Mean 24-hour Heart Rate Research Articles

Assessment of heart rate measurements obtained from a smart collar compared to 24-hour Holter Monitoring in Healthy Dogs.

ObjectivesThe primary objective was to compare the 24-hour mean heart rate (HR) provided by a smart collar with 24-hour ambulatory electrocardiography (Holter) in healthy dogs. The secondary objective was to compare the two-minute HR values between the two methods during periods of activity and rest. Animals, Materials, and MethodsTwelve healthy dogs were fitted with both Holter and smart collars. Passing-Bablok regression and Bland-Altman agreement (BA) analysis were used to compare the 24-hour mean HR between two methods. The BA analysis for repeated measures and bias plots were used to compare two-minute HR between methods. ResultsThe regression analysis showed no significant differential or proportional bias between the methods to estimate 24-hour mean HR. The BA analysis showed a mean bias of 2.2 beats per minute (bpm) (95% confidence interval (CI) = -0.2, 4.8) with an upper limit of agreement (LOA) of 9.6 bpm (5.1, 14.1) and a lower LOA of -5.1 bpm (-9.5 to -0.6). However, BA analysis of two-minute HR showed poor agreement between methods with wide LOA at rest and during activity. The smart collar did not provide any HR information for 43% of the total possible recording duration (range = 24% to 79%). ConclusionsThe smart collar can provide a potentially clinically useful estimate of 24-hour HR in dogs with normal sinus rhythm. The collar did not provide reliable two-minute HR measurements due to inaccuracies in HR estimation during periods of activity and the inability to report any HR during large periods of the recording.

Quality of life, neuro-humoral status and physical performance in adolescents with sinus tachycardia

The variety of causes, conditions and prognosis of sinus tachycardia (ST) had determined the study examining the quality of life, neurohumoral status as well as ST course in 17-year-old adolescents compared to their peers without heart rhythm disorders. The aim was to study neurohumoral status, quality of life and physical performance in adolescents of both sexes, aged 17 years with diagnosed ST during preventive examination using 24-hour ECG monitoring. Materials and methods. In the open prospective study, 165 adolescents (74 boys and 91 girls) with a mean age of 17.5 ± 0.5 years were enrolled. 24-hour ECG monitoring showed increased heart rate >90 bpm in 12 boys and 19 girls considered themselves healthy. All the children were examined according to a program including 24-hour blood pressure monitoring, heart rate variability, serum concentrations of the main hormones, endothelin and copeptin. Health-related quality of life was measured by the SF-36 questionnaire. A physical work capacity test (PWC170) on a bicycle ergometer was evaluated in an 8-month physical rehabilitation program. Results. Adolescents of both sexes with ST were hypersympathicotonic with humoral dysregulation of the sinoatrial node, grade I arterial hypertension, elevated blood levels of estradiol and osteocalcin and low renin in females. ST in adolescents was associated with reduced physical performance, the restoration of which was accompanied by ST termination. Conclusions. The examination of the 165 adolescents with the mean age of 17.5 years who considered themselves healthy has revealed 12 (16.6 %) males and 19 (22.9 %) females with ST and mean 24-hour heart rate >90 bpm. The children have been clinically diagnosed with inappropriate ST based on international classification, that were inadequate to healthy state. ST was accompanied by hypersympathicotonic type of sinoatrial node humoral dysregulation, grade I arterial hypertension in boys, abnormal pubertal development in girls with elevated blood levels of total estradiol and osteocalcin and low free renin levels, lowered levels of quality of life on role functioning of the SF-36 questionnaire. Adolescents with ST had lower performance in the PWC170 tests. The completion of the 8-week physical rehabilitation program via stationary cycling exercises has resulted in improved physical performance based on the PWC170 test from baseline levels of 8.6 ± 1.9 kgm/min per kg body weight to 12.8 ± 2.1 kgm /min per kg in girls (p = 0.08) and from 13.2 ± 1.5 kgm/min to 15.9 ± 1.6 kgm/min per kg body weight in boys (p > 0.1), that was accompanied by ST termination.

Does dysautonomia contribute to inappropriate sinus tachycardia in patients with post-COVID-19 syndrome?

