Doses Of Adenosine Research Articles

Comparison of initial adenosine dose conversion rate for supraventricular tachycardia in the emergency department

ObjectiveTo evaluate the rate of supraventricular tachycardia (SVT) termination between 6 mg and 12 mg initial adenosine doses. MethodsThis multi-center, retrospective cohort study evaluated patients presenting to the emergency department (ED) from January 1, 2020 to June 30, 2022 in SVT and received adenosine. The primary objective of the study is to compare the rate of SVT termination between adenosine 6 mg and 12 mg as documented on a formal electrocardiogram. Secondary endpoints include termination of SVT with subsequent adenosine dose, time to ED disposition, adverse effects, and subgroup analyses of patients with a body mass index greater than or equal to 40 kg/m2 and a history of SVT. ResultsOf 213 patients included, a 6 mg initial adenosine dose was administered to 117 patients (54.9 %) and a 12 mg initial adenosine dose was administered to 96 patients (45.1 %). SVT termination following the initial dose of 6 mg or 12 mg was 56.4 % and 79.1 %, respectively (p < 0.001). Among the 46 patients who failed to terminate SVT with an initial 6 mg dose, 33 converted to sinus rhythm with a subsequent adenosine dose in comparison to 1 of the 7 patients receiving an initial dose of 12 mg (71.7 % vs 14.3 %, p = 0.007). Median time to ED disposition, either inpatient admission or discharge, was 209 and 161 min, respectively (p = 0.104). There was no statistical difference in either subgroup analyses. ConclusionA higher rate of SVT termination was observed with an initial adenosine dose of 12 mg in the ED in comparison to the guideline recommended dose of 6 mg. There were no significant differences in adverse effects observed.

Safety of adenosine for pediatric tachyarrhythmia treatment in the emergency department: a multi-hospital 10-year cross-sectional study

BackgroundSupraventricular tachycardia is the most common dysrhythmia in children. Initial vagal maneuvers are successful less than half of the time. Adenosine, a potent AV nodal blocker with a short half-life, is recommended as first line pharmacotherapy. Minor side effects from adenosine are common, but report of serious side effects such as sustained ventricular tachycardia, torsades de pointes, syncope or hypotension are confined to small case series or studies greater than 20 years old. We aimed to specifically identify the incidence of serious side effects of adenosine in children in the emergency department.MethodsBetween 2002 and 2022, all children less than 18 years old who received adenosine for tachyarrhythmia treatment in two emergency departments were included. The electronic record was reviewed for demographic information, patient history, treatments given, and side effects or complications were observed. Electrocardiograms before, during and after adenosine administration were reviewed.Results77 patients met inclusion criteria. There were 74 patients with an initial rhythm of typical SVT. The other three patients included one with a junctional rhythm, one with atrial fibrillation, and one with an undetermined narrow complex tachycardia. 49 patients had cardiac rhythm monitoring during adenosine administration. 17 of these patients had three or more consecutive ventricular beats following adenosine, however no patients required treatment. No patients had syncope. One patient had brief hypotension after adenosine that normalized without intervention. Four patients were electrically cardioverted after adenosine, all for persistent dysrhythmias: two for persistent SVT with hypotension, one for atrial fibrillation and one for an undetermined rhythm. Twelve patients were placed on continuous antiarrhythmic medication for persistent SVT. Age, gender, prior SVT history, initial adenosine dose, and need for additional doses were not significant risk factors for a prolonged sinus pause or greater than two ventricular beats.ConclusionsAdenosine treatment in typical supraventricular tachycardia in pediatric patients is safe.

Catheter-based examination for pulmonary microcirculatory function in patients with pulmonary hypertension.

