Ventricular arrhythmias in horses: Diagnosis, prognosis and treatment

Ventricular arrhythmias (VAs) are often incidental or coincidental with systemic disease. Ventricular arrhythmias are also the most likely cause of many sudden cardiac deaths in horses. This dichotomy creates challenges in the management of horses with VAs. This review presents current knowledge of diagnosis, prognosis and treatment of VAs in horses.

Characterization of microminipig as a laboratory animal for safety pharmacology study by analyzing fluvoxamine-induced cardiovascular and dermatological adverse reactions

Fluvoxamine is a selective serotonin-reuptake inhibitor, of which IC₅₀ values for serotonin- and noradrenaline-uptake process were reported to be 3.8 and 620 nmol/L, respectively, also known to directly inhibit cardiac Na⁺, Ca²⁺, and K⁺ channels. We characterized microminipig as a laboratory animal by analyzing fluvoxamine-induced cardiovascular and dermatological responses under halothane anesthesia. Fluvoxamine maleate was infused in doses of 0.1, 1, and 10 mg/kg over 10 min with a pause of 20 min (n = 4). The peak plasma concentrations were 35, 320, and 1906 ng/mL, of which free plasma concentrations were estimated as 20, 187, and 1108 nmol/L, respectively. The low and middle doses did not alter any cardiovascular variable. The high dose increased heart rate and mean blood pressure, prolonged QRS width, but shortened QT interval, whereas no significant change was detected in PR interval or QTcF. Moreover, it induced systemic erythema on the skin. Pretreatment of H₁/5-HT_2A antagonist cyproheptadine hydrochloride sesquihydrate in a dose of 0.3 mg/kg significantly attenuated the fluvoxamine-induced pressor response; but tended to further enhance sinus automaticity, atrioventricular nodal conduction; and ventricular repolarization in addition to intraventricular conduction delay; whereas it markedly suppressed onset of systemic erythema (n = 4). In microminipigs, cardiovascular adverse effects of the high dose may be manifested as a sum of its inhibitory action on the cardiac ionic channels and its stimulatory effects on serotonergic and adrenergic systems, whereas dermatologic reaction can be induced primarily through H₁/5-HT_2A receptor-dependent mechanism. Thus, microminipigs may be used for analyzing such multifarious adverse events of clinical serotonergic pharmacotherapy.

A novel TRPM6 variant (c.3179T>A) causing familial hypomagnesemia with secondary hypocalcemia

SUMMARY

Familial hypomagnesemia with secondary hypocalcemia (FHSH) is a rare autosomal recessive disorder (OMIM# 602014) characterized by profound hypomagnesemia associated with hypocalcemia. It is caused by mutations in the gene encoding transient receptor potential cation channel member 6 (TRPM6). It usually presents with neurological symptoms in the first months of life. We report a case of a neonate presenting with recurrent seizures and severe hypomagnesemia. The genetic testing revealed a novel variant in the TRPM6 gene. The patient has been treated with high-dose magnesium supplementation, remaining asymptomatic and without neurological sequelae until adulthood. Early diagnosis and treatment are important to prevent irreversible neurological damage.

LEARNING POINTS

Loss-of-function mutations of TRPM6 are associated with FHSH. FHSH should be considered in any child with refractory hypocalcemic seizures, especially in cases with serum magnesium levels as low as 0.2 mM. Normocalcemia and relief of clinical symptoms can be assured by administration of high doses of magnesium. Untreated, the disorder may be fatal or may result in irreversible neurological damage.

Postural Orthostatic Tachycardia Syndrome (POTS): A critical assessment

Although diagnostic criteria have been developed characterizing postural orthostatic tachycardia syndrome (POTS), no single set of criteria is universally accepted. Furthermore, there are gaps in the present criteria used to identify individuals who have this condition. The reproducibility of the physiological findings, the relationship of symptoms to physiological findings, the presence of symptoms alone without any physiological findings and the response to various interventions confuse rather than clarify this condition. As many disease entities can be confused with POTS, it becomes critical to identify what this syndrome is. What appears to be POTS may be an underlying condition that requires specific therapy. POTS is not simply orthostatic intolerance and symptoms or intermittent orthostatic tachycardia but the syndrome needs to be characterized over time and with reproducibility. Here we address critical issues regarding the pathophysiology and diagnosis of POTS in an attempt to arrive at a rational approach to categorize the syndrome with the hope that it may help both better identify individuals and better understand approaches to therapy.

