Intravenous Adenosine Research Articles

Abstract 10459: Adenosine versus Diltiazem in Stable Supraventricular Tachycardia Unresponsive to Vagal Maneuver

Introduction: The treatment of stable supraventricular tachycardia (SVT) in the emergency department includes intravenous adenosine. There is evidence to show that calcium channel blockers such as diltiazem have a better conversion rate. This study was conducted to determine the relative effectiveness and to examine the adverse effects of these drugs on converting stable SVT into sinus rhythm. Methods: A prospective randomized controlled study with one group receiving an intravenous bolus dose of 6mg adenosine followed by 12mg if conversion not achieved, and followed by diltiazem if not reverted, and other group receiving diltiazem 0.25mg/kg IV followed by 0.35mg/kg if conversion is not achieved which was followed by continuous infusion. Heart rate and blood pressures were continuously monitored for 1-hour post-conversion with monitoring of other adverse events results: A total of 52 patients with stable SVT were enrolled and were randomized into two groups. Of these 26 patients were given IV Adenosine in one arm and 26 patients were given IV Diltiazem. The conversion rates with adenosine 76.9% were statistically lesser than the diltiazem group 100% with the statistically significant p value of 0.023. The mean change in the blood pressures in either group was statistically insignificant and also the adverse events in either group had no significance. Conclusion: Calcium channel blockers such as diltiazem may be superior to adenosine in the emergency department in the treatment of stable SVT. In this study IV Diltiazem had better conversion rates than the IV adenosine bolus with minimal adverse events. Hence calcium channel blockers are found to be better, safe, and cost-effective in converting stable SVT.

Respiration-related variations in Pd/Pa ratio and fractional flow reserve in resting conditions and during intravenous adenosine administration.

AimsWe evaluated the occurrence and physiology of respiration‐related beat‐to‐beat variations in resting Pd/Pa and FFR during intravenous adenosine administration, and its impact on clinical decision‐making.Methods and ResultsCoronary pressure tracings in rest and at plateau hyperemia were analyzed in a total of 39 stenosis from 37 patients, and respiratory rate was calculated with ECG‐derived respiration (EDR) in 26 stenoses from 26 patients. Beat‐to‐beat variations in FFR occurred in a cyclical fashion and were strongly correlated with respiratory rate (R2 = 0.757, p < 0.001). There was no correlation between respiratory rate and variations in resting Pd/Pa. When single‐beat averages were used to calculate FFR, mean ΔFFR was 0.04 ± 0.02. With averaging of FFR over three or five cardiac cycles, mean ΔFFR decreased to 0.02 ± 0.02, and 0.01 ± 0.01, respectively. Using a FFR ≤ 0.80 threshold, stenosis classification changed in 20.5% (8/39), 12.8% (5/39) and 5.1% (2/39) for single‐beat, three‐beat and five‐beat averaged FFR. The impact of respiration was more pronounced in patients with pulmonary disease (ΔFFR 0.05 ± 0.02 vs 0.03 ± 0.02, p = 0.021).ConclusionBeat‐to‐beat variations in FFR during plateau hyperemia related to respiration are common, of clinically relevant magnitude, and frequently lead FFR to cross treatment thresholds. A five‐beat averaged FFR, overcomes clinically relevant impact of FFR variation.

Adenosine plasma levels and adenosine receptor levels determine the outcome of adenosine test and head-up tilt test in syncopal patients with a normal heart