A device that can evaluate human pulmonary microcirculation is currently unavailable. This study aimed to establish a novel approach for assessing pulmonary microcirculation in patients with pulmonary hypertension (PH). We used a guidewire embedded with temperature and pressure sensors to measure the following pulmonary microcirculatory function indicators: pulmonary flow reserve, pulmonary index of microcirculatory resistance (PIMR), and pulmonary resistive reserve ratio. Adenosine was administered to patients to induce hyperemia in the pulmonary artery for assessment. The correlation between these indicators and various parameters, including serum biomarkers, hemodynamic and respiratory functions, and exercise capacity, were examined. The procedure was performed in 19 patients with moderate PH, without major complications. The minimum effective adenosine dosage for maximal hyperemia, without severe side effects, was 150 μg∙kg-1∙min-1. Multivariate stepwise analysis revealed a positive correlation between the hyperemic PIMR and serum uric acid (p < 0.001) and N-terminal probrain natriuretic peptide levels (p = 0.014). Therefore, this catheter-based method offers an effective means to assess pulmonary microcirculatory function in patients with PH, and the optimal dose of adenosine for this evaluation was 150 μg∙kg-1∙min-1.

The relation between fractional flow reserve and vascular dilation ration in predicting myocardial ischemia

Abstract Introduction Fractional flow reserve (FFR) is the gold standard for evaluation of myocardial ischemia but requires invasive pressure wire. Laplace’s Law states that the tension in the wall if a vessel is proportional to the pressure inside the vessel and its radius. The vascular dilation ratio (VDR) is the degree of dilation in the vessel proximal to the stenosis. Our aim was to test VDR using routine angiographic images and its correlation with FFR. Method Patients who performed coronary angiography with FFR were enrolled. After the images were reconstructed using ciunterpint and binarization analysis, VDR was calculated using the ratio of the maximal diameter minus the minimal diameter divided by the minimal diameter after contrast injection. Lesion’s characteristics, including adenosine dose and FFR were collected. The lesions were divided into two groups based on their FFR values: FFR≤ 0.8 and FFR &amp;gt;0.8. Result A total of 31 patients were enrolled, with a mean age 62.0 ± 13.3 years, and 19 of them were male). Of the 31 de-novo lesions analyzed, 23 were located in the left anterior descending artery, 4 in left circumflex artery, and 4 in right coronary artery. VDR was significantly higher in the group of lesions with FFR≤ 0.8, compared to the group with FFR &amp;gt;0.8 (P&amp;lt;0.01) (Table 1). The negative correlation coefficient between VDR and FFR was -0.92 (Figure 1). Conclusion The high negative correlation between VDR and FFR suggests that VDR could be a useful pre-FFR test for evaluating the severity of myocardial ischemia. Further studies with larger sample sized are warranted to confirm these finding.Table 1Figure 1

Emergency Department Pediatric Code Cart In Situ Rolling Refresher Training Program

BackgroundEmergency department nurses manage the code cart during infrequent pediatric emergencies in a rural, tertiary care center. A rolling refresher training program was developed to educate nurses on this low-frequency, high-risk skill. MethodsAn uncontrolled intervention study was completed with a 6-month follow-up. A program was created consisting of four scenarios and 17 code cart skills based on pediatric advanced life support algorithms. Each participant was assessed and trained to master each skill. ResultsAbout 56 participants were included. There was retained statistically significant improvement in first attempt successes between training 1 and 3 in the following skills: obtaining supplies for placing an IV and for intraosseous needle placement, delivering a weight-based appropriate fluid bolus, preparation and delivery of a weight-based epinephrine infusion, preparation and delivery of weight-based dose of adenosine, and a weight-based appropriate dose of epinephrine. ConclusionOur training program demonstrated improvement in a majority of these low-frequency, high-risk skills after an initial and repeated training every 6 months.

Changes in plasma alpha-1 acid glycoprotein following hemorrhagic trauma: Possible role in dose differences of ALM drug therapy in rat and pig resuscitation.