Hemodynamic effects of carbetocin administered as an intravenous bolus or infusion during cesarean delivery

Background

Postpartum hemorrhage is the leading cause of maternal mortality. Oxytocin being the most popular uterotonic agent, has been routinely administered after both vaginal delivery and cesarean section. Carbetocin is a newer uterotonic agent and provides the benefit of a longer duration of action without additional administration post-delivery.

Methods

We recruited 34 women undergoing elective cesarean section under spinal anesthesia. All patient was received spinal anesthesia using 0.5% hyperbaric Marcaine 8–10 mg in conjugation with fentanyl 20 μg in the left lateral decubitus position. Hartmann’s solution 10–15 ml/kg was administered before carbetocin. The operation started as soon as sensory block at level T4–T6 was confirmed. A non-invasive hemodynamic monitoring cuff (Finometer^®) was attached to the patient’s finger soon after the induction of spinal anesthesia. Using the Finometer, we recorded the heart rate and mean arterial pressure at every 15 s, starting from 15 s before the administration of carbetocin to 5 min after. After the removal of the placenta, the bolus group was administered intravenous bolus injection of carbetocin 100 μg and the infusion group was administered carbetocin 100 μg diluted in 50 ml normal saline, over 5 min using an infusion pump.

Results

The demographic data showed no significant difference between the two groups. Furthermore, there were no significant hemodynamic differences between the two groups.

Conclusions

The method of administration of carbetocin does not influence its hemodynamic effects.

The effect of bleeding on children's haemodynamic indices: an analysis of previous post-tonsillectomy bleeding cases

OBJECTIVE

Post-surgical bleeding after tonsillectomy occurs in 2-7 per cent of cases. This study examined whether heart rate and haematocrit changes are associated with the amount of bleeding.

METHOD

In this retrospective analytical study, data were collected from the medical charts of patients admitted with post-surgical bleeding.

RESULTS

Over the course of 10 years, there were 218 cases of post-operative bleeding in children aged under 18 years. There was a significant increase in heart rate after the bleeding had started, and a significant decrease in both haemoglobin and haematocrit levels (p < 0.05). There was no significant correlation between the differences in haemoglobin and haematocrit and changes in heart rate.

CONCLUSION

No correlation was found between the differences in haemoglobin and haematocrit levels and the changes in heart rate from before the surgery to after the bleeding had started. The monitoring of paediatric patients' heart rate after tonsillectomy surgery solely for the purpose of predicting acute blood loss is therefore discouraged.

Cardiac-cerebral-renal associations in pediatric traumatic brain injury: Preliminary findings

OBJECTIVE

The clinical epidemiology of organ outcomes in pediatric traumatic brain injury (TBI) has not been examined. We describe associated markers of cerebral, cardiac and renal injury after pediatric TBI.

DESIGN

Prospective observational study.

PATIENTS

Children 0-18 years who were hospitalized with TBI.

MEASUREMENTS

Measures of myocardial (at least one elevated plasma troponin [cTnI] ≥ 0.4 ng/ml) and multiorgan (hemodynamic variables, cerebral perfusion, and renal) function were examined within the first ten days of hospital admission and within 24 h of each other.

MAIN RESULTS

Data from 28 children who were 11[IQR 10.3] years, male (64.3%), with isolated TBI (67.9%), injury severity score (ISS) 25[10], and admission Glasgow coma score (GCS) 11[9] were examined. Overall, 50% (14 children) had elevated cTnI, including those with isolated TBI (57.9%; 11/19), polytrauma (33.3%; 3/9), mild TBI (57.1% 8/14), and severe TBI (42.9%; 6/11). Elevated cTnI occurred within the first six days of admission and across all age groups, in both sexes, and regardless of TBI lesion type, GCS, and ISS. Age-adjusted admission tachycardia was associated with cTnI elevation (AUC 0.82; p < 0.001). Reduced urine output occurred more commonly in patients with isolated TBI (27.3% elevated cTnI vs. 0% normal cTnI).