Abstract Background/Introduction The neurohumoral profile underlying the manifestation of reflex syncope remains incompletely understood. Adenosine plasma (ADP) and adenosine receptor (ADR) levels may differentiate the outcomes of head-up tilt table test (HUTT) and adenosine test (ADT) but their role in the diagnostic evaluation of patients with syncope has yet to be determined. Purpose We sought to assess the ADP and ADR levels in patients without structural heart disease who underwent HUTT and ADT tests as part of the diagnostic workup of syncope. We specifically investigated differences in the outcomes of the HUTT and ADT tests as well as to the ADP levels during HUTT. Methods HUTT and ADT were performed as per the standard protocols. ADT was considered positive in the event of asystole &amp;gt;6 seconds or heart block for &amp;gt;10 seconds after intravenous Adenosine 0.15 mg/kg administration in the supine position. ADP levels were assessed at three timepoints during the HUTT: at baseline (supine), immediately after bed tilt and, in cases of a positive HUTT, at the time of syncope. Patients were categorized in quintiles of very low, low, intermediate, high and very high baseline ADP levels. We also assessed the A2A ADR levels of monocytes. Results We prospectively analyzed 124 patients (71 women, age 46.78±21.01 years). ADT was positive in 12.9% of patients and HUTT in 44.4% of patients. Patients with very low baseline ADP levels (lowest quintile) more frequently presented with a positive ADT (odds ratio [OR] 4.08, 95% Confidence Interval [CI] 1.40 to 13.13, p&amp;lt;0.05). Baseline ADP did not differ between patients with positive and negative HUTT. However, patients with vasodepressor response to HUTT exhibited increase in ADP from baseline to bed tilt (0.33±1.03 vs. 0.42±1.14 ppm/Um/L, p&amp;lt;0.05) and in syncope (0.70±1.89, P&amp;lt;0.05), while no difference was noted in patients with cardioinhibitory or mixed response. Patients with positive ADT and negative HUTT had higher ADR levels (221.5±88.56 MFI) as compared to patients with negative ADT and positive HUTT (59.78±83.65 MFI, p&amp;lt;0.05) and to patients with positive ADT and HUTT (33.29±35.77 MFI, p&amp;lt;0.05). Within patients with positive HUTT, those with onset of syncope in the Isoprenaline provocation phase (&amp;gt;20 min) had lower ADR levels (80.88±238.98 vs 89.43±96.08 MFI, p&amp;lt;0.05). Conclusion(s) Baseline ADP levels are related to the outcome of ADT while an ADP increase immediately after bed tilt and in syncope is evident in vasodepressor response to HUTT. Higher ADR levels are related to positive ADT and negative HUTT. Lower ADR levels are associated with more delayed onset of syncope during HUTT. ADP and ADR levels warrant further investigation as they may characterize a subset of patients with specific responses to ADT and HUTT and may be implicated in the pathophysiology of reflex syncope. Funding Acknowledgement Type of funding sources: None.

Supraventricular Tachycardia in Pregnancy: Gestational and Labor Differences in Treatment.

Supraventricular tachycardia (SVT) is a tachyarrhythmia characterized by a heart rate above 120 beats per minute (BPM). Patients with SVT exhibit the following symptoms: palpitations, shortness of breath, chest pain, hemodynamic instability, or possibly asymptomatic. The increase in cardiac output and the increase in resting heart rate during pregnancy predispose pregnant women to SVT. The management of SVT in pregnancy, although remarkably similar, varies slightly based on the trimester of pregnancy. Atenolol and verapamil are effective methods of treating SVT, which can be used during the second and third trimesters. Both medications are contraindicated in the first trimester. At the same time, intravenous adenosine can be used in all three trimesters, including labor. Electrical cardioversion is an effective treatment method for hemodynamically unstable or drug-refractory patients, which has proven to be safe in all three trimesters, including labor but can result in pre-term labor in the third trimester. Non-fluoroscopic ablation proved to be the only treatment method that definitively resolved SVT without recurrence.

The Role of Coronary Computed Tomography Angiography in Evaluation of High Troponin Patients with Narrow-Complex Supraventricular Tachycardia.

Aim:The aim of this study was to investigate the relation of high-sensitive cardiac troponin T (hs-cTnT) elevation with characteristics of supraventricular tachycardia (SVT) episode (duration and maximum heart rate) and coronary computed tomography angiography (CCTA) findings in patients with SVT who presented to the emergency room with palpitation.Methods:This retrospective, single-center, noninvasive study included all patients aged between 18 years and 65 years who presented to the emergency department due to narrow-complex SVT and underwent CCTA to rule out coronary artery disease (CAD) due to elevation of hs-cTnT and reverted back to sinus rhythm after intravenous adenosine. The first, second, and the maximum hs-cTnT levels were obtained from the database. The patients were classified into normal coronaries, nonobstructive CAD, and obstructive CAD according to findings of the CCTA. The findings of the groups were compared.Results:Eighty-five patients were enrolled in the study. Of them, 21 (26%) patients were female. Sixty-three patients (74%) had normal coronary arteries as per CCTA results, whereas 22 patients (22%) had nonobstructive CAD and two patients (2%) had obstructive CAD. The groups did not differ statistically in respect to hs-cTnT measurements, duration of the arrhythmia, and maximum heart rate at SVT episode. There was no significant statistical correlation between hs-cTnT and the study parameters except the maximum heart rate.Conclusion:Cardiac troponins may increase in patients with paroxysmal SVT irrespective of the presence of coronary lesions, and the CCTA may not be an appropriate investigation in the differential diagnosis of paroxysmal SVT with elevated hs-cTnT.

