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.

[Mapping and ablation of cardiac arrhythmias : Never forget where you are coming from]

With the rapid development of new mapping and imaging technologies as well as catheter ablation technologies, it is increasingly important to understand the basic concepts of conventional mapping and ablation of cardiac arrhythmias. Prerequisite for successful ablation is the exact identification of the tachycardia mechanism and subsequent localization of the origin or tachycardic substrate. Only intracardiac electrograms provide decisive information regarding activation time and signal morphology. In some arrhythmias, it is necessary to supplement conventional mapping with so-called pace and/or entrainment mapping. This article aims to discuss and demonstrate the fundamentals of intracardiac mapping as it relates to the mapping and ablation of supraventricular and ventricular arrhythmias based on representative clinical cases. Modern three-dimensional mapping methods make it possible to individually optimize established ablation strategies with significantly better spatial resolution. The authors aimed to demonstrate that intracardiac uni- and bipolar electrograms provide essential information about timing and morphology guiding successful catheter ablation. Furthermore, our article provides useful information about conventional cardiac mapping techniques including activation mapping, pace mapping, and individual substrate mapping.

Neonatal and Pediatric Arrhythmias: Clinical and Electrocardiographic Aspects

Arrhythmias have acquired a specific identity in pediatric cardiology, but for pediatric cardiologists it has always been difficult to recognize and treat them. Changes in anatomy and physiology result in electrocardiogram features that differ from the normal adult pattern and vary according to the age of the child. Sinus arrhythmia, ectopic atrial rhythm, "wandering pacemaker," and junctional rhythm can be normal characteristics in children (15%-25% of healthy children can have these rhythms on the electrocardiogram). Tachyarrhythmias and bradyarrhythmias must be treated according to the severity of symptoms, and the patient's age and weight.

Long-term clinical outcomes of catheter ablation in patients with atrial fibrillation predisposing to tachycardia-bradycardia syndrome: a long pause predicts implantation of a permanent pacemaker

Background

There is a controversy as to whether catheter ablation should be the first-line therapy for tachycardia-bradycardia syndrome (TBS) in patients with atrial fibrillation (AF).

Methods

We aimed to investigate long-term clinical outcomes of catheter ablation in patients with TBS and AF. Among 145 consecutive patients who underwent catheter ablation of AF with TBS, 121 patients were studied.

Results

Among 121 patients, 11 (9.1%) received implantation of a permanent pacemaker during a mean 21 months after ablation. Length of pause on termination of AF was significantly greater in patients who received pacemaker implantation after ablation than those who underwent ablation only (7.9 ± 3.5 vs. 5.1 ± 2.1 s, p < 0.001). Using a multivariate model, a long pause of 6.3 s or longer after termination of AF was associated with the requirement to implant a permanent pacemaker after ablation (HR 1.332, 95% CI 1.115-1.591, p = 0.002).

Conclusion

This study suggests that, in patients with AF predisposing to TBS, long pause on termination of AF predicts the need to implant a permanent pacemaker after catheter ablation.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0834-0) contains supplementary material, which is available to authorized users.

MicroDAIMON study: Microcirculatory DAIly MONitoring in critically ill patients: a prospective observational study

Background

Until now, the prognostic value of microcirculatory alterations in critically ill patients has been mainly evaluated in highly selected subgroups. Aim of this study is to monitor the microcirculation daily in mixed group of Intensive Care Unit (ICU)-patients and to establish the association between (the evolution of) microcirculatory alterations and outcome.

Methods

This is a prospective longitudinal observational single-centre study in adult patients admitted to a 12-bed ICU in an Italian teaching hospital. Sublingual microcirculation was evaluated daily, from admission to discharge/death, using Sidestream Dark Field imaging. Videos were analysed offline to assess flow and density variables. Laboratory and clinical data were recorded simultaneously. A priori, a Microvascular Flow Index (MFI) < 2.6 was defined as abnormal. A binary logistic regression analysis was performed to evaluate the association between microcirculatory variables and outcomes; a Kaplan–Meier survival curve was built. Outcomes were ICU and 90-day mortality.

