Influence of heart rate on mortality after acute myocardial infarction

Physiological effects of ivabradine in heart failure and beyond

Ivabradine is a pharmacologic agent that inhibits the funny current responsible for determining heart rate in the sinoatrial node. Ivabradine's clinical potential has been investigated in the context of heart failure since it is associated with reduced myocardial oxygen demand, enhanced diastolic filling, stroke volume, and coronary perfusion time; however, it is yet to demonstrate definitive mortality benefit. Alternative effects of ivabradine include modulation of the renin-angiotensin-aldosterone system, sympathetic activation, and endothelial function. Here, we review key clinical trials informing the clinical use of ivabradine and explore opportunities for leveraging its potential pleiotropic effects in other diseases, including treatment of hyperadrenergic states and mitigating complications of COVID-19 infection.

Association between admission heart rate and in-hospital mortality in patients with acute exacerbation of chronic obstructive pulmonary disease and respiratory failure: a retrospective cohort study

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) combined with respiratory failure (RF) is a chronic respiratory disease that seriously endangers human health. This study aimed to specifically evaluate the relationship between admission heart rate (AHR) and in-hospital mortality in patients with combined AECOPD and RF to better inform clinical treatment.

METHODS

This retrospective cohort study included 397 patients admitted to a Chinese hospital between January 2021 and March 2023. The primary outcome measure was all-cause in-hospital mortality. Multivariate logistic regression analyses were performed to calculate adjusted hazard ratios (OR) with corresponding 95% confidence intervals (CI), and curve fitting and threshold effect were performed to address nonlinear relationships.

RESULTS

In total, 397 patients with AECOPD/RF were screened. The mean (± SD) age of the study cohort was 72.6 ± 9.5 years, approximately 49.4% was female, and the overall in-hospital mortality rate was 5%. Multivariate logistic regression analysis and smooth curve fitting revealed a nonlinear association between AHR and in-hospital mortality in the study population, with 100 beats/min representing the inflection point. Left of the inflection point, the effect size (OR) was 0.474 (95% CI 0.016 ~ 13.683; p = 0.6635). On the right side, each 1 beat/min increase in AHR resulted in an effect size (OR) of 1.094 (95% CI 1.01 ~ 1.186; p = 0.0281).

CONCLUSIONS

Results of the present study demonstrated a nonlinear relationship between AHR and in-hospital mortality in patients with AECOPD/RF. When AHR was < 100 beats/min, it was not statistically significant; however, AHR > 100 beats/min was a predictor of potential mortality, which increased by 9.4% for every 1 beat/min increase in AHR.

Heart rate reduction after genetic ablation of L-type Cav1.3 channels induces cardioprotection against ischemia-reperfusion injury

Background

Acute myocardial infarction (AMI) is the major cause of cardiovascular mortality worldwide. Most ischemic episodes are triggered by an increase in heart rate, which induces an imbalance between myocardial oxygen delivery and consumption. Developing drugs that selectively reduce heart rate by inhibiting ion channels involved in heart rate control could provide more clinical benefits. The Cav1.3-mediated L-type Ca2+ current (ICav1.3) play important roles in the generation of heart rate. Therefore, they can constitute relevant targets for selective control of heart rate and cardioprotection during AMI.

Objective

We aimed to investigate the relationship between heart rate and infarct size using mouse strains knockout for Cav1.3 (Cav1.3-/-) L-type calcium channel and of the cardiac G protein gated potassium channel (Girk4-/-) in association with the funny (f)-channel inhibitor ivabradine.

Methods

Wild-type (WT), Cav1.3+/-, Cav1.3-/- and Girk4-/- mice were used as models of respectively normal heart rate, moderate heart rate reduction, bradycardia, and mild tachycardia, respectively. Mice underwent a surgical protocol of myocardial IR (40 min ischemia and 60 min reperfusion). Heart rate was recorded by one-lead surface ECG recording, and infarct size measured by triphenyl tetrazolium chloride staining. In addition, Cav1.3-/- and WT hearts perfused on a Langendorff system were subjected to the same ischemia-reperfusion protocol ex vivo, without or with atrial pacing, and the coronary flow was recorded.

Results

Cav1.3-/- mice presented reduced infarct size (-29%), while Girk4-/- displayed increased infarct size (+30%) compared to WT mice. Consistently, heart rate reduction in Cav1.3+/- or by the f-channel blocker ivabradine was associated with significant decrease in infarct size (-27% and -32%, respectively) in comparison to WT mice.

Conclusion

Our results show that decreasing heart rate allows to protect the myocardium against IR injury in vivo and reveal a close relationship between basal heart rate and IR injury. In addition, this study suggests that targeting Cav1.3 channels could constitute a relevant target for reducing infarct size, since maximal heart rate dependent cardioprotective effect is already observed in Cav1.3+/- mice.

Increased discharge heart rate might be associated with increased short-term mortality after acute coronary syndrome

BACKGROUND

In acute coronary syndrome (ACS) patients there are mostly studies evaluating prognostic value of admission heart rate. We tried to understand the prognostic value of discharge heart rate in a spectrum of ACS patients.

METHODS

A total of 473 consecutive ACS patients were included in the study. Forty-three (9.1%) of them were unstable angina pectoris, 268 (56.7%) were non-ST elevation myocardial infarction and 162 (34.2%) of them were ST elevation myocardial infarction patients. Discharge heart rates of the patients were recorded and the patients were followed-up for 1 year. The primary end-point was all-cause mortality.

RESULTS

The mean age of the patients was 64 ± 12. The patients were divided into three subgroups according to discharge heart rates (<78, 78-89, ≥90 beats per minute). Patients with a higher discharge heart rate had higher serum troponin, glucose levels and higher admission heart rates, had lower ejection fraction values and had acute heart failure complication more frequently than the patients with a lower discharge heart rate. A total of 72(16%) patients died during 1 year follow-up. In multivariate logistic regression analysis, an increased discharge heart rate was independently associated with 1-month mortality after ACS, but it was not independently associated with 6-month or 1-year mortality after ACS. Every 1 bpm increase in discharge heart rate resulted in a significant increased risk of 8.2% in 1-month all-cause mortality.

CONCLUSION

Increased heart rate at discharge is an independent predictor of 1-month mortality in ACS patients. This relationship disappears after 1-month through 1-year follow-up.

Risk Factors for Arrhythmic Death, Overall Mortality, and Ventricular Tachyarrhythmias Requiring Shock After Myocardial Infarction

The VEST (Vest Prevention of Early Sudden Death Trial) showed a trend toward decreased sudden death and lower overall mortality with a wearable cardioverter-defibrillator (WCD) in the postmyocardial infarction (post-MI) period. However, it is unclear which patients should receive WCD therapy. We aimed to identify the risk factors for arrhythmic death, all-cause mortality, and ventricular tachyarrhythmias requiring appropriate shock to identify patients most likely to benefit from a WCD. The VEST trial included patients with acute MI with ejection fraction ≤35%. Using logistic regression, 7 risk factors were evaluated for association with arrhythmic death, all-cause mortality, and appropriate shock. Among 2,302 participants, 44 had arrhythmic death (1.9%) and 86 died of any cause (3.7%). Among 1,524 participants randomized to WCD, 20 experienced appropriate shock (1.3%) over 90 days. In the multivariable analyses, lower systolic blood pressure (SBP; odds ratio [OR] 1.64 per 10 mm Hg) and higher heart rate at discharge (OR 1.19 per 10 beats/min) were associated with arrhythmic death. Lower SBP (OR 1.37) and higher heart rate (OR 1.10) were associated with all-cause mortality. Higher heart rate (OR 1.20) was associated with appropriate shock. Patients with both SBP ≤100 and heart rate ≥100 were at increased odds of arrhythmic death (OR 4.82), all-cause mortality (OR 3.10), and appropriate shock (OR 6.13). In patients with acute MI and reduced ejection fraction, lower SBP and higher heart rate at discharge were strongly associated with arrhythmic death and all-cause mortality. In conclusion, these risk factors identify a select group at high risk of adverse events in a setting where WCD therapy is reasonable.

