Orthostatic intolerance in chronic fatigue syndrome

Background

Orthostatic intolerance (OI) is a significant problem for those with chronic fatigue syndrome (CFS). We aimed to characterize orthostatic intolerance in CFS and to study the effects of exercise on OI.

Methods

CFS (n = 39) and control (n = 25) subjects had recumbent and standing symptoms assessed using the 20-point, anchored, ordinal Gracely Box Scale before and after submaximal exercise. The change in heart rate (ΔHR ≥ 30 bpm) identified Postural Orthostatic Tachycardia Syndrome (POTS) before and after exercise, and the transient, exercise-induced postural tachycardia Stress Test Activated Reversible Tachycardia (START) phenotype only after exercise.

Results

Dizziness and lightheadedness were found in 41% of recumbent CFS subjects and in 72% of standing CFS subjects. Orthostatic tachycardia did not account for OI symptoms in CFS. ROC analysis with a threshold ≥ 2/20 on the Gracely Box Scale stratified CFS subjects into three groups: No OI (symptoms < 2), Postural OI (only standing symptoms ≥ 2), and Persistent OI (recumbent and standing symptoms ≥ 2).

Conclusions

Dizziness and Lightheadedness symptoms while recumbent are an underreported finding in CFS and should be measured when doing a clinical evaluation to diagnose orthostatic intolerance. POTS was found in 6 and START was found in 10 CFS subjects. Persistent OI had symptoms while recumbent and standing, highest symptom severity, and lability in symptoms after exercise.

Trial registration The trial was registered at the following: https://clinicaltrials.gov/ct2/show/NCT03567811

Cardiovascular Collapse with Intravenous Amiodarone in Children: A Multi-Center Retrospective Cohort Study

OBJECTIVE

To determine the incidence of cardiovascular collapse in children receiving intravenous (IV) amiodarone and to identify the population at risk.

DESIGN

A multicenter study of patients ≤ 18 years of age who received intravenous amiodarone between January 2005 and December 2015. A retrospective analysis was performed to identify patients who developed cardiovascular collapse (bradycardia and/or hypotension).

RESULTS

Of 456 patients who received amiodarone, cardiovascular collapse occurred in 47 patients (10%). Patient risk factors for collapse in a univariate analysis were as follows: age < 3 months (p = 0.04), depressed cardiac function (p < 0.001), blood pressure below 3rd percentile (p < 0.001), high lactate at baseline (p < 0.001). Administration risk factors included bolus administration (p = 0.04), and bolus administration over ≤ 20 min (p = 0.04). In multivariate analysis, age, baseline blood pressure less than 3rd percentile, and rapid bolus delivery were independent risk factors for cardiovascular collapse in the study group. The mortality rate was significantly higher in the collapse group (28% versus 8%).

CONCLUSION

We found an association between IV amiodarone administration and the risk of developing cardiovascular collapse in a significant subset of children. Extreme caution and careful hemodynamic monitoring is recommended when using IV amiodarone in this population, especially in young infants, hemodynamically compromised patients, and in patients receiving rapid amiodarone bolus administration.

Complex Arrhythmias Due to Reversible Causes

Abnormalities in cardiac rhythm are caused by disorders of impulse generation, conduction, or a combination of the 2, and may be life-threatening because of a reduction in cardiac output or myocardial oxygenation. Cardiac arrhythmias are commonly classified as tachycardias (supraventricular or ventricular) or bradycardias. Bradycardias are uncommon in the critically ill patient and often are caused by an underlying reversible disorder (eg, hyperkalemia, drug toxicity). Supraventricular and ventricular tachycardias are more often encountered in the critically ill patient and often have underlying treatable disorders that precipitate their development (eg, hypokalemia, hypomagnesemia, antiarrhythmic proarrhythmia, myocardial ischemia).

Addition of a β1-Blocker to Milrinone Treatment Improves Cardiac Function in Patients with Acute Heart Failure and Rapid Atrial Fibrillation

BACKGROUND

Tachycardia worsens cardiac performance in acute decompensated heart failure (ADHF). We investigated whether heart rate (HR) optimization by landiolol, an ultra-short-acting β1-selective blocker, in combination with milrinone improved cardiac function in patients with ADHF and rapid atrial fibrillation (AF).