Abstract Funding Acknowledgements None. Introduction Post-COVID-19 syndrome (PCS) refers to a wide spectrum of health issues experienced by individuals who have previously had COVID-19, starting three months after acute COVID-19 and enduring for a minimum of two months. Approximately 20% of PCS patients encounter inappropriate sinus tachycardia (IST), defined as the mean 24-hour heart rate greater than 90 bpm. IST is often accompanied by symptoms including palpitations and breathlessness that hinder patients in their daily tasks. Previous research has suggested that dysautonomia, a dysfunction in the autonomic nervous system, might underlie most PCS symptoms. Yet, its role in the development of IST within the context of PCS has not been fully investigated. Purpose This retrospective study examines IST prevalence and cardiovascular symptoms in PCS patients. It also assesses cardiac autonomic function through analysing the time and frequency fluctuations between successive heart rates, termed heart rate variability, to investigate the role of dysautonomia in the development of IST in PCS. Methods Patients who continued to experience PCS symptoms 12 weeks after their initial SARS-CoV-2 infection were referred to a multidisciplinary PCS unit at our hospital. Using our electronic patient record system, we identified 685 eligible patients who underwent 24-hour Holter monitoring between March 2020 and February 2023. After excluding patients with various conditions that could affect heart rate, we performed a comparative sub-analysis on 524 patients, dividing them into two age- and gender-matched groups of IST (n=100) and non-IST (n=424). The ECG data extracted from the 24-hour Holter records of these patients were entered into the KUBIOS software for HRV analysis and assessment of sympathetic and parasympathetic activity which could indicate cardiac dysautonomia. Demographic data was analysed using basic descriptive statistics and a chi-square test between the two groups. The normality of each parameter was tested using the Shapiro-Wilk test. Using Mann-Whitney and unpaired t-tests, we statistically analysed the differences between the IST and non-IST groups on the GraphPad Prism software. Results The LF/HF ratio was significantly higher in the IST group (2.78 ± 1.89) compared to the non-IST group (2.15 ± 1.93, p<0.001). The sympathetic nervous system (SNS) index was significantly higher in the IST group (1.50 ± 0.77 versus -0.13 ±0.70, p<0.001), whilst the parasympathetic nervous system (PNS) index was significantly lower in the IST group (-1.75 ± 0.65 versus -0.16 ± 1.61, p<0.001). Conclusions In PCS patients with IST, cardiac dysautonomia leads to a shift in the cardiac sympathovagal balance towards PNS and subsequently increased SNS activity, with a more pronounced effect on the parasympathetic side. Addressing dysautonomia and promoting parasympathetic activity could thereby improve PCS diagnostic and treatment strategies to restore a balanced autonomic regulation of the heart.

Natural History of Nonsurgical Complete Atrioventricular Block in Children and Predictors of Pacemaker Implantation

BackgroundData on the natural history of complete atrioventricular block (CAVB) in children are scarce, and criteria for pacemaker (PM) implantation are based on low levels of evidence. ObjectivesThis study aimed to evaluate the natural course and predictors of PM implantation in a nationwide cohort of pediatric patients with nonsurgical CAVB. MethodsAll children with CAVB in the absence of structural heart disease presenting from 1977 to 2016 were retrospectively identified, yielding 95 subjects with a mean age of 4.05 years at the first presentation with a follow-up median of 0.80 years (IQR: 0.02-6.82 years). PM implantation was performed according to the available guidelines. Serial 24-hour Holter recordings and echocardiograms were reviewed. Predictors of PM implantation performed >1 month after the first presentation were evaluated. ResultsThe minimum and mean 24-hour heart rates and maximum RR intervals had a nonlinear correlation with age (P < 0.0001 for all). The left ventricular (LV) size was moderately increased, and the shortening fraction was normal in the majority throughout follow-up. PM implantation was performed in 62 patients (65.3%) reaching guideline criteria. The mean 24-hour heart rate at presentation was a predictor of subsequent PM implantation (HR: 0.938; 95% CI: 0.894-0.983; P = 0.003 per unit increase) regardless of age at presentation. Patients presenting with a mean 24-hour heart rate >58 beats/min (>75th percentile) had a high probability of freedom from PM within the subsequent 5 years (91.7% vs 44.4%; P < 0.001). ConclusionsPediatric patients with CAVB showed an age-dependent decrease in heart rate, moderate LV dilation, and preserved LV function. The probability of subsequent PM implantation could be predicted by the heart rate profile at presentation, defining a low-risk group and allowing for individualized follow-up.

Efficacy Evaluation of the Mahuang-Fuzi-Xixin Decoction in Combination with Shenmai Injection for Bradyarrhythmia Treatment: A Systematic Review and Meta-Analysis.