Thirty-six months recurrence after acute ischemic stroke among patients with comorbid type 2 diabetes: A nested case-control study

Background

Stroke patients have to face a high risk of recurrence, especially for those with comorbid T2DM, which usually lead to much more serious neurologic damage and an increased likelihood of death. This study aimed to explore determinants of stroke relapse among patients with comorbid T2DM.

Materials and methods

We conducted this case-control study nested a prospective cohort of ischemic stroke (IS) with comorbid T2DM. During 36-month follow-up, the second stroke occurred in 84 diabetic IS patients who were allocated into the case group, while 613 patients without recurrence were the controls. We collected the demographic data, behaviors and habits, therapies, and family history at baseline, and measured the variables during follow-up. LASSO and Logistic regression analyses were carried out to develop a prediction model of stroke recurrence. The receiver operator characteristic (ROC) curve was employed to evaluate the performance of the prediction model.

Results

Compared to participants without recurrence, the higher levels of pulse rate (78.29 ± 12.79 vs. 74.88 ± 10.93) and hypertension (72.6 vs. 61.2%) were recorded at baseline. Moreover, a lower level of physical activity (77.4 vs. 90.4%), as well as a higher proportion of hypoglycemic therapy (36.9 vs. 23.3%) was also observed during 36-month follow-up. Multivariate logistic regression revealed that higher pulse rate at admission (OR = 1.027, 95 %CI = 1.005–1.049), lacking physical activity (OR = 2.838, 95% CI = 1.418–5.620) and not receiving hypoglycemic therapy (OR = 1.697, 95% CI = 1.013–2.843) during follow-up increased the risk of stroke recurrence. We developed a prediction model using baseline pulse rate, hypoglycemic therapy, and physical activity, which produced an area under ROC curve (AUC) of 0.689.

Conclusion

Physical activity and hypoglycemic therapy play a protective role for IS patients with comorbid diabetes. In addition to targeted therapeutics, the improvement of daily-life habit contributes to slowing the progress of the IS.

Feasibility and First Results of Heart Failure Monitoring Using the Wearable Cardioverter-Defibrillator in Newly Diagnosed Heart Failure with Reduced Ejection Fraction

The wearable cardioverter-defibrillator (WCD) is used in patients with newly diagnosed heart failure and reduced ejection fraction (HFrEF). In addition to arrhythmic events, the WCD provides near-continuous telemetric heart failure monitoring. The purpose of this study was to evaluate the clinical relevance of additionally recorded parameters, such as heart rate or step count. We included patients with newly diagnosed HFrEF prescribed with a WCD. Via the WCD, step count and heart rate were acquired, and an approximate for heart rate variability (HRV5) was calculated. Multivariate analysis was performed to analyze predictors for an improvement in left ventricular ejection fraction (LVEF). Two hundred and seventy-six patients (31.9% female) were included. Mean LVEF was 25.3 ± 8.5%. Between the first and last seven days of usage, median heart rate fell significantly (p < 0.001), while median step count and HRV5 significantly increased (p < 0.001). In a multivariate analysis, a delta of HRV5 > 23 ms was an independent predictor for LVEF improvement of ≥10% between prescription and 3-month follow-up. Patients with newly diagnosed HFrEF showed significant changes in heart rate, step count, and HRV5 between the beginning and end of WCD prescription time. HRV5 was an independent predictor for LVEF improvement and could serve as an early indicator of treatment response.

Assessment of Selected Baseline and Post-PCI Electrocardiographic Parameters as Predictors of Left Ventricular Systolic Dysfunction after a First ST-Segment Elevation Myocardial Infarction

OBJECTIVE

To assess the performance of ten electrocardiographic (ECG) parameters regarding the prediction of left ventricular systolic dysfunction (LVSD) after a first ST-segment-elevation myocardial infarction (STEMI).

METHODS

We analyzed 249 patients (74.7% males) treated with primary percutaneous coronary intervention (PCI) included into a single-center cohort study. We sought associations between baseline and post-PCI ECG parameters and the presence of LVSD (defined as left ventricular ejection fraction [LVEF] ≤ 40% on echocardiography) 6 months after STEMI.

RESULTS

Patients presenting with LVSD (n = 52) had significantly higher values of heart rate, number of leads with ST-segment elevation and pathological Q-waves, as well as total and maximal ST-segment elevation at baseline and directly after PCI compared with patients without LVSD. They also showed a significantly higher prevalence of anterior STEMI and considerably wider QRS complex after PCI, while QRS duration measurement at baseline showed no significant difference. Additionally, patients presenting with LVSD after 6 months showed markedly more severe ischemia on admission, as assessed with the Sclarovsky-Birnbaum ischemia score, smaller reciprocal ST-segment depression at baseline and less profound ST-segment resolution post PCI. In multivariate regression analysis adjusted for demographic, clinical, biochemical and angiographic variables, anterior location of STEMI (OR 17.78; 95% CI 6.45-48.96; p < 0.001), post-PCI QRS duration (OR 1.56; 95% CI 1.22-2.00; p < 0.001) expressed per increments of 10 ms and impaired post-PCI flow in the infarct-related artery (IRA; TIMI 3 vs. <3; OR 0.14; 95% CI 0.04-0.46; p = 0.001) were identified as independent predictors of LVSD (Nagelkerke's pseudo R2 for the logistic regression model = 0.462). Similarly, in multiple regression analysis, anterior location of STEMI, wider post-PCI QRS, higher baseline number of pathological Q-waves and a higher baseline Sclarovsky-Birnbaum ischemia score, together with impaired post-PCI flow in the IRA, higher values of body mass index and glucose concentration on admission were independently associated with lower values of LVEF at 6 months (corrected R2 = 0.448; p < 0.00001).

CONCLUSIONS

According to our study, baseline and post-PCI ECG parameters are of modest value for the prediction of LVSD occurrence 6 months after a first STEMI.

Andrographolide protects against isoproterenol-induced myocardial infarction in rats through inhibition of L-type Ca2+ and increase of cardiac transient outward K+ currents

Myocardial infarction (MI) is the irreversible injury of the myocardium caused by prolonged myocardial ischemia and is a major cause of heart failure and eventual death among ischemic patients. The present study assessed the protective potentials of andrographolide against isoproterenol-induced myocardial infarction in rats. Animals were randomly divided into four groups: Control (Ctr) group received 0.9% saline solution once daily for 21 days, Isoproterenol (Iso) group received 0.9% saline solution once daily for 19 days followed by 80 mg/kg/day of isoproterenol hydrochloride solution on day 20 and 21, Andrographolide (Andro) group received 20 mg/kg/day of andrographolide for 21 days, and Andrographolide plus Isoproterenol (Andro + Iso) group received 20 mg/kg/day of andrographolide for 21 days with co-administration of 80 mg/kg/day of isoproterenol hydrochloride solution on day 20 and 21. After all treatments, cardiac-specific parameters that define cardiac health and early subacute MI were measured in all groups using both biophysical and pharmacological assay methods. Isoproterenol administration significantly (P < 0.05) increased cardiac mass indexes, systemic cardiac biomarkers, infarct size and caused cardiac histological alterations; significantly (P < 0.05) increased heart rate, QRS & QTc intervals and caused ST-segment elevation; significantly (P < 0.05) increased myocytes shortening, action potential duration (APD), L-type Ca²⁺ current (I_Ca,L) density and significantly (P < 0.05) decreased transient outward K⁺ current (I_to) density typical of the early subacute MI. Interestingly, pretreatment with andrographolide prevented and or minimized these anomalies, notably, by reducing I_Ca,L density and increasing I_to density significantly. Therefore, andrographolide could be seen as a promising therapeutic agent capable of making the heart resistant to early subacute infarction and it could be used as template for the development of semisynthetic drug(s) for cardiac protection against MI.