METHODS AND RESULTS

We enrolled9 ADHF patients (New York Heart Association classification IV; HR, 138 ± 18 bpm; left ventricular [LV] ejection fraction, 28 ± 8%; cardiac index [CI], 2.1 ± 0.3 L/min-1/m-2; pulmonary capillary wedge pressure [PCWP], 24 ± 3 mm Hg), whose HRs could not be reduced using standard treatments, including diuretics, vasodilators, and milrinone. Landiolol (1.5-6.0 µg/kg-1/min-1, intravenous) was added to milrinone treatment to study its effect on hemodynamics. The addition of landiolol (1.5 µg/kg-1/min-1) significantly reduced HR by 11% without changing systolic blood pressure (BP) and resulted in a significant decrease in PCWP and a significant increase in stroke volume index (SVI), suggesting that HR reduction restores incomplete LV relaxation. Administration of more than 3.0 µg/kg-1/min-1 of landiolol decreased BP, CI, and SVI.

CONCLUSION

The addition of landiolol at doses of <3.0 µg/kg/min to milrinone improved cardiac function in decompensated chronic heart failure with rapid atrial fibrillation by selectively reducing HR.

Bilateral pheochromocytoma after kidney transplantation in neurofibromatosis type 1

We present the case of a 25-year-old male with a history of neurofibromatosis type 1 and bilateral pheochromocytoma 4 years after kidney transplantation that was successfully treated with simultaneous bilateral posterior retroperitoneoscopic adrenalectomy. Learning points: Hypertensive patients with NF1 should always be screened for pheochromocytoma. Pheochromocytoma is rarely associated with transplantation, but it must be ruled out in patients with genetic susceptibility. Posterior retroperitoneoscopic adrenalectomy (PRA) allows more direct access to the adrenal glands, especially in patients with previous abdominal surgeries.

Coronary sinus cannulation predicts atrioventricular nodal reentry as mechanism of supraventricular tachycardia

Introduction

Common clinical teaching, for invasive electrophysiology, is that if the first year fellow cannulates the coronary sinus (CS) in his first attempt, the arrhythmia is more likely to be atrioventricular nodal reentry tachycardia (AVNRT). This general perception has not yet been clinically tested. We evaluated this theory in prospective patients undergoing an electrophysiological study (EPS) for paroxysmal supraventricular tachycardia (PSVT).

Methods

Cohort study. CS ease of cannulation (CSCS) was graded as: 1) 1st year fellow cannulates in first attempt; 2) 1st year fellow needs more than one attempt or maneuver to cannulate the CS; 3) staff physician cannulates in first attempt after the fellow was unsuccessful; 4) staff physician requires more than one maneuver to cannulate the CS; 5) staff physician judges that the cannulation process was extremely difficult.

Results

Of the 1361 patients undergoing EPS in our institution, 165 were selected. Age was 49 ± 15 years. AVNRT occurred in 77.6%, atrioventricular reentry tachycardia (AVRT) in 15.1% and atrial tachycardia (AT) in 7.3% of cases. The CSCS = 1 was more prevalent in AVNRT, 89% versus 68% AVRT and 58.3% of AT (P = 0.0005). Patients with CSCS = 1 have a higher chance of the PSVT being AVNRT (odds ratio: 4.41; 95CI: 1.84–10.56; P = 0.0009).

Conclusion

The CSCS predicts the likelihood of the induced PSVT being AVNRT as compared to AVRT and AT. More studies are required to try to associate this finding to clinical patient characteristics to create a score for PSVT mechanism prediction.

[Clinical characteristics and treatment of congenital long QT syndrome in 58 children]