CONCLUSIONS

Myocardial injury commonly occurs during the first six days after pediatric TBI irrespective of injury severity, age, sex, TBI lesion type, or polytrauma. Age-adjusted tachycardia may be a clinical indicator of myocardial injury, and elevated troponin may be associated with cardio-cerebro-renal dysfunction.

Primary adrenal lymphoma as a cause of adrenal insufficiency, a report of two cases

SUMMARY

Primary adrenal lymphoma (PAL) is a rare cause of adrenal insufficiency. More than 90% is of B-cell origin. The condition is bilateral in up to 75% of cases, with adrenal insufficiency in two of three patients. We report two cases of adrenal insufficiency presenting at the age of 70 and 79 years, respectively. Both patients had negative 21-hydroxylase antibodies with bilateral adrenal lesions on CT. Biopsy showed B-cell lymphoma. One of the patients experienced intermittent disease regression on replacement dosage of glucocorticoids.

LEARNING POINTS

Primary adrenal lymphoma (PAL) is a rare cause of adrenal insufficiency. Bilateral adrenal masses of unknown origin or in individuals with suspected extra-adrenal malignancy should be biopsied quickly when pheochromocytoma is excluded biochemically. Steroid treatment before biopsy may affect diagnosis. Adrenal insufficiency with negative 21-hydroxylase antibodies should be evaluated radiologically.

[Electrical storm : Recognition and management]

The electrical storm (ES) defined as ≥3 sustained episodes of ventricular tachycardia within a 24 h period comprises a wide spectrum of clinical entities. Mostly patients suffer from severe heart insufficiency and comorbidities making an immediate transfer into a heart center with multidisciplinary expertise in the treatment of ES mandatory. As these patients are often traumatized by ongoing tachycardia despite multiple cardioversions, early deep sedation and β‑blockade to break the vicious circle of sympathico-adrenergic hyperactivation is very effective. Multiple ICD discharges suggesting the diagnosis of ES are inadequate in one third of cases. Pharmacological suppression, frequency control or ablation of supraventricular tachycardias (SVT) help in most cases. In some cases "oversensing" demands optimization of ICD programming. Even so not all adequate ICD discharges, however, are necessary. Since every ICD discharge worsens the patient's prognosis, any kind of ICD discharge should be prevented as far as hemodynamically feasible. After clinical stabilization of the patient with simultaneous acquisition of ECG and testing for reversible causes of ES, ES should be terminated by external or internal cardioversion followed by urgent but elective therapy. Some cases of ES, however, may require immediate escalation of therapy with emergency ablation or revascularization sometimes with circulatory support systems. If ES still persists, a further step in escalation may be taken by cardiac sympathetic denervation. Due to the poor prognosis of patients after ES, close monitoring of the patient, preferably with telemedicine, is indicated.

Arrhythmias in Children with Peripherally Inserted Central Catheters (PICCs)

To analyze the prevalence, types, and risk factors for cardiac arrhythmias associated with peripherally inserted central catheters (PICCs) in children. This is a case-control single center retrospective study. From 3180 PICCs inserted in children (< 18 years old) between 2009 and 2013, cases with new onset arrhythmias were identified. Demographics, type and timing of arrhythmias, and possible risk factors were analyzed. ECGs, rhythm strips, physicians' records, and anti-arrhythmic management were confirmatory. The level of the PICC's tip in the superior vena cava (SVC) or right atrium (RA) was ascertained from chest X-rays and counted in rib units (RU) and vertebra units (VU). Cases were matched (1:1 ratio) to controls by weight and date of insertion. Descriptive statistics were performed. A two-sided p value < 0.05 was considered significant. Thirty-one children (1%) developed arrhythmias, 16/31 (56%) were males, and 24/31 (77%) were < 1-year age. Arrhythmias were atrial 22 (71%), ventricular 4 (13%), and undetermined 5 (16%). Median PICC dwell time was 16 days. 14/31 (45%) cases and 9/31 (29%) controls had underlying structural heart disease. PICCs central tip position was lower among cases than controls (RU 6 vs 5). Odds Ratio for developing arrhythmia was 4.5 (95% CI 0.98-20.83) if the tip lays below 6.25RU. Arrhythmias were resolved with anti-arrhythmic agents in 52% (16/31) and with PICC exchange/manipulation in 32% (10/31) cases. Two children died unrelated to arrhythmia. Prevalence of arrhythmias associated with PICCs in children is low (1%). Arrhythmias are 4.5 times more likely when PICC's central tip position is deeper than 6.25RU.