Predictors of all-cause 1-year mortality in myocardial infarction patients

Compared with the general population, myocardial infarction (MI) survivors have a higher risk of mortality in the first year after the index event.The aim of this study was to determine the associations between variables obtained during the index admission and 1-year all-cause mortality on follow-up.A cohort of 296 patients was enrolled in the study, with a median age of 63.8 ± 12.68 years. All patients received a coronary angiography and stent implantation by percutaneous coronary intervention. Each variable was tested for association with all-cause mortality, using chi-square tests for categorical and binary variables and t tests for continuous variables. The relative prognostic power of each significant variable was further evaluated by logistic regression before and after adjustment for differences in baseline characteristics.Patients who were deceased after 1-year of MI had significantly higher mean age, increased prevalence of diabetes, and elevated heart rate as compared to those who were surviving. Univariate analysis indicated that patient mortality within 1-year of MI was strongly correlated with higher rates of pump failure on admission (P < .0001), bleeding complications (P = .02), the severity of coronary artery disease measured by Gensini score (P = .04), and decreased left ventricular ejection fraction (LVEF) (P < .0001). After adjustment of baseline variables, only pump failure (P = .006) and reduced LVEF (P < .0001) were independently associated with 1-year mortality.Our study shows that LVEF dysfunction and pump failure are independent predictors of 1-year all-cause post-MI mortality, while the severity of coronary artery disease and bleeding did not qualify as independent predictors. Also, age, history of diabetes, and elevated heart rate may be used as markers for increased mortality rates.

Neuromodulating Influence of Two Electroacupuncture Treatments on Heart Rate Variability, Stress, and Vagal Activity

Introduction: Although the clinical use of electro-acupuncture is widespread, the neuromodulating influence of various applied frequencies is not well established. Objectives: Heart rate variability (HRV), stress and parasympathetic recovery are closely related to health, longevity and vitality in humans. This study was undertaken to determine the influence of different electro-therapy frequencies on various autonomic nervous system markers when applied to a Battlefield Acupuncture Protocol (BFA). Design: A detailed comparison of autonomic nervous system (ANS) response to low frequency (LF) 2.5 Hz electro-acupuncture and mid-frequency (MF) 15 Hz electro-acupuncture applied by point stimulation to acupuncture points was undertaken on 2 groups of 12 patients. Interventions: Both LFEA and MFEA were applied to Battlefield Acupuncture protocol, consisting of five (5) key acupuncture ear (auricular) points that isolate the autonomic nervous system (ANS) and central nervous system's role in the chronic/acute pain cycle. Evaluations entailed an advanced status of autonomic nervous system (ANS) function through Electro-Cardiogram (ECG) baseline markers reflecting: sympathetic stress (SI); parasympathetic vagal tone (high frequency [HF]) and heart rate variability (HRV = total power). All were repeated subsequent to electro-therapy using 2 separate electro-modalities of low-frequency (2.5 Hz) electro-acupuncture (LFEA) and Mid-Frequency (15 Hz) electro-acupuncture (MFEA). All 24 patients received one (1) elector-acupuncture session. Results: The autonomic nervous system response to LFEA (2.5 Hz) reflected a statistically significant pre-post improvement in three of the markers collected: heart rate variability (HRV) improved by 61% [p = 0.002]; sympathetic stress (SI) reduced 42% [p = 0.002]; and parasympathetic vagal tone (HF) increased 56% [p = 0.017]. In contrast, MFEA (15 Hz) showed positive but non-significant changes in outcomes in all nervous system markers. Conclusions: The autonomic nervous system response with LFEA showed a measurable reduction in sympathetic stress with subsequent improvement in vagal tone, and HRV. This positive sympathetic nervous system deactivation from LFEA application shown in this study could have a major impact on other pathologies related to human health and longevity. Further cohort studies are warranted to determine the validity of these outcomes.

Effects of heart rate reduction with ivabradine on vascular stiffness and endothelial function in chronic stable coronary artery disease

INTRODUCTION

Epidemiological and clinical studies have shown a relevant association between heart rate and cardiovascular mortality. Experimental studies identified vascular effects of heart rate reduction with the If channel inhibitor ivabradine. Therefore, the effects of heart rate reduction on endothelial function and indices of arterial stiffness were examined in patients with stable coronary artery disease in a prospective, placebo-controlled clinical crossover study.

METHODS AND RESULTS

Twenty-three patients (18 men and 5 women) with a resting heart rate (HR) of at least 70 beats per minute (bpm) and stable coronary artery disease were enrolled in this study. In a cross-over design, all patients were treated with ivabradine (Iva, 7.5 mg b.i.d.) and placebo for 6 months each. Iva reduced heart rate by 11.4 bpm (Iva 58.8 ± 8.2 bpm vs. placebo 70.2 ± 8.3 bpm, P < 0.0001). Augmentation index (AIx75), carotid-femoral pulse wave velocity (cfPWV) and central aortic blood pressure were measured using applanation tonometry (SphygmoCor). HRR by Iva increased AIx75 by 12.4% (Iva 24.3 ± 10.5% vs. placebo 21.3 ± 10.1%, P < 0.05) and reduced cfPWV by 14.1% (Iva 6.3 ± 1.7 m/s vs. placebo 7.3 ± 1.4 m/s, P < 0.01). Iva increased mean central blood pressure by 7.8% (Iva 107.5 ± 15.4 mmHg vs. placebo 99.1 ± 12.2 mmHg, P < 0.001). Endothelial function was determined measuring the flow-mediated vasodilation (FMD) of the brachial artery. HRR by Iva increased FMD by 18.5% (Iva 7.3 ± 2.2% vs. placebo 6.0 ± 2.0%, P < 0.001). Aortic distensibility was characterized by MRI. HRR by Iva increased aortic distensibility by 33.3% (Iva 0.003 ± 0.001/mmHg vs. placebo 0.002 ± 0.010/mmHg, P < 0.01) and circumferential cyclic strain by 37.1% (Iva 0.062 ± 0.027 vs. placebo 0.039 ± 0.018, P < 0.0001).

CONCLUSION

Heart rate reduction with Iva increased endothelium-dependent vasodilation and reduced arterial stiffness in patients with stable CAD. These findings corroborate and expand the results collected in experimental studies and indicate the importance of heart rate as a determinant of vascular function.

Heart rate as cardiovascular risk factor

Heart rate is a parameter that is widely used by the general population as a marker of health. The availability of wearable electronic heart rate monitoring devices and use of specific apps are widely used both at rest and during daily life activities. Resting heart rate values gained more relevance with the evidence of association between elevated heart rate values at rest and diseases and adverse events. Also longitudinal studies demonstrated a clear association between increase in heart rate over time and cardiovascular and all-cause mortality. The increased knowledge of physiological mechanisms of heart rate control and the pathophysiological mechanisms responsible for its dysfunction allows identification of the cutoff value of normalcy. This information can be used to select non-pharmacological and pharmacological interventions to reduce the cardiovascular risk both in the general population and in patients with pathophysiological conditions. This review provides an overview of the current knowledge of resting heart rate as cardiovascular risk factor.

Predictors of sudden cardiac death in high-risk patients following a myocardial infarction

AIMS

To develop a risk model for sudden cardiac death (SCD) in high-risk acute myocardial infarction (AMI) survivors.

METHODS AND RESULTS

Data from the Effect of Carvedilol on Outcome After Myocardial Infarction in Patients With Left Ventricular Dysfunction trial (CAPRICORN) and the Valsartan in Acute Myocardial Infarction Trial (VALIANT) were used to create a SCD risk model (with non-SCD as a competing risk) in 13 202 patients. The risk model was validated in the Eplerenone Post-AMI Heart Failure Efficacy and Survival Study (EPHESUS). The rate of SCD was 3.3 (95% confidence interval 3.0-3.5) per 100 person-years over a median follow-up of 2.0 years. Independent predictors of SCD included age > 70 years; heart rate ≥ 70 bpm; smoking; Killip class III/IV; left ventricular ejection fraction ≤30%; atrial fibrillation; history of prior myocardial infarction, heart failure or diabetes; estimated glomerular filtration rate < 60 mL/min/1.73 m² ; and no coronary reperfusion or revascularisation therapy for index AMI. The model was well calibrated and showed good discrimination (C-statistic = 0.72), including in the early period after AMI. The observed 2-year event rates increased steeply with each quintile of risk score (1.9%, 3.6%, 6.2%, 9.0%, 13.4%, respectively).

CONCLUSION

An easy to use SCD risk score developed from routinely collected clinical variables in patients with heart failure, left ventricular systolic dysfunction or both, early after AMI was superior to left ventricular ejection fraction. This score might be useful in identifying patients for future trials testing treatments to prevent SCD early after AMI.