Objective: To assess the clinical characteristics, pathogenic genes and therapeutic effects of congenital long QT syndrome (LQTS) in children. Methods: A retrospective analysis included 58 LQTS children (37 boys, 21 girls; age of diagnosis (8.0±4.1) years, range 0.1 to 16.0 years) at Division of Pediatric Cardiology, First Hospital of Tsinghua University from August 2013 to November 2017. Each patient was evaluated with a detailed medical history, 12-lead resting electrocardiogram, Doppler echocardiography, and molecular genetic analysis. Results: Forty-eight of the children (83%) had a delay to diagnosis (0.7 (0.1, 2.0)years) and initially received a misdiagnosis. QT prolongation of unknown origin was found in 10 cases (17%), complex arrhythmic conditions in 27 cases (47%), myocarditis in 3 cases (5%), syncope of unknown origin in 3 cases (5%), epilepsy in 2 cases (3%), myocardial infarction in 1 case (2%), cardiomyopathy in 1 case (2%), and vasovagal syncope in 1 case (2%). Nine children presented with the positive family history of LQTS and three children had congenital nervous deafness. Twenty-one (36%) children presented with recurrent syncope, and 14 cases of whom had symptoms during physical activity and/or emotional stress. The common arrhythmias were ventricular arrhythmia (26 cases), sinus node dysfunction (18 cases), atrioventricular block (AVB) (12 cases), and atrial arrhythmia (6 cases). LQTS-associated pathologic or possibly pathologic mutations were found in 41 children (71%). Thirty-three children (57%) were treated with propranolol (22 cases), permanent pacemaker (PM) combined with propranolol (5 cases), PM (4 cases), and implantable cardioverter defibrillator (ICD) combined with propranolol (2 cases). Eighteen children (55%) were asymptomatic, thirteen children (39%) reported infrequent syncope, and one case (2%) died. Conclusions: LQTS in children is potentially malignant and present as phenotypic diversity and complex arrhythmias. LQTS-related pathogenic or possibly pathogenic mutations are identified in most of the children. Beta-blockers therapy is effective in reducing the risk of malignant cardiac events. Some children with LQTS should receive PM or ICD therapy.

[One case of patient with bilateral ectopic subclavian vein catheterization]

One female patient aged 18 years, with severe burns and inhalation injury was admitted to our unit on June 5th, 2013. After admission, the right subclavian vein catheterization was performed for rapid fluid infusion against shock. Escharectomy on both upper extremities was planned to carry out and repaired with medium-thickness skin on right thigh 52 hours after injury. However, after general anesthesia, the right subclavian vein catheter was with poor fluid infusion, and the left subclavian vein catheterization was performed. Supraventricular tachycardia and decreased blood pressure occurred followed by fluid replacement and dilatation, cardiotonics, and diuretics. Postanesthetic 1.3 hours, the patient's vital signs were stable, and the operation began. Postoperative chest X-ray film showed that distal ends of the left and right subclavian vein catheters were respectively located in the right atrium and the right internal carotid vein, and the catheters were removed immediately. This case suggests that clinical physician should be careful to prevent catheter heterotopia in subclavian vein catheterization, and postoperative routine chest X-ray examination is necessary to identify position of the catheter.

Paraganglioma presenting as stress cardiomyopathy: case report and literature review

Pheochromocytoma/paraganglioma (PPGL) are neuroendocrine tumors that can secrete catecholamines. The authors describe a challenging case who presented as stress cardiomyopathy and myocardial infarction (MI). A 76-year-old man, with a medical history of Parkinson's disease, type 2 diabetes mellitus, hypertension, dyslipidaemia and a previous inferior MI in 2001, presented to the emergency department due to chest pain, headaches and vomiting. He also reported worsening blood glucose levels and increasing constipation over the preceding weeks. BP was 185/89 mmHg (no other relevant findings). EKG had ST segment depression in leads V2-V6, T troponin was 600 ng/L (<14) and the echocardiogram showed left ventricular hypokinesia with mildly compromised systolic function. Nevertheless, he rapidly progressed to severe biventricular dysfunction. Coronary angiogram showed a 90% anterior descendent coronary artery occlusion (already present in 2001), which was treated with angioplasty/stenting. In the following days, a very labile BP profile and unexplained sinus tachycardia episodes were observed. Because of sustained severe constipation, the patient underwent an abdominal CT that revealed a retroperitoneal, heterogeneous, hypervascular mass on the right (62 × 35 mm), most likely a paraganglioma. Urinary metanephrines were increased several fold. 68Ga-DOTANOC PET-CT scan showed increased uptake in the abdominal mass (no evidence of disease elsewhere). He was started on a calcium-channel blocker and alpha blockade and underwent surgery with no major complications. Eight months after surgery, the patient has no evidence of disease. Genetic testing was negative for known germline mutations. This was a challenging diagnosis, but it was essential for adequate cardiovascular stabilization and to reduce further morbidity. Learning points: PPGL frequently produces catecholamines and can manifest with several cardiovascular syndromes, including stress cardiomyopathy and myocardial infarction. Even in the presence of coronary artery disease (CAD), PPGL should be suspected if signs or symptoms attributed to catecholamine excess are present (in this case, high blood pressure, worsening hyperglycaemia and constipation). Establishing the correct diagnosis is important for adequate treatment choice. Inodilators and mechanical support might be preferable options (if available) for cardiovascular stabilization prior to alpha blockade and surgery. Laboratory interference should be suspected irrespective of metanephrine levels, especially in the context of treated Parkinson's disease.