The binding of drugs to plasma proteins is an important consideration in drug development. We have reported that the dose of adenosine, lidocaine, and magnesium (ALM) fluid therapy for resuscitation from hemorrhagic shock is nearly 3-times higher for pigs than rats. Since lidocaine strongly binds to serum alpha-1-acid glycoprotein (AGP), the aim of the study was to investigate the effect of hemorrhagic shock on levels of AGP in rats and pigs. Healthy adult male Sprague-Dawley rats and female crossbred pigs (n = 33 each) underwent tail vein and peripheral ear vein blood sampling, respectively, to collect plasma for AGP measurements. Rats (n = 17) and pigs (n = 16) underwent surgical instrumentation and uncontrolled hemorrhage via liver resection, and were treated with 3% NaCl ± ALM IV bolus followed 60 min later by 4 h 0.9% NaCl ± ALM IV drip. Rats were monitored for 72 h with blood samples taken post-surgery, and at 5.25, 24, and 72 h. Pigs were monitored for 6 h with blood samples taken post-surgery, and at 60 min and 6 h. Plasma AGP was measured with rat- and pig-specific enzyme-linked immunosorbent assay kits. Baseline AGP levels in rats were 3.91 μg/mL and significantly 83-fold lower than in pigs (325 μg/mL). Surgical instrumentation was associated with ~10-fold increases in AGP in rats and a 21% fall in pigs. AGP levels remained elevated in rats after hemorrhage and resuscitation (28-29 μg/mL). In contrast, no significant differences in plasma AGP were found in ALM- or Saline-treated pigs over the monitoring period. We conclude that the trauma of surgery alone was associated with significant increases in AGP in rats, compared to a contrasting decrease in pigs. Higher levels of plasma AGP in pigs prior to hemorrhagic shock is consistent with the higher ALM doses required to resuscitate pigs compared with rats.

Tolerability and efficacy of a reduced dose adenosine stress cardiac magnetic resonance protocol under general anesthesia in infants and children.

Intravenous adenosine induces pharmacological stress by causing vasodilatation and thus carries the risk of severe hypotension when combined with vasodilatory effects of anesthetic agents. This study describes our experience with a reduced dose adenosine cardiac magnetic resonance imaging (MRI) protocol in young children under general anesthesia (GA). This is a retrospective report of all patients from birth to 18years who underwent adenosine stress cardiac MRI under GA between August 2018 and November 2022. Based on our anecdotal experience of severe adverse effects in patients receiving adenosine infusion under GA and in discussion with the pediatric anesthesia team, we developed a modified protocol starting at a dose of 110 mcg/kg/min with incremental escalation to a full dose of 140 mcg/kg/min to achieve desired hemodynamic effect. Twenty-two children (mean age 6.5years, mean weight 28kg) satisfied the inclusion criteria. The diagnoses included Kawasaki disease (7), anomalous aortic origin of left coronary artery (3), anomalous aortic origin of right coronary artery (2), coronary fistula (3), repaired d-transposition of great arteries (2), repaired anomalous left coronary artery from pulmonary artery (2), repaired truncus arteriosus with left coronary artery occlusion (1), extracardiac-Fontan with left coronary artery myocardial bridge (1), and post heart transplantation (1). Nine patients needed dose escalation beyond 110 mcg/kg/min. Two patients had transient hypotension during testing (systemic blood pressure drop > 25mmHg). No patient developed significant heart block or bronchospasm. Six patients (repeat study in one) demonstrated inducible perfusion defects (27%) on stress perfusion sequences-5 of whom had confirmed significant coronary abnormalities on angiography or direct surgical inspection. A reduced/incremental dose adenosine stress cardiac MRI protocol under GA in children is safe and feasible. This avoids severe hypotension which is both unsafe and may result in inaccurate data.

Patient Characteristics Associated with Hospital Admission or Antiarrhythmic Medication Changes After Emergency Department Evaluation of Supraventricular Tachycardia.

Supraventricular tachycardia (SVT) is a relatively frequent diagnosis in the pediatric emergency department (ED). However, there are no consensus guidelines for ED disposition, and there are limited data on ED outcomes. Better understanding of those who are admitted or have antiarrhythmic medication changes may avoid potentially unnecessary transfers or admissions. Our objective was to identify patient factors associated with discharge from the emergency department without medication initiation or modification after management of SVT in the pediatric ED. A retrospective review of children aged 0-18 years seen in the emergency department for SVT was conducted using electronic medical record data over a ten-year period at a single academic tertiary children's hospital. Patients with congenital cardiac disease or prior cardiac surgeries were excluded. Multivariable logistic regression analysis was used to determine association between patient factors of interest and the primary outcome of admission and secondary outcome of change to antiarrhythmic medications. We analyzed 197 patients encounters. The mean age was 7 years. Of these 104 (52.8%) were admitted to the hospital or discharged with antiarrhythmic medication changes. This primary outcome was associated with younger age (aOR 0.77, 95% CI 0.67-0.86), history of pre-excitation (aOR 5.82, 95% CI 2.01-18.8), intercurrent illness (aOR 3.75, 95% CI 1.27-12.1), number of adenosine doses prior to arrival (aOR 5.45, 95% CI 1.55-22.3), and in-person cardiology consultation (aOR 6.42, 95% CI 2.43-19.4). Nearly half of children treated in a pediatric ED for SVT are discharged without changes in medications. We identified patient factors associated with hospital admission or antiarrhythmic medication changes. These factors represent high value care and can be assessed when considering transfer from a referring facility. Risk stratification using these patient characteristics may reduce potentially avoidable transfers and admissions.