Instantaneous wave-free ratio compared with fractional flow reserve in PCI: A cost-minimization analysis

BackgroundCoronary physiology is a routine diagnostic tool when assessing whether coronary revascularization is indicated. The iFR-SWEDEHEART trial demonstrated similar clinical outcomes when using instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) to guide revascularization. The objective of this analysis was to assess a cost-minimization analysis of iFR-guided compared with FFR-guided revascularization. MethodsIn this cost-minimization analysis we used a decision-tree model from a healthcare perspective with a time-horizon of one year to estimate the cost difference between iFR and FFR in a Nordic setting and a United States (US) setting. Treatment pathways and health care utilizations were constructed from the iFR-SWEDEHEART trial. Unit cost for revascularization and myocardial infarction in the Nordic setting and US setting were derived from the Nordic diagnosis-related group versus Medicare cost data. Unit cost of intravenous adenosine administration and cost per stent placed were based on the average costs from the enrolled centers in the iFR-SWEDEHEART trial. Deterministic and probabilistic sensitivity analyses were carried out to test the robustness of the result. ResultsThe cost-minimization analysis demonstrated a cost saving per patient of $681 (95% CI: $641 - $723) in the Nordic setting and $1024 (95% CI: $934 - $1114) in the US setting, when using iFR-guided compared with FFR-guided revascularization. The results were not sensitive to changes in uncertain parameters or assumptions. ConclusionsIFR-guided revascularization is associated with significant savings in cost compared with FFR-guided revascularization.

The Effectiveness of Adenosine in Treating the Acute Attacks of Supra-ventricular Tachycardia

Background: Adenosine is a natural adenine nucleoside available endogenously that decreases heart beat by blocking atrioventricular (AV) node transiently so that extend the duration of conduction in (AV) node when injected intravenously. It has a curative value in the conversion of majority of supraventricular tachycardia (SVT) to sinus rhythm. In order to evaluate the adenosine in the management of arrhythmias we conduct this study. Objective: This study was conducted to evaluate the safety and efficacy of intravenous adenosine therapy for treatment of (SVT), to determine the optimal adenosine dose effective in (SVT), and to determine the underlying conditions affecting the effective dose. And to evaluate the effectiveness of vagal maneuvers in terminating of spontaneous SVT patients and methods: A cross-sectional study conducts in a group consist of 69 patients ranged from 23-70 years old admitted to the Coronary care unit in Azadi Teaching Hospital ,in Kirkuk city, from July 2014 to June 2016. The diagnosis of (SVT) was made by present of tachycardia which is of narrow complex with a heart beat rate greater than 140 beats/ min by 12 leads chest electrocardiography (ECG). In patients who are hemodynamically stable, vagal maneuvers were carried out initially in the form of carotid sinus massage, gag reflex and Valsalva maneuver, if this failed intravenous administration of adenosine as recommended doses were preformed. If three doses of adenosine boluses were unsuccessful to convert the arrhythmia, patients were managed with other available antiarrythmias or managed with direct electrical cardio version (DC). In unstable patients were managed with (DC). Results: Of 69 included patients, diagnosed as (SVT), M: F ratio was 1:2.1. Their age ranged from 23 years to 70 years with mean age of 57 years. Vagal maneuvers (VM) resulted in restoration of sinus rhythm (SR) in 8patients (7.6%). Out of 57 episodes of (SVT), Adenosine was effective in reverting 51 episodes of SVT to sinus rhythm (89.5%). Of those converted, 18 required a single dose (6mg) (31.6%), fifteen required one additional (12mg) dose (26.3%), and another 18 required two additional doses (81mg) (31.6%).four patients were hemo-dynamically unstable (systolic blood pressure <90 mm Hg) which required (DC). Six patients (10.5%) not responding to full adenosine dose(81mg), started treatment with other medication, 1 with verapamil, 4 with amiodarone, and1 with digoxin. All of them were successfully treated. Conclusions: Adenosine is an effective medicine in treating (SVT) in those patients in whom vagal maneuvers has unsuccessful. It demonstrates a high rate of success in terminating acute attack of SVT. A higher dose may be required in majority of patients specially

