Search

We present a case of a young man with a new-onset supraventricular arrhythmia accompanied by polyuria and natriuresis with subsequent renal salt-wasting causing hypovolemic hyponatremia. Resolution of the electrolyte imbalance occurred only after successful atrial flutter ablation., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale: Non-paroxysmal junctional tachycardia (NPJT) is a self-limiting supraventricular tachycardia associated with primary heart disease, cardiac surgery, digitalis toxicity, and metabolic or electrolyte imbalances. However, NPJT caused enhanced normal automaticity even in the absence of structural heart disease can be fatal if not managed properly., Patient Concerns: A 74-year-old hypertensive female patient was scheduled for transureteroureterostomy and right ureteroneocystostomy under general anesthesia., Diagnosis: The patient developed NPJT without visible P wave and severe hypotension due to adrenergic stimulation in response to massive hemorrhage during surgery., Interventions: NPJT with hypotension was initially converted to sinus rhythm with normotension with administration of adenosine and esmolol. However uncontrolled surgical hemorrhage and administration of large dose of vasopressors eventually perpetuated NPJT refractory to antiarrhythmic drugs., Outcomes: Despite intravenous fluid resuscitation and massive transfusion, the patient was deteriorated hemodynamically due to uncontrolled bleeding and persistent NPJT, which resulted in hypovolemic shock and fatal disseminated intravascular coagulation (DIC)., Lessons: NPJT can occur by enhanced automaticity due to increased catecholamine during severe surgical hemorrhage. Although NPJT is generally self-limiting, it can be refractory to antiarrhythmic agents and accelerate hypotension if the surgical bleeding is uncontrolled. Therefore, aggressive management of the primary pathologic condition is crucial for the management of NPJT and hemodynamic collapse even in the absence of structural heart disease., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

A young woman with Rogers syndrome (thiamine-responsive megaloblastic anaemia, diabetes mellitus and sensorineural deafness) presented with headache, recurrent supraventricular tachycardia and features of an upper gastrointestinal bleed, 1 month after radiofrequency cardiac ablation for supraventricular tachycardia. She deteriorated rapidly after endoscopy and subsequently died. Brain imaging during the acute deterioration showed diffuse intracranial air embolism and hypoxic-ischaemic injury. Postmortem examination showed an atrio-oesophageal fistula, a rare complication of cardiac ablation. Clinicians should suspect this condition in patients with acute neurological deterioration after cardiac ablation who have diffuse air embolism on imaging., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Speech-induced atrial tachycardia (AT) with presyncope is extremely rare. A 52-year-old woman employed at a supermarket reported recurrent presyncope while speaking out loud at her job. Holter electrocardiography revealed AT while swallowing without presyncope. The patient's blood pressure decreased during AT, and she experienced presyncope while saying "IRASSHAIMASE" loudly during a tilt table test. Accordingly, bisoprolol 1.25 mg was prescribed, and the patient did not experience episodes of presyncope with recurrence of AT for 2 years. This case suggests that provocation of arrhythmia in the tilting position may be useful for demonstrating a relationship between arrhythmia and presyncope and/or syncope.

We report the case of a 52-year-old marathon runner admitted to our emergency department for exertional heat stroke (EHS). The electrocardiogram (ECG) showed a supraventricular tachycardia, probably an atrial flutter with 2:1 block, conducted with left bundle branch block. After 10 minutes of aggressive fluid management and rapid external cooling, the ECG returned to normal. As the high-sensitivity cardiac troponin I was elevated, coronary angiography and an electrophysiological study were performed, revealing normal coronary arteries and excluding inducible arrhythmias. As reported in the current literature, our findings confirm that the electrocardiographic changes and elevation of cardiac markers in EHS do not reflect cardiac ischemia, but rather a myocardial injury due to the pathophysiological response to dehydration and hyperthermia, which markedly impaired stroke volume and cardiac output. EHS is a life-threatening condition with a complex pathophysiology caused by thermoregulatory failure. Diagnosis is not always straightforward, but early recognition and timely management (the "golden hour") with rapid cooling and intravenous fluids are crucial to prevent irreversible and fatal organ damage. EHS is defined by a rectal temperature > 40.5 °C with symptoms or signs of neurological dysfunction, such as confusion, drowsiness, or seizures, which can rapidly worsen with delirium, coma, and cardiac arrest. With this case report, we want to remind emergency physicians that early diagnosis and appropriate management of EHS can avoid death and inappropriate treatment. (www.actabiomedica.it).