Results

A total of 97 patients were included. An abnormal MFI was present on day 1 in 20.6%, and in 55.7% of cases during ICU admission. Patients with a baseline MFI < 2.6 had higher ICU, in-hospital and 90-day mortality (45 vs. 15.6%, p = 0.012; 55 vs. 28.6%, p = 0.035; 55 vs. 26%, p = 0.017, respectively). An independent association between baseline MFI < 2.6 and outcome was confirmed in a binary logistic analysis (odds ratio 4.594 [1.340–15.754], p = 0.015). A heart rate (HR) ≥ 90 bpm was an adjunctive predictor of mortality. However, a model with stepwise inclusion of mean arterial pressure < 65 mmHg, HR ≥ 90 bpm, lactate > 2 mmol/L and MFI < 2.6 did not detect significant differences in ICU mortality. In case an abnormal MFI was present on day 1, ICU mortality was significantly higher in comparison with patients with an abnormal MFI after day 1 (38 vs. 6%, p = 0.001), indicating a time-dependent significant difference in prognostic value.

Conclusions

In a general ICU population, an abnormal microcirculation at baseline is an independent predictor for mortality. In this setting, additional routine daily microcirculatory monitoring did not reveal extra prognostic information. Further research is needed to integrate microcirculatory monitoring in a set of commonly available hemodynamic variables.

Trial registration NCT 02649088, www.clinicaltrials.gov. Date of registration: 23 December 2015, retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0411-9) contains supplementary material, which is available to authorized users.

Implications for paediatric shock management in resource-limited settings: a perspective from the FEAST trial

BACKGROUND

Although the African "Fluid Expansion as Supportive therapy" (FEAST) trial showed fluid resuscitation was harmful in children with severe febrile illness managed in resource-limited hospitals, the most recent evidence reviewed World Health Organization (WHO) guidelines continue to recommend fluid boluses in children with shock according to WHO criteria "WHO shock", arguing that the numbers included in the FEAST trial were too small to provide reasonable certainty.

METHODS

We re-analysed the FEAST trial results for all international definitions for paediatric shock including hypotensive (or decompensated shock) and the WHO criteria. In addition, we examined the clinical relevance of the WHO criteria to published and unpublished observational studies reporting shock in resource-limited settings.

RESULTS

We established that hypotension was rare in children with severe febrile illness complicating only 29/3170 trial participants (0.9%). We confirmed that fluid boluses were harmful irrespective of the definitions of shock including the very small number with WHO shock (n = 65). In this subgroup 48% of bolus recipients died at 48 h compared to 20% of the non-bolus control group, an increased absolute risk of 28%, but translating to an increased relative risk of 240% (p = 0.07 (two-sided Fisher's exact test)). Examining studies describing the prevalence of the stringent WHO shock criteria in children presenting to hospital we found this was rare (~ 0.1%) and in these children mortality was very high (41.5-100%).

CONCLUSIONS

The updated WHO guidelines continue to recommend boluses for a very limited number of children presenting at hospital with the strict definition of WHO shock. Nevertheless, the 3% increased mortality from boluses seen across FEAST trial participants would also include this subgroup of children receiving boluses. Recommendations aiming to differentiate WHO shock from other definitions will invariably lead to "slippage" at the bedside, with the potential of exposing a wider group of children to the harm of fluid-bolus therapy.

Long-term symptom improvement and patient satisfaction following catheter ablation of supraventricular tachycardia: insights from the German ablation registry

Aims

To analyse outcomes of supraventricular tachycardia (SVT) ablations performed within a prospective German Ablation Quality Registry.