Thyroid storm after coronary artery bypass surgery: a case report

Background

Thyroid storm is a rare, life-threatening disease triggered by an acute event or trauma, such as surgery of the thyroid or another area, and infection. However, recent studies have shown that irregular use or discontinuation of antithyroid drugs is the most common cause of thyroid storm. A cardiovascular event caused by thyroid storm following coronary artery bypass graft (CABG) is high output heart failure with extreme tachycardia, which can be fatal. Thyroid storm after nonthyroidal surgery, especially CABG, has been rarely reported, with only one reported case until now. Herein, we present a case of thyroid storm onset in a patient who underwent CABG.

Case presentation

A 74-year-old woman with a history of antithyroid medication discontinuation against medical advice underwent urgent CABG. The patient exhibited extreme tachycardia postoperatively, which is highly suggestive of thyroid storm. Although a higher infection risk is an important consideration, a high-dose steroid was used to control the intractable tachycardia that did not respond to beta-blocker administration. Despite appropriate antibiotic treatment, the patient’s condition was exacerbated, and she developed multiple organ failure resulting from adult respiratory distress syndrome progression, and she died on day 8 after surgery.

Conclusions

Risk factors for thyroid storm after CABG and its treatment outcomes are rarely reported. Patients with a history of inappropriate antithyroid medication prescription should be in a euthyroid state before surgery. If surgery is imminent, anticipating thyroid storm and its treatment as well as a euthyroid state can improve recovery outcomes postoperatively.

Pulmonary Embolism in Children: A Case Series

Background

Pulmonary embolism (PE) is a life-threatening event with a mortality of ~10%. It is relatively uncommon in children and literature regarding the condition is sparse. In adults, the classical clinical presentation is with pleuritic chest pain, hemoptysis, and dyspnea, whereas in children, the presentation is often nonspecific.

Materials and methods

Clinical features, risk factors, and outcome of children with PE presenting to our unit between December, 19 and March, 2020 were recorded.

Results

Four children [mean age: 10 (6–16) years, 3 females], all presenting with tachycardia and dyspnea were diagnosed with PE. Different risk factors such as deep vein thrombosis, nephrotic syndrome, softtissue infection, and infective endocarditis (IE) were identified in all patients. One child died while others responded to anticoagulation.

Conclusion

We aim to highlight the importance of timely recognition of PE in children with known risk factors for the same. Early recognition and timely treatment of PE are critical to save lives.

How to cite this article

Agrawal S, Shrivastava Y, Bolia R, Panda PK, Sharawat IK, Bhat NK. Pulmonary Embolism in Children: A Case Series. Indian J Crit Care Med 2020;24(12):1272–1275.

Assessment of ventricular tachyarrhythmia in patients with hypertrophic cardiomyopathy with machine learning-based texture analysis of late gadolinium enhancement cardiac MRI

OBJECTIVE

To assess the diagnostic value of machine learning-based texture feature analysis of late gadolinium enhancement images on cardiac magnetic resonance imaging (MRI) for assessing the presence of ventricular tachyarrhythmia (VT) in patients with hypertrophic cardiomyopathy.