Wolf-Parkinson-White (WPW) accessory pathway (AP) may be associated with reentry supraventricular tachycardia (SVT) in addition to ventricular dyssynchrony and cardiac dysfunction. Electrophysiological studies (EPS) are the gold standard for the localization of the AP; however, 2D speckle-tracking echocardiography (2D-STE) may help in the localization of the AP noninvasively. Our study aims to evaluate the capability of 2D-STE for AP localization and the identification of AP-related contractile abnormalities and dyssynchrony in pediatric patients with WPW syndrome. This prospective multicenter cohort study involved 18 pediatric patients with ventricular preexcitation from January 2021 to January 2023. Tissue Doppler imaging (TDI), conventional echocardiography, and 2D-STE were done. Myocardial velocities, myocardial performance index (MPI), the global and segmental longitudinal strain of the left ventricle (LV), and time-to-peak longitudinal strain (TPLS) were measured before and after ablation. The longitudinal strain of the LV segments supplied by the AP, or the nearby segments close to the AP, was significantly impaired and improved after ablation (P = 0.0001). The abnormal strain pattern in the affected segments could predict the location of the AP. The TPLS of the affected segments significantly increased after ablation (P = 0.0001), denoting improved dyssynchrony. The ejection time and the LV MPI measured at the basal septum improved significantly after ablation., Conclusions: 2D STE may be used for noninvasive localization of the AP and to evaluate cardiac function and dyssynchrony in patients with WPW. Further research on more patients is necessary to validate this method for AP localization., What Is Known: • Accessory pathways (AP) associated with the Wolf-Parkinson-White (WPW) syndrome have been linked to supraventricular tachycardia (SVT). Even without SVT, WPW can cause left ventricular dyssynchrony, contractile dysfunction, and cardiomyopathy. • Electrophysiology study is the gold standard for the localization of the AP in WPW syndrome., What Is New: • The combination of 2D-speckle-tracking echocardiography (2D-STE) and the modified Arruda algorithm can precisely localize the AP associated with WPW syndrome. • 2D-STE can potentially assess cardiac function and dyssynchrony related to WPW syndrome. Additionally, 2D-STE can be utilized to evaluate the effectiveness of ablation in restoring cardiac function and dyssynchrony., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aims: Wolff-Parkinson-White (WPW) syndrome is a conduction disorder characterized by an accessory electrical pathway between the atria and ventricles, which may predispose to supraventricular tachycardia (SVT) and sudden cardiac death. It can be seen as an isolated finding or associated with structural heart disease. Our aims were to determine the prevalence of a WPW pattern in a large and unselected cohort of neonates and to describe the electro- and echocardiographic characteristics as well as the natural history during early childhood., Methods and Results: Electrocardiograms and echocardiograms of neonates (aged 0-30 days) from a large, prospective, population-based cohort study were included. Neonates with a WPW pattern were identified and matched 1:4 to controls. Localization of the accessory pathway was assessed by different algorithms. Among 17 489 neonates, we identified 17 (76% boys) with a WPW pattern consistent with a prevalence of 0.1%. One neonate had moderate mitral regurgitation while other echocardiographic parameters were similar between cases and controls (all P > 0.05). The accessory pathways were primarily predicted to be left-sided. At follow-up (available in 14/17 children; mean age 3.2 years) the pre-excitation pattern persisted in only four of the children and none of the children had experienced any episodes of SVT., Conclusion: The prevalence of a WPW pattern in our cohort of unselected neonates was 0.1%. The WPW pattern was more frequent in boys and generally not associated with structural heart disease, and the accessory pathways were primarily left-sided. At follow-up, the WPW pattern had disappeared in most of the children suggesting either an intermittent nature or that normalization occurs., Clinical Trial Registration: Copenhagen Baby Heart, NCT02753348., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background Data on the incidence of arrhythmias, associated cardiac interventions, and outcome in patients with dextro-transposition of the great arteries and atrial switch are scarce. Methods and Results In this multicenter analysis, we included adult patients with dextro-transposition of the great arteries and atrial switch regularly followed up at 3 Swiss tertiary care hospitals. The primary outcome was a composite of left ventricular assist device, heart transplantation, and death. The secondary outcome was occurrence of ventricular tachycardia, ventricular fibrillation, or sudden cardiac death. We identified 207 patients (34% women; median age at last follow-up, 35 years) with dextro-transposition of the great arteries and atrial switch. Arrhythmias occurred in 97 patients (47%) at a median age of 22 years. A pacemaker or an implantable cardioverter-defibrillator was implanted in 39 (19%) and 13 (6%) patients, respectively, and 33 (16%) patients underwent a total of 51 ablation procedures to target 60 intra-atrial re-entry tachycardias, 4 atrioventricular nodal re-entry tachycardias, and 1 atrial fibrillation. The primary outcome occurred in 21 patients (10%), and the secondary outcome occurred in 18 patients (9%); both were more common in patients with concomitant ventricular septum defect than in those without (hazard ratio [HR], 3.06 [95% CI, 1.29-7.27], P =0.011; and HR, 3.62 [95% CI, 1.43-9.18], P =0.007, respectively). Conclusions In patients with dextro-transposition of the great arteries and atrial switch reaching adulthood, arrhythmias occur in almost half of patients, and associated rhythm interventions are frequent. One-tenth of those patients do not survive until the age of 35 years free from left ventricular assist device or heart transplantation, and the outcome is worse in patients with concomitant ventricular septum defect.

Background: The LifeVest® wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death in at-risk patients who are not candidates for an implantable defibrillator. The safety and efficacy of the WCD may be impacted by inappropriate shocks (IAS)., Objective: The purpose of this study was to assess the causes and clinical consequences of WCD IAS in survivors of IAS events., Methods: The Food and Drug Administration's Manufacturers and User Facility Device Experience database was searched for IAS adverse events (AE) that were reported during 2021 and 2022., Results: A total of 2568 IAS-AE were found (average number of IAS per event: 1.5 ± 1.9; range 1-48). IAS were caused by tachycardias (1255 [48.9%]), motion artifacts (840 [32.7%]), and oversensing (OS) of low-level electrical signals (473 [18.4%]) (P <.001). Tachycardias included atrial fibrillation (AF) (828 [32.2%]), supraventricular tachycardia (SVT) (333 [13.0%]), and nonsustained ventricular tachycardia/fibrillation (NSVT/VF) (87 [3.4%]). Activities responsible for motion-induced IAS included riding a motorcycle, lawnmower, or tractor (n = 128). In 19 patients, IAS induced sustained ventricular tachycardia or ventricular fibrillation that subsequently were terminated by appropriate WCD shocks. Thirty patients fell and suffered physical injuries. Conscious patients (n = 1905) did not use the response buttons to abort shocks (47.9%) or used them improperly (20.2%). IAS resulted in 1190 emergency room visits or hospitalizations, and 17.3% of patients (421/2440) discontinued the WCD after experiencing IAS, especially multiple IAS., Conclusions: The LifeVest WCD may deliver IAS caused by AF, SVT, NSVT/VF, motion artifacts, and oversensing of electrical signals. These shocks may be arrhythmogenic, result in injuries, precipitate WCD discontinuation, and consume medical resources. Improved WCD sensing, rhythm discrimination, and methods to abort IAS are needed., (Copyright © 2023. Published by Elsevier Inc.)

Introduction: While narrow complex tachycardia (NCT) is a common presentation to the emergency department (ED), little is known about its incidence in the ED or about emergency physician expertise in its diagnosis and management. We sought to compare cases of NCT due to primary arrhythmias to those with a rapid heart rate secondary to a medical issue, as well as to determine the accuracy of ED physician diagnosis and appropriateness of treatment., Methods: We conducted a health records review at a large academic hospital ED staffed by 95 physicians and included consecutive adult patients over 7 months (2020-2021) with NCT (heart rate ≥ 130 bpm and QRS < 120 ms). Cases were reviewed for accuracy of ECG diagnosis and for correctness of treatment as per guidelines by an adjudication committee., Results: We identified 310 ED visits (0.8% of all ED visits), mean age 65.1 years, 52.6% female. Primary arrhythmias accounted for 54.8%. ED physicians correctly interpreted 86.6% of ECGs. The most common arrhythmias and accuracy of ED physician ECG interpretation were atrial fibrillation 44.5% (95.1%), sinus tachycardia 24.2% (90.5%), atrial flutter 15.8% (61.5%), and supraventricular tachycardia (SVT) 12.9% (81.6%). Treatments were judged optimal in 96.5% of primary NCT and 99.3% in secondary NCT. Treatments were suboptimal for failure to reduce heart rate < 100 bpm prior to discharge in 2.1% of primary cases and failure to treat underlying cause in 0.7% of secondary cases., Conclusion: NCT was found in 0.8% of all ED visits, with more being primary NCT. ED physicians correctly interpreted 86.6% of ECGs but had difficulty differentiating atrial flutter and SVT. They implemented appropriate care in most cases but sometimes failed to adequately control heart rate or to treat the underlying condition, suggesting opportunities to improve care of NCT in the ED., (© 2023. The Author(s), under exclusive licence to Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