The Value of Baseline and Arrhythmic ECG in the Interpretation of Arrhythmic Mechanisms

Owing to the rapid development of new electrophysiologic techniques, our understanding of arrhythmias and their underlying mechanisms has reached unprecedented levels. In some cases, baseline ECG alterations can be identified before arrhythmia development; early recognition of these alterations is of utmost importance to start appropriate preventive therapies and stratify the risk according to patients' outcomes. Hereby, we report a systematic revision of main baseline ECG abnormalities and their implications on clinical outcomes.

What is the impact of mother's bed incline on episodes of decreased oxygen saturation in healthy newborns in skin-to-skin contact after delivery: Study protocol for a randomized controlled trial

BACKGROUND

Early mother-child skin-to-skin contact (SSC) in the first 2 h postpartum is highly beneficial for both mother and child. However, cases have been reported of newborns who have experienced apparently life-threatening events (ALTEs) or sudden death during this procedure. The causes of these events are unknown. Newborn's prone position could influence the onset of these events but there is very little evidence to support any recommendation. We hypothesize that newborns' breathing obstruction episodes increase as mothers lie more horizontally. The main objective of this study is to compare the occurrence of desaturation and bradycardia episodes as a function of mother's bed incline. The study is designed as a randomized, controlled, assessor blind, multicenter, superiority trial with two parallel groups and 1:1 allocation ratio.

METHODS

The study participants will be full-term healthy mother-newborn dyads from ten hospitals in Spain. Participants will be randomly assigned to one of two study arms defined by mother's bed inclination (45° or 15°). The planned sample size is 5866. Centralized permuted blocks randomization and assessor blinding will be implemented. The newborns will be monitored remotely with pulse oximetry, from 10 min to 2 h after delivery. We established SO2 and heart rate (HR) limit alarms, as well as an action protocol in the event of alarm activation. The primary outcome is the number of healthy newborns who undergo episodes of SO2 ≤ 90%. Secondary outcomes are the mean SO2 level, the number of newborns who experience episodes of SO2 ≤ 85%, the time to SSC discontinuation due to abnormal SO2 or HR, and episodes of HR < 111 beats per minute (bpm) or > 180 bpm. Subgroups and pooled analysis will be performed to identify if breast-feeding and mother and child positions favor the occurrence of desaturation or bradycardia episodes.

DISCUSSION

A simple intervention such as modifying mother's bed angle of inclination while in SSC with her child during the first 2 h postpartum could favor newborn's hemodynamic and respiratory stabilization and thus contribute to reducing the onset of ALTEs.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02585492 . Registered on 22nd October 2015.

PROTOCOL VERSION

2 (30th June 2015).

Glucagonoma-associated dilated cardiomyopathy refractory to somatostatin analogue therapy

A 67-year-old woman presented with a generalised rash associated with weight loss and resting tachycardia. She had a recent diagnosis of diabetes mellitus. Biochemical evaluation revealed elevated levels of circulating glucagon and chromogranin B. Cross-sectional imaging demonstrated a pancreatic lesion and liver metastases, which were octreotide-avid. Biopsy of the liver lesion confirmed a diagnosis of well-differentiated grade 2 pancreatic neuroendocrine tumour, consistent with metastatic glucagonoma. Serial echocardiography commenced 4 years before this diagnosis demonstrated a progressive left ventricular dilatation and dysfunction in the absence of ischaemia, suggestive of glucagonoma-associated dilated cardiomyopathy. Given the severity of the cardiac impairment, surgical management was considered inappropriate and somatostatin analogue therapy was initiated, affecting clinical and biochemical improvement. Serial cross-sectional imaging demonstrated stable disease 2 years after diagnosis. Left ventricular dysfunction persisted, however, despite somatostatin analogue therapy and optimal medical management of cardiac failure. In contrast to previous reports, the case we describe demonstrates that chronic hyperglucagonaemia may lead to irreversible left ventricular compromise. Management of glucagonoma therefore requires careful and serial evaluation of cardiac status. Learning points: In rare cases, glucagonoma may present with cardiac failure as the dominant feature. Significant cardiac impairment may occur in the absence of other features of glucagonoma syndrome due to subclinical chronic hyperglucagonaemia. A diagnosis of glucagonoma should be considered in patients with non-ischaemic cardiomyopathy, particularly those with other features of glucagonoma syndrome. Cardiac impairment due to glucagonoma may not respond to somatostatin analogue therapy, even in the context of biochemical improvement. All patients with a new diagnosis of glucagonoma should be assessed clinically for evidence of cardiac failure and, if present, a baseline transthoracic echocardiogram should be performed. In the presence of cardiac impairment these patients should be managed by an experienced cardiologist.