Bradyarrhythmia treatment is often not timely enough, posing a potential threat to health. It is necessary to find a strategy with stable curative effects and high safety. Mahuang-Fuzi-Xixin (MFX) decoction and Shenmai injection (SMI) are compound Chinese Patent Medicines. Recent evidence has shown that the combined use of these two drugs can effectively treat bradyarrhythmia. To evaluate the effect of MFX decoction combined with SMI on bradyarrhythmia. PRISMA was followed as the guideline for this systematic review. RevMan 5.4 software was applied for meta-analysis. Eight studies were included in the analysis, with a total of 340 patients in the intervention and control groups. The results of the meta-analysis showed that the effective rate of MFX combined with SMI treatment was higher than that of SMI alone (OR = 3.27, 95% CI (2.18, 4.89), P < 0.01); after treatment, MFX combined with SMI treatment and SMI alone had no significant difference in heart rate. In the subgroup of patients with an age less than 60, the effect of MFX combined with SMI treatment on the 24-hour mean heart rate was better than that of SMI alone (MD = 3.68, 95% CI (3.14, 4.22), P < 0.01), as did the 24-hour minimal heart rate (MD = 3.48, 95% CI (3.03, 3.93), P < 0.01). In addition, the effect of MFX combined with SMI treatment on the Traditional Chinese Medicine syndrome score (TCMSS) was significantly better than that of SMI alone (MD = -2.69, 95% CI (-3.10, -2.28), P < 0.01). In terms of safety, two adverse events were reported in the SMI combined with MFX group compared to 12 in the SMI alone group. MFX combined with SMI treatment is effective in treating bradyarrhythmia. However, the results were heterogeneous. The safety of MFX combined with SMI treatment should be verified and treated with caution.

Targeting heart rate variability in heart failure: an expert opinion review on Ivabradine

Heart rate variability (HRV) in patients with chronic heart failure (CHF) predicts mortality outcomes. Assessed in time-domain and frequency-domain measures, HRV can be used to risk stratify patients with CHF. Among various interventions, lifestyle measures and various medications used to treat CHF can improve HRV. Here, we reviewed current evidence with ivabradine and its effect on HRV in patients with CHF. Besides reducing the resting and 24-hour mean heart rate (HR), ivabradine improves the HRV in patients with CHF. The improved HRV is evident in awake phase as well as during sleep. The improved HRV is seen on top of guideline-directed optimal medical therapy inclusive of beta-blockers. In our opinion, HRV should be assessed routinely in patients with CHF. Further research is required to understand the impact of improved HRV in altering the outcomes in patients with CHF. In conclusion, for CHF patients with reduced HRV, addition of ivabradine improves HRV on top of exiting therapy.

Prevalence of inappropriate sinus tachycardia among patients with sinus tachycardia

Background: The inappropriate sinus tachycardia (IST) is a syndrome characterized by increased heart rate with disturbing symptoms without obvious cause. IST is defined as a sinus heart rate &gt; 100 bpm at rest with a mean 24-hour heart rate &gt;90 bpm not due to primary causes and is associated with distressing symptoms. This study aims to assess the prevalence of inappropriate sinus tachycardia (IST) among patients presented with sinus tachycardia. Methods: This study enrolled 107 patients. All had been referred to the cardiac center of Shar teaching hospital of Sulaimaniyah city/Iraq, for tachycardia assessment. All candidates had been evaluated first by ECG, those who had resting heart rate more than 100 and had sinus rhythm were selected and further assessed by 24 hours cardiac Holter monitoring. Patients met criteria for IST when a sinus heart rate of ≥100 beats/minute at rest with a mean 24-hour HR of ≥90 bpm , in the absence of any primary cause. Results: One hundred seven patients were enrolled, majority ( 70.1%) were females . 40.2 % of them were in age group of 20-29 years old. The prevalence of IST is 4.7% ( 5 patients ).