Admission Heart Rate Is Associated With Coronary Artery Disease Severity and Complexity in Patients With Acute Coronary Syndrome

We evaluated the relationship between admission heart rate (HR) and coronary artery disease severity and complexity in patients with acute coronary syndrome (ACS). A total of 884 patients (mean age 59 [11] years, 24.7% female) who underwent coronary angiography for ACS and were treated with primary or selective percutaneous coronary intervention were included in this cross-sectional study. The measurement of admission HR was based on the first available resting electrocardiogram after admission. The SYNTAX score (SS) was calculated. Patients with an SS ≤ 22 (n = 538) were classified as the low SS group and those with an SS > 22 (n = 346) were classified as the intermediate-to-high SS group. Admission HR was greater in the intermediate-to-high SS group compared with the low SS group (75 [10] bpm vs 67 [8] bpm, P < .001). Admission HR was positively and significantly correlated with the SS (r = 0.475, P < .001). After multivariate analysis, admission HR (per 1 standard deviation, ie, 10 bpm) remained an independent predictor of intermediate-to-high SS (odds ratio: 3.135, 95% confidence interval: 2.538-3.873, P < .001). Admission HR is independently and positively associated with the SS. Thus, elevated admission HR may be useful to identify patients with ACS with a high coronary atherosclerotic plaque burden.

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.

Discharge Heart Rate After Hospitalization for Myocardial Infarction and Long-Term Mortality in 2 US Registries

Background Although admission heart rate predicts higher mortality after acute myocardial infarction ( AMI ), less is known about discharge heart rate. We tested the hypothesis that higher discharge heart rate after AMI is related to increased long-term mortality independent of admission heart rate, and assessed whether β blockers modify this relationship. Methods and Results In 2 prospective US multicenter registries of AMI , we evaluated the associations of discharge and admission heart rate with 3-year mortality using Cox models. Among 6576 patients with AMI , discharge heart rate was modestly associated with initial heart rate ( r=0.28), comorbidities, and infarct severity. In this cohort, 10.7% did not receive β blockers at discharge. After full adjustment for demographic, psychosocial, and clinical covariates, discharge heart rate (hazard ratio [HR]=1.14 per 10 beats per minute [bpm]; 95% CI =1.07-1.21 per 10 bpm) was more strongly associated with risk of death than admission heart rate (HR=1.05 per 10 bpm; 95% CI=1.02-1.09 per 10 bpm) when both were entered in the same model ( P=0.043 for comparison). There was a significant interaction between discharge heart rate and β-blocker use ( P=0.004) on mortality, wherein risk of death was markedly higher among those with high discharge heart rate and not on β blockers (HR=1.35 per 10 bpm; 95% CI=1.19-1.53 per 10 bpm) versus those with a high discharge heart rate and on β blockers at discharge (HR=1.10 per 10 bpm; 95% CI=1.03-1.17 per 10 bpm). Conclusions Higher discharge heart rate after AMI was more strongly associated with 3-year mortality than admission heart rate, and the risk associated with higher discharge heart rate was modified by β blockers at discharge. These findings highlight opportunities for risk stratification and intervention that will require further investigation.

Importance of elevated heart rate in the very early phase of ST-segment elevation myocardial infarction: Results from the DANAMI-3 trial

Background:

Elevated heart rate is associated with poor clinical outcome in patients with acute myocardial infarction. However, in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention the importance of elevated heart rate in the very early phase remains unknown. We evaluated the impact of elevated heart rate in the very early pre-hospital phase of ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention on cardiovascular magnetic resonance markers of reperfusion success and clinical outcome.

Methods:

In this DANAMI-3 substudy, 1560 ST-segment elevation myocardial infarction patients in sinus rhythm without cardiogenic shock were included in the analyses of clinical outcome and 796 patients underwent cardiovascular magnetic resonance to evaluate area at risk, infarct size and left ventricular ejection fraction. Heart rate was assessed on the first electrocardiogram with ST-elevation (time of diagnosis).

Results:

Despite equal area at risk (33%±11 versus 36%±16, p=0.174) patients with a pre-hospital heart rate ⩾100 beats per minute developed larger infarcts (19% (interquartile range, 9–17) versus 11% (interquartile range, 10–28), p=0.001) and a lower left ventricular ejection fraction (54%±12 versus 58%±9, p=0.047). Pre-hospital heart rate ⩾100 beats per minute was independently associated with an increased risk of all-cause mortality and heart failure (hazard ratio 2.39 (95% confidence interval 1.58–3.62), p<0.001).

Conclusions:

Very early heart rate ⩾100 beats per minute in ST-segment elevation myocardial infarction was independently associated with larger infarct size, reduced left ventricular ejection fraction and an increased risk of all-cause mortality and heart failure, and thus serves as an easily obtainable and powerful tool to identify ST-segment elevation myocardial infarction patients at high risk.

Heart rate in patients with reduced ejection fraction: relationship between single time point measurement and mean heart rate on prolonged implantable cardioverter defibrillator monitoring

Background

Heart rate (HR) is a prognostic marker that is increasingly used as a therapeutic target in patients with cardiovascular disease. The association between resting and mean HR remains unclear. We therefore set out to determine the relationship between resting HR on the electrocardiogram (ECG) obtained at a single time point, and mean HR on implantable cardioverter defibrillator (ICD) interrogation amongst patients with a reduced left ventricular ejection fraction (LVEF).

Methods

Prospective ICD data were obtained from 54 patients with LVEF < 40%. Mean HR determined using the ICD HR histograms was compared with resting HR measured on the ECG performed in the clinic.

Results

Average resting and ICD mean HRs were 67.9 ± 10.1 and 67.8 ± 9.6 bpm respectively. There was good correlation in the overall cohort (r = 0.79), in those with resting ECG HRs ≤ 70 bpm (r = 0.62), and amongst the 27 patients on intermediate-to-high dose beta-blockers (r = 0.91). However, Bland-Altman analysis demonstrated wide limits of agreement in the overall cohort (− 12.5, 12.7 bpm), at resting HRs ≤ 70 bpm (− 12.7, 9.8 bpm), and on intermediate-to-high dose beta-blockers (− 8.9, 7.4 bpm). Moreover, resting HR did not predict the 10-bpm interval where the most time was spent.

Conclusions

While resting HR correlated with mean HR in patients with reduced LVEF, and in important subgroups, the limits of agreement were unacceptably wide raising concern over the use of single time point resting HR as a therapeutic target.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0751-2) contains supplementary material, which is available to authorized users.

Association of Heart Rate with N-Terminal Pro-B-Type Natriuretic Peptide in Septic Patients: A Prospective Observational Cohort Study

BACKGROUND

Excessive sympathetic stress has multiple adverse effects during critical illness including sepsis. Recent studies showed that heart rate control had a significant effect on reducing mortality in septic shock patients. Furthermore, elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in septic patients were reportedly associated with adverse outcome. However, no study has evaluated the relationship between hemodynamic profiles of septic patients and the circulating cardiac biomarker. Our objective was to determine whether hemodynamic profiles, specifically tachycardia and new-onset atrial fibrillation (AF), were associated with NT-proBNP elevation in septic patients.

METHODS

We consecutively enrolled patients admitted to our intensive care unit (ICU). NT-proBNP levels, heart rate, and rhythm at ICU admission were measured, and all clinical and laboratory data were prospectively collected. Tachycardia was defined as a heart rate of above 100 bpm.

RESULTS

Ninety-five patients out of 267 patients (35.6%) were diagnosed as sepsis. Of these septic patients, 47 presented with tachycardia and 6 developed new-onset AF. Multivariate Cox regression analysis revealed that tachycardia was an independent predictor of 28-day overall survival in septic patients (hazard ratio, 4.22; 95% confidence interval, 1.10-27.72; P < 0.05), but not in nonseptic patients. Multivariate linear regression analysis demonstrated that the presence of tachycardia was an independent determinant of NT-proBNP elevation (P < 0.05) in septic patients, but not in nonseptic patients.

CONCLUSIONS

Tachycardia was significantly and independently associated with NT-proBNP elevation and lower survival rate in septic patients, although no association was observed in nonseptic patients. Increased NT-proBNP in sepsis with tachycardia might predict poor outcomes in ICU.