Methods and results

Data from 12 566 patients who underwent catheter ablation of SVT between January 2007 and January 2010 to treat atrial fibrillation (AFIB, 37.2% of procedures), atrial flutter (AFL, 29.9%), atrioventricular nodal re-entrant tachycardia (AVNRT, 23.2%), atrioventricular re-entrant tachycardia (6.3%), and focal atrial tachycardia (AT, 3.4%) were prospectively collected. Patients were followed for at least 1 year. The periprocedural success rate was 96.3%, ranging from 84.3% (focal AT) to 98.9% (AVNRT). Kaplan-Meier mortality estimate at 1 year was 1.4% overall, and as high as 2.6% in the AFL group and 2.8% in the focal AT group. Recurrence of ablated or another symptomatic SVT was observed in 3783 (32.6%) of patients, ranging from 17.2% (AVNRT) to 45.6% (AFIB). Repeat ablation was performed in 12.0% of patients. After 1 year, 74.1% of survivors perceived ablation therapy as successful, 15.7% as partly successful, and 9.6% as unsuccessful. Even in those patients with arrhythmia recurrence, 76.0% perceived ablation as successful or partly successful and 89.6% would still undergo repeat ablation in the same institution.

Conclusion

Ablation therapy for SVT is a safe procedure bringing symptomatic improvement and satisfaction to three quarters of patients after 1 year. Even in patients with arrhythmia recurrence, a high satisfaction level and adherence to the ablating institution could be documented. Strikingly high mortality and stroke rates in follow-up were observed in AFL patients, who apparently need consistent long-term anticoagulation and more medical attention.

Clinical characteristics, prevalence, and factors related to delirium in children of 5 to 14 years of age admitted to intensive care

OBJECTIVE

To evaluate the clinical characteristics, prevalence and factors associated with delirium in critical patients from 5 to 14 years of age.

DESIGN

An analytical, cross-sectional observational study was made. Delirium was assessed with the Pediatric-Confusion Assessment Method for the Intensive Care Unit (pCAM-ICU) and motor classification was established with the Delirium Rating Scale Revised-98.

SETTING

A pediatric Intensive Care Unit.

PATIENTS

All those admitted over a one-year period were assessed during the first 24-72h, or when possible in deeply sedated patients.

EXCLUSION CRITERIA

Patients in stupor or coma, with severe communication difficulty, subjected to deep sedation throughout admission, and those with denied consent.

RESULTS

Twenty-nine of the 156 assessed patients suffered delirium (18.6%) and 55.2% were hypoactive. The neurocognitive alterations evaluated by the pCAM-ICU were similar in the three motor groups. Intellectual disability (OR=17.54; 95%CI: 3.23-95.19), mechanical ventilation (OR=18.80; 95%CI: 4.29-82.28), liver failure (OR=54.88; 95%CI: 4.27-705.33), neurological disease (OR=4.41; 95%CI: 1.23-15.83), anticholinergic drug use (OR=3.23; 95%CI: 1.02-10.26), different psychotropic agents (OR=4.88; 95%CI: 1.42-16.73) and tachycardia (OR=4.74; 95%CI: 1.21-18.51) were associated to delirium according to the logistic regression analysis.

CONCLUSION

The frequency of delirium and hypoactivity was high. It is therefore necessary to routinely evaluate patients with standardized instruments. All patients presented with important neurocognitive alterations. Several factors related with the physiopathology of delirium were associated to the diagnosis; some of them are modifiable through the rationalization of medical care.

Role of neuronal nitric oxide synthase (nNOS) at medulla in tachycardia induced by repeated administration of ethanol in conscious rats

Background

Intake of ethanol (alcohol) has been shown to influence cardiovascular function; the underlying brain mechanism remains unclear. Noting that nitric oxide (NO) system in the CNS is involved in the regulation of cardiovascular function, the present study examined the role of NO in medulla in ethanol-induced cardiovascular changes.

Methods

Ethanol was administered by oral gavage at dose of 3.2 g/kg once every day for 8 consecutive days. Changes in blood pressure (BP) and heart rate (HR) in response to ethanol were measured by radiotelemetry method in freely moving female Sprague-Dawley rats. NO modulators were applied by intracerebroventricular (ICV) injection. The protein levels of nitric oxide synthase (NOS) and NO content in rostroventral medulla were measured by Western blot and nitrate/nitrite colorimetric assay kit, respectively.