Prognostic significance of remotely monitored nocturnal heart rate in heart failure patients with reduced ejection fraction

Elevated resting heart rate is a risk factor for cardiovascular events. The purpose of this study was to investigate the clinical significance of nocturnal heart rate (nHR) and 24-hour mean heart rate (24h-HR) obtained by continuous remote monitoring (RM) of implantable devices. We analyzed daily-sampled trends of nHR, 24h-HR, and physical activity in patients on β-blocker therapy for chronic heart failure and with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators (CRT-Ds). Patients were grouped by average nHR and 24h-HR quartile during follow-up to estimate the respective incidence of nonarrhythmic death and device-treated ventricular tachycardia/fibrillation (VT/VF). The study cohort included 1330 patients (median age 69 years [interquartile range 61-77 years]; 41% [n = 550] with CRT-D; median follow-up 25 months [interquartile range 13-42 months]). Compared with patients in the lowest nHR quartile (≤57 beats/min) group, patients in the highest quartile group (>65 beats/min) had an increased risk of nonarrhythmic death (adjusted hazard ratio [AHR] 2.25; 95% confidence interval [CI] 1.13-4.50; P= .021) and VT/VF (AHR 1.98; 95% CI 1.40-2.79; P < .001) and were characterized by the lowest level of physical activity (P≤.0004 vs every other nHR quartiles). The highest 24h-HR quartile group (>75 beats/min) showed an increased risk of VT/VF (AHR 2.13; 95% CI 1.52-2.99; P< .001) and a weaker though significant association with nonarrhythmic mortality (AHR 1.80; 95% CI 1.00-3.22; P= .05) as compared with the lowest 24h-HR quartile group (≤65 beats/min). In remotely monitored patients with implantable cardioverter-defibrillator/CRT-D on β-blocker therapy for heart failure, elevated heart rates (nHR >65 beats/min and 24h-HR >75 beats/min) were associated with increased mortality and VT/VF risk. nHR showed a stronger association than 24h-HR with worst prognosis and lowest physical activity.

Heart rhythm and autonomic regulation disorders in chronic coronary syndrome patients with community-aсquired pneumonia

Pneumonia presents a considerable challenge in patients with cardiovascular disease due to an increase in the incidence, difficulties of diagnosis and treatment, high mortality. Aim: to study the characteristics of cardiac arrhythmias and heart rhythm autonomic regulation in patients with chronic coronary syndrome (CCS) and community-acquired pneumonia (CAP), and to define their relationship with the clinical features of the disease. Materials and methods. A monocenter cross-sectional study analyzed 90 patients with CCS in parallel groups. The main group included 60 CCS patients with CAP; the control group consisted of 30 patients without concomitant CAP. A complex clinical examination of patients was performed on 1–3 days of hospital stay in accordance with the National Recommendations. Holter ECG monitoring was performed using a CARDIOSENS K device (XAI-MEDICA, Ukraine). Results. Based on the results of 24-hour ECG monitoring, heart rhythm disorders, increased duration of myocardial ischemia and ST-segment depression depth with an increase in the total duration of tachycardia episodes within 24 hours were more common in the main group patients. The severity of CAP on the PSI/PORT scale was correlated with the 24-hour mean heart rate (r = +0.31, P &lt; 0.05), the number of ventricular extrasystoles – with respiratory rate (r = +0.29, P &lt; 0.05), supraventricular extrasystoles – with the duration of ST-segment depression (r = +0.57, P &lt; 0.05). In patients with CCS and CAP, there was a decrease in the total heart rate variability (HRV), mainly in the passive period, combined with an increase in the LF/HF ratio and stress index (SI), which was directly correlated with the severity of CAP and intoxication syndrome. Conclusions. Patients with CCS and CAP are characterized by the increased 24-hour heart rate, duration of ST-segment depression, frequency of supraventricular and ventricular arrhythmias on 24-hour Holter monitoring, paroxysms of atrial fibrillation with the decreased total HRV combined with significantly increased activity of the sympathetic autonomic nervous system.

Comparison of heart rate obtained from shorter duration Holter recordings to 24-hour mean heart rate in dogs with atrial fibrillation.

The objective of this study was to evaluate the accuracy of short duration electrocardiographic (ECG) recordings extracted from ambulatory continuous ECG (Holter) to assess 24-hour mean heart rate in dogs with atrial fibrillation. In this retrospective study, Holter recordings obtained from 20 dogs with atrial fibrillation were selected for analysis. Ten out of 20 dogs were receiving drugs to control heart rate at the time of Holter evaluation. From the Holter recordings, heart rate averages were calculated for various sample durations (five-minutes, 30 minutes, one-hour, two-hours, and three-hours) for each dog. Percentage of these shorter duration ECG obtained HR averages that fell within ±10%, ±15% and ± 20% of 24-hour mean heart rate was determined for each sample duration and for each dog. Seventy five percent of heart rate averages obtained from three-hour ECG recordings fell within ±10% of 24-hour mean HR. All the heart rate averages obtained from two-hour ECG recordings fell within ±20% of 24-hour mean heart rate. Based on the results of this study it can be concluded that the duration of the ECG recording affects the prediction accuracy for 24-hour Holter mean HR. Only two and three hours of Holter recordings provided all heart rate averages within ±20% of 24-hour mean heart rate. No significant differences were noted in the prediction accuracy of shorter duration ECG recordings based on rate control therapy status. Further prospective studies are needed to assess the accuracy of HR obtained at home using various ECG recording devices to predict 24-hour mean heart rate in dogs with atrial fibrillation.