Adenosine response and failure to convert paroxysmal supraventricular tachycardia in the emergency department.

Although adenosine is the recommended first-line therapy for patients with paroxysmal supraventricular tachycardia (SVT), it may fail to restore normal sinus rhythm. The factors associated with this failure remain unclear. To assess the response rate to adenosine and identify the factors causing adenosine failure in the management of paroxysmal SVT. This retrospective study was conducted on adult patients diagnosed with paroxysmal SVT and treated with adenosine in the emergency departments of two large tertiary hospitals between June 2015 and June 2021. The primary outcome of the study was the patient response to adenosine, defined as the restoration of sinus rhythm documented in the patients' files. Backward-stepwise multivariate logistic regression was used to examine the predictors of adenosine failure based on the overall response to adenosine therapy. A total of 404 patients, with a mean age of 49 (SD 15) years and a BMI of 32 (SD 8) kg/m 2 , and treated with adenosine for paroxysmal SVT, were included. Sixty-nine percent of patients were women. The overall response rate to any adenosine dose was 86% (n = 347). The baseline heart rate did not significantly differ between adenosine responders and non-responders (179.6 ± 23.1 vs. 183.2 ± 23.4). An association was observed between the history of paroxysmal SVT and successful response to adenosine (odds ratio = 2.08; 95% confidence interval 1.05-4.11). The findings of this retrospective study suggested that the use of adenosine restored normal sinus rhythm in 86% of patients with paroxysmal SVT. Furthermore, a history of paroxysmal SVT and older age were associated with an increased chance of adenosine success.

Supraventricular Tachycardia, Types and Immediate Management; Experience at a Tertiary Care Hospital of South Punjab

Objectives: The objective of this study was to determine efficacy of different optimal adenosine doses in children presenting with supraventricular tachycardia (SVT) at a tertiary care hospital. Methods: A descriptive case series design was undertaken at the Department of Cardiology at the Chaudhry Pervez Elahi Institute of Cardiology in Multan between June 2021 and June 2022. Both genders, age groups less than 14 years, and patients with SVT. The data collection procedure involved the use of a specialized proforma to record the findings of the study. Adenosine was quickly dispensed in escalating doses of 100, 200, and 300 μg/kg. The reaction was captured using a 12-lead ECG, and instances of pre-excitation were noted. The success of the therapy was assessed by identifying a sustained sinus rhythm for a period exceeding three minutes as a positive outcome. Results: A total of 71 participants were included in the study. Out of these, 55 (77.5%) were males. 33.8% presented with a predisposing factor. The most common predisposing factor was LRTI and diarrhea in 47 (66.2%) patients. As per our findings, out of 71 patients who were administered 100 ug per kg of adenosine for SVT, 27 (38.0%) while the remaining refractory 42 patients were administered 200 ug per kg of adenosine. Out of these 42, 26 (61.9%) reverted back to sinus rhythm i.e. 200 ug per kg dose of adenosine was effective in 61.9% cases of SVT. The remaining patients reverted back at 300 ug per kg dose of adenosine. Conclusion: A higher dose of 200 ug per kg was effective in 61.9% of cases. This indicates that a higher dose of adenosine is more effective in treating SVT in children. Additionally, the study found that LRTI and diarrhea were the most common predisposing factors for SVT in children. These findings can be useful in improving the management of SVT in children, especially when considering the optimal dose of adenosine for treatment. Keywords: Adenosine, Supraventricular tachycardia, Pediatric cardiology, Dose optimization, Predisposing factors Sinus rhythm