ST-Elevation Myocardial Infarction Patients with Hyperglycemia: Effects of Intravenous Adenosine

BackgroundAdmission hyperglycemia is common in subjects with acute myocardial infarction (AMI). Reperfusion therapy with primary percutaneous coronary intervention (PPCI) represents the leading therapeutic choice, in particular in ST-segment elevation myocardial infarction (STEMI). Despite this, mortality, re-hospitalizations and complications remain a relevant problem. Adenosine, a purine nucleoside, may reduce no-reflow. Therefore, whe studied the effects of intravenous infusion of adenosine in addition to primary percutaneous coronary intervention (PPCI) in hyperglycemic patients with STEMI. MethodsWe evaluated 836 patients with STEMI and admission hyperglycemia (glycemia >140 mg/dL). At the end, 399 patients were entered into the database. Patients were grouped on the basis of whether they received adenosine or not. ResultsA total of 199 patients received intravenous adenosine infusion and PPCI and 200 patients did not. Kaplan–Meier analysis demonstrated significant differences in all death, cardiac death, re-hospitalization for heart failure and for acute coronary syndrome in the adenosine treated group. ConclusionsThe effects of intravenous infusion of adenosine and PPCI on clinical outcomes are significant but we need future larger studies with larger follow-up and statistical analysis to confirm our results.

Intravenous regadenoson versus intracoronary adenosine for fractional flow reserve measurement

Intravenous regadenoson versus intracoronary adenosine for fractional flow reserve measurement

Cardiorespiratory Effects of Three Infusion Doses of Adenosine in Conscious Goats: A Preliminary Study

Adenosine (AD) has been implicated in human healthcare as an endogenous signaling nucleotide in both physiologic and pathologic states. The effects of AD on cardiorespiratory parameters in ruminants has not yet been studied. The objective of this study was to evaluate the cardiac and respiratory changes that resulted from an intravenous AD infusion in goats. Six clinically healthy adult goats weighing 28 ± 2 kg were randomly assigned to one of four treatments in a crossover design with a seven day washout period. The goats received a 0.9 % saline solution (SAL treatment) and three AD treatments (AD 50, 100 and 200) intravenously at a dose rate of 50, 100 and 200 μg/kg/min. Cardiorespiratory and key cardiac parameters were measured before the treatment (baseline), during the infusion (dInf) and at 1, 3, 5 and 10 min after each infusion was discontinued. The AD 100 produced a significant increase in HR (p = 0.001) and the AD 200 resulted in significant rises in HR (p = 0.006) and RR (p = 0.001) compared with the baseline. This study concluded that the AD infusion could trigger an increase in HR and RR in a dose-dependent manner in healthy goats.

Comparing invasive hemodynamic responses in adenosine hyperemia versus physical exercise stress in chronic coronary syndromes

ObjectivesAdenosine hyperemia is an integral component of the physiological assessment of obstructive coronary artery disease in patients with chronic coronary syndrome (CCS). The aim of this study was to compare systemic, coronary and microcirculatory hemodynamics between intravenous (IV) adenosine hyperemia versus physical exercise stress in patients with CCS and coronary stenosis. MethodsTwenty-three patients (mean age, 60.6 ± 8.1 years) with CCS and single-vessel coronary stenosis underwent cardiac catheterization. Continuous trans-stenotic coronary pressure-flow measurements were performed during: i) IV adenosine hyperemia, and ii) physical exercise using a catheter-table-mounted supine ergometer. Systemic, coronary and microcirculatory hemodynamic responses were compared between IV adenosine and exercise stimuli. ResultsMean stenosis diameter was 74.6% ± 10.4. Median (interquartile range) FFR was 0.54 (0.44–0.72). At adenosine hyperemia versus exercise stress, mean aortic pressure (Pa, 91 ± 16 mmHg vs 99 ± 15 mmHg, p < 0.0001), distal coronary pressure (Pd, 58 ± 21 mmHg vs 69 ± 24 mmHg, p < 0.0001), trans-stenotic pressure ratio (Pd/Pa, 0.63 ± 0.18 vs 0.69 ± 0.19, p < 0.0001), microvascular resistance (MR, 2.9 ± 2.2 mmHg.cm−1.sec−1 vs 4.2 ± 1.7 mmHg.cm−1.sec−1, p = 0.001), heart rate (HR, 80 ± 15 bpm vs 85 ± 21 bpm, p = 0.02) and rate-pressure product (RPP, 7522 ± 2335 vs 9077 ± 3200, p = 0.0001) were all lower. Conversely, coronary flow velocity (APV, 23.7 ± 9.5 cm/s vs 18.5 ± 6.8 cm/s, p = 0.02) was higher. Additionally, temporal changes in Pa, Pd, Pd/Pa, MR, HR, RPP and APV during IV adenosine hyperemia versus exercise were all significantly different (p < 0.05 for all). ConclusionsIn patients with CCS and coronary stenosis, invasive hemodynamic responses differed markedly between IV adenosine hyperemia versus physical exercise stress. These differences were observed across systemic, coronary and microcirculatory hemodynamics.