Cardiac findings in pediatric patients with spinal muscular atrophy types 2 and 3.

It is unclear whether the heart is affected in pediatric patients with milder forms of spinal muscular atrophy (SMA). Therefore, we aimed to determine the presence of any cardiac abnormalities in these patients. We conducted a cross-sectional study of children and adolescents with SMA types 2 and 3 between July 2018 and July 2019. All patients underwent a comprehensive cardiac evaluation, including history-taking, physical examination, electrocardiography, echocardiography, measurement of cardiac biomarkers (cardiac troponin T [cTnT] and N-terminal pro-brain natriuretic peptide [NT-proBNP]), and 24-hour Holter monitoring. In total, 42 patients were enrolled (27 and 15 with SMA type 2 and 3, respectively). No patient had structural heart disease, except for one with mitral valve prolapse. None had signs of ventricular dysfunction on echocardiography. Both cTnT and NT-proBNP levels were normal in all patients. Electrocardiography showed sinus tachycardia in seven patients (16.7%), and prolonged P-R interval in one (2.4%). Holter monitoring detected benign ventricular arrhythmias in two patients (4.8%), and rare supraventricular premature beats in one. The mean 24-hour heart rate was elevated in six patients (14.3%), whereas both the minimum 24-hour heart rate and the maximum R-R interval were increased in 23 (54.8%). The prevalence of cardiac disease in pediatric patients with SMA types 2 and 3 is low; however, these patients may have increased resting heart rates. A complete cardiac history and physical examination are a useful screen. Additional cardiac investigations may be performed as needed.

Night-Time Premature Ventricular Complex Positively Correlates With Cardiac Sympathetic Activity in Patients Undergoing Radiofrequency Catheter Ablation

Patients with premature ventricular complexes (PVCs) usually experience accompanying alterations of the autonomic nerve system. The timing of PVC occurrence is associated with different circadian rhythms, which may be related to the autonomic nerve imbalance. The relationship between night-time PVC and cardiac autonomic nervous activity is still obscure. Our study aimed to investigate the relationship between the number of night-time PVCs and cardiac autonomic nervous activity. We enrolled 72 patients with frequent PVCs and 27 without PVCs. The patients with PVCs were divided into two groups based on the number of night-time PVCs (i.e., PVCs occurring between 10 pm and 6 am/24-hr total PVCs; group 1: n=34, <30%; group 2: n=38, >30%). At baseline, 12-lead electrocardiogram and 24-hour Holter recording were performed. When the number of PVCs declined significantly after radiofrequency catheter ablation, Holter monitoring was performed again. Heart rate (HR) variability, mean 24-hour HR, mean daytime HR, and mean night-time HR were analysed. With a greater number of night-time PVCs, group 2 had a lower standard deviation of all NN intervals (SDNN; 116.5±38.3 vs 135.3±37.8 ms; p=0.035) and increased mean 24-hour HR (77.3±9.2 vs 73.4±7.5 beats per min; p=0.05) than group 1. The SDNN was negatively correlated with the number of night-time PVCs and mean night-time HR (r= -3.04 and r= -0.504, respectively; p=0.009 and p=<0.001, respectively), and night-time PVC proportion was positively correlated with the ratio of low-frequency power (LF)/high-frequency power (HF; r=0.319 [p=0.013]). Multivariate linear regression analysis showed that the number of night-time PVCs was an independent predictor of decreased SDNN (β= -0.446, p=0.030) and increased LF/HF ratio (β=0.027, p=0.038). After PVCs disappeared, SDNN increased significantly and the frequency domain of the square root of the mean of the sum of the squares of differences between adjacent NN intervals, NN50 count divided by the total number of all NN intervals, the time domain of natural logarithm of HF, natural logarithm of LF, and mean 24-hour HR were significantly decreased in the two PVC groups. An increased number of night-time PVCs was accompanied by enhanced cardiac sympathetic activity. After PVCs diminished, both cardiac parasympathetic and sympathetic nervous activity declined.