PO-05-222 NOVEL APPROACHES FOR THE DIAGNOSIS OF CONCEALED NODO-VENTRICULAR AND HIS-VENTRICULAR PATHWAYS

Concealed nodo-ventricular (cNV) or His-ventricular (cHV) pathways are rare accessory pathway variants that represent important challenges for the clinician to separate from the more common supraventricular tachycardia arrhythmias. To describe novel observations to aid in diagnosing cNV or cHV pathways. We present a case series of seven patients with re-entrant arrhythmias involving cNV (5 cases) or cHV (2 cases) pathways. We focus on several laboratory observations: (1) differential ventricular overdrive pacing (VOD) from the right ventricular base vs. apex, (2) response to His refractory premature ventricular complexes (PVCs), (3) paradoxical atriohisian (AH) response in long RP tachycardia, and (4) the role of adenosine to aid in the diagnosis. (1) Three cases underwent differential basal vs. apical VOD during tachycardia. All demonstrated a shorter post-pacing interval minus tachycardia cycle length during basal pacing than apical pacing with one case exhibiting apical VOD results compatible with atrioventricular nodal reentrant tachycardia (AVNRT). In one case with a cHV pathway, basal VOD was useful for localizing the ventricular connection and guiding the ablation site. (2) In 3 cases, His refractory PVCs reset the tachycardia without conduction the atrium, which excluded atrioventricular reentry, atrial tachycardia, or AVNRT alone. One case had His refractory PVCs followed by subsequent constant AA and HH intervals and then tachycardia termination, suggesting a bystander cNV pathway involvement. (3) Two cNV pathway cases presented with long RP tachycardia had shorter AH intervals during tachycardia than those during sinus rhythm of >15ms, suggesting parallel activation of the atrium and the atrioventricular node. (4) Low-dose adenosine (3 and 6 mg) terminated the tachycardia with a retrograde block in 2 cases with cNV pathways, while high dose adenosine titrated up to 18 mg failed to convert in a case with a HV pathway. cNV and cHV pathways mediated tachyarrhythmias can present with variable clinical presentations. We emphasized (1) the role of differential VOD and the importance of the basal VOD for a proper diagnosis and pathway localization (Figure, Panel A), (2) the importance of His refractory PVCs that reset or terminate the tachycardia without conducting the atrium (Panel B), (3) the importance of paradoxical AH response in long RP tachycardia (Panel C), and the use of adenosine for possibly distinguishing cNV from cHV pathways (Panel D).

The effect of patient weight on the success of converting sinus rhythm in patients with PSVT treated with standard dose adenosine

PurposeThe study aimed to investigate whether there is a difference in the amount of adenosine per kilogram (mg/kg) between the patient groups that can and cannot be converted to sinus rhythm (SR) with adenosine therapy in patients with supraventricular tachycardia (SVT). Material and methodThis single-centered, retrospectively designed study was conducted in the ED of a training and research hospital between December 1, 2019 and December 1, 2022 on patients who were admitted to the ED with SVT diagnosis and treated with a 6–12–18 mg adenosine protocol. The main analyses were carried out in three stages. The first analysis was performed considering the first 6 mg dose of adenosine administered. The second analysis was performed by considering the 12 mg adenosine administered as the second dose because it did not respond to the first dose. Finally, the third analysis was performed by considering the 18 mg adenosine administered as the third dose because it did not respond to preciously dosages. The primary outcome variable was determined to be converting SR and created two groups according to this; the success SR group and the failure SR group. ResultsDuring the study period, 73 patients who were admitted to the ED with PSVT diagnosis and treated with intravenous adenosine were included. After the first 6 mg of adenosine treatment was administered to all 73 patients, SR was achieved in only 38% of patients. The mean adenosine dose (mg/kg) was significantly lower in the failure SR group, 0.07373 ± 0.014, compared with 0.08885 ± 0.017 mg/kg in the success SR group (mean difference with 95% CI: −0.01511 [−0.023 to −0.0071]; p < 0.001).In the second and third stage analyses, considering 12 and 18 mg adenosine doses, when the administrations with successful and failed SR were compared, no difference was found in terms of the applied adenosine doses per kilogram. ConclusionThis study suggest that the success of terminating SVT with the first 6 mg dose of adenosine appears to be dependent on patient weight. In patients given larger doses of adenosine, determinants of PSVT termination success may be factors other than patient weight.