MATERIALS AND METHODS

This retrospective study included 64 patients with hypertrophic cardiomyopathy who underwent cardiac MRI and 24-hour Holter monitoring within 1 year before cardiac MRI. There were 42 men and 22 women with a mean age of 48.13±13.06 (SD) years (range: 20-70 years). Quantitative textural features were extracted via manually placed regions of interest in areas with high and intermediate signal intensity on late gadolinium-chelate enhanced images. Feature selection and dimension reduction were performed. The diagnostic performances of machine learning classifiers including support vector machines, Naive Bayes, k-nearest-neighbors, and random forest for predicting the presence of VT were assessed using the results of 24-hour Holter monitoring as the reference test. All machine learning models were assessed with and without the application of the synthetic minority over-sampling technique (SMOTE).

RESULTS

Of the 64 patients with hypertrophic cardiomyopathy, 21/64 (32.8%) had VT. Of eight machine learning models investigated, k-nearest-neighbors with SMOTE exhibited the best diagnostic accuracy for the presence or absence of VT. k-nearest-neighbors with SMOTE correctly identified 40/42 (95.2%) VT-positive patients and 40/43 (93.0%) VT-negative patients, yielding 95.2% sensitivity (95% CI: 82.5%-99.1%), 93.0% specificity (95% CI: 79.8%-98.1%) and 94.1% accuracy (95% CI: 88.8%-98%).

CONCLUSION

Machine learning-based texture analysis of late gadolinium-chelate enhancement-positive areas is a promising tool for the classification of hypertrophic cardiomyopathy patients with and without VT.

Pediatric Bupropion Ingestions in Adolescents vs. Younger Children-a Tale of Two Populations

BACKGROUND

Bupropion is a unique class of antidepressant. In overdose, it is associated with tachycardia, altered mental status, and a dose-dependent risk of seizures, which can be delayed. Despite being a common medication, there is a paucity of data comparing toxicity in younger versus older children with bupropion exposures. The primary purpose of this study is to examine bupropion toxicity in pediatric patients and assess for toxicity differences between younger and older (teenaged) groups.

METHODS

This single-center, observational cohort study reviewed pediatric patients presenting to a toxicology service between 2011 and 2018. The primary outcome measures evaluated were the presence of any seizure, delayed seizure (defined as occurring at least 6 hours after hospital arrival), and a composite endpoint of seizure, hypotension, or need for endotracheal intubation. Patients were subdivided into two groups-those 12 years and under, compared with those 13-17 years.

RESULTS

A total of 80 unique pediatric cases were identified. Overall, the median (IQR) age was 14 (2.4-16) years. Patients under 13 years accounted for 31 (39%) of cases, whereas the remaining 49 cases were adolescents. Compared with the adolescents, the younger patients were less likely to be female (41.9% vs. 71.4%; p = 0.009) and more likely to have an unintentional ingestion (100% vs. 10.2%; p < 0.001). The younger group was more likely to present to health care earlier after the ingestion (median 61 (IQR 39-103) min vs. 139 (67-399) min; p = 0.002). The older group was more likely to be tachycardic (73.5% vs. 19.4%; p < 0.001), have sustained tachycardia (71.4% vs. 29% p < 0.001), and more likely to have altered mental status on arrival (38.8% vs. 6.5%; p < 0.001). Seizures were also much more likely in the older group (40.8% vs. 3.2%; p < 0.001). Adolescents were much more likely than younger children to reach the pre-defined composite endpoint (42.9% vs. 6.5%; p < 0.001), but this was largely driven by the seizures.

CONCLUSION

Bupropion ingestions are relatively common among pediatric patients. However, adolescents are much more likely to present with more severe toxicity. Seizures are uncommon among younger children with exploratory ingestions.