Devices and interventions for the prevention of adverse outcomes of tachycardia on heart failure

Heart failure (HF) is the leading cause of hospitalization in the USA. Despite advances in pharmacologic management, the incidence of HF is on the rise and survivability is persistently reduced. Sympathetic overdrive is implicated in the pathophysiology of HF, particularly HF with reduced ejection fraction (HFrEF). Tachycardia can be particularly deleterious and thus has spurred significant investigation to mitigate its effects. Various modalities including vagus nerve stimulation, baroreceptor activation therapy, spinal cord stimulation, renal sympathetic nerve denervation, left cardiac sympathetic denervation, and carotid body removal will be discussed. However, the effects of these modalities on tachycardia and its outcomes in HFrEF have not been well-studied. Further studies to characterize this are necessary in the future.

Predicting tachycardia as a surrogate for instability in the intensive care unit

Tachycardia is a strong though non-specific marker of cardiovascular stress that proceeds hemodynamic instability. We designed a predictive model of tachycardia using multi-granular intensive care unit (ICU) data by creating a risk score and dynamic trajectory. A subset of clinical and numerical signals were extracted from the Multiparameter Intelligent Monitoring in Intensive Care II database. A tachycardia episode was defined as heart rate ≥ 130/min lasting for ≥ 5 min, with ≥ 10% density. Regularized logistic regression (LR) and random forest (RF) classifiers were trained to create a risk score for upcoming tachycardia. Three different risk score models were compared for tachycardia and control (non-tachycardia) groups. Risk trajectory was generated from time windows moving away at 1 min increments from the tachycardia episode. Trajectories were computed over 3 hours leading up to the episode for three different models. From 2809 subjects, 787 tachycardia episodes and 707 control periods were identified. Patients with tachycardia had increased vasopressor support, longer ICU stay, and increased ICU mortality than controls. In model evaluation, RF was slightly superior to LR, which accuracy ranged from 0.847 to 0.782, with area under the curve from 0.921 to 0.842. Risk trajectory analysis showed average risks for tachycardia group evolved to 0.78 prior to the tachycardia episodes, while control group risks remained < 0.3. Among the three models, the internal control model demonstrated evolving trajectory approximately 75 min before tachycardia episode. Clinically relevant tachycardia episodes can be predicted from vital sign time series using machine learning algorithms.

Fetal dysrhythmias

Fetal dysrhythmias are common abnormalities, usually manifesting as irregular rhythms. Although most irregularities are benign and caused by isolated atrial ectopics, in a few cases, rhythm irregularity may indicate partial atrioventricular block, which has different etiological and prognostic implications. We provide a flowchart for the initial management of irregular rhythm to help select cases requiring urgent specialist referral. Tachycardias and bradycardias are less frequent, can lead to hemodynamic compromise, and may require in utero therapy. Pharmacological treatment of tachycardia depends on the type (supraventricular tachycardia or atrial flutter) and presence of hydrops, with digoxin, flecainide, and sotalol being commonly used. An ongoing randomized trial may best inform about their efficacy. Bradycardia due to blocked bigeminy normally resolves spontaneously, but if it is due to established complete heart block, there is no effective treatment. Ongoing research suggests hydroxychloroquine may reduce the risk of autoimmune atrioventricular block. Sinus bradycardia (rate <3rd centile) may be a prenatal marker for long-QT syndrome.