Does resting heart rate measured by the physician reflect the patient's true resting heart rate? White-coat heart rate

OBJECTIVES

In cardiology, resting heart rate (HR) and blood pressure (BP) are key elements and are used to adapt treatment. However HR measured in consultation may not reflect true resting HR. We hypothesize that there may be a "white-coat" effect like with BP and that there may be an association between HR variations and BP variations.

METHODS

This prospective, monocentric, observational, pilot study (January-April 2016) included 57 consecutive ambulatory patients at Poitiers University Hospital, France (58% male, mean age 64 years). Patients' resting HR and BP were recorded with the same automated blood pressure sphygmomanometer in consultation by the physician then with self-measurement at home.

RESULTS

In the overall cohort, we found that HR was significantly higher in consultation (70.5bpm±12.6 vs. 68.1bpm±10.1, p=0.034). HR also correlated with diastolic BP (r=0.45, p=0.001). Patients were divided into three groups to look for associations with BP: masked HR, (higher HR at home, 38.6%), white-coat HR, (lower HR at home 52.6%) and iso HR, (no change between HR at home and consultation, 8.8%). Although there was no difference between groups in diastolic BP measured in consultation, home diastolic BP was lower in the white-coat HR group (74.3mmHg±9.8 vs. 77.9mmHg±7.5, p=0.016).

CONCLUSIONS

Our study brings to light an exciting idea that could have a major therapeutic and maybe prognostic impact in cardiology: resting HR measured by the physician in consultation does not reflect true resting HR. This must be taken into account to adapt treatment.

Correlation of Admission Heart Rate With Angiographic and Clinical Outcomes in Patients With Right Coronary Artery ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: HORIZONS-AMI (The Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

BACKGROUND

Bradycardia on presentation is frequently observed in patients with right coronary artery ST-segment elevation myocardial infarction, but it is largely unknown whether it predicts poor angiographic or clinical outcomes in that patient population. We sought to determine the prognostic implications of admission heart rate (AHR) in patients with ST-segment elevation myocardial infarction and a right coronary artery culprit lesion.

METHODS AND RESULTS

We analyzed 1460 patients with ST-segment elevation myocardial infarction and a right coronary artery culprit lesion enrolled in the randomized HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trial who underwent primary percutaneous coronary intervention. Patients presenting with high-grade atrioventricular block were excluded. Outcomes were examined according to AHR range (AHR <60, 61-79, 80-99, and ≥100 beats per minute). Baseline and procedural characteristics did not vary significantly with AHR except for a more frequent history of diabetes mellitus, longer symptom-to-balloon time, more frequent cardiogenic shock, and less frequent restoration of thrombolysis in myocardial infarction 3 flow in patients with admission tachycardia (AHR >100 beats per minute). Angiographic analysis showed no significant association between AHR and lesion location or complexity. On multivariate analysis, admission bradycardia (AHR <60 beats per minute) was not associated with increased 1-year mortality (hazard ratio 1.33; 95% CI 0.41-4.34, P=0.64) or major adverse cardiac events (hazard ratio 1.08; 95% CI 0.62-1.88, P=0.78), whereas admission tachycardia was a strong independent predictor of mortality (hazard ratio 5.02; 95% CI 1.95-12.88, P=0.0008) and major adverse cardiac events (hazard ratio 2.20; 95% CI 1.29-3.75, P=0.0004).

CONCLUSIONS

In patients with ST-segment elevation myocardial infarction and a right coronary artery culprit lesion undergoing primary percutaneous coronary intervention, admission bradycardia was not associated with increased mortality or major adverse cardiac events at 1 year.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00433966.

Ivabradine in Patients with Stable Coronary Artery Disease: A Rationale for Use in Addition to and Beyond Percutaneous Coronary Intervention

Heart rate is an established prognostic marker for longevity and is an important contributor in the pathophysiology of various cardiovascular diseases, including ischemic heart disease and heart failure. Most ischemic episodes are triggered by an increase in heart rate, which causes an imbalance between myocardial oxygen delivery and consumption. In addition, increased heart rate is a modifiable risk factor for chronic heart failure. Ivabradine, an inhibitor of I_f ion channels, is an approved second-line anti-ischemic drug for the treatment of angina. Ivabradine has been shown to decrease the risk of hospitalization in patients with chronic heart failure who were previously treated with β-blockers, renin-angiotensin system blockers or mineralocorticoid receptor antagonists. This review describes the rationale for the pathophysiological and clinical use of ivabradine as an anti-ischemic agent in patients with stable coronary disease and highlights its benefits and drawbacks compared with other first- and second-line anti-anginal drugs. The review also highlights the role of ivabradine as a treatment for patients with high-risk coronary artery disease in whom first-line anti-anginal drugs are insufficient or inadequate and percutaneous coronary intervention is contraindicated or revascularization is incomplete or unsuitable.

Heart rate at admission is a predictor of in-hospital mortality in patients with acute coronary syndromes: Results from 58 European hospitals: The European Hospital Benchmarking by Outcomes in acute coronary syndrome Processes study

Aims:

The purpose of this study was to investigate the relationship between heart rate at admission and in-hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods:

Consecutive ACS patients admitted in 2008–2010 across 58 hospitals in six participant countries of the European Hospital Benchmarking by Outcomes in ACS Processes (EURHOBOP) project (Finland, France, Germany, Greece, Portugal and Spain). Cardiogenic shock patients were excluded. Associations between heart rate at admission in categories of 10 beats per min (bpm) and in-hospital mortality were estimated by logistic regression in crude models and adjusting for age, sex, obesity, smoking, hypertension, diabetes, known heart failure, renal failure, previous stroke and ischaemic heart disease. In total 10,374 patients were included.

Results:

In both STEMI and NSTE-ACS patients, a U-shaped relationship between admission heart rate and in-hospital mortality was found. The lowest risk was observed for heart rates between 70–79 bpm in STEMI and 60–69 bpm in NSTE-ACS; risk of mortality progressively increased with lower or higher heart rates. In multivariable models, the relationship persisted but was significant only for heart rates >80 bpm. A similar relationship was present in both patients with or without diabetes, above or below age 75 years, and irrespective of the presence of atrial fibrillation or use of beta-blockers.

Conclusion:

Heart rate at admission is significantly associated with in-hospital mortality in patients with both STEMI and NSTE-ACS. ACS patients with admission heart rate above 80 bpm are at highest risk of in-hospital mortality.

Ivabradine treatment prevents dobutamine-induced increase in heart rate in patients with acute decompensated heart failure

BACKGROUND

Ivabradine is a heart rate (HR)-lowering agent acting by inhibiting the If-channel. Dobutamine does increase the HR and has some deleterious effects on myocardium. So, we aimed to evaluate whether ivabradine treatment blunts a dobutamine-induced increase in HR.

METHODS

The main study population consisted of 58 acute decompensated heart failure patients requiring inotropic support with left-ventricular ejection fraction below 35%, who were randomized to ivabradine (n = 29) or control (n = 29). All patients underwent Holter recording for 6 h and then dobutamine was administered at incremental doses of 5, 10 and 15 μg/kg/min, with 6-h steps. Holter recording was continued during dobutamine infusion. Ivabradine 7.5 mg was given at the initiation of dobutamine and readministered at 12 h of infusion. Also, a nonrandomized beta-blocker group with 15 patients receiving beta-blocker was included in the analysis. Control and beta-blocker groups did not receive ivabradine.

RESULTS

In the control group, mean HR gradually and significantly increased at each step of dobutamine infusion (81 ± 11, 90 ± 16, 97 ± 14 and 101 ± 16 b.p.m., respectively; P = 0.001), whereas no significant increase in HR was observed in the ivabradine group (82 ± 17, 82 ± 15, 85 ± 14 and 83 ± 12 b.p.m., respectively; P = 0.439). Mean HR was also found to significantly increase during dobutamine infusion in the beta-blocker group (75 ± 13, 82 ± 13, 86 ± 14 and 88 ± 13 b.p.m., respectively; P = 0.001). The median increase in HR from baseline was significantly higher in the control group compared to those in the ivabradine group (5 vs. 2 b.p.m.; P = 0.007 at first step, 13 vs. 5 b.p.m.; P = 0.001 at second step and 18 vs. 6 b.p.m.; P = 0.0001 at third step of dobutamine, respectively).