Fulminant hepatitis and elevated levels of sIL-2R in thyroid storm

SUMMARY

We report the case of a 48-year-old man with thyroid storm associated with fulminant hepatitis and elevated levels of soluble interleukin-2 receptor (sIL-2R). Fatigue, low-grade fever, shortness of breath, and weight loss developed over several months. The patient was admitted to the hospital because of tachycardia-induced heart failure and liver dysfunction. Graves' disease with heart failure was diagnosed. He was treated with methimazole, inorganic iodide, and a β-blocker. On the day after admission, he became unconscious with a high fever and was transferred to the intensive care unit. Cardiogenic shock with atrial flutter was treated with intra-aortic balloon pumping and cardioversion. Hyperthyroidism decreased over 10 days, but hepatic failure developed. He was diagnosed with thyroid storm accompanied by fulminant hepatitis. Laboratory investigations revealed elevated levels of sIL-2R (9770 U/mL). The fulminant hepatitis was refractory to plasma exchange and plasma filtration with dialysis, and no donors for liver transplantation were available. He died of hemoperitoneum and gastrointestinal hemorrhage due to fulminant hepatitis 62 days after admission. Elevated circulating levels of sIL-2R might be a marker of poor prognosis in thyroid storm with fulminant hepatitis.

LEARNING POINTS

The prognosis of thyroid storm when fulminant hepatitis occurs is poor. Liver transplantation is the preferred treatment for fulminant hepatitis induced by thyroid storm refractory to plasma exchange. Elevated levels of soluble interleukin-2 receptor might be a marker of poor prognosis in patients with thyroid storm.

Prolonged acidosis is a feature of SGLT2i-induced euglycaemic diabetic ketoacidosis

SUMMARY

We describe two cases of SGLT2i-induced euglycaemic diabetic ketoacidosis, which took longer than we anticipated to treat despite initiation of our DKA protocol. Both patients had an unequivocal diagnosis of type 2 diabetes, had poor glycaemic control with a history of metformin intolerance and presented with relatively vague symptoms post-operatively. Neither patient had stopped their SGLT2i pre-operatively, but ought to have by current treatment guidelines.

LEARNING POINTS

SGLT2i-induced EDKA is a more protracted and prolonged metabolic derangement and takes approximately twice as long to treat as hyperglycaemic ketoacidosis. Surgical patients ought to stop SGLT2i medications routinely pre-operatively and only resume them after they have made a full recovery from the operation. While the mechanistic basis for EDKA remains unclear, our observation of marked ketonuria in both patients suggests that impaired ketone excretion may not be the predominant metabolic lesion in every case. Measurement of insulin, C-Peptide, blood and urine ketones as well as glucagon and renal function at the time of initial presentation with EDKA may help to establish why this problem occurs in specific patients.

Clinical challenges of a co-secreting TSH/GH pituitary adenoma

SUMMARY

Co-secreting thyrotropin/growth hormone (GH) pituitary adenomas are rare; their clinical presentation and long-term management are challenging. There is also a paucity of long-term data. Due to the cell of origin, these can behave as aggressive tumours. We report a case of a pituitary plurihormonal pit-1-derived macroadenoma, with overt clinical hyperthyroidism and minimal GH excess symptoms. The diagnosis was confirmed by pathology showing elevated thyroid and GH axes with failure of physiological GH suppression, elevated pituitary glycoprotein hormone alpha subunit (αGSU) and macroadenoma on imaging. Pre-operatively the patient was rendered euthyroid with carbimazole and underwent successful transphenoidal adenomectomy (TSA) with surgical cure. Histopathology displayed an elevated Ki-67 of 5.2%, necessitating long-term follow-up.

LEARNING POINTS

Thyrotropinomas are rare and likely under-diagnosed due to under-recognition of secondary hyperthyroidism. Thyrotropinomas and other plurihormonal pit-1-derived adenomas are more aggressive adenomas according to WHO guidelines. Co-secretion occurs in 30% of thyrotropinomas, requiring diligent investigation and long-term follow-up of complications.

Supraventricular Tachycardia

The term paroxysmal supraventricular tachycardia encompasses a heterogeneous group of arrhythmias with different electrophysiologic characteristics. Knowledge of the mechanism of each supraventricular tachycardia is important in determining management in the office, at the bedside, and in the electrophysiology laboratory. Paroxysmal supraventricular tachycardias have an abrupt onset and offset, typically initiating and terminating with premature atrial ectopic beats. In the acute setting, both vagal maneuvers and pharmacologic therapy can be effective in arrhythmia termination. Catheter ablation has revolutionized therapy for many supraventricular tachycardias, and newer techniques have significantly improved ablation efficacy and decreased periprocedural complications and procedure times.