Tachycardia induced Cardiomyopathy

Recent studies on radiofrequency catheter ablation (RFCA) in atrial fibrillation show its effectiveness in heart failure (HF) patients; hence, tachycardia-induced cardiomyopathy (T-CMP) is gaining attention. Tachycardia-mediated cardiomyopathy is a reversible left ventricular (LV) dysfunction, which can be induced by any tachyarrhythmia. Early recognition of T-CMP with appropriate treatment of the arrhythmia culprit will lead to the recovery of LV function. Patients with tachycardia and LV dysfunction should be suspected of having T-CMP, with or without established etiology of HF, because T-CMP may present by itself or contribute as a co-existent component. Therapeutic options include rate control, anti-arrhythmic drugs, or catheter ablation. Unlike in animal models, clinical data on human T-CMP is limited. Hence, future research should be more focused on tachyarrhythmia-induced cardiomyopathy as its burden is increasing.

Fifty Years of Ventricular Tachycardia in a Single Patient

We report a patient who first presented during childhood in the early 1960's with several episodes of ventricular tachycardia (VT) and we describe her management which reflected the best medical knowledge at the time. She then presented more than 50 years later, again with VT, at which time a definitive diagnosis of the underlying cause was made. Her case illustrates the evolution in the understanding and management of VT over the past 50 years. This in turn reflects the clinical and technological advances in the management of cardiovascular disease over time.

The modular cardiac rhythm management system: the EMPOWER leadless pacemaker and the EMBLEM subcutaneous ICD

Cardiac implantable electronic devices have been successfully treating patients with brady- and tachyarrhythmias for decades. However, there are still significant complications related to this therapy modality, many related to the transvenous lead. Paradigm-shifting technologies, such as the subcutaneous implantable cardioverter-defibrillator (S-ICD) and leadless cardiac pacemakers (LCP), have emerged to address these complications. The novel modular cardiac rhythm management (mCRM) system, consisting of a communicating antitachycardia pacing-enabled LCP and S‑ICD, is the first system to integrate wireless intrabody communication between devices to allow for coordination of leadless pacing and defibrillator therapy delivery. In this review, the design and concept of the mCRM system are presented and available evidence is summarized.

Landiolol in patients with septic shock resident in an intensive care unit (LANDI-SEP): study protocol for a randomized controlled trial

Background

In patients with septic shock, the presence of an elevated heart rate (HR) after fluid resuscitation marks a subgroup of patients with a particularly poor prognosis. Several studies have shown that HR control in this population is safe and can potentially improve outcomes. However, all were conducted in a single-center setting. The aim of this multicenter study is to demonstrate that administration of the highly beta1-selective and ultrashort-acting beta blocker landiolol in patients with septic shock and persistent tachycardia (HR ≥ 95 beats per minute [bpm]) is effective in reducing and maintaining HR without increasing vasopressor requirements.

Methods

A phase IV, multicenter, prospective, randomized, open-label, controlled study is being conducted. The study will enroll a total of 200 patients with septic shock as defined by The Third International Consensus Definitions for Sepsis and Septic Shock criteria and tachycardia (HR ≥ 95 bpm) despite a hemodynamic optimization period of 24–36 h. Patients are randomized (1:1) to receive either standard treatment (according to the Surviving Sepsis Campaign Guidelines 2016) and continuous landiolol infusion to reach a target HR of 80–94 bpm or standard treatment alone. The primary endpoint is HR response (HR 80–94 bpm), the maintenance thereof, and the absence of increased vasopressor requirements during the first 24 h after initiating treatment.

Discussion

Despite recent studies, the role of beta blockers in the treatment of patients with septic shock remains unclear. This study will investigate whether HR control using landiolol is safe, feasible, and effective, and further enhance the understanding of beta blockade in patients with septic shock.

Trial registration

EU Clinical Trials Register; EudraCT, 2017-002138-22. Registered on 8 August 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3024-6) contains supplementary material, which is available to authorized users.

Long-term exposure to fine particulate matter and tachycardia and heart rate: Results from 10 million reproductive-age adults in China

BACKGROUND

Epidemiological evidence of the association of long-term ambient fine particulate matter (aerodynamic diameter ≤2.5 μm; PM_2.5) exposure with resting heart rate is limited. We explored the association of long-term (3-year average) ambient PM_2.5 exposure with tachycardia and resting heart rate.