Improved First Dose Conversion of Supraventricular Tachycardia Using Weight-Based Adenosine.

Introduction Paroxysmal supraventricular tachycardia (PSVT) is an often-recurring tachyarrhythmia that frequently results in emergency department visits and is commonly treated using intravenous adenosine. Given the anecdotal variable success of adenosine, the question arose of which patient factors may affect its success. This retrospective cohort analysis seeks to test the hypothesis that adult patients who receive adenosine at doses of ≥0.1mg/kg will have greater rates of successful conversion upon receipt of the first dose of adenosine. Methods This retrospective cohort analysis examines the charts from patients with known paroxysmal supraventricular tachycardia from November 1, 2015, through March 31, 2020, who were treated with intravenous adenosine. The primary outcome was the first-dose success of adenosine when stratified by patient weight (greater than 0.1mg/kg or less than 0.1mg/kg). Baseline characteristics and adverse effects were also collected. Results Seventy-six patients were included in the analysis. Patients who received adenosine at doses greater than or equal to 0.1mg/kg were more likely to convert to sinus rhythm than those who received doses less than 0.1mg/kg (p=0.006). No difference in adverse effects was noted between the groups (p=0.75). Conclusion This retrospective cohort analysis found that patients who received adenosine at doses greater than or equal to 0.1mg/kg for the treatment of PSVT were more likely to convert to sinus rhythm than those who received lower doses, with no difference in adverse effects. This hypothesis-generating finding provides the basis for a subsequent randomized, controlled trial to investigate the effectiveness and safety of weight-based adenosine.

Early dose of Adenosine, postRadiofrequency abLation of accessory pathwaYin determining acute procedural success (EARLY study).

Post ablation of the accessory pathway (AP), the patient is observed in the catheterization laboratory for a variable period for resumption of pathway conduction. Aim of the study was to determine whether the administration of intravenous adenosine at 10 min after ablation of APwould have the same diagnostic accuracy as waiting for 30 min in predicting the resumption of AP conduction. This was a prospective interventional study conducted in two centers. Post ablation of the AP, intravenous adenosine was administered at 10 min to look for dormant pathway conduction. The response was recorded as positive (presence of pathway conduction), negative (absence), or indeterminate (not able to demonstrate AV and VA block and inability to ascertain AP conduction). The study included 110 procedures performed in 109 patients. Adenosine administration at 10 min showed positive result in 3 cases (2.7%), negative result in 99 cases (90%) and indeterminate result in 8 cases (7.3%). Reconnection of accessory pathway at 30 min postablation was seen in 8 cases (7.3%). Of these 8 cases, 10 minadenosine administration showed positive test in 3 patients and negative test in 5 patients. Adenosine test at 10 min has a sensitivity, specificity, positive predictive value, and negative predictive value of 37.5%, 100%, 100%, and 94.9% in identifying the recurrence of accessory pathway conduction at 30 min, respectively. Absence of pathway conduction on administration of adenosine 10 min postablation does not help predict the absence of resumption of conduction thereafter.

A Clinical Score for Predicting the Paroxysmal Supraventricular Tachycardia's Recurrence Risk; a Retrospective Cross-sectional Study.

Identifying prognostic variables associated with the probability of recurrent paroxysmal supraventricular tachycardia (PSVT) would aid decision-making regarding disposition of the patients. This study aims to develop a clinical scoring system to predict PSVT recurrence after adenosine administration in the emergency department (ED). This retrospective cross-sectional study was conducted on patients who were referred to the emergency department of Ramathibodi Hospital, a university-affiliated super-tertiary care hospital in Bangkok, Thailand, with diagnosis of PSVT during a 10-year period from 01 January 2010 until 31 December 2020. The cases were divided into recurrent and non-recurrent PSVT based on the response to standard treatment and the independent predictors of recurrence were studied using multivariable logistic regression analysis. 264 patients were diagnosed with PSVT and successfully converted by adenosine. 24 (9.1%) had recurrent PSVT, and 240 (90.9%) had no recurrent PSVT in the same ED visit. The risk of PSVT recurrence in ED corresponded with the history of hypertension (p = 0.059), valvular heart disease (p = 0.052), heart rate ≥ 100 (p = 0.012), and systolic blood pressure < 100 after electrocardiogram (ECG) converted to sinus rhythm (p = 0.022) and total dose of adenosine (p = 0.002). We developed a clinical prediction score of PSVT recurrence with an accuracy of 79.5%. A score of 0 (low risk), 1-2 (moderate risk), and > 2 (high risk) had a positive likelihood ratio (LR+) of 0.31, 0.56 and 2.33, respectively. It seems that, using the PSVT recurrence score we could screen the high-risk patients for PSVT recurrence (score>2) who need to be observed for at least 6-12 hours and receive cardiologist consultation in ED. In addition, the moderate and low-risk group (score 0-2) need to be observed for 1 hour and can be discharged from ED.