[Arrhythmias in patients with pulmonary hypertension and chronic lung disease]

Pulmonary arterial hypertension (PAH) occurs in 1% of the global population and can be divided in different disease groups. Pathophysiological aspects leading to supraventricular arrhythmias in these patients are due to increased pulmonary and right atrial pressure, increased activity of the sympathetic nervous system leading to right atrial electrical remodeling and ischemia in the right atrium. In the clinical setting these patients present with atrial flutter, atrial fibrillation or with ectopic atrial tachycardia. Regarding ventricular tachycardia there is a lack of data. Occurrence of arrhythmia in these patients leads to a deterioration of PAH, so rhythm control should be the aim. This can be achieved by right atrial ablation, especially in patients presenting with atrial flutter; electric cardioversion or antiarrhythmic drug therapy are without definite guideline recommendations since there are too few clinical trials. Ablation with a transseptal approach in the left atrium is considered rather dangerous and should be avoided. Regarding arrhythmias in patients with chronic lung disease, few data are available. For patients with chronic obstructive pulmonary disease (COPD), there are good data available. These patients often suffer from coronary heart disease, atrial fibrillation, and ventricular tachycardia. Beta-blockers play an important role in COPD patients, even during exacerbation. Interventional therapies are safe but the arrhythmogenic foci often located outside of the pulmonary veins (in the right atrium).

[Clinical analysis of right atrial appendage aneurysms complicated by atrial tachyarrhythmias in three children]

Objective: To investigate the clinical features and results of treatment for right atrial appendage aneurysms complicated by atrial tachyarrhythmias in children. Methods: This retrospective study included three children with right atrial appendage aneurysm complicated by atrial tachyarrhythmias (aged 1.0 to 5.3 years, weight 10 to 17.1 kg) who were hospitalized at the Pediatric Cardiology Department (Heart Center) of the First Hospital of Tsinghua University (Beijing Huaxin Hospital) during the period from January 2016 through April 2018. The patients' clinical features, the results of electrocardiogram (ECG) and echocardiography, the effects of therapeutic interventions (antiarrhythmics, radiofrequency ablation, and surgical resection of right atrial appendage aneurysm) and the results of pathological assessment were analyzed. Results: Three cases of right atrial appendage aneurysm were diagnosed at 36 weeks of gestational age, 1 month and 4 months after birth respectively. In two cases, ECG showed alternating episodes of atrial tachyarrhythmias including atrial tachycardia, atrial flutter, and atrial fibrillation, and echocardiography showed aneurysmal dilatation of right atrial appendage. These two cases underwent right atrial appendage aneurysm resection. In the remaining one case of atrial tachycardia, echocardiography did not visualize important lesions in the right atrium, thus the intracardiac electrophysiologic study and radiofrequency ablation were performed; and focal atrial tachycardia originating from the apex of right atrial appendage was mapped but failed to be ablated; consequently, the patient received the right atrial appendage resection, in which the right atrial appendage aneurysm was found. Preoperative multiple antiarrhythmics showed only modest or no efficacy for all the three cases. The atrial tachyarrhythmias disappeared in all the three cases after right atrial appendage aneurysm resection. Postoperative atrial tachycardias associated with new foci of impulse formation developed in two cases. These two patients reverted to normal sinus rhythm and remained in this rhythm by using antiarrhythmics. Pathological assessment showed cystic dilation of parts of atrial cavity, fibrosis of cyst wall, generalized fibrosis of atrial myocardium combined with myocardial atrophy and cystic dilation, as well as uneven myocardial thickness with generalized myocardial interstitial fibrosis. Conclusions: For patients with congenital right atrial appendage aneurysm, atrial tachyarrhythmias might develop during fetal stage or early postpartum period. Reliance on echocardiography might often lead to the missed diagnosis. These patients with atrial tachyarrhythmias responded poorly to antiarrhythmics. Radiofrequency ablation might be associated with a high risk and limited efficacy. Surgical resection of right atrial appendage aneurysm showed satisfactory results and should be highly recommended.