Abstract P177: The Dissociation of Heart Rate and Blood Pressure Masks the Regulatory Role of Heart Rate in Systemic Hemodynamics

Blood pressure (BP) and heart rate (HR) are independent cardiovascular risk factors but there is little information about interactions among HR, BP, and systemic hemodynamics throughout the day. We performed 24-hour ambulatory pulse wave analysis (Mobil-O-Graph, IEM, Stolberg, DE) with measurements at 20 minute intervals. Variables measured were: systolic and diastolic BP (SBP and DBP), HR, oscillometric pulse wave velocity (oPWV), stroke volume index (SVI), and total vascular resistance index (TVRI). We also performed regression analyses within-subjects to determine the slopes of the SVI-HR and TVRI-HR relationships within individuals and for the group. We studied 89 individuals (mean age 61 years, weight 84 kg, BP 138/82 mm Hg (38 normal or controlled BP, 51 uncontrolled BP), resting HR 69 beats/min (bpm), 36% non-white, 64% female); 24-hour mean HR was not correlated with corresponding SBP or DBP values (r= -0.013 and r= 0.154, pNS, respectively) and this dissociation persisted in corresponding day-time vs. night-time comparisons and subgroup stratification by BP control status, age, and gender. In contrast, 24-hour mean HR was strongly correlated with 24-hour mean cardiac index (r=0.629, p&lt;0.000) but strongly inversely related to mean 24-hour SVI and TVRI (r= -0.508 and r= -0.505, p&lt;0.000 each); each 10 beat/min change in mean HR was associated with a 2.3 mL/m 2 (6%) change in SVI and a corresponding 6% change in TVRI. Analysis of individual 24-hour studies also revealed no correlations between HR and BP but the within-individual slopes and correlation coefficients between HR and SVI or TVRI were more variable; higher oPWV (which correlated with the SD of SBP, p=.01) was associated with a lesser sensitivity of SVI to HR change and a greater sensitivity of TVRI to HR change (p&lt;0.001 each) independent of age, gender, or BP. We conclude that BP is normally independent of HR, which plays a hidden but important regulatory role in the underlying systemic hemodynamics between and within individuals. The clinical impact of differential sensitivity of systemic hemodynamics to HR change is not established but people with stiffer arteries display diminished SVI sensitivity and greater TVRI sensitivity to HR change, which may contribute to their greater SBP variability.

Prevalence of inappropriate sinus tachycardia and the comparison of the heart rate variability characteristics with propensity score-matched controls.

Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated resting heart rate with distressing symptoms and no secondary cause of sinus tachycardia. This study was conducted to evaluate both the prevalence of IST among symptomatic patients and heart rate variability (HRV) characteristics. The records of all consecutive symptomatic patients who had undergone 24-hour Holter monitoring between September 2015 and November 2016 at a single center were retrospectively evaluated. IST was defined as a 24-hour mean heart rate (HR) of ≥90 beats/minute and a resting HR of ≥100 beats/minute in the absence of any secondary cause of sinus tachycardia. All of the study data related to clinical characteristics, symptoms, concomitant diseases, and Holter electrocardiogram parameters were obtained from the electronic hospital records. A propensity age- and sex-matched control group was selected from a non-IST patient cohort. A total of 1865 consecutive patients were evaluated and 32% were excluded due to an inadequate Holter recording period or insufficient quality, atrial fibrillation episodes, atrioventricular block, or >1% atrial or ventricular extrasystoles. Among 1265 patients with sinus rhythm, 4.98% (n=63) had IST. The IST patients were younger (39.6±17.4 vs. 50.2±17.2 years; <0.001), and female gender was more prominent (60.3% vs. 43.8%; p=0.009). All of the time and frequency domain parameters of HRV except the low frequency/high frequency ratio were significantly reduced in the IST group compared with the propensity-matched controls. The IST prevalence among symptomatic patients in sinus rhythm was 4.98%. IST was primarily seen in younger women, and they had diminished time and frequency domain HRV parameters.

