were similarly lowered for 24 h. A tachycardic response was associated with an increase or lesser reduction in PWV in a group treated with nifedipine (r = 0.584, P < .01). These data suggest that long-term treatment with valsartan could reduce arterial stiffness better than nifedipine-coat core. The favorable vascular effect of valsartan was due in part to its nonhypotensive effect. The expected decrease in arterial stiffness may be offset by reflex sympathetic activation in some patients treated with nifedipine.

Autonomic nervous function, arterial stiffness and blood pressure in patients with Type I diabetes mellitus and normal urinary albumin excretion

Type I diabetic patients (DM-1) with an elevated urinary albumin excretion (UAE>30 mg/24 h) have a high cardiovascular risk. However, DM-1 patients with normal UAE have incipient abnormalities of the cardiovascular and nervous systems, such as elevations of blood pressures, increases in arterial stiffness and deterioration of autonomic nervous function. We studied the interrelationships of these abnormalities in normoalbuminuric DM-1 patients. In 76 patients, we performed two cardiovascular reflex tests (deep in- and expiration test (IE test) and lying-to-standing test (LS test)), and determined aortic pulse wave velocity (PWV), local arterial compliances of the common carotid, femoral and brachial arteries, and 24-h blood pressures. The DeltaRRmax value of the LS test was associated with aortic PWV (negatively) and the compliance coefficients of the carotid, femoral and brachial arteries. Per 100-ms increase in DeltaRRmax, pulse wave velocity decreased by 0.39 m/s, compliance coefficients of the carotid, femoral and brachial arteries increased by 0.06, 0.08 and 0.05 mm2/kPa, respectively. These associations were independent of age, 24-h mean arterial pressure and 24-h heart rate. Increases in arterial stiffness were associated with increases in 24-h systolic and pulse pressure (per 1 m/s increase in PWV, systolic and pulse pressure increased by 2.1 and 1.7 mmHg, respectively). In normoalbuminuric DM-1 patients, deterioration of autonomic nervous function is associated with an increase in arterial stiffness, which, in turn, was associated with, and may cause, increased systolic and pulse pressure. These findings suggest that preventive strategies targeting autonomic dysfunction may reduce cardiovascular morbidity in diabetes.

Improvement of left ventricular hypertrophy and arrhythmias after lanreotide-induced GH and IGF-I decrease in acromegaly. A prospective multi-center study.

We report the results of a prospective Italian multi-center study of the effects of lanreotide, a slow-release somatostatin analog, on left ventricular morphology and function and on the prevalence of ventricular arrhythmic events in 19 patients with active, newly diagnosed, uncomplicated acromegaly. Cardiac features were evaluated with Doppler-echocardiography and 24-h Holter ECG monitoring at baseline and after 6 months of lanreotide therapy. Fifteen patients (78.9%) had left ventricular hypertrophy. Lanreotide treatment significantly decreased the left ventricular mass (127.8+/-6.9 vs 140.7+/-7.1 g/m2, p<0.001) and left ventricular hypertrophy significantly disappeared in 6 of these patients. Treatment did not significantly affect systolic function, whereas it increased the Doppler-derived early-to-late mitral flow velocity, (E/A) ratio, of early-to-late trans-mitral flow velocity (1.34+/-0.1 vs 1.09+/-0.06, p=0.001). Stroke volume was slightly but not significantly increased after treatment, whereas systolic BP was significantly higher (134+/-14 vs 129+/-13 mmHg, p<0.05). The 24-h mean heart rate was significantly reduced after treatment (66.5+/-11 vs 71.5+/-20 beats/min, p<0.05). Supra-ventricular premature beats (>50/24 h) occurred in 16.6% of patients and were unaffected by treatment. Differently, ventricular premature beats (>50/24 h) occurred in 33.3% of patients before treatment vs 16.5%, after treatment. In conclusion, lanreotide reduced the left ventricular mass, and improved ventricular filling and ventricular arrhythmic profile.

Effects of GH replacement on 24-h ambulatory blood pressure and its circadian rhythm in adult GH deficiency.