Results

Ethanol intake had little effects on basal BP and HR following 8 consecutive day treatments. A significant increase in HR but not BP following ethanol intake was observed at 6th and 8th, but not at 1st and 4th day treatments as compared with saline group. A decrease in the protein expression of neuronal NOS (nNOS) but not inducible NOS or endothelial NOS and a decline in the level of NO in the medulla 30 min after ethanol administration was observed at 8th day treatment. ICV treatment with NO donors attenuated ethanol-induced tachycardia effects at 8th day treatment. Ethanol produced significantly tachycardia responses when ICV nNOS inhibitors were given at 1st day treatment.

Conclusion

Our results suggest that medulla nNOS/NO pathways play an important role in ethanol regulation of HR.

Catheter ablation of symptomatic idiopathic ventricular arrhythmias : A five-year single-centre experience

Aims

This study was designed to gain insight into the patient characteristics, results and possible complications of ablation procedures for symptomatic idiopathic premature ventricular complexes (PVC) and idiopathic ventricular tachycardia (VT).

Methods

Data were collected from all patients who underwent radiofrequency catheter ablation for symptomatic PVCs and idiopathic VT in the Catharina Hospital between 1 January 2011 and 31 December 2015. The procedural endpoint was elimination or non-inducibility of the clinical arrhythmia. Successful sustained ablation was defined as the persistent elimination of at least 80% of the PVCs or the absence of VTs at follow-up. In case of suspected PVC-induced cardiomyopathy, the systolic left ventricular function was reassessed 3 months post procedure.

Results

Our cohort consisted of 131 patients who underwent one or more ablation procedures; 99 because of symptomatic premature ventricular complexes, 32 because of idiopathic VT. In total 147 procedures were performed. The procedural ablation success rate was 89%. Successful sustained ablation rate was 82%. Eighteen (13.2%) patients had suspected PVC-induced cardiomyopathy. In 15 of them (83%), successful sustained ablation was achieved and the left ventricular ejection fraction improved from a mean of 39% (±8.8) to 55.4% (±8.1). Most arrhythmias originated from the right ventricular outflow tract (60%) or aortic cusps (13%). Complications included three tamponades.

Conclusion

Catheter ablation therapy for idiopathic ventricular arrhythmias is very effective with a sustained success rate of 82%. In patients with PVC-induced cardiomyopathy, it leads to improvement of systolic left ventricular function. However, risk for complications is not negligible, even in experienced hands.

Mirabegron Toxicosis in Dogs: a Retrospective Study

Mirabegron is a selective beta (B)₃ adrenoreceptor agonist marketed for human treatment of an overactive bladder (OAB). It has a wide margin of safety in humans, but in dogs, severe adverse effects have occurred. We sought to determine the effects and outcome of mirabegron toxicosis in dogs. A retrospective review of all calls within the Pet Poison Helpline (PPH), an international animal poison control center, database was performed for mirabegron exposures between 2013 and 2015. Potential ingested doses ranging from 1.31 to 8.3 mg/kg. Many dogs remained asymptomatic and no fatalities occurred in any dogs. The most commonly reported signs were tachycardia and erythema. While mirabegron was found to have a very narrow margin of safety and high toxicity risk to dogs during preclinical trials, effects appear to differ greatly in the nonclinical field environment and further study is needed.

Familial atrioventricular nodal re-entrant tachycardia: A case seriers and a systematic review

Multiple reports of familial clustering suggest that genetic factors may contribute in the pathogenesis of atrioventricular nodal re-entrant tachycardia (AVNRT). We report three cases of AVNRT in a father and his two sons along with a review of literature of other similar cases. Electrophysiological studies induced typical AVNRT, which was successfully eliminated by radiofrequency ablation in all of them. Of the 22 reported cases, 96% had typical (slow-fast) variant of AVNRT. The predominant pattern of inheritance appears to be autosomal dominant, though other patterns may exist. Further research is needed to understand the genetic influence of AVNRT and its pathophysiology.