METHODS

This cross-sectional study surveyed 10,427,948 reproductive-age (20-49 years) adults across China in 2015. Tachycardia was classified as a resting heart rate of >80 beats per minute (bpm). The annual average ambient PM_2.5 concentrations were obtained from a hybrid satellite-based geophysical statistical model. Linear mixed models and mixed effects logistic regressions adjusted for potential confounding were performed to explore the associations of PM_2.5 with resting heart rate and PM_2.5 with tachycardia, respectively. The effect modifiers by sex, age, body mass index, urbanity, race, region, smoking status, and drinking status were also assessed. Attributable cases and population fraction were estimated according to the PM_2.5- tachycardia relationship.

RESULTS

The mean age was 28 years, and 16.3% of the participants had tachycardia. The odds ratio for tachycardia was 1.018 (95% confidence intervals [CI]: 1.017, 1.020) per 10 μg/m³ increase in the 3-year average PM_2.5 exposure. A 10 μg/m³ increase in the 3-year average ambient PM_2.5 level was associated with a 0.076 (95% CI: 0.073, 0.079) bpm elevation in the resting heart rate. Of the tachycardia burden, 4.0% (95% CI: 3.8%, 4.3%) could be attributed to ambient PM_2.5 exposure in Chinese reproductive-age adults.

CONCLUSIONS

Exposures to ambient PM_2.5 were associated with elevated resting heart rate. It might be possible to decrease China's avoidable tachycardia burden in reproductive-age adults through decreasing PM_2.5 levels.

Tachycardic and non-tachycardic responses in trauma patients with haemorrhagic injuries

BACKGROUND

Analyses of large databases have demonstrated that the association between heart rate (HR) and blood loss is weaker than what is taught by Advanced Trauma Life Support training. However, those studies had limited ability to generate a more descriptive paradigm, because they only examined a single HR value per patient.

METHODS

In a comparative, retrospective analysis, we studied the temporal characteristics of HR through time in adult trauma patients with haemorrhage, based on documented injuries and transfusion of ≥3 units of red blood cells (RBCs). We analysed archived vital-sign data of up to 60 min during either pre-hospital or emergency department care.

RESULTS

We identified 133 trauma patients who met the inclusion criteria for major haemorrhage and 1640 control patients without haemorrhage. There were 55 haemorrhage patients with a normal median HR and 78 with tachycardia. Median ΔHR was -0.8 and +0.7 bpm per 10 min, respectively. Median time to documented hypotension was 8 and 5 min, respectively. RBCs were not significantly different; median volumes were 6 (IQR: 4-13) and 10 units (IQR: 5-16), respectively. Time-to-hypotension and mortality were not significantly different. Tachycardic patients were significantly younger (P < 0.05). Only 10 patients with normal HR developed transient/temporary tachycardia, and only 11 tachycardic patients developed a transient/temporary normal HR.

CONCLUSIONS

The current analysis suggests that some trauma patients with haemorrhage are continuously tachycardic while others have a normal HR. For both cohorts, hypotension typically develops within 30 min, without any consistent temporal increases or trends in HR.

Persistent tachycardia in clozapine treated patients: A 24-hour ambulatory electrocardiogram study

Tachycardia is associated with cardiovascular mortality. Tachycardia is also a known clozapine adverse effect. However, whether clozapine-associated tachycardia is persistent is not known. Thirty clozapine-treated patients with clinical tachycardia were investigated with 24-hour ambulatory electrocardiography (ECG). Baseline peripheral heart rate (HR) was 106.7±7.8. The ambulatory ECG 24-hour-HR was 98.7±9.7. Baseline HR and 24-hour-HR correlated strongly (r=0.74, p=0.000003). Daytime HR was 106.4±9.9 and nighttime HR 89.2±12.0. Low dose bisoprolol reduced HR significantly. The high 24-hour-HR indicates a persistent tachycardia. Tachycardia should not discourage from clozapine use but the findings indicate a need of guidelines for detection and treatment of clozapine-associated tachycardia.

The detrimental potential of arrhythmia-induced cardiomyopathy

Here we discuss a case of arrhythmia‐induced cardiomyopathy (AIC) with consecutive severe multiple organ failure. In relation to this imposing case, we discuss the significance of this potentially underestimated cause of newly occurred left‐ventricular systolic dysfunction and concomitant arrhythmia. We further delineate the diagnostic algorithm and differential diagnoses of AIC.