Increased prevalence of hypertension and cardiovascular mortality have been reported in hypopituitary patients who had been appropriately replaced with conventional pituitary hormones except GH. Growth hormone replacement (GHR) results in improvement of surrogate markers of cardiovascular function. Data on effects of GHR on blood pressure (BP) in adult growth hormone deficiency (AGHD), however, remain contradictory. There are as yet no reports on BP circadian rhythms in untreated or treated AGHD. Therefore, in a 12-month follow-up study, we evaluated the effects of GHR on ambulatory blood pressure (ABP) in AGHD patients. A prospective, open treatment design study to determine the effects of GHR on ABP and heart rate in AGHD patients. GH was commenced at a daily dose of 0.5 IU, and titrated up by increments of 0.25 IU at 4-weekly intervals to achieve and maintain IGF-I standard deviation score (IGF-I SD) between the median and upper end of the age-related reference range. Twenty-two, post-pituitary surgery, severe AGHD patients (11 men), defined as peak GH response < 9 mU/l to provocative testing were recruited. The mean age +/- SEM was 48.8 +/- 2.5 years. Twenty-one patients required additional pituitary replacement hormones following pituitary surgery and were on optimal doses at recruitment. Twenty-four-hour ABP and heart rate (HR), body mass index (BMI), waist hip ratio (WHR) and total body water (TBW) were measured before and after 12 months on GHR. Cosinor analysis was used to analyse BP and HR circadian rhythm parameter estimates. Target IGF-I SD was achieved within 3 months of commencement of GHR in all patients (-3.5 +/- 0.4 at baseline vs. 0.8 +/- 0.2 at 3 months, P < 0.001) and remained within range at 12 months (1.1 +/- 0.2, P < 0.001 compared to baseline). A significant increase in TBW (45.8 +/- 1.2 vs. 47.8 +/- 1.5 kg, P < 0.05) but no significant change in BMI (30.7 +/- 2.2 vs. 31.8 +/- 2.7, P = NS) or WHR (0.95 +/- 0.02 vs. 0.93 +/- 0.02, P = NS) was observed after 12 months on GHR. The 24-h mean systolic ABP (SBP; 126.2 +/- 2.8 vs. 120.1 +/- 2.7 mmHg, P < 0.001) and diastolic ABP (DBP; 78.2 +/- 1.6 vs. 71.4 +/- 1.8 mmHg, P < 0.001) significantly decreased following GHR with a parallel increase in 24-h mean HR (69.6 +/- 2.5 vs. 73.8 +/- 2.5 beats/min; P < 0.001). A significant nocturnal decrease in SBP and DBP was observed both before (SBP; daytime, 129.1 +/- 2.8 vs. night time, 115.9 +/- 3.0 mmHg, P < 0.001 and DBP; daytime, 80.7 +/- 1.6 vs. night time, 69.2 +/- 1.8 mmHg, P < 0.001) and following GHR (SBP; daytime, 122.8 +/- 2.6 vs. night time, 110.0 +/- 3.6 mmHg, P < 0.001 and DBP; daytime, 73.9 +/- 1.8 vs. night time, 62.0 +/- 2.3 mmHg, P < 0.001). Individual and population-mean cosinor analysis demonstrated significant circadian rhythms for SBP, DBP and HR before and after 12 months on GHR (P < 0.001), suggesting that SBP, DBP and HR circadian rhythms were not altered by GHR. There was, however, a significant reduction in SBP (124.2 +/- 2.8 vs. 118.4 +/- 2.8 mmHg, P < 0.001) and DBP (77.0 +/- 1.6 vs. 70.2 +/- 1.8 mmHg, P < 0.001) MESOR with an increase in HR MESOR (68.9 +/- 2.5 vs. 72.2 +/- 2.4 beats/min, P < 0.01) following GHR. Systolic and diastolic BP and HR circadian rhythms are preserved in AGHD following 12 months of GHR. However, there is a significant decrease in 24-h mean SBP and DBP and increase in 24-h mean HR after 12 months on GHR. We postulate that this decrease in 24-h mean SBP and DBP may result in a reduction of cardiovascular morbidity and mortality and may explain the beneficial effects of GHR on cardiovascular system previously reported in AGHD patients.