CONCLUSIONS

Ivabradine treatment prevents dobutamine-induced increase in HR and may be useful in reducing HR-related adverse effects of dobutamine.

Evaluation of heart rate measurements in clinical studies: a prospective cohort study in patients with heart disease

Purpose

The purpose of this study was to evaluate the measurement of heart rate undertaken in clinical studies by (1) assessing the repeatability and reproducibility of heart rate measurements by various methods and under various conditions and (2) determining whether a single heart rate measurement at rest is representative of the circadian and inter-day variation of heart rate.

Methods

Prospective cohort study in 102 patients with various types of heart disease at Duisburg Heart Center, Germany between 2011 and 2012. The heart rate measurements were based on self-assessment, ECG tracings at rest, and bicycle stress ECG in the office as well as 24-h Holter ECG.

Results

Office measurements and self-assessment at rest as well as 24-h Holter ECG and self-assessment at rest are highly correlated, but no correlation between self-assessment and office recordings/24 h recordings under exercise conditions was seen. Coefficient of variability was below 10 % for the self-assessment and for office measurements at rest. There were no differences in coefficient of variability during the day and within the 6 days for self-assessment of heart rate at rest and circadian variation was normal.

Conclusions

At rest heart rate measurements by various methods agree sufficiently and inter-day/circadian variation is adequately represented. Under exercise conditions self-assessment of heart rate is not valuable and use of 24 h Holter as well as stress ECG recordings is necessary. Thus, self-reported heart rate measurements by the patient at rest seem to be reliable, but should be used in clinical studies only for heart rate assessment at rest.

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.

Web-Based Mindfulness Intervention in Heart Disease: A Randomized Controlled Trial

BACKGROUND

Evidence is accumulating that mindfulness training has favorable effects on psychological outcomes, but studies on physiological outcomes are limited. Patients with heart disease have a high incidence of physiological and psychological problems and may benefit from mindfulness training. Our aim was to determine the beneficial physiological and psychological effects of online mindfulness training in patients with heart disease.

METHODS

The study was a pragmatic randomized controlled single-blind trial. Between June 2012 and April 2014 we randomized 324 patients (mean age 43.2 years, 53.7% male) with heart disease in a 2:1 ratio (n = 215 versus n = 109) to a 12-week online mindfulness training in addition to usual care (UC) compared to UC alone. The primary outcome was exercise capacity measured with the 6 minute walk test (6MWT). Secondary outcomes were other physiological parameters (heart rate, blood pressure, respiratory rate, and NT-proBNP), subjective health status (SF-36), perceived stress (PSS), psychological well-being (HADS), social support (PSSS12) and a composite endpoint (all-cause mortality, heart failure, symptomatic arrhythmia, cardiac surgery, and percutaneous cardiac intervention). Linear mixed models were used to evaluate differences between groups on the repeated outcome measures.

RESULTS

Compared to UC, mindfulness showed a borderline significant improved 6MWT (effect size, meters: 13.2, 95%CI: -0.02; 26.4, p = 0.050). There was also a significant lower heart rate in favor of the mindfulness group (effect size, beats per minute: -2.8, 95%CI: -5.4;-0.2, p = 0.033). No significant differences were seen on other outcomes.

CONCLUSIONS

Mindfulness training showed positive effects on the physiological parameters exercise capacity and heart rate and it might therefore be a useful adjunct to current clinical therapy in patients with heart disease.

TRIAL REGISTRATION

Dutch Trial Register 3453.

[No reflow: What are the predictors?]

INTRODUCTION

During the past 20 years, significant progress has been made in the recanalization of ACS with ST elevation. It is now accepted that the reopening of the large coronary vessels in the acute phase of infarction by thrombolysis or angioplasty is necessary but not sufficient, because in 20-50% of cases, the coronary recanalization is an illusion of reperfusion. This phenomenon is called "no reflow".

OBJECTIVE

The main objective of our study was to identify predictors of poor perfusion or "no reflow" in the acute phase of myocardial infarction.

METHODS

Observational prospective study, in the department of cardiology and internal medicine, university hospital of Blida, over a period of 28 months from 1st September 2010 to 31st January 2013. We identified all patients hospitalized for myocardial infarction in acute phase, who underwent primary angioplasty or thrombolysis with angiographic control during a good TIMI flow. The endpoint was regression of ST segment (regression<50% ST-segment defined no reflow).

RESULTS

Three hundred and seventy-nine patients were included. The mean age was 56.3±2.1, 87.8% of patients were male. In total, 35.9% hypertensive, 27.1% diabetic type 2, 50.1% and 10.8% dyslipidemia, smoking. One hundred and forty-seven (38.8%) developed a no reflow. Mortality was 3.9%, strongly correlated with no reflow (P=0.001). Predictors of no reflow after multivariate analysis were: age (OR 98, 0.961-0.996 95%, P=0.02), heart rate (1.01, 95% CI 0.998-1.02, P=0.035), the type 2 diabetes (odds ratio 1.87, CI 1.2-3.0, P=0.08), reaching the core (OR 7, 95% CI 1.2-18.4, P=0.027), direct stenting (OR 0.48, 95% CI 0.31-0.78, P=0.003). An interesting subgroup of patients was identified namely the subgroup strategy deferred primary angioplasty with stenting best reperfusion (OR 3.7, 95% CI 1.5-8.8, P=0.04), a lower rate of reocclusion of culprit artery and a lower rate of stenting with 23/51 (45.1%) versus 136/136 (100%) of immediate stenting group with a P<0.001.

CONCLUSION

No reflow is a common phenomenon, strongly correlated with mortality predictors are age, heart rate, diabetes, achieving the core and direct stenting. The distal embolization in primary angioplasty is an important phenomenon, a delayed stenting strategy appears to limit this phenomenon.

Admission heart rate in relation to presentation and prognosis in patients with acute myocardial infarction. Treatment regimens in German chest pain units

BACKGROUND

Higher heart rates on admission have been associated with poor outcomes in patients with an acute coronary syndrome in previous cohorts. Whether such a linear relationship still exists in contemporary high-level care is unclear.

METHODS

Prospectively collected data from patients presenting with myocardial infarction (MI) in centers participating in the Chest Pain Unit (CPU) Registry between December 2008 and July 2014 were analyzed. Patients were classified according to their initial heart rate (I: < 50; II: 50-69; III: 70-89; IV: ≥ 90 bpm). A total of 6,168 patients out of 30,339 patients presenting to 38 centers were included in the study.

RESULTS

Patients in group IV had more comorbidities, while patients in group I more often had a history of MI. Patients in the lowest heart rate group presented significantly earlier to the hospital (4 h 31 min vs. 7 h 37 min; p < 0.05) and had the highest rate of interventions. The overall survival after 3 months was significantly worse in group IV after adjusting for baseline variables. In the subgroup analysis, heart rate was a prognostic factor in the non-ST-segment elevation MI group but not in the ST-segment elevation MI group. The correlation between heart rate and major adverse cardiac events followed a J-shaped curve with worst outcomes in the lowest and highest heart rate groups.

CONCLUSION

Patients admitted to a dedicated CPU with the diagnosis of MI and a heart rate > 90 bpm experience reduced survival at 3 months despite optimal treatment. Patients with bradycardia also seem to be at increased risk for cardiovascular events despite much earlier presentation and treatment.

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.

Heart rate and use of β-blockers in Mexican stable outpatients with coronary artery disease

OBJECTIVE

To evaluate the use of β-blockers and to monitor heart rate in Mexican patients with coronary artery disease.

METHODS

CLARIFY is an outpatients registry with stable CAD. A total of 33,283 patients from 45 countries were enrolled between November 2009 and July 2010 from which 1342 were Mexican patients.