Effects of adenosine and dipyridamole on serum levels of some biochemical markers in rabbits: Running title: Biochemical effects of adenosine and dipyridamole

Adenosine is a nucleoside which occurs naturally in a diverse forms in all cells of the body and in most biological fluids. Under basal conditions, the extracellular adenosine concentration is maintained within certain limits. Dipyridamol inhibits adenosine reuptake by erythrocytes, endothelial cells and platelet increasing plasma levels of adenosine Aims: study the effects of adenosine and dipyridamole on serum levels of serum urea, creatinine, alkaline phosphatase(ALP), lactate dehydrogenase (LDH), Aspartate Aminotransferase (GOT), and Alanine Aminotransferase (GPT). Material and methods: Thirty-five male rabbits were included in the study. The animals were divided into 3 groups: Group one(5 animals): injected intraperitoneal (i.p) with 2 ml of distilled water/day (control group). Group two (15 animals): were treated by i.p injection of adenosine, they were divided into 3 sub groups (5 animals) according to adenosine dose:1 mg/kg, 2mg/kg and 4 mg/kg.Group 3 (15 animals): were treated by dipyridamole orally, they were divided into 3 sub-groups (5 animals) according to dipyridamole dose:4 mg/kg, 8 mg/kg and 12 mg/kg. Result: Significant differences among 3 groups were found in blood urea, LDH, GOT levels, and in GPT levels. While statistical analysis of serum levels of S. creatinine and ALP showed no significant differences among 3 study groups. Conclusion: both adenosine, dipyridamole cause Significant differences among 3 groups were found in blood urea, LDH, GOT levels, and in GPT levels in rabbit

Comparison of sinus conversion rates and body weights after 6 mg adenosine administration in supraventricular tachycardia

BackgroundTo evaluate the relationship between body weight and the success rate of supraventricular tachycardia (SVT) termination after an initial 6-mg adenosine administration. MethodsThis retrospective observational study was conducted with medical records of patients who visited a single tertiary emergency department and underwent an electrophysiologic study with an SVT diagnosis. Patients under 18 years of age or those with SVT aberrancy, recurring SVT after radiofrequency catheter ablation, premedication of non-dihydropyridine calcium channel blocker, and signs of shock were excluded. ResultsData from 124 patients were collected. There were 69 women (55.6%); mean age, 49.7 years. The mean weight and height were 66.8 kg and 164.8 cm, respectively. Adenosine dose was 0.09 mg/kg. For the first sinus conversion (SC) success group (83 patients, 67%), the mean weight, height, and adenosine dose were 61.0 ± 11.5 kg, 161.9 ± 8.1 cm, and 0.10 ± 0.02 mg/kg. For the first SC failure group, these values were 78.4 ± 17.0 kg, 170.7 ± 8.9 cm, and 0.079 ± 0.02 mg/kg, respectively. To evaluate factors associated with the first SC, we performed bivariate logistic regression with weight (odds ratio [OR]: 1.093; 95% confidence interval [CI]: 1.045–1.144; P < 0.001) and height (OR: 1.071; 95% CI: 1.008–1.138; P = 0.027). Receiver operating characteristics curves and the cut-off values for adenosine dose and weight were 0.90 mg/kg and 66.5 kg with 71.1% sensitivity and 73.2% specificity (area under the curve: 0.814; 95% CI: 0.73–0.90; P < 0.001). ConclusionWeight and height were significant predictors of the first SC success rate among SVT patients. Consequentially, it is necessary to consider other adenosine administration methods, including increasing the initial drug dose or changing the flushing strategy after adenosine injection.