Background There are limited data on risk of arrhythmias among patients with lymphoproliferative disorders. We designed this study to determine the risk of atrial and ventricular arrhythmia during treatment of lymphoma in a real-world setting. Methods and Results The study population comprised 2064 patients included in the University of Rochester Medical Center Lymphoma Database from January 2013 to August 2019. Cardiac arrhythmias-atrial fibrillation/flutter, supraventricular tachycardia, ventricular arrhythmia, and bradyarrhythmia-were identified using International Classification of Diseases, Tenth Revision ( ICD-10 ) codes. Multivariate Cox regression analysis was used to assess the risk of arrhythmic events with treatments categorized as Bruton tyrosine kinase inhibitor (BTKi), mainly ibrutinib/non-BTKi treatment versus no treatment. Median age was 64 (54-72) years, and 42% were women. The overall rate of any arrhythmia at 5 years following the initiation of BTKi was (61%) compared with (18%) without treatment. Atrial fibrillation/flutter was the most common type of arrhythmia accounting for 41%. Multivariate analysis showed that BTKi treatment was associated with a 4.3-fold ( P <0.001) increased risk for arrhythmic event ( P <0.001) compared with no treatment, whereas non-BTKi treatment was associated with a 2-fold ( P <0.001) risk increase. Among subgroups, patients without a history of prior arrhythmia exhibited a pronounced increase in the risk for the development of arrhythmogenic cardiotoxicity (3.2-fold; P <0.001). Conclusions Our study identifies a high burden of arrhythmic events after initiation of treatment, which is most pronounced among patients treated with the BTKi ibrutinib. Patients undergoing treatments for lymphoma may benefit from prospective focused cardiovascular monitoring prior, during, and after treatment regardless of arrhythmia history.

Fetal arrhythmia develops in 0.1-5% of pregnancies and may cause fetal heart failure and fetal hydrops, thus increasing fetal, neonatal, and infant mortality. The timely initiation of transplacental antiarrhythmic therapy (ART) promotes the conversion of fetal tachycardia to sinus rhythm and the regression of the concomitant non-immune fetal hydrops. The optimal treatment regimen search for the fetus with tachyarrhythmia is still of high value. Polymorphisms of these genes determines the individual features of the drug pharmacokinetics. The aim of this study was to study the pharmacokinetics of transplacental anti-arrhythmic drugs in the fetal therapy of arrhythmias using HPLC-MS/MS, as well as to assess the effect of the multidrug-resistance gene ABCB1 3435C > T polymorphism on the efficacy and maternal/fetal complications of digoxin treatment. The predisposition to a decrease in the bioavailability of the digoxin in patients with a homozygous variant of the CC polymorphism showed a probable association with the development of ART side effects. A pronounced decrease in heart rate in women with the 3435TT allele of the ABCB1 gene was found. The homozygous TT variant in the fetus showed a probable association with an earlier response to ART and rhythm disruptions on the digoxin dosage reduction. high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) methods for digoxin and sotalol therapeutic drug monitoring in blood plasma, amniotic fluid, and urine were developed. The digoxin and sotalol concentrations were determined in the plasma blood, urine, and amniotic fluid of 30 pregnant women at four time points (from the beginning of the transplacental antiarrhythmic therapy to delivery) and the plasma cord blood of 30 newborns. A high degree of correlation between the level of digoxin and sotalol in maternal and cord blood was found. The ratio of digoxin and sotalol in cord blood to maternal blood was 0.35 (0.27 and 0.46) and 1.0 (0.97 and 1.07), accordingly. The digoxin concentration in the blood of the fetus at the moment of the first rhythm recovery episode, 0.58 (0.46, 0.8) ng/mL, was below the therapeutic interval. This confirms the almost complete transplacental transfer of sotalol and the significant limitation in the case of digoxin. Previously, ABCB1/P-glycoprotein had been shown to limit fetal exposure to drugs. Further studies (including multicenter ones) to clarify the genetic features of the transplacental pharmacokinetics of antiarrhythmic drugs are needed., Competing Interests: The authors declare no conflict of interest.

Supraventricular tachycardia (SVT) is a frequent cause of tachyarrhythmia in infants < 1 year of age and ambulatory cardiac monitoring is an important tool for diagnosis and follow-up of these patients. We retrospectively reviewed 594 infants (mean age 4.05 months, SD 3.55; 54% M) who underwent ambulatory cardiac monitoring (69% 24 h Holter, 31% extended monitor) through the Pocket ECG system (MediLynx) between January 2016 and July 2020. 170 patients who had the ICD-10 code I47.1 for SVT used at enrollment were analyzed separately. 49 (8.3%) patients had sustained SVT or non-sustained SVT (nSVT) during the study period, including 20 patients (11.8%) who had the ICD-10 code I47.1 at enrollment. Extended ambulatory cardiac monitors detected 61% of all patients with nSVT or SVT and was superior when compared to 24 h Holter (p < 0.0001). In the overall group, the first episode of SVT or nSVT was detected within 24 h of monitoring in 40/49 patients (82%). 48/49 patients (98%) were diagnosed within a week of monitoring and the single remaining patient was diagnosed with nSVT at day 15 of monitoring. There was no significant difference in minimal, maximal, and average heart rate between patients with and without ICD-10 code I47.1 at enrollment or between patients with and without SVT or nSVT. Despite their low yield, ambulatory cardiac monitors are an important diagnostic tool. The ideal length of monitoring in patients with known or suspected SVT has yet to be defined, although all patients in our cohort were identified by day 15 of monitoring., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Marijuana use among all age groups has been increasing, including among older adults aged ≥65 years. There is a lack of epidemiologic data examining arrhythmia risk among users of marijuana. We evaluated cross-sectional associations between current and past marijuana smoking and arrhythmias among 1485 participants from the Multiethnic Study of Atherosclerosis who underwent extended ambulatory electrocardiographic monitoring with the Zio Patch XT. Outcomes included premature atrial contractions, runs of supraventricular tachycardia, premature ventricular contractions, and runs of nonsustained ventricular tachycardia (NSVT). Compared with never users, participants reporting current use of marijuana (n = 40, 3%) had more supraventricular tachycardia/day (adjusted geometric mean ratio [GMR] 1.42, 95% confidence interval [CI] 0.87 to 2.32), more premature atrial contractions/hour (GMR 1.22, 95% CI 0.72, 2.13), and more NSVT/day (GMR 1.28, 95% CI 0.95 to 1.73); although, CIs overlapped 1. Additionally, more frequent marijuana use was associated with more runs of NSVT/day (GMR 1.56, 95% CI 1.13, 2.17). In conclusion, our results suggest that current marijuana use may be associated with a greater burden of arrhythmias. There is a need for additional research, mainly using a prospective design, to clarify if marijuana use causes atrial and ventricular arrhythmias or other cardiovascular complications among older adults., Competing Interests: Disclosures BMS reports grant funding from the National Institutes of Health related to the content of this study, and the Canadian Institutes of Health Research, the Quebec Health Research Fund, the Canadian Lung Association, and the Quebec Lung Association. All authors report funding from the National Institutes of Health during the conduct of this study., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Prognosis of fetuses with hydrops and tachyarrhythmia has been portrayed as poor in most published reports. This might lead to biased counselling, unnecessary caesarean section, preterm delivery, and even termination of pregnancy., Aims: To evaluate contemporary fetal and postnatal outcomes of hydropic fetuses with fetal tachyarrhythmia when it is treated effectively and monitored systematically., Methods: This is a retrospective review of a single centre experience at the University Hospital of Wales over a 20-year period. All fetuses received high doses of flecainide and digoxin combination treatment. Tachycardia response rate, time to arrhythmia and hydrops resolution, fetal and postnatal morbidity, and mortality rates were analysed., Results: Twenty fetuses were diagnosed with hydrops fetalis and received treatment. The mechanism of fetal tachyarrhythmia was supraventricular tachycardia in thirteen and atrial flutter in eight cases. Among the 20 fetuses treated, the overall tachycardia response rate was 90% (18/20) with the restoration of sinus rhythm in 85% (17/20) of the cases. The median time to restore sinus rhythm or to rate control of the arrhythmia was 1.5 days (range 12 hours to 13 days). Hydrops resolved in 17 of the 20 fetuses, with a median time of 12 days (range 3-21 days). Four fetuses went into spontaneous preterm birth and one fetus was delivered early due to worsening hydrops. No significant neurological morbidity was observed in surviving neonates and infants on clinical examination. There was one postnatal death due to respiratory complications of prematurity in the non-responsive supraventricular tachycardia case., Conclusions: High-dose flecainide and digoxin combination offers effective treatment strategy in fetuses with hydrops and tachyarrhythmia with favourable outcomes. This study may guide more realistic counselling for pregnancies complicated by tachyarrhythmia and hydrops.