Ketosis-prone diabetes and SLE co-presenting in an African lady with previous gestational diabetes

We describe the case of an African woman who was diagnosed with ketosis-prone diabetes with diabetes-associated autoantibodies, after being admitted for diabetic ketoacidosis (DKA) precipitated by her first presentation of systemic lupus erythematosus (SLE). She had a seven-year history of recurrent gestational diabetes (GDM) not requiring insulin therapy, with return to normoglycaemia after each pregnancy. This might have suggested that she had now developed type 2 diabetes (T2D). However, the diagnosis of SLE prompted testing for an autoimmune aetiology for the diabetes, and she was found to have a very high titre of GAD antibodies. Typical type 1 diabetes (T1D) was thought unlikely due to the long preceding history of GDM. Latent autoimmune diabetes of adults (LADA) was considered, but ruled out as she required insulin therapy from diagnosis. The challenge of identifying the type of diabetes when clinical features overlap the various diabetes categories is discussed. This is the first report of autoimmune ketosis-prone diabetes (KPD) presenting with new onset of SLE.

Swallowing-induced atrial tachycardia in an adolescent with hypertrophic cardiomyopathy: a case report

Swallowing-induced tachycardia is a rare phenomenon, with only 50 cases documented worldwide. We present a unique case of an adolescent with hypertrophic cardiomyopathy (HCM) who presented with palpitations and a near syncopal episode. The patient was found to have a swallowing-induced atrial tachycardia. He underwent radiofrequency isolation of the right superior pulmonary vein and ablation of the right anterior ganglionated plexus, which led to a resolution of his symptoms. This case highlights the possible association between HCM and autonomic instability as potential aetiological mechanism for the tachycardia.

Cardiac tamponade in a patient with autoimmune polyglandular syndrome type 2

We describe a case of a 40-year-old woman who was admitted to the intensive care unit with a rapid onset of dyspnea and orthopnea. She presented progressive weakness, weight loss and secondary amenorrhea during last year, while intermittent fever was present for the last two months. Initial biochemical evaluation showed anemia, hyponatremia and increased C-reactive protein levels. Clinical and echocardiographic evaluation revealed cardiac tamponade, which was treated with pericardiocentesis. Pleural fluid samples were negative for malignancy, tuberculosis or bacterial infection. Hormonal and serologic evaluation led to the diagnosis of autoimmune polyglandular syndrome (APS) type 2 (including primary adrenal insufficiency and autoimmune thyroiditis), possibly coexisting with systemic lupus erythematosus. After symptomatic rheumatologic treatment followed by replacement therapy with hydrocortisone and fludrocortisone, the patient fully recovered. In patients with the combination of polyserositis, cardiac tamponade and persistent hyponatremia, possible coexistence of rheumatologic and autoimmune endocrine disease, mainly adrenal insufficiency, should be considered. Early diagnosis and non-invasive treatment can be life-saving.

LEARNING POINTS

In patients with the combination of polyserositis, cardiac tamponade and persistent hyponatremia, possible coexistence of rheumatologic and autoimmune endocrine disease, mainly adrenal insufficiency, should be considered.Early diagnosis and non-invasive treatment can be life-saving for these patients.Primary adrenal insufficiency requires lifelong replacement therapy with oral administration of 15-25 mg hydrocortisone in split doses and 50-200 µg fludrocortisone once daily.

Blood Pressure and Heart Rate Changes During Clozapine Treatment

People with schizophrenia are 3-4 times more likely to die from cardiovascular disease than the general population. Clozapine (CLZ) is the gold standard of treatment for refractory schizophrenia. It has been associated with tachycardia and recent evidence shows individuals prescribed CLZ may develop blood pressure (BP) elevation and hypertension. The purpose of this study was to examine the effects of CLZ on BP and heart rate (HR). This was a retrospective chart review of patients 18-75 years old with a DSM IV diagnosis of Schizophrenia or Schizoaffective disorder. Primary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR measured 12 weeks before and 24 weeks during CLZ treatment. Eighteen patient records were included in this study. The mean stabilized CLZ dose was 441.7 ± 171.8 mg/day. DBP (t = 1.02, df = 79.5, = 2.00, 0.049) and HR (t = 1.32, df = 355  = -4.61, < 0.0001) were significantly higher after CLZ initiation. A trend was noted for increase in SBP (p = 0.071). 22 % of patients met criteria for hypertension before CLZ and 67 % during CLZ treatment (Chi Square = 6.25, df = 1, p = 0.0124). No significant changes in weight or renal function occured during CLZ treatment. No patients had evidence of cardiomyopathy. The data suggest CLZ may be associated with a rise in BP and HR. The results of this study support previous literature that found an increase in SBP/DBP regardless of CLZ dose, occurring early in treatment. Due to high risk of cardiovascular morbidity and mortality, more work is needed to determine risk factors and understand the mechanism of action that may cause this side effect.