Fractional flow reserve: Comparing intravenous regadenoson and intravenous adenodsine

Background and Aims: Creating an environment of maximal hyperemia is required for adequate fractional flow reserve (FFR) measurements and ultimately an effective percutaneous intervention. Currently the gold standard method is via intravenous adenosine, but it has side effects through it non-selective activation of adenosine receptors. Intravenous regadenoson has been proposed as a safe alternative, but a recent trial used regadenoson with aminophylline. The goal of this meta-analysis is to compare the previous four studies with this newly designed trial.

Invasive Assessment of Microvascular Resistance in Hypertrophic Cardiomyopathy With Echocardiographic Correlates

Hypertrophic cardiomyopathy (HCM) is often associated with ischaemia despite lack of focal epicardial coronary stenosis. Our aim was to assess invasive coronary microvascular circulation and correlate findings with echocardiography. We prospectively enrolled patients with HCM and controls who were referred for diagnostic coronary angiography. A pressure-temperature sensor coronary guidewire was used with intracoronary injections of room-temperature saline to measure mean coronary transit time during rest and hyperaemia induced with intravenous adenosine. The index of microvascular resistance (IMR) was calculated. Left ventricular mass was calculated during echocardiographic studies. Patients with HCM (n=12) and controls (n=7), had similar demographics. Left ventricular ejection fraction was higher in HCM (76.7%±11.0% vs 55.0%±15.9%, p=0.003). IMR was non-significantly higher in HCM (21.7±10.2 vs 15.3±4.8, p=0.16). Only patients with HCM had abnormal IMR (>25). Coronary flow reserve was non-significantly higher in HCM (2.7±1.6 vs 2.1±1.2, p=0.34). IMR correlated with left ventricular mass in hypertrophic cardiomyopathy subjects (Pearson r=0.68, p=0.02). Microvascular dysfunction as assessed by IMR may be abnormal in HCM and is correlated with left ventricular mass.

Simplified Assessment of the Index of Microvascular Resistance.

Background To validate a simplified invasive method for the calculation of the index of microvascular resistance (IMR). Methods This is a prospective, single-center study of patients with chronic coronary syndromes presenting with nonobstructive coronary artery disease. IMR was obtained using both intravenous (IV) adenosine and intracoronary (IC) papaverine. Each IMR measurement was obtained in duplicate. The primary objective was the agreement between IMR acquired using adenosine and papaverine. Secondary objectives include reproducibility of IMR and time required for the IMR measurement. Results One hundred and sixteen IMR measurements were performed in 29 patients. The mean age was 68.8 ± 7.24 years, and 27.6% was diabetics. IMR values were similar between papaverine and adenosine (17.7 ± 7.26 and 20.1 ± 8.6, p=0.25; Passing-Bablok coefficient A 0.58, 95% CI −2.42 to 3.53; coefficient B 0.90, 95% CI −0.74 to 1.07). The reproducibility of IMR was excellent with both adenosine and papaverine (ICC 0.78, 95% CI 0.63 to 0.88 and ICC 0.93, 95% CI 0.87 to 0.97). The time needed for microvascular assessment was significantly shortened by the use of IC papaverine (3.23 (2.84, 3.78) mins vs. 5.48 (4.94, 7.09) mins, p < 0.0001). Conclusion IMR can be reliably measured using IC papaverine with similar results compared to intravenous infusion of adenosine with increased reproducibility and reduced procedural time. This approach simplifies the invasive assessment of the coronary microcirculation in the catheterization laboratory.