Background There is limited information regarding the clinical use and effectiveness of IV sotalol in pediatric patients and patients with congenital heart disease, including those with severe myocardial dysfunction. A multicenter registry study was designed to evaluate the safety, efficacy, and dosing of IV sotalol. Methods and Results A total of 85 patients (age 1 day-36 years) received IV sotalol, of whom 45 (53%) had additional congenital cardiac diagnoses and 4 (5%) were greater than 18 years of age. In 79 patients (93%), IV sotalol was used to treat supraventricular tachycardia and 4 (5%) received it to treat ventricular arrhythmias. Severely decreased cardiac function by echocardiography was seen before IV sotalol in 7 (9%). The average dose was 1 mg/kg (range 0.5-1.8 mg/kg/dose) over a median of 60 minutes (range 30-300 minutes). Successful arrhythmia termination occurred in 31 patients (49%, 95% CI [37%-62%]) with improvement in rhythm control defined as rate reduction permitting overdrive pacing in an additional 18 patients (30%, 95% CI [19%-41%]). Eleven patients (16%) had significant QTc prolongation to >465 milliseconds after the infusion, with 3 (4%) to >500 milliseconds. There were 2 patients (2%) for whom the infusion was terminated early. Conclusions IV sotalol was safe and effective for termination or improvement of tachyarrhythmias in 79% of pediatric patients and patients with congenital heart disease, including those with severely depressed cardiac function. The most common dose, for both acute and maintenance dosing, was 1 mg/kg over ~60 minutes with rare serious complications.

There is limited evidence on characterization and natural history of supraventricular tachycardia (SVT)-induced left ventricular (LV) dysfunction. The aim of this work was to characterize clinical features and long-term evolution of SVT-induced LV dysfunction. Patients consecutively admitted with sustained SVT and heart rate >100 bpm as the only known cause of a new onset LV systolic dysfunction (i.e., LV ejection fraction [EF] <50%) were analyzed. Patients were then revaluated periodically. Recovered LVEF (i.e., ≥50%) and a composite of death, heart transplant or first episode of major ventricular arrhythmias were evaluated as study end-points. We enrolled 83 patients. After SVT therapy, 56 (67%) showed a recovered LVEF at the last follow-up of median 54 (interquartile range 36 to 87) months. Seventeen (30%) of those patients had a temporary new drop in LVEF during follow-up associated to high-rate SVT relapse. At presentation, patients with recovered LVEF were younger (52 vs 67 years respectively, p <0.001) and had higher LVEF (34% vs 27% respectively, p = 0.005) compared to non-recovered LVEF patients. Finally, 4% of recovered LVEF patients vs 26% of nonrecovered LVEF patients experienced death/heart transplant/major ventricular arrhythmias during follow-up (p = 0.004). In conclusion, after almost 5 years of follow-up, two-thirds of patients with high-rate SVT causing a newly diagnosed LV systolic dysfunction recovered and maintained normal LV function after SVT control, with a subsequent benign outcome. Long term individual surveillance is required in those patients, as arrhythmic recurrences and new drops in LVEF are common in the long term., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Syncope represents a relatively uncommon symptom of supraventricular tachycardia (SVT). It is likely that an impaired autonomic vasomotor response to the hemodynamic stress of tachycardia is the determinant of hemodynamic changes leading to cerebral hypoperfusion and syncope. In this regard, tilt-table test may detect abnormalities in the autonomic nervous function and predict the occurrence of syncope during SVT. Electrophysiology studies may reproduce the SVT, distinguish it from other life-threatening ventricular tachyarrhythmias, and exclude other causes of syncope. Not infrequently mixed syncope mechanisms are revealed during the above diagnostic workup raising doubts about the operating mechanism in the clinical setting. In such cases of uncertainty, an implantable loop recorder, providing long-term cardiac monitoring, may play a pivotal role in the establishment of the diagnosis, confirming the association of an arrhythmic event with the symptom. Herein, we present four such cases with recurrent unexplained syncope finally attributed to paroxysmal SVT guiding them to a potentially radical treatment through radiofrequency catheter ablation., (© 2021 The Authors. Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

To investigate prenatal and postnatal outcomes of atrial flutter and its association with the development of a second tachycardia, following restoration of sinus rhythm, in the fetus or newborn. This study is a retrospective review of all fetuses that presented with atrial flutter from January 2001 to December 2019 at the University Hospital of Wales, Cardiff, UK. The specific type of arrhythmia, its time of appearance and clinical characteristics, echocardiographic findings, medical management, and postnatal outcomes were evaluated. Sixteen fetuses were diagnosed with atrial flutter (AFL). Thirteen fetuses had persistent AFL and three fetuses had intermittent AFL. Seven patients had hydrops, of which one had Ebstein's anomaly and the other six had normal hearts. Three of the fetuses that presented with AFL were diagnosed at 20, 21, and 23 weeks' gestation and the remainder were diagnosed in the third trimester. Thirteen patients with AFL received antiarrhythmic drugs and three were delivered without any treatment. Five fetuses with AFL developed atrioventricular reciprocating tachycardia following DC cardioversion after birth, and four of them exhibited pre-excitation on the ECG. These five patients (31.3%) required postnatal antiarrhythmic treatment for up to 2 years. Pre-excitation disappeared in two patients during follow-up and two asymptomatic patients with neonatal pre-excitation required accessory pathway ablation. Fetal atrial flutter has a strong association with atrioventricular reciprocating tachycardia and ventricular pre-excitation in the neonatal period. Therefore, electrocardiograms should be carefully reviewed in newborns following the initial resolution of atrial flutter.