A17879 True resistance to antihypertensive treatment is not associated with increased activity of sympathetic nervous system

Objectives: Refractory hypertension (uncontrolled BP on ≥ 5 antihypertensive medications) is proposed as a form of resistance to antihypertensive therapy driven by sympathetic over-activity. Previous studies were conducted without an objective exclusion of non-adherence to blood pressure lowering. We examined associations between the degree of resistance to antihypertensive treatment and sympathetic nervous system activity in biochemically confirmed adherent patients Methods: This retrospective study included 96 patients with uncontrolled blood pressure on ≥3 medications from two specialist hypertension centres (UK and Czech Republic). Adherence was confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Blood pressure was assessed by 24-hour ambulatory blood pressure monitoring. Sympathetic activity was assessed by mean 24-hour heart rate (24HR) and its variability (24HRV). All analyses were conducted after dividing patients into three groups based on the number of prescribed antihypertensives Results: Results are as per Table 1 (univariate analysis). 24HR and 24HRV were higher in patients on 3 antihypertensive medications than those on 4 and 5+ blood pressure lowering agents (P < 0.001). In multivariate analysis (including adjustment for beta-blockers) the differences in measures of sympathetic system activity were no longer associated with the degree of therapeutic resistance to antihypertensive treatment. Use of beta-blockers, diabetes and obstructive sleep apnoea showed association with the degree of therapeutic adherence to antihypertensive treatment (P < 0.05). Conclusion: This study has demonstrated no association between sympathetic activity and degree of resistance to antihypertensive treatment once pseudo-resistance is excluded. Larger studies are required to corroborate these findings.

Usefulness of Heart Rate Control in Atrial Fibrillation Patients With Obstructive Sleep Apnea

In patients without atrial fibrillation and flutter (AF), obstructive sleep apnea (OSA) is associated with cyclic and often marked changes in heart rate (HR). We aimed to assess whether presence of OSA impacts optimal HR control in patients in AF. We retrospectively correlated diurnal HR patterns (recorded by 24-hour Holter monitoring) in patients with AF who independently also underwent diagnostic polysomnography. Exclusion criteria were paced rhythm or inadequate recordings from polysomnography and Holter monitoring. The relationship between the presence and severity of OSA and the mean, minimum, maximum HR, as well as pauses (>2 seconds) and their diurnal variation were studied. Of the 494 studied patients (age 69 ± 10 years; 26% women) mild-moderate OSA (apnea hypoxia index ≥5 and <20) was present in 171 (34%) and severe OSA (apnea hypoxia index ≥20) in 254 (51%). Mean 24-hour HR in patients with severe OSA and mild-moderate OSA was similar to those without OSA (78 vs 80 vs 79 beats per minute; p = 0.39), and there was no significant difference observed in minimum and maximum HR of these groups. However, the frequency of short pauses was greater in OSA patients (p = 0.009), with a prominent nocturnal distribution. In conclusion, OSA was not associated with increased HR in patients with AF suggesting that adequate HR control was similarly achievable in patients with and without OSA. The increased frequency of nocturnal pauses in OSA patients may function as a clinical hallmark, and the timing of pauses (during sleep vs wakefulness) should be noted before making therapeutic decisions regarding HR control.

Abstract 073: Blood Pressure Variability and Control by 24-hour Ambulatory Blood Pressure Monitoring Before and After Resection of Catecholamine-secreting Neuroendocrine Tumors

Background: Measurements obtained by 24-hour ambulatory blood pressure monitoring (ABPM), such as nocturnal dipping and 24-hour blood pressure variability, are strongly associated with long-term renal and cardiovascular outcomes. Sparse data exist about how these parameters change after resection of catecholamine-secreting neuroendocrine tumors (NETs). Methods: We performed a prospective observational study of patients who underwent resection of catecholamine-secreting NETs at Penn between January 2014 and December 2016. Patients underwent 24-hour ABPM 1-3 weeks prior to and 6-8 weeks following resection. Results: Of the 32 patients who underwent resection, median age was 56 years, with 44% males (14 of 32), 78% Caucasians (25 of 32), and 84% (27 of 32) on at least one antihypertensive medication pre-operatively. Following resection, 50% (16 of 32) were on no antihypertensive medications and 74% (20 of 27) were on less medications than at baseline. There was a significant decline in clinic systolic blood pressure ([SBP] 134.6 vs. 122.5 mmHg, p&lt;0.001), clinic pulse pressure (56.0 vs. 50.7 mmHg, p=0.037), clinic heart rate (80.8 vs. 75.5 mmHg, p=0.029), 24-hour mean SBP (133.1 vs. 127.4 mmHg, p=0.036), 24-hour SBP average real variability (10.0 vs. 9.0, p=0.031), 24-hour mean pulse pressure (54.5 vs. 51.6 mmHg, p=0.012), and 24-hour mean heart rate (78.5 vs. 74.0 bpm, p=0.023). Although the decline in nocturnal mean SBP (125.2 vs. 116.3 mmHg, p=0.007) was greater than the decline in daytime mean SBP (135.2 vs. 128.4, p=0.035), there was no reduction in non-dipping (38% vs. 44%, 12 vs. 14 of 32, p=0.854). Among patients who had masked (7 of 32), white coat (4 of 32), or sustained hypertension (9 of 32) at baseline, 60% (12 of 20, p=0.002) had controlled hypertension upon follow up. Conclusion: Following resection of catecholamine-secreting NETs, patients had a significant decline in 24-hour blood pressure variability and many experienced resolution of white coat, masked, and sustained hypertension, on less antihypertensive medications compared to baseline. There was no significant decline in non-dipping. NET resection may have greater prognostic significance than appreciated by changes in in-office blood pressure measurements and related parameters.