High-dose adenosine for refractory supraventricular tachycardia: a case report and literature review

Supraventricular tachycardia is the most common significant arrhythmia in children. If prolonged, it may cause heart failure and progress to cardiogenic shock warranting prompt treatment. The recommended interventions following vagal manoeuvres are intravenous adenosine and in the unstable patient electrical cardioversion. We present an infant with an unstable supraventricular tachycardia that was resistant to electrical cardioversion and recommended doses of adenosine. He reverted to sinus rhythm with a higher dose of adenosine, suggesting that such doses may be required in refractory supraventricular tachycardia.

Cardiopulmonary Exercise Test in Leukemia Patients After Chemotherapy: A Feasibility Study

Objective

To explore the feasibility of cardiopulmonary exercise test (CPET) in leukemia patients after chemotherapy.

Methods

Leukemia patients with histologically confirmed hematologic malignancies were reviewed. We evaluated for CPET, between receiving chemotherapy and undergoing stem cell transplantation after 2 weeks. We recorded exercise testing and physiologic parameters during CPET between January 2013 to May 2015. All patients were subjected to symptoms limited to exercise testing, according to the Modified Bruce Protocol. We considered that if respiratory exchange ratio achieved was over 1.10, participants had successfully completed CPET. We dichotomized all participants into two groups (normal group, normal range of resting heart rate; higher group, over 100 per minute of heart rate).

Results

30 patients were finally enrolled. All participants had no adverse effects during the exercise test. Mean peak double product was 26,998.60 mmHg·beats/min (range, 15,481–41,004), and mean peak oxygen consumption (VO₂ peak) was 22.52±4.56 mL/kg/min. Significant differences were observed in the normal group with VO₂ peak (mean, 24.21 mL/kg/min; p=0.027) and number of prior intensive chemotherapy, compared to the higher group (mean, 1.95; p=0.006).

Conclusion

Our results indicate that CPET in leukemia patients before stem cell transplantation was very safe, and is an efficient method to screen for patients with poor cardiac functions. As CPET presents the parameters which reveal the cardiopulmonary functions, including VO₂ peak, double product and exercise capacity, this exercise test would help to predict the physical performance or general condition of the leukemia patients.

The neural bases of ictal tachycardia in temporal lobe seizures

OBJECTIVE

Due to limited information from scalp electroencephalographic (EEG) recordings, brain areas driving changes in cardiac rhythm during Temporal lobe (TL) seizures are not clearly identified. Using stereotactic EEG (SEEG) recordings, we aimed at identifying which of the brain regions involved in autonomic control trigger ictal tachycardia.

METHODS

The neural activity of several mesial temporal lobe structures including amygdala, hippocampus, insula, and lateral temporal lobe recorded with SEEG were collected during 37 TL seizures in 9 patients, using indices based on High Frequency Activity (HFA). R-R intervals (RR) monitoring and time-frequency spectral analysis were performed to assess parasympathetic (High frequency power (HF)) and sympathetic (Low frequency/High frequency (LF/HF) ratio) reactivities.

RESULTS

Tachycardia was associated with a significant increase in LF/HF ratio and decrease in HF. Autonomic cardiac changes were accompanied by simultaneous SEEG signal changes with an increase in seizure-related HFA in anterior hippocampal formation and amygdala, but not in insula.

CONCLUSION

In our sample, TL seizures are thus accompanied by an early decrease in parasympathetic control of cardiac rhythm and by an increase of sympathetic tone, concomitant to seizure activity in anterior hippocampus and amygdala.

SIGNIFICANCE

These results support a pivotal role of hippocampus and amygdala in tachycardia occurring during TL seizures.