Background: CKD is associated with sudden cardiac death and atrial fibrillation (AF). However, other types of arrhythmia and different measures of the burden of arrhythmias, such as presence and frequency, have not been well characterized in CKD., Methods: To quantify the burden of arrhythmias across CKD severity in 2257 community-dwelling adults aged 71-94 years, we examined associations of major arrhythmias with CKD measures (eGFR and albuminuria) among individuals in the Atherosclerosis Risk in Communities study. Participants underwent 2 weeks of noninvasive, single-lead electrocardiogram monitoring. We examined types of arrhythmia burden: presence and frequency of arrhythmias and percent time in arrhythmias., Results: Of major arrhythmias, there was a higher prevalence of AF and nonsustained ventricular tachycardia among those with more severe CKD, followed by long pause (>30 seconds) and atrioventricular block. Nonsustained ventricular tachycardia was the most frequent major arrhythmia (with 4.2 episodes per person-month). Most participants had ventricular ectopy, supraventricular tachycardia, and supraventricular ectopy. Albuminuria consistently associated with higher AF prevalence and percent time in AF, and higher prevalence of nonsustained ventricular tachycardia. When other types of arrhythmic burden were examined, lower eGFR was associated with a lower frequency of atrioventricular block. Although CKD measures were not strongly associated with minor arrhythmias, higher albuminuria was associated with a higher frequency of ventricular ectopy., Conclusions: CKD, especially as measured by albuminuria, is associated with a higher burden of AF and nonsustained ventricular tachycardia. Additionally, eGFR is associated with less frequent atrioventricular block, whereas albuminuria is associated with more frequent ventricular ectopy. Use of a novel, 2-week monitoring approach demonstrated a broader range of arrhythmias associated with CKD than previously reported., (Copyright © 2021 by the American Society of Nephrology.)

We described a 15-year-old boy who underwent the catheter ablation for the nodoventricular (NV) tachycardia that had difficulty in differentiation from atrioventricular nodal reentrant tachycardia with upper common pathway. The modification of the fast pathway revealed an anterograde conduction of the NV fiber. We successfully performed the catheter ablation targeting for the right ventricular insertion site of the NV fiber., (© 2020 Wiley Periodicals LLC.)

Background: Fetal supraventricular tachycardia is a relatively uncommon cardiac rhythm abnormality which is often associated with adverse perinatal outcomes if untreated. Although there are several treatment modalities and protocols in use globally, there is no consensus as to the most effective antiarrhythmic to manage this condition., Aim: This study aimed to evaluate perinatal outcomes following prenatal maternal therapy for fetal supraventricular tachycardia., Materials and Methods: This was a 20-year retrospective cohort study. Institutional records were reviewed for antenatal therapy choice and maternal and fetal outcomes., Results: Sixty-nine cases met diagnostic criteria for fetal SVT, of which 56 (81%) received maternal antiarrhythmic therapy. Digoxin was the most common, but least effective, first-line therapy in 28 patients, achieving successful rate reversion in 35.7%. Thirty-one patients (55%) required second-line therapy, and this was most successful with digoxin and flecainide polytherapy achieving rate reversion in 17 of 18 cases (94.5%) at a median of 3 days (1.5-7). Hydrops was present in 23 (33%) cases at initial presentation, 16 of which achieved rate reversion. There was minimal difference in treatment efficacy comparing single- or multiple-agent treatment in the setting of hydrops (50% vs. 42.8%). Side effects occurred in 14/56 treated patients (25%) but were severe in only 8 (14.3%) women, most commonly with digoxin and flecainide polytherapy (6 of 8 cases). There were 3 (4%) fetal deaths amongst the study cohort., Conclusions: Digoxin and flecainide polytherapy were well tolerated and successfully achieved rhythm and rate control in fetuses with prenatally diagnosed supraventricular tachycardia. The presence of hydrops was a poor prognostic feature., (© 2021 The Author(s) Published by S. Karger AG, Basel.)

Competing Interests: Competing interests: None declared.

BACKGROUND Radiofrequency ablation (RFA) is the criterion standard treatment for patients with atrioventricular nodal reentrant tachycardia (AVNRT). Knowledge about RFA in patients with dextrocardia and situs inversus is limited due to their rare incidence and complexity. The incidence of dextrocardia is reported to be 1 in 12 000 births, with situs inversus occurring in one-third of the cases. The incidence of congenital heart disease is about 5% in these patients. However, data on rhythm and conduction disorders in this group of patients are currently limited, making management more difficult owing to their individual anatomy. CASE REPORT We report the case of an obese 21-year-old man with complex congenital heart disease (CCHD) (situs inversus dextrocardia, pulmonary atresia, single ventricle, common atrium with single atrioventricular valve), asplenia, and multiple cardiac-corrective surgeries (Fontan repair, bidirectional Glenn anastomosis, and Blalock-Taussig shunt) who underwent successful RFA of recurrent supraventricular tachycardia. CONCLUSIONS Supraventricular arrhythmias are common in the setting of CCHD. Although catheter ablation procedures are technically challenging to perform in patients with CCHD, they remain the best therapeutic option for these arrhythmias. To our knowledge, this case is the first to be described in the literature of successful ablation of AVNRT in a patient with situs inversus dextrocardia, pulmonary atresia, a single ventricle, a common atrium with a single atrioventricular valve, and multiple cardiac-corrective surgeries.

