Non-paroxysmal junctional tachycardia complicating disseminated intravascular coagulation during massive surgical hemorrhage: A case report.

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.

Fatal cerebral air embolism from atrio-oesophageal fistula following cardiac ablation.

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.

Reversible supraventricular tachycardia and left bundle branch block in a marathon runner with exertional heat stroke in the Po Valley.

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).

The Wolff-Parkinson-White pattern in neonates: results from a large population-based cohort study.

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.

Arrhythmias and Clinical Outcomes in a Swiss Multicenter Cohort of Patients With Dextro-Transposition of the Great Arteries and Atrial Switch.

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.

Using 2D speckle-tracking echocardiography to localize the accessory pathway and evaluate cardiac function and dyssynchrony in pediatric patients with Wolf-Parkinson-White syndrome.

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.

Causes and clinical consequences of inappropriate shocks experienced by patients wearing a cardioverter-defibrillator.

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.

Arrhythmogenic Cardiotoxicity Associated With Contemporary Treatments of Lymphoproliferative Disorders.

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.

Transplacental Therapeutic Drug Monitoring in Pregnant Women with Fetal Tachyarrhythmia Using HPLC-MS/MS.

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.

Diagnosis and management of patients who present with narrow complex tachycardia in the emergency department.

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.

RéSUMé: INTRODUCTION: Bien que la tachycardie à complexe QRS étroite (narrow complex tachycardia [NCT]) soit une présentation courante au service des urgences (SU), on sait peu de choses sur son incidence dans le SU ou sur l'expertise des médecins urgentistes dans son diagnostic et sa prise en charge. Nous avons cherché à comparer les cas de NCT dus à des arythmies primaires à ceux avec une fréquence cardiaque rapide secondaire à un problème médical, ainsi que pour déterminer l'exactitude du diagnostic de médecin ED et la pertinence du traitement. MéTHODES: Nous avons effectué un examen des dossiers médicaux dans les urgences d'un grand hôpital universitaire où travaillent 95 médecins et avons inclus des patients adultes consécutifs sur 7 mois (2020-2021) présentant une NCT (fréquence cardiaque ≥ 130 bpm et QRS < 120 ms). Les cas ont été examinés par un comité d'adjudication pour vérifier l'exactitude du diagnostic ECG et la justesse du traitement conformément aux directives. RéSULTATS: Nous avons recensé 310 visites aux urgences (0,8 % de toutes les visites aux urgences), l'âge moyen étant de 65,1 ans, 52,6 % de femmes. Les arythmies primaires représentaient 54,8 %. Les médecins urgentistes ont correctement interprété 86,6 % des ECG. Les arythmies les plus fréquentes et la précision de l'interprétation de l'ECG par le médecin de l'urgence étaient la fibrillation auriculaire 44,5 % (95,1 %), la tachycardie sinusale 24,2 % (90,5 %), le flutter auriculaire 15,8 % (61,5 %) et la tachycardie supraventriculaire (TSV) 12,9 % (81,6 %). Les traitements ont été jugés optimaux dans 96,5 % des NCT primaires et 99,3 % des NCT secondaires. Les traitements étaient sous-optimaux en raison de l'incapacité à réduire la fréquence cardiaque < 100 bpm avant la sortie de l'hôpital dans 2,1 % des cas primaires et de l'incapacité à traiter la cause sous-jacente dans 0,7 % des cas secondaires. CONCLUSION: Une NCT a été constatée dans 0,8 % de toutes les visites aux urgences, la plupart étant des NCT primaires. Les médecins des services d'urgence ont interprété correctement 86,6 % des ECG mais ont eu des difficultés à différencier le flutter auriculaire et la TSV. Ils ont mis en œuvre des soins appropriés dans la plupart des cas, mais n'ont parfois pas réussi à contrôler adéquatement la fréquence cardiaque ou à traiter l'affection sous-jacente, ce qui laisse entrevoir des possibilités d'améliorer la prise en charge des NCT aux urgences.

Speech-induced Atrial Tachycardia with Presyncope.

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.

Self-reported marijuana use and cardiac arrhythmias (from the Multiethnic Study of Atherosclerosis).

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.

IV Sotalol Use in Pediatric and Congenital Heart Patients: A Multicenter Registry Study.

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.

Ambulatory Cardiac Monitoring in Infants with Supraventricular Tachycardia.

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.

Rapid wide QRS tachycardia with an unknown cause.

One-to-one atrioventricular conduction during atrial flutter is one of the most severe life-threatening arrhythmias and is hemodynamically perilous. Rapid wide QRS tachycardia often not only occurs in patients with ventricular tachycardia but is also found in supraventricular tachycardia/atrial flutter with preexistent QRS prolongation, supraventricular tachycardia/atrial flutter with QRS prolongation caused by an IC antiarrhythmic drug, and supraventricular tachycardia/atrial flutter with preexcitation. Furthermore, atrial flutter with 1:1 AVC via an accessory pathway is an uncommon presentation of Wolff-Parkinson-White syndrome. We present a case of atrial flutter with 1:1 rapid AVC in the presence of Wolff-Parkinson-White syndrome. Physicians should be familiar with the rapid wide QRS complex ECG pattern associated with AFL with 1:1 AVC via an accessory pathway. Establishing the definitive diagnosis is essential for selecting an appropriate treatment strategy for improving outcomes.

Favourable outcome for hydrops or cardiac failure associated with fetal tachyarrhythmia: a 20-year review.

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.

Management of Fetal Supraventricular Tachycardia: Case Series from a Tertiary Perinatal Cardiac Center.

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.

Supraventricular Tachycardia Causing Left Ventricular Dysfunction.

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.

Syncope associated with supraventricular tachycardia: Diagnostic role of implantable loop recorders.

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.

Association of Fetal Atrial Flutter with Neonatal Atrioventricular Re-entry Tachycardia Involving Accessory Pathway: A Link to be Remembered.

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.