Ultra-high density mapping to characterize effective cryoballoon ablation of roof line in persistent atrial fibrillation: a pilot study

Abstract Funding Acknowledgements Type of funding sources: None. Background Roof Posterior Wall (RPW) debulking may be important in the maintenance of AF activity as reducing the surface area below a critical mass can prevent persistent AF. No data exists on a combined cryoballoon ablation (CBA) approach guided by ultra-high density mapping (UHDM) system. Objective To explore, through UHDM, generation of consistent linear lesions at the left atrial (LA) roof using CBA in patients (pts) with persistent AF. Methods Once PVI was completed, the CB (Arctic Front Advance) was used to perform RPW isolation (RPWI). CBA was applied to create a continuous lesion connecting the ostial areas of the right and left superior PVs. Optimal position of the CB along the different segments of the RPW was obtained by advancing/retracting the inner lumen catheter distally/proximally within the PV. A detailed pre- and post-ablation 3D map was created in each pt using the Orion catheter and the Rhythmia UHDM system. Areas and type of isolation over the RPW and the entire LA were precisely identified and measured. Ablation endpoint was PVI and RPWI as assessed by entrance and exit block and after administration of intravenous adenosine. Results Ten consecutive pts were included (mean LA volume = 126 ± 36 ml, mean points per map = 10800 ± 8500, mean roof area = 22 ± 4 cm²). A mean of 4.6 ± 0.8 freezes at PV and 5.4 ± 2 at the roof per pt were required (mean nadir temperature (T) = −45°C ± 6°C and −41°C ± 3°C, respectively, mean T at the roof = −33°C ± 4°C) during a mean CBA time of 954 ± 73 s for PVs and 810 ± 311 s for the roof. The mean conduction delay along the roof line at the shortest segment was 55 ± 13 ms. Resulting low-voltage areas (&amp;lt;0.1 mV, 12 ± 4cm², 53% of the roof area) and complete electrical quiescence areas (&amp;lt;0.05 mV, 8 ± 3cm², 32% of the roof area) correlated well with the linear roofline of CB positions. At the first pass all PVs were successfully isolated in all study pts. In two cases at the RPWs UHDM revealed a small conductive corridor (&amp;lt;0.1 mV) along a posterior takeoff that required adjunct RFA to complete RPW isolation. No complications were reported. Conclusions In our preliminary experience PVI plus RPWI can be achieved safely and effectively using the CB in conjunction with UHDM. The use of UHDM allowed a precise definition of the effective isolation areas.

Antiarrhythmic drugs-safety and efficacy during pregnancy.

When deciding on antiarrhythmic drug (AAD) treatment, athorough knowledge of the physiological adaptation processes that occur during pregnancy and their effect on metabolism and the efficacy of AAD is mandatory. Beyond the desired effects of AAD therapy, side effects can occur in pregnant women. Furthermore, potential harm to fetal development-depending on gestational age-needs to be considered. Athorough evaluation of potential risks opposed to expected benefits for mother and fetus should be carried out before initiation of AAD treatment. Regular maternal echocardiography and fetal sonographic examination during pregnancy under AAD treatment are advisable. If possible, serum concentrations of AAD should be measured on aregular basis. Due to electrolyte and volume imbalances after delivery, maternal monitoring is recommended for approximately 48 h under AAD therapy. Current guidelines are based on almost historic analyses, where AAD were often prescribed for other indications than rhythm disorders. In clinical practice, AAD predominantly used during pregnancy are intravenous adenosine for acute treatment of atrioventricular nodal dependent tachycardias, whereas betablockers, sotalol, and flecainide can be orally administered for long-term therapy.

Care of Children with Supraventricular Tachycardia in the Emergency Department.