Objective: To investigate the clinical characteristics of focal atrial tachycardia (FAT) and the efficacy of radiofrequency catheter ablation (RFCA) in pediatric FAT. Methods: A total of 125 children with FAT who were treated with RFCA in the First Hospital of Tsinghua University from January 2010 to July 2018 were involved in the study. The clinical characteristics, origin of FAT, success rate of RFCA and recurrence rate and complications post RFCA were retrospectively analyzed, and the efficacy and X-ray radiation were compared between two-dimensional (2D) and 3D mapping system by t test or Chi-square analysis. Results: Among the 125 children, 57 were males and 68 females, age of (7.6±3.5) years old and body weight of (27.7±13.3) kg; and 62 (49.6%) had paroxysmal FAT, and 63 (50.4%) incessant FAT. Twenty-seven patients (21.6%) presented with tachycardia-induced cardiomyopathy (TIC), and 22 of whom (81.5%) were secondary to the incessant FATs. Most of the FATs originated from atrial auricle (46/125, 36.8%). Ablation was successful in 111 children (88.8%), and the recurrence rate was 25.2% (28/111). No complications were identified in the whole group. The efficacy and safety of 3D mapping system (87 cases) was better than that of the 2D mapping system (38 cases), according to the lower recurrence rate ((19.0% (15/79) vs. 40.6% (13/32), χ 2 = 3.849, P= 0.049), shorter X-ray exposure time ((4.9±2.3) vs. (12.5±5.7) min, t= 7.942, P< 0.01) and lower radiation doses ((5.3±3.3) vs. (10.9±3.7) mGy, t =8.038, P< 0.01). Conclusions: FAT in children is mainly originated from atrial auricle, and incessant FAT is prone to progress to tachycardia-induced cardiomyopathy. RFCA is safe and effective for drug-resistant or drug-intolerant FAT in children, and 3D mapping system should be preferred.

A 21-year-old G3P2011 Caucasian woman at 27 weeks' gestation presented with fetal tachyarrhythmia between 240 and 270 beats per minute. Fetal supraventricular tachycardia, abdominal ascites, pleural effusion and pericardial effusion indicated hydrops fetalis. Management with digoxin and flecainide converted the fetus to sinus rhythm and resolved the ascites and pleural effusion within 4 days of treatment. Flecainide was discontinued at 31 weeks' gestation due to elevated liver enzymes. Intrahepatic cholestasis was treated with ursodiol. Caesarean section was performed at 37 weeks' gestation. Neonatal echocardiogram revealed a bicuspid aortic valve with mild regurgitation and a patent foramen ovale, and the infant showed no subsequent evidence of tachyarrhythmia or hydrops after delivery. Treatment of hydrops fetalis in the antenatal period is complex, and early diagnosis and treatment can quickly resolve supraventricular tachycardia-induced hydrops fetalis., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Necrotizing enterocolitis (NEC) and supraventricular tachycardia (SVT) are serious emergencies in the neonatal period. Although these conditions are recognized as distinct pathologies, literature reports suggest that recurrent episodes of SVT may predispose patients to NEC via disturbances in mesenteric blood flow and a decrease in tissue perfusion., Case Presentation: We present a case of a preterm infant affected by recurrent episodes of SVT who developed the initial stage of NEC on the 17th day of life. Moreover, a detailed description of all the cases described in the literature is reported., Materials and Methods: An integrative review of the updated literature in the Medline database and PubMed and scientific books and articles was conducted. The research from October 2019 to December 2019 was searched for with MeSH and free terms (necrotizing enterocolitis, supraventricular tachycardia) and was linked by Boolean operators., Conclusions: SVT can be considered a risk factor for the development of NEC. Therefore, clinicians should have a high level of suspicion for NEC in infants affected by SVT. This article is the first structured literature review analysing the association between SVT and NEC.

Atrial high rate episodes (AHREs), also termed, subclinical atrial tachyarrhythmias or subclinical atrial fibrillation (AF) are an important cardiovascular condition. Advancement in implantable cardiac devices such as pacemakers or internal cardiac defibrillators has enabled the continuous assessment of atrial tachyarrhythmias in patients with an atrial lead. Patients with device-detected AHREs are at an elevated risk of stroke and may have unmet anticoagulation needs. While the benefits of oral anticoagulation for stroke prevention in patients with clinical AF are well recognised, it is not known whether the same risk-benefit ratio exists for anticoagulation therapy in patients with AHREs. The occurrence and significance of AHRE are increasingly acknowledged but these events are still not often acted upon in patients presenting with stroke and TIA. Additionally, patients with AHRE show a significant risk for major adverse cardiovascular events (MACE) including acute heart failure, myocardial infarction, cardiovascular hospitalisation, ventricular tachycardia/fibrillation, which is dependent on AHRE burden. In this review, we present an overview of this relatively new entity, its associated thromboembolic risk and its management implications.

A 70-year-old male patient presented with acute respiratory failure. ECG at admission showed atrial tachycardia with macro T-wave alternans that disappeared as soon as normal sinus rhythm had returned. This ECG shape was not accompanied by either QT-prolongation or acute ischaemia. This case draws attention to atrial tachycardia (provoked here in a context of respiratory insufficiency) that may be the sole reason for macro T-wave alternans. Orv Hetil. 2020; 161(7): 275-277.

Sustained fetal supraventricular tachycardia (SVT) complicated by hydrops fetalis carries a significant risk of morbidity and mortality. While there is no clear consensus on first- and second-line therapy options for the management of fetal SVT with or without hydrops fetalis, there exists significant nonrandomized experience with a number of antiarrhythmic agents that has founded the basis for management. Furthermore, recently published meta-analyses and ongoing multicenter prospective studies have aimed to bridge the gap in the literature. We report two cases of sustained fetal SVT with severe secondary hydrops fetalis managed successfully with flecainide-sotalol combination therapy in one case and sotalol-digoxin combination therapy in the second and review the literature for the management of fetal SVT.

Background: Cardiac arrhythmias are sometimes encountered in patients with hereditary myopathies and muscular dystrophies. Description of arrhythmias in myopathies and muscular dystrophies is very important, because arrhythmias have a strong impact on the outcomes for these patients and are potentially treatable., Case Presentation: A girl with severe congenital RYR1-related myopathy exhibited atrial tachycardia and sinus node dysfunction during infancy. She was born after uncomplicated caesarian delivery. She showed no breathing, complete ophthalmoplegia, complete bulbar paralysis, complete facial muscle paralysis, and extreme floppiness. At 5 months old, she developed persistent tachycardia around 200-210 beats per minutes. Holter monitoring revealed ectopic atrial tachycardia during tachyarrhythmia and occasional sinus pauses with junctional escape beats. Propranolol effectively alleviated tachyarrhythmia but was discontinued due to increased frequency and duration of the sinus pauses that led to bradyarrhythmia. There was no evidence of structural heart diseases or heart failure. The arrhythmia gradually resolved spontaneously and at 11 months old, she showed complete sinus rhythm., Conclusions: Although supraventricular arrhythmia is sometimes encountered in congenital myopathies, this is the first report of cardiac arrhythmia requiring drug intervention in RYR1-associated myopathy.