Independent association between age and circadian systolic blood pressure patterns in adults with hypertension.

Previous studies indicate a preliminary association between age and circadian blood pressure (BP) variation. This association would be affected by confounding factors in real-world populations. The authors investigated whether this is a convincingly independent association in a real-world population of adults with hypertension. Clinical data and findings of 24-hour ambulatory BP monitoring were obtained from 297 consecutive adults with hypertension (60.19±0.77years). BP dipping patterns were categorized based on the percentage of nocturnal BP drop. Multivariate linear regression analysis identified an independent correlation between age and percentage of nocturnal systolic BPdrop (β=-7.296; 95% CI, -10.430 to -4.162 [P<.001]). Reverse dippers were the oldest and extreme dippers were the youngest. A significant age difference was noted among patients grouped into four BP dipping patterns with and without adjustments for sex, body mass index, drugs, diabetes mellitus, smoking, 24-hour mean heart rate, and 24-hour mean systolic and diastolic BP.

The effect of the physical activity on polymorphic premature ventricular complexes in chronic kidney disease

BackgroundPolymorphic premature ventricular complexes (PVCs) are very common, appearing most frequently in patients with hypertension, obesity, sleep apnea, and structural heart disease. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of ventricular arrhythmias. Endurance exercise training clearly lowers sympathetic activity in sympatho-excitatory disease states and may be tolerated by patients with chronic kidney disease (CKD).MethodsWe assessed 40 CKD patients with hypertension with polymorphic PVCs. Patients underwent a complete medical history and physical examination. We evaluated the effectiveness of β blocker only or β blocker + exercise during 12 months of follow-up regarding the changes of the numbers of PVCs and mean heart rate (HR) by 24-hour-Holter.ResultsWe observed in the β blocker group a significant decrease in the number of polymorphic PVCs from baseline 36,515 ± 3,518 to 3, 6, 9 and 12 months of follow-up, 28,314 ± 2,938, 23,709 ± 1,846, 22,564 ± 1,673, and 22,725 ± 1,415, respectively (P < 0.001). In the β blocker + exercise group a significant decrease in the number of polymorphic PVCs also occurred from baseline 36,091 ± 3,327 to 3, 6, 9 and 12 months of follow-up, 29,252 ± 3,211, 20,948 ± 2,386, 14,238 ± 3,338, and 6,225 ± 2,319, respectively (P < 0.001). Comparisons between the two groups at the same time point showed differences from the sixth month onwards: the 6th (Δ = −2,761, P = 0.045), 9th (Δ = −8,325, P < 0.001) and 12th (Δ = −16,500, P < 0.001) months. There was an improvement during the 12 months of follow-up vs. baseline, after the β blocker or β blocker + exercise in mean 24-hour HR Holter monitoring, creatinine values, eGFR, and ACR.ConclusionPolymorphic PVCs may be modifiable by physical activity in CKD patients with hypertension without structural heart disease.

Effects of dronedarone on ventricular repolarization and repolarization dynamics in patients with preserved left ventricular systolic function

1. Mean 24-hour heart rate (HR) and normal 24-hour RR-intervals (NNMEAN) 2. Mean 24-hour QT interval (QTe), measured from the beginning of the R-wave to the end of the T-wave 3. Mean heart rate corrected 24-hourQT interval (QTc) using the Bazett correction formula: QTc = RR 4. Standard deviation of mean 24-hour NN-intervals (SDNN), proportion of NN50 divided by total number of NNs (pNN50) and Root