Ventricular and vascular stiffening in ischemia with no obstructed coronary arteries: novel insight from pressure-volume analysis

Abstract Background Ischemia with no obstructed coronary arteries (INOCA) is prevalent among women and associated with an increased risk of developing heart failure with preserved ejection fraction (HFpEF), however the mechanism linking these conditions remains poorly understood. Coronary vascular dysfunction is common in INOCA, representing a putative mechanism driving heart failure progression. Purpose To evaluate the role of coronary vascular dysfunction on left ventricular (LV) function in women with INOCA. Methods Women with suspected INOCA, defined as having signs and symptoms of ischemia but no obstructive coronary artery disease, underwent LV pressure-volume assessment at rest and during 3 minutes of isometric handgrip stress at 30% of maximal voluntary contraction. Coronary function testing was performed by infusing standard doses of adenosine, acetylcholine, and nitroglycerine through a guiding catheter placed in the left main coronary artery, per our published protocols. Using standardized definitions of normal versus abnormal responses, cases with zero abnormal coronary pathways (n=12) were compared to cases with three abnormal coronary pathways (n=7). Results At rest, end-systolic pressure and end-systolic elastance were elevated in cases with abnormal coronary vascular function (Figure), while normalized peak filling rate was lower (0.45±0.15 s mmHg–1 vs 0.37±0.08 s mmHg–1). With isometric handgrip, end-systolic pressure and end-systolic elastance increased similarly between groups, remaining highest in those with abnormal coronary vascular function (Figure). End-diastolic pressure-volume declined with handgrip in those without coronary vascular dysfunction, while increasing (up and to the left) in those with coronary vascular dysfunction (Figure). Likewise, normalized peak filling rate improved with handgrip in those without coronary vascular dysfunction, but did not change in those with coronary vascular dysfunction (0.66±0.37 s mmHg–1 vs 0.38±0.15 s mmHg–1). Conclusions We show heightened ventricular and vascular stiffness in women with INOCA who have abnormal coronary vascular function. These preliminary data support the hypothesis that coronary vascular dysfunction may be a putative mechanistic pathway driving heart failure progression in INOCA. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health

A CASE OF CORTICOSTEROID-ASSOCIATED SUPRAVENTRICULAR TACHYCARDIA STORM

A CASE OF CORTICOSTEROID-ASSOCIATED SUPRAVENTRICULAR TACHYCARDIA STORM

Assessing splenic switch-off in Adenosine stress CMR for patients with atrial fibrillation: a propensity-matched study.

Splenic switch-off (SSO) is a validated indicator of adequate vasodilator stress unique to adenosine stress cardiac MR (CMR). Patients in atrial fibrillation (AF) may have a reduced adenosine response due to lower hyperaemic coronary flow reserve and may achieve SSO less frequently versus sinus rhythm (SR). 1100 stress CMR studies were identified from a clinical CMR database (2016-2021). 70 patients in AF were propensity score matched to a SR group for age, sex, and body mass index. The adenosine dose administered, symptoms, heart-rate change and scan result were recorded. SSO was evaluated subjectively and semi-quantitatively via changes in splenic and myocardial signal intensity (SI) from rest to stress. SSO occurred significantly less frequently in AF than SR (34/70 [49%] vs 53/70 [76%], p = 0.003). Semi-quantitative assessment supported this, with a smaller splenic SI difference between stress and rest in AF vs SR (median splenic stress:rest peak SI ratio 0.92 [IQR:0.61-1.11] vs 0.56 [IQR:0.45-0.75], p < 0.001). A heart-rate increase >10 bpm predicted visual SSO in SR but not AF. Fewer patients in AF than SR had inducible ischaemia (9/70 [13%] vs 17/69 [25%], p = 0.058). This difference was not driven by inducible ischaemia rates in patients who did not achieve SSO (6/36 [17%] AF vs 4/17 [24%] SR, p = 0.403). SSO occurs significantly less frequently with AF. This may risk the under diagnosis of inducible ischaemia and requires further assessment. SSO, a validated marker of adequate stress in CMR, occurs significantly less frequently in the presence of AF, risking a suboptimal functional assessment of coronary disease.