Objective: This study explored a unique form of atrioventricular nodal reentrant tachycardia (AVNRT) in which certain acutely ill patients have a first episode of supraventricular tachycardia (SVT) with a short RP interval., Methods: A retrospective chart review was conducted of patients at a single institution who developed SVT with short RP and yielded 19 patients., Results: None of the 19 patients had a prior history of AVNRT or any other arrhythmia. The mean age was 58 years, the majority of patients were male (13/19), and there was a presence of hypertension (10/19), diabetes mellitus (5/19), hyperlipidemia (7/19), congestive heart failure (2/19), coronary artery disease (3/19), obstructive sleep apnea (2/19), and active cancer (8/19). The reasons for admission were planned surgery (8/19), sepsis (8/19), drug abuse (2/19), and neurological disorder (2/19). The AVNRT either terminated spontaneously or following the administration of adenosine. The patients were treated with amiodarone (12/19), metoprolol (6/19), or diltiazem (1/19). Follow-up (mean: 370 days) details revealed that patients were on amiodarone (3/19), metoprolol (6/19), were not taking any cardiac medication (5/19), or had passed away (5/19). Only 1 patient had a recurrence of AVNRT, and none of the patients required ablation therapy., Conclusion: 'AVNRT of the sick' has not been previously described in the medical literature, to our knowledge. It can be successfully treated with medications and the chance of recurrence after resolution of the acute illness is small.

Introduction: Supraventricular arrhythmias contribute to haemodynamic compromise in septic shock. A retrospective study generated the hypothesis that propafenone could be more effective than amiodarone in achieving and maintaining sinus rhythm (SR). Certain echocardiographic parameters may predict a successful cardioversion and help in the decision on rhythm or rate control strategy., Methods and Analysis: The trial includes septic shock patients with new-onset arrhythmia, but without severe impairment of the left ventricular ejection fraction. After baseline echocardiography, the patient is randomised to receive a bolus and maintenance dose of either amiodarone or propafenone. The primary outcome is the proportion of patients that have achieved rhythm control at 24 hours after the start of the infusion. The secondary outcomes are the percentages of patients that needed rescue treatments (DC cardioversion or unblinding and crossover of the antiarrhythmics), the recurrence of arrhythmias, intensive care unit mortality, 28-day and 1-year mortality. In the posthoc analysis, we separately assess subgroups of patients with pulmonary hypertension and right ventricular dysfunction. In the exploratory part of the study, we assess whether the presence of a transmitral diastolic A wave and its higher velocity-time integral is predictive for the sustainability of mechanical SR and whether the indexed left atrial endsystolic volume is predictive of recurrent arrhythmia. Considering that the restoration of SR within 24 hours occurred in 74% of the amiodarone-treated patients and in 89% of the patients treated with propafenone, we plan to include 200 patients to have an 80% chance to demonstrate the superiority of propafenone at p=0.05., Ethics and Dissemination: The trial is recruiting patients according to its second protocol version approved by the University Hospital Ethical Board on the 6 October 2017 (No. 1691/16S-IV). The results will be disseminated through peer reviewed publications and conference presentations., Trial Registration Number: NCT03029169., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Aim: The optimal treatment for foetal supraventricular tachycardia (SVT) in twin pregnancies is unclear because of the possible impact on the second twin. This review compared a foetus we treated with antiarrhythmic drugs with the previous case studies., Methods: Our case was a dichorionic diamniotic twin pregnancy, where one twin developed foetal hydrops secondary to SVT at 22 weeks of gestation. We searched PubMed to look for previous cases of SVT in twin pregnancies., Results: Treatment with transplacental antiarrhythmic therapy from 22 to 36 weeks of gestation successfully resolved the SVT in our affected twin without any impact on the healthy twin or mother. We only found seven similar cases of SVT in twin pregnancies from 1999 to 2017. Although there was no consensus on the treatment that should be provided, none of the studies reported side effects in the twins or the mothers., Conclusion: Despite a lack of data on SVT in twin pregnancies, our case, and the previous cases we identified, allowed us to conclude that transplacental antiarrhythmic treatment can successfully achieve cardioversion in the affected twin. It can do this without side effects for the healthy foetus or the mother, even if the treatment lasts for a long period of time., (©2019 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Aims: Recurrent atrial tachycardia is common after repair of many types of congenital heart disease, and surgical ablation with a maze procedure represents a potential treatment strategy. The objective of this study is to report a single-centre 19 years' experience with maze surgery in congenital heart patients., Methods and Results: Patients undergoing maze procedure concomitantly with cardiac surgical procedures were retrospectively analysed. The maze procedure was classified as therapeutic if the patient demonstrated preoperative atrial arrhythmias, or as prophylactic if done because the patient was considered high risk for post-operative arrhythmias. Acute outcomes and longer-term freedom from atrial arrhythmias were analysed. Maze surgery was performed in 166 patients: 137 in the therapeutic group, and 29 in the prophylactic group. The most common congenital heart lesion was single ventricle for the therapeutic group (27%) and Ebstein's anomaly for the prophylactic group (76%). Surgery consisted of a right atrial maze in 63%, left atrial maze in 4%, and bilateral maze in 33%. There were no direct complications or mortality related to the maze procedure itself. For the therapeutic group, freedom from arrhythmias was 82% and 67% at 1 and 5 years post-maze. Younger age at the time of surgery correlated with a lower long-term recurrence risk., Conclusion: Maze procedure at the time of an elective anatomic surgery is reasonably effective to prevent and treat atrial arrhythmias in patients with congenital heart disease at short- and mid-term, with low morbidity and mortality., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background The efficacy of nifekalant in preexcited atrial fibrillation ( AF ) has not been assessed. Methods and Results The study populations consisted of patients with sustained preexcited AF (n=51), paroxysmal supraventricular tachycardia (n=201), and persistent AF (n=87). Effects of intravenous infusion of nifekalant were assessed on electrophysiological and clinical parameters. Nifekalant prolonged the shortest preexcited R-R, the average preexcited R-R, and the average R-R intervals from 290±35 to 333±44 ms, 353±49 to 443±64 ms, and 356±53 to 467±75 ms, respectively, in patients with preexcited AF (all P<0.001). Nifekalant also decreased the percentage of preexcited QRS complexes, heart rate, and increased systolic pressure (all P<0.001). Nifekalant terminated AF in 33 of 51 patients (65%). Similar effects were also observed in a subgroup of 12 patients with preexcited AF and impaired left ventricular function. In patients with paroxysmal supraventricular tachycardia, nifekalant significantly prolonged the effective refractory period, the block cycle length of the antegrade accessory pathway, and the atrial effective refractory period (all P<0.001). Nifekalant had no effect on the effective refractory period of the antegrade atrioventricular node. Finally, in patients with persistent AF without an accessory pathway, nifekalant did not significantly decrease the ventricular rate of AF . One patient developed Torsades de Pointes. No other adverse effects were observed. Conclusions Nifekalant prolongs the effective refractory period of the antegrade accessory pathway and atrium without blocking antegrade conduction through the atrioventricular node, leading to slowing and/or to termination of preexcited AF . Thus, nifekalant might be an effective and a relatively safe drug in patients with preexcited AF .