RESULTS

The mean HR pulse was 70 bpm (beats per minute). Patients in Mexico were compared with the remaining global CLARIFY population. Patients in Mexico had a higher incidence of acute myocardial infarction and percutaneous coronary intervention, and lower incidence of revascularization surgery compared with the remaining CLARIFY population. More often, Mexican patients presented with diabetes, but less often hypertension and stroke. These patients were split into three mutually exclusive groups of HR ≤ 60 (N=263), HR 61-69 (N=356) and HR ≥ 70 (N=722). Patients with elevated HR had a higher incidence of diabetes and higher diastolic blood pressure on average than those with controlled HR. Regarding the use of β-blockers, they were used in 63.3% of patients, 2.7% showed intolerance or contraindication to treatment to monitor heart rate, and ivabradine was used in 2.3%. Out of approximately 849 patients receiving treatment of β-blockers, 52.1% had ≥ 70 bpm HR.

CONCLUSIONS

In a large proportion of Mexican patients with stable coronary disease the HR remain elevated, > 70 bpm, even with the use of β-blockers; this requires further attention.

Is there a role for ivabradine beyond its conventional use?

Results of recent clinical trials in patients with stable angina and chronic heart failure have successfully demonstrated a beneficial role of use of ivabradine in addition to the conventional therapy. Based on the results of these trials, the aim of our review was to give an overview of the literature about the use of ivabradine in clinical settings outside its usual purpose.

Resting heart rate: risk indicator and emerging risk factor in cardiovascular disease

Resting heart rate is central to cardiac output and is influenced by changes occurring in numerous diseases. It predicts longevity and cardiovascular diseases, and current evidence suggests that it is also an important marker of outcome in cardiovascular disease, including heart failure. Beta-blockers improve outcomes in heart failure; however, they have effects outside reducing heart rate. Ivabradine has demonstrated efficacy in reducing rehospitalizations and mortality in heart failure and in improving exercise tolerance and reducing angina attacks in patients with coronary artery disease, whereas selective heart rate reduction may also prove to be beneficial in therapeutic areas outside those in which ivabradine has already demonstrated clinical efficacy. This review provides an update on the associations between heart rate and cardiovascular outcomes in various conditions, the experimental effects of heart rate reduction with ivabradine, and the potential new indications in cardiovascular disease.

Resting heart rate in first year survivors of myocardial infarction and long-term mortality: a community study

OBJECTIVE

To evaluate the long-term prognostic effect of resting heart rate (HR) at index myocardial infarction (MI) and during the first year after MI among 1-year survivors.

PATIENTS AND METHODS

The community-based cohort consisted of 1571 patients hospitalized with an incident MI from January 1, 1983, through December 31, 2007, in Olmsted County, Minnesota, who were in sinus rhythm at index MI and had HR measurements on electrocardiography at index and during the first year after MI. Outcomes were all-cause and cardiovascular deaths.

RESULTS

During a median follow-up of 7.0 years, 627 deaths and 311 cardiovascular deaths occurred. Using patients with HRs of 60/min or less as the referent, this study found that long-term all-cause mortality risk increased progressively with increasing HR at index (hazard ratio, 1.62; 95% CI, 1.25-2.09) and even more with increasing HR during the first year after MI (hazard ratio, 2.16; 95% CI, 1.64-2.84) for patients with HRs greater than 90/min, adjusting for clinical characteristics and β-blocker use. Similar results were observed for cardiovascular mortality (adjusted hazard ratio, 1.66; 95% CI, 1.14-2.42; and adjusted hazard ratio, 1.93; 95% CI, 1.27-2.94; for HR at index and within 1 year after MI, respectively).

CONCLUSION

These data from a large MI community cohort indicate that HR is a strong predictor of long-term all-cause and cardiovascular mortality not only at initial presentation of MI but also during the first year of follow-up.

Discharge heart rate and mortality after acute myocardial infarction

BACKGROUND

We aimed to describe the determinants of discharge heart rate in acute coronary syndrome patients and assess the impact of discharge heart rate on 5-year mortality in hospital survivors.

METHODS

French Registry of Acute ST-Elevation or non-ST-elevation Myocardial Infarction (FAST-MI) 2005 is a nationwide French registry that included all consecutive patients with acute myocardial infarction over 1 month in 223 institutions in 2005. Discharge heart rate was recorded in 3079 patients discharged alive; all had 5-year follow-up. Logistic regression was used to detect predictors of high heart rate at discharge. Cox's proportional hazards model was used to assess the hazard ratio for mortality at 5 years. Heart rate was categorized into 4 groups by quartiles (<60, 61-67, 68-75, >75 beats per minute). High heart rate was defined as ≥75 beats per minute. Landmark analysis was performed at 1 year.

RESULTS

Independent predictors of heart rate ≥75 beats per minute at discharge were female sex, ST-segment elevation myocardial infarction, diabetes, chronic obstructive pulmonary disease, bleeding/transfusion during hospitalization, left ventricular dysfunction, renal dysfunction, and prescription (type, but not dose category) of beta-blockers at discharge. Discharge heart rate was significantly related to mortality at 1 year (hazard ratio 1.13; 95% confidence interval, 1.03-1.24 per 10 beats per minute, P = .02); this was confirmed by landmark analysis, with a 39% increase (hazard ratio 1.39; 95% confidence interval 1.05-1.84) in the risk of 1-year death for discharge heart rate ≥75 beats per minute vs <75 beats per minute. This relationship was no longer significant between 2 and 5 years.

CONCLUSIONS

After acute myocardial infarction, patients discharged with high heart rate (≥75 beats per minute) are at higher risk of death during the first year, but not later, irrespective of beta-blocker use.

Non-dipping heart rate and microalbuminuria in type 2 diabetes mellitus

OBJECTIVES

The aim of this study was to identify factors which are independently associated with non-dipping heart rate (HR) in a type 2 diabetic population at high risk of cardiovascular disease.

METHODS

The study recruited 179 type 2 diabetic subjects with a mean diabetes duration of 18.3 years and with proliferative retinopathy. All underwent 24-hour blood pressure and HR monitoring, and were assessed for markers of inflammation, insulin resistance, albuminuria, presence of peripheral neuropathy and peripheral vascular disease. Subjects whose night-time HR did not decrease by more than 10% as compared to daytime readings were classified as non-dippers.

RESULTS

Univariate analysis revealed that non-dippers had significantly higher logarithmic albumin-creatinine ratio (ACR; p = 0.001) and higher platelet count (p = 0.014). Also, non-dippers were more likely to be on β-blockers (p = 0.037). Binary logistic regression analysis showed that logarithmic ACR (p = 0.001) and platelet count (p = 0.026) were independent predictors of non-dipping HR, even when correcting for β-blocker use.

CONCLUSIONS

In this high-risk type 2 diabetic population, non-dipping HR was independently associated with ACR and platelet count, suggesting that non-dipping HR might give an indication of underlying generalised atherosclerosis in diabetic patients. Also, non-dipping HR may represent a novel mechanism explaining the association of nephropathy with cardiovascular events. This merits further study.

Initial heart rate and cardiovascular outcomes in patients presenting with acute coronary syndrome

OBJECTIVES

To assess the impact of on-admission heart rate (HR) in patients presenting with acute coronary syndrome (ACS).

METHODS

Data were collected retrospectively from the second Gulf Registry of Acute Coronary Events. Patients were divided according to their initial HR into: (I: < 60, II: 60-69, III: 70-79, IV: 80-89 and V: ≥ 90 bpm). Patients' characteristics and hospital and one- and 12-month outcomes were analyzed and compared.

RESULTS

Among 7939 consecutive ACS patients, groups I to V represented 7%, 13%, 20%, 23.5%, and 37%, respectively. Mean age was higher in groups I and V. Group V were more likely males, diabetic and hypertensive. ST-elevation myocardial infarction was the main presentation in groups I and V. Reperfusion therapies were less likely given to group V. Beta blockers were more frequently prescribed to group III in comparison to groups with higher HR. Groups I and V were associated with worse hospital outcomes. Multivariate analysis showed initial tachycardia as an independent predictor for heart failure (OR 2.2; 95%CI: 1.39-3.32), while bradycardia was independently associated with higher one-month mortality (OR 2.0; 95%CI: 1.04-3.85) CONCLUSION: The majority of ACS patients present with tachycardia. However, low or high HR is a marker of high risk that needs more attention and management.