Non-invasive continuous haemodynamic monitoring and response to intervention in haemodynamically unstable patients during rapid response team review

INTRODUCTION

During rapid response team (RRT) management of haemodynamic instability (HI), continuous non-invasive haemodynamic monitoring may provide supplemental physiological information.

OBJECTIVES

To continuously and non-invasively obtain the cardiac index (CI) and mean arterial pressure (MAP) in patients with HI at baseline and during RRT management using the ClearSight™ device.

METHODS

We performed a prospective observational study in adult patients managed by the RRT for tachycardia or hypotension or both. We assessed changes from baseline in heart rate (HR), MAP, CI, stroke volume index (SVI) and systemic vascular resistance index (SVRI) (i) at 5-minutely intervals up to 20 min, and (ii) over the entire 20-min period. We analysed patients by RRT trigger (tachycardia/hypotension) and intervention (fluid bolus therapy [FBT]/ no FBT).

RESULTS

We successfully recorded the CI in 47 of 50 (94%) patients. RRT reviews triggered by hypotension rather than tachycardia had a lower baseline HR (-45.4 bpm, p = <0.0001), MAP (-16.1 mmHg, p = 0.0007) and CI (1.0 L/min/m², p = 0.0025). Compared to baseline, in the tachycardia group, there was a small increase in MAP overall and at the 15-20 min time-block from 83.2 mmHg to 87.1 mmHg (+3.9 mmHg, p = 0.0066) and 85.5 mmHg (+2.3 mmHg, p = 0.0061), respectively. In those who received FBT, there was a statistically significant increase in MAP overall and at the 15-20 min time-block compared to baseline, from 70.1 mmHg to 73.5 mmHg (+3.4 mmHg, p = 0.0036) and 74.3 mmHg (+4.2 mmHg, p = 0.0037), respectively. However, there were no statistically significant changes in mean HR, CI, SVI, or SVRI when comparing baseline to the entire 20-min period or 5-min time-blocks within any group.

CONCLUSIONS

Continuous non-invasive measurement of haemodynamics during RRT management for HI was possible for 20 min. Patients with hypotension rather than tachycardia had lower baseline HR, MAP and CI values. There was a statistically significant but small increase in MAP at the 15-20 min time-block and overall, for both the tachycardia and FBT groups.

Use of low-dose β1-blocker for sinus tachycardia in patients with catecholamine support following cardiovascular surgery: a retrospective study

Background

Sinus tachycardia coupled with high-dose catecholamine is common after cardiopulmonary bypass (CPB). The present study assessed the hemodynamic efficacy and safety of combination therapy using low-dose β₁-selective adrenergic blocker (landiolol) and inotropes.

Methods

This was a retrospective, single center, self-comparison study at post-anesthesia care unit within a tertiary care center. The study included adults who underwent cardiac surgery with CPB and received landiolol between April 2007 and November 2011. We assessed hemodynamic data prior to and 1 h after initiation of landiolol therapy.

Results

We evaluated 11 patients who were administered 2.6 ± 1.3 μg/kg/min (mean ± SD) landiolol with sinus tachycardia and received catecholamine therapy after on-pump cardiovascular surgery. Landiolol administration led to a significant reduction in heart rate (HR; 112.4 ± 5.8 vs 126.0 ± 7.6 beats/min, p < 0.001), and a significant increase in stroke volume index (SVI) assessed by pulmonary artery catheterization (22.4 ± 5.4 vs. 18.9 ± 4.2 mL/m², p = 0.04). Only one patient showed no HR reduction, whereas seven patients showed decreased HR and increased SVI (64, 95% confidence interval: 30–98%). Moreover, all five patients who received high-dose catecholamine support showed improved hemodynamics. In terms of safety, no patients required cessation of landiolol therapy.

Conclusions

Low-dose landiolol therapy may safely decrease HR and improve hemodynamics among patients with sinus tachycardia receiving catecholamine treatment after cardiovascular surgery.

Trial registration

This study is retrospective. Registration number: 11. Duration of registration: April 2007~November 2011.