Introduction: Atrial fibrillation (AFIB) with rapid ventricular response (RVR) is a common tachydysrhythmia encountered by Emergency Medical Services (EMS). Current guidelines suggest rate control in stable, symptomatic patients., Problem: Little is known about the safety or efficacy of rate-controlling medications given by prehospital providers. This study assessed a protocol for prehospital administration of diltiazem in the setting of AFIB with RVR for provider protocol compliance, patient clinical improvement, and associated adverse events., Methods: This was a retrospective, cohort study of patients who were administered diltiazem by providers in the Orange County EMS System (Florida USA) over a two-year period. The protocol directed a 0.25mg/kg dose of diltiazem (maximum of 20mg) for stable, symptomatic patients in AFIB with RVR at a rate of &gt;150 beats per minute (bpm) with a narrow complex. Data collected included patient characteristics, vital signs, electrocardiogram (ECG) rhythm before and after diltiazem, and need for rescue or additional medications. Adverse events were defined as systolic blood pressure &lt;90mmHg or administration of intravenous fluid after diltiazem administration. Clinical improvement was defined as a heart rate decreased by 20% or less than 100bmp. Original prehospital ECG rhythm interpretations were compared to physician interpretations performed retrospectively., Results: Over the study period, 197 patients received diltiazem, with 131 adhering to the protocol. The initial rhythm was AFIB with RVR in 93% of the patients (five percent atrial flutter, two percent supraventricular tachycardia, and one percent sinus tachycardia). The agreement between prehospital and physician rhythm interpretation was 92%, with a Kappa value of 0.454 (P &lt;.001). Overall, there were 22 (11%) adverse events, and 112 (57%) patients showed clinical improvement. When diltiazem was given outside of the existing protocol, the patients had higher rates of adverse events (18% versus eight percent; P = .033). Patients who received diltiazem in adherence with protocols were more likely to show clinical improvement (63% versus 46%; P = .031)., Conclusion: This study suggests that prehospital diltiazem administration for AFIB with RVR is safe and effective when strict protocols are followed.Rodriguez A, Hunter CL, Premuroso C, Silvestri S, Stone A, Miller S, Zuver C, Papa L. Safety and efficacy of prehospital diltiazem for atrial fibrillation with rapid ventricular response. Prehosp Disaster Med. 2019;34(3):297-302.

Objective: To describe the successful management of 2 dogs with septic shock and persistent tachycardia using norepinephrine and esmolol, a short-acting beta receptor antagonist., Series Summary: Two cases are reviewed. In the first case, septic shock with ventricular tachycardia was diagnosed in a 4-year-old neutered female Great Dane that underwent jejunoileal resection and anastomosis for a partial mesenteric torsion. The patient's tachyarrhythmias failed to respond to lidocaine, and an esmolol infusion was used for heart rate control. The condition of the dog improved and she was discharged after 4 days of hospitalization. The second case was a 7-year-old neutered female Cavalier King Charles Spaniel with septic peritonitis. Following surgery for intestinal resection and anastomosis, supraventricular tachycardia developed that was not responsive to volume resuscitation and was treated with an esmolol infusion. The condition of the dog improved and she was discharged after 6 days of hospitalization. Both patients were doing well at the time of long-term follow-up., New or Unique Information Provided: This case series highlights a novel method of managing dogs in septic shock with persistent tachycardia based on recently published data in the human literature. The use of esmolol may be considered in certain veterinary patients with septic shock to improve persistent tachycardia not related to hypovolemia., (© Veterinary Emergency and Critical Care Society 2019.)

Background: Atrial high-rate episodes (AHREs) are common in pacemaker patients. Our aims were to compare patients with AHREs to those without them and to assess if, in those with AHREs, the initiation of oral anticoagulation (OAC) has any clinical impact on the occurrence of ischemic and hemorrhagic events., Methods: From 2014-2017 we selected patients with pacemaker in whom AHREs were detected. AHREs were defined as episodes lasting more than 6 minutes if the electrogram was available or more than 6 hours if not. We used an age- and gender-matched population with pacemaker but no AHRE as a control group (observational study). Those with AHRE were referred to their assistant physician to decide OAC initiation, based on individual circumstances (interventional study). In interventional study, the primary outcome was a composite of systemic thromboembolism or major bleeding. Secondary outcomes were clinical relevant nonmajor bleeding, major and nonmajor bleeding, CV death, and death from all causes., Results: AHREs were detected in 86 patients: 69 patients initiated OAC and the remaining 17 patients did not. When comparing patients with and without AHRE, baseline characteristics were not different between the groups, except for indexed left atrium volume-40 mL (IQR: 34-50) in AHRE group versus 35 mL (IQR: 34-40) in control group (P = .014). AHREs were associated with future development of atrial fibrillation (AF) and the risk was higher if AHRE duration was superior to 6 hours. Death and cardiovascular (CV) death were not significantly different between the groups with and without AHRE. Primary outcome occurred in 4.9 per 100 person-year in OAC group versus 3.4 per 100 person-year in non-OAC group (HR 1.4, 95% CI .2-11.3, P = .78). Secondary outcomes were not significantly different in the groups., Conclusions: In this group of patients with pacemakers, the presence of AHREs was useful for predicting the future development of AF and the risk of AF was higher in those with a longer duration of AHRE. In the AHRE group, OAC therapy was not associated with a significant difference in the risk of thromboembolism or major bleeding., (Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background: Dextrocardia with situs inversus is a rare cardiac positional anomaly. Catheter ablation procedures performed in this set of patients have not been sufficiently reported., Methods: A total of 10 patients with dextrocardia and situs inversus who received catheter ablation for supraventricular tachycardia (SVT) were included from a cohort of over 20 000 cases of catheter ablation for SVT in three centers from 2005 to 2016. All patients underwent electrophysiologic study and catheter ablation of SVT. Ablation targets were selected based on different tachycardia mechanisms with the primary endpoint of noninduction of tachycardia., Results: The average age was 32.4 ± 5.6 years. Congenitally corrected transposition of great arteries (TGA) with situs inversus and D-looping of the ventricles and aorta (congenitally corrected TGA {I,D,D}) was found in four patients, while the other six patients exhibited mirror-image dextrocardia {I,L,L}. The mechanisms of SVT were atrioventricular nodal reentrant tachycardia in four patients, atrioventricular reentrant tachycardia in three, typical atrial flutter in one, intra-atrial reentrant tachycardia in one, and focal atrial tachycardia in one. Immediate procedural success was achieved in 9 out of 10 patients with no procedural complications. During a follow-up period of 6.3 ± 3.5 years on average, all patients remained free from recurrent tachycardia., Conclusions: For patients with dextrocardia and situs inversus, catheter ablation of SVT is safe and feasible. Differences in catheter maneuver and fluroscopy projection, along with difficulties in distorted anatomy are major obstacles for successful ablation., (© 2019 Wiley Periodicals, Inc.)