Prior studies have characterized children with supraventricular tachycardia (SVT) in inpatient settings, however there is a paucity of data regarding pediatric SVT in the Emergency Department (ED) setting. We sought to describe pediatric ED visits for SVT and assess whether variability exists in care. We performed a cross-sectional study of ED visits for SVT among children < 18years old from 2010 to 2017 at 33 pediatric hospitals. Visits were included if made for a primary International Disease Classification Ninth or Tenth Revision diagnosis code for SVT and intravenous (IV) adenosine was given on the initial or 2nd hospital day. We evaluated factors associated with hospital admission using multivariate logistic regression and described variability in frequency of rate of hospitalization, second-line IV antiarrhythmic medication usage, and diagnostic testing across sites. We included 2329 ED visits made by 1738 children and the median patient age was 6.3years (IQR 1.5-11.9). There were 2 deaths (0.1% of visits). Marked variability existed between centers in rates of admission to the hospital (range 17-85%) and ICU (range 4-60%). Factors associated with admission included: younger age, male sex and presence of comorbid conditions. A second IV antiarrhythmic agent was used in 17% of visits (range 4-41% across hospitals). There was variability in rates of diagnostic testing between centers [chest x-ray (range 10-47%), complete blood count (range 10-72%), electrolytes (range 22-86%), echocardiography (range 3-68%)]. Management of SVT is variable across pediatric hospitals, suggesting an opportunity for standardization in care.

Intravenous Nicorandil Versus Adenosine for Fractional Flow Reserve Measurement to Assess Coronary Artery Stenosis: A Systematic Review and Meta-Analysis

Intravenous Nicorandil Versus Adenosine for Fractional Flow Reserve Measurement to Assess Coronary Artery Stenosis: A Systematic Review and Meta-Analysis

The non-invasive coronary flow reserve predicts exercise capacity in patients undergoing cardiac rehabilitation

The benefit of exercise on peripheral muscles is established but the exact role of the coronary microcirculation in exercise capacity after cardiac rehabilitation (CR) is unclear. Our aim was to test the relationship between non-invasive coronary flow reserve (CFR) and exercise capacity in patients undergoing CR after acute myocardial infarction (AMI). CFR was performed by transthoracic Doppler echocardiography in the left anterior descending artery 24 h after angioplasty (CFR1) and after 20 sessions of CR program (at 4 ± 1 months)(CFR2) in 60 consecutive patients (57 ± 11 years, 30% women) with an anterior AMI successfully treated by primary coronary angioplasty. CFR was performed in a modified parasternale view using intravenous adenosine infusion (0.14 mg/kg/min within 2 minutes). CR program consisted of a half hour of fractioned exercise added of a half hour session of general gymnastics and bodybuilding. To test the exercise capacity, symptom limited exercise echocardiography was performed just after the CFR2, in a semi-supine position, starting at 25 watts, with 20-25 watts increments of workload every two minutes. CFR was measured successfully in all patients, and CFR2 was significantly higher than CFR1 (2.9 ± 0.65 vs. 1.9 ± 0.4, P < 0.001). Though CFR1 was correlated to left ventricular systolic function and its improvement at follow-up (all, P < 0.01), CFR2 was independently related to exercise capacity (mean workload 100 ± 30 watts, percent maximal heart rate 83 ± 12%, no ischemia, no new wall motion abnormalities in all tests) after adjusting for age, sex, and body mass index ( r = 0.6, P < 0.01). CFR predicts exercise capacity in patients undergoing a CR program after AMI. The improvement of CFR contributes to cardiac performance.

Neonatal Arrhythmia

Arrhythmias are seldom observed in the newborn period and rarely lead to serious consequences. Because they may be a continuation of fetal arrhythmias, newborn arrhythmias are different from those occurring at later ages. Here we describe a case of a newborn presented with tachycardia at birth. A female baby of 1950 grams born by emergency cesarean section for fetal distress at 36 weeks of gestation. Fetal tachycardia of 251 bpm was detected prenatally. Electrocardiography showed supraventricular tachycardia (SVT). Hematological and biochemical tests done were within normal limits. Echocardiography revealed normal anatomy with severe tachycardia, dilated chambers with moderate to severe TR with moderately reduced ventricle function. For persisting SVT intravenous adenosine was administered with no significant decrease in heart rate, then continuous intravenous amiodarone infusion was started resulting in a transient decrease in heart rate, however again increased, hence baby was started on intravenous digoxin which responded well. Repeated echocardiography showed normal cardiac chambers and function. Baby was discharged on maintenance oral digoxin and was gradually weaned and stopped after 12 months of age. Neonatal arrhythmias is not an uncommon condition in newborns, however it should be early recognized and evaluated for a better outcome of the baby. Although the frequency of arrhythmias in the newborn period is not high, SVT are the most frequently observed arrhythmias in this period.