Effect of ivabradine-induced heart rate reduction on flow-mediated dilation measured with high-sensitivity ultrasound in patients with stable coronary heart disease

Background

Experimental data suggests that exclusive heart rate reduction with ivabradine is associated with the amelioration of the endothelial function. Since it is presently unknown whether this also applies to humans, the aim of this pilot study was to investigate whether heart rate reduction with ivabradine modulates the endothelial function in humans with an established coronary heart disease.

Methods

Using high-sensitivity ultrasound, we analysed the flow-mediated (FMD) and nitro-mediated dilation (NMD) of the brachial artery in 25 patients (62.9 ± 8.4 years) with a stable coronary heart disease and a resting heart rate of ≥70 beats per minute (bpm). To assess acute effects, measurements were performed before and 4 hours after the first intake of ivabradine 7.5 mg. Sustained effects of an ivabradine therapy (5 mg to 7.5 mg twice daily) were investigated after 4 weeks.

Results

We found a significant decrease in heart rate, both 4 hours after the intake of 7.5 mg of ivabradine (median -8 [interquartile range (IQR) -14 to -4] bpm) and after 4 weeks of twice daily intake (median -10 [IQR-17 to -5] bpm) (p < 0.05). However, the FMD did not change significantly: neither after first dose of ivabradine nor after sustained therapy (baseline FMD: median 5.0 [IQR 2.4 to 7.9]%; FMD 4 hours after 7.5 mg of ivabradine: median 4.9 [IQR 2.7 to 9.8]%; FMD after 4 weeks of ivabradine therapy: median 6.1 [IQR 4.3 to 8.2]%). No significant changes of the NMD were observed. In regression analysis, the heart rate and FMD did not correlated, irrespective of the ivabradine intake (r² = 0.086).

Conclusion

In conclusion, in our study heart rate reduction through ivabradine does not improve the endothelial function in patients with a stable coronary heart disease. Moreover, we found no correlation between the heart rate and the endothelial function.

Heart rate and heart failure: the role of ivabradine therapy

PURPOSE OF REVIEW

The clinical data about the impact of heart rate reduction in heart failure therapy will be reviewed.

RECENT FINDINGS

Clinical and experimental studies showed an association between elevated resting heart rate and mortality risk in heart failure patients. This review summarizes that heart rate level at rest and its extent of reduction is a sensitive indicator for outcome in heart failure. In addition to the nonspecific heart rate reducing drugs like β-blockers, cardiac glycosides and Ca(2+) antagonists, ivabradine is a highly selective heart rate reducing agent without modifying ventricular contractility and atrioventricular conduction in humans and animals, and has recently been shown to improve cardiovascular outcomes in patients with systolic heart failure by lowering the heart rate only. The present and future role of heart rate reduction in the spectrum of heart failure disease and therapy will be outlined and evaluated.

SUMMARY

Elevated heart rate at rest represents a key indicator of adverse outcome in heart failure and implies a major treatment target in these patients.

Resting heart rate and outcomes in patients with cardiovascular disease: where do we currently stand?

BACKGROUND

Data from large epidemiological studies suggest that elevated heart rate is independently associated with cardiovascular and all-cause mortality in patients with hypertension and in those with established cardiovascular disease. Clinical trial findings also suggest that the favorable effects of beta-blockers and other heart rate-lowering agents in patients with acute myocardial infarction and congestive heart failure may be, at least in part, due to their heart rate-lowering effects. Contemporary clinical outcome prediction models such as the Global Registry of Acute Coronary Events (GRACE) score include admission heart rate as an independent risk factor.

AIMS

This article critically reviews the key epidemiology concerning heart rate and cardiovascular risk, potential mechanisms through which an elevated resting heart rate may be disadvantageous and evaluates clinical trial outcomes associated with pharmacological reduction in resting heart rate.

CONCLUSIONS

Prospective randomised data from patients with significant coronary heart disease or heart failure suggest that intervention to reduce heart rate in those with a resting heart rate >70 bpm may reduce cardiovascular risk. Given the established observational data and randomised trial evidence, it now appears appropriate to include reduction of elevated resting heart rate by lifestyle +/- pharmacological therapy as part of a secondary prevention strategy in patients with cardiovascular disease.

Effect of plant polyphenols on ischemia-reperfusion injury of the isolated rat heart and vessels

In the present study, we investigated the potential protective effect of selected natural substances in a rat model of heart and mesenteric ischemia-reperfusion (I/R). Experiments were performed on isolated Langendorff-perfused rat hearts, subjected to 30-min global ischemia, followed by 30-min reperfusion. Arbutin, curcumin, rosmarinic acid and extract of Mentha x villosa were applied in the concentration of 1 × 10⁻⁵ mol/l 10 min before the onset of ischemia and during reperfusion, through the perfusion medium. Mesenteric ischemia was induced by clamping the superior mesenteric artery (SMA) for 60 min, subsequent reperfusion lasted 30 min. Production of reactive oxygen species (ROS) by SMA ex vivo was determined by luminol-enhanced chemiluminiscence (CL). The effect of the substances was tested after their incubation with tissue. Curcumin and extract of Mentha x villosa were found to be the most effective in reducing reperfusion-induced dysrhythmias--ventricular tachycardia and fibrillation. This effect was accompanied by bradycardic effect. The mesenteric I/R induced an increase in CL in vascular tissue which was dampened by substances tested. All substances tested were found to have antioxidant properties, as demonstrated by a reduction in ROS production in mesenteric vessels. This effect was confirmed in curcumin and extract of Mentha x villosa which reduced reperfusion dyshythmias.

Evaluation of pharmacokinetic and pharmacodynamic profiles and tolerability after single (2.5, 5, or 10 mg) and repeated (2.5, 5, or 10 mg bid for 4.5 days) oral administration of ivabradine in healthy male Korean volunteers

BACKGROUND

Ivabradine, a selective inhibitor of the pacemaker current in the sinoatrial node, has shown pure heart rate (HR)-reducing effects with anti-ischemic efficacy as well as improvement in heart failure outcomes.

OBJECTIVE

The purpose of this study was to explore pharmacokinetic (PK) and pharmacodynamic (PD) characteristics and tolerability in healthy male Korean volunteers, as well as to compare them with PK/PD profiles of white subjects.

METHODS

This was a randomized, double-blind, placebo-controlled Phase I study conducted in healthy male subjects. For each of the 3 dosing groups, 9 subjects were randomized to receive ivabradine and 3 to receive placebo. Subjects received a single oral dose of ivabradine 2.5, 5, or 10 mg and after a 3-day washout period, repeat doses of 2.5, 5, or 10 mg BID for 4.5 days. Blood and urine samples were collected over 72 hours during each period, and levels of ivabradine and its metabolite S18982 were determined by using validated LC-MS/MS, followed by noncompartmental PK analysis. For PD properties and tolerability, 24-hour Holter recordings were obtained: at baseline, after a single dose, after repeated doses, and after the last dose. Serial resting 12-lead ECG assessments were also performed throughout the study.

RESULTS

Forty-eight subjects were enrolled, and 45 completed the study. After single doses of 2.5, 5, and 10 mg, respective mean Cmax levels of ivabradine were 9, 15, and 39 ng/mL, and mean AUC0-last values were 30, 52, and 121 ng h/mL. At steady state, mean Cmax,ss levels were 11, 19, and 42 ng/mL, reached at a median Tmax of 0.67 hour for all 3 doses. The mean AUC0-τ levels were 43, 58, and 139 ng h/mL, respectively. The PK findings were linear with dose and time. Decreases in mean HR on both the Holter recordings and ECGs were observed in all of the ivabradine groups compared with placebo. After the repeated doses, mean decreases in HR were greater than those for the single doses for the same period. Statistically significant differences were observed between the 5- and 10-mg ivabradine groups and placebo. A total of 3 adverse events were reported in 2 subjects receiving ivabradine; both fully recovered without sequelae.

CONCLUSIONS

Single and repeated administration of ivabradine were generally well tolerated in these healthy male Korean volunteers. Ivabradine induced significant reductions in HR, especially at doses of 5 and 10 mg. PK/PD characteristics were similar to those found in white subjects, suggesting that the dose concentration-response relationship of ivabradine is similar between Korean and white subjects.