Episodes Of Supraventricular Tachycardia Research Articles

A Rare Case of Supraventricular Tachycardia During Pregnancy and Successful Management in Crisis Situation with Electrical Cardioversion and Radiofrequency Ablation.

The occurrence of symptomatic maternal arrhythmias during pregnancy is a cause of concern for the well-being of both the mother and the fetus. In women of reproductive age, the commonest arrhythmia is paroxysmal supraventricular tachycardia (SVT). SVT in pregnancy is defined as any tachyarrhythmia with a heart rate greater than 120 beats/min [1]. There are no reliable data on the incidence of paroxysmal SVT in pregnant women. The incidence in the general population is 35 per 1,00,000 person-years [2]. Over half of these patients are asymptomatic. The main mechanism for the development of SVT is via reentry (atrioventricular nodal reentrant tachycardia in 60 % of cases and atrioventricular reentrant tachycardia in 30 % cases) [3]. Episodes of SVT occur with increased frequency during pregnancy particulary in third trimester. Proposed mechanisms include the hyperdynamic circulation, the altered hormonal milieu, increased circulating levels of catecholamines, increased adrenergic receptor sensitivity and increased maternal effective circulating volume causing atrial stretch [4, 5]. Potential risk factor for SVT in pregnancy is underlying congenital or structural heart disease [6]. In most cases, there is no history of heart disease. Physical treatment like sinus carotid massage or Valsalva maneuvers followed by drug therapy is tried in hemodynamically stable patients. In cases of failure of above measure or when there is hemodynamic compromise, electrical cardioversion or invasive method like radiofrequency ablation is justified, which may jeopardize the mother and her fetus. No large-scale studies or randomized control trials regarding safety of ECV in pregnancy and agents for successful cardioversion are available [7]. The recommendations published by American College of Cardiology/American Heart Association Task Force on Practice Guidelines/European Society of Cardiology Committee for Practice Guidelines are solely based on expert consensus [8]. We present a case of maternal SVT with hemodynamic instability which failed to respond to physical and drug therapy.

Non-sustained ventricular tachycardia in patients with congenital heart disease: An important sign?

BackgroundSustained ventricular tachycardia (susVT) and ventricular fibrillation (VF) are observed in adult patients with congenital heart disease (CHD). These dysrhythmias may be preceded by non-sustained ventricular tachycardia (NSVT). The aims of this study are to examine the 1] time course of ventricular tachyarrhythmia (VTA) in a large cohort of patients with various CHDs and 2] the development of susVT/VF after NSVT. MethodsIn this retrospective study, patients with VTA on ECG, 24-hour Holter or ICD-printout or an out-of-hospital-cardiac arrest due to VF were included. In patients with an ICD, the number of shocks was studied. ResultsPatients (N=145 patients, 59% male) initially presented with NSVT (N=103), susVT (N=25) or VF (N=17) at a mean age of 40±14years. Prior to VTA, 58 patients had intraventricular conduction delay, 14 an impaired ventricular dysfunction and 3 had coronary artery disease. susVT/VF rarely occurred in patients with NSVT (N=5). Fifty-two (36%) patients received an ICD; appropriate and inappropriate shocks, mainly due to supraventricular tachycardia (SVT), occurred in respectively 15 (29%) (NSVT: N=1, susVT: N=9, VF: N=5) and 12 (23%) (NSVT: N=4, susVT: N=5, VF: N=3) patients. ConclusionsVTA in patients with CHD appear on average at the age of 40years. susVT/VF rarely developed in patients with only NSVT, whereas recurrent episodes of susVT/VF frequently developed in patients initially presenting with susVT/VF. Hence, a wait-and-see treatment strategy in patients with NSVT and aggressive therapy of both episodes of VTA and SVT in patients with susVT/VF seems justified.

Incidental retroperitoneal paraganglioma in patient candidate to radical prostatectomy: Concurrent surgical treatments by robotic approach.

We report a case of a 75-year-old male with biopsy-proven prostate cancer and candidate for radical prostatectomy. The patient's medical history includes hypertension and atrial fibrillation in prophylactic treatment; however, he was suffering from recurrent paroxysmal episodes of supraventricular tachycardia. Abdominal magnetic resonance performed for prostate cancer staging detected a non-lymphatic inter-cavo-aortic mass of 42 × 37 × 43 cm. Results of biochemical screening confirmed the clinical diagnosis of symptomatic paraganglioma. The patient was subjected in a single robotic session for concurrent excision of the inter-aortocaval mass and radical prostatectomy with bilateral pelvic lymph-node dissection. During the procedure, there were no anesthesiological or surgical complications. The postoperative course was uneventful and the patient was discharged on postoperative day 5. Six months after surgery, his prostate-specific antigen level was undetectable and the abdominal magnetic resonance imaging was negative for local recurrence or metastasis of paraganglioma. No more episodes of tachycardia were reported or antihypertensive therapy was necessary.

Recalcitrant Supraventricular Tachycardia: Occult Albuterol Toxicity Due to a Factitious Disorder

BackgroundWe report a case of a factitious disorder presenting with recurrent episodes of supraventricular tachycardia (SVT). Case ReportA 26-year-old woman presented with recurrent episodes of SVT. Medical history included SVT, asthma, anxiety, depression, type 2 diabetes, and migraine headaches. The patient had frequent emergency department (ED) visits with complaints of chest pain, palpitations, and heart rates typically between 130 and 150 beats/min. Electrocardiograms revealed sinus tachycardia; laboratory studies were consistently normal except for periodic episodes of hypokalemia. Over the 3 years, the patient had more than 50 visits for health care and underwent multiple diagnostic evaluations, including comprehensive laboratory testing, echocardiography, Holter monitoring, and event monitoring. Given the constellation of clinical features, a plasma albuterol concentration was obtained during an ED visit for SVT, which was 17 ng/mL (reference range for peak plasma concentration after 0.04–0.1-mg inhaler dose = 0.6–1.4 ng/mL). A subsequent ED visit with a similar presentation revealed a plasma albuterol level of 11 ng/mL. The patient adamantly denied using this medication. Due to concerns about a factitious disorder, a multidisciplinary hospital discussion was planned for subsequent interventions; however, the patient was lost to follow-up. Why Should an Emergency Physician Be Aware of This?This is a compelling case report of a factitious disorder and occult albuterol abuse resulting in recalcitrant SVT with numerous ED visits and interventions. Patients with factitious disorders can have multiple visits for emergency care and are challenging to evaluate and treat. Albuterol toxicity can present with pronounced sinus tachycardia, fine tremor, and often with transient hypokalemia.

Sugammadex Use in a Patient with Wolff-Parkinson-White (WPW) Syndrome.

Wolff-Parkinson-White (WPW) syndrome is a disease associated with episodes of supraventricular tachycardia and ventricular pre-excitation or atrial fibrillation. WPW is characterized by an aberrant electrical conduction pathway between atria and ventricles. The major anesthetic problem connected with WPW syndrome is the risk of tachyarrhythmias due to accessory pathway. Therefore, it has been proposed that the aim of anesthetic management should be the avoidance of tachyarrhythmia and sympathetic stimulation. Sugammadex was administered as a neuromuscular reversal agent in this case. To our knowledge, this is the first case report of sugammadex use in a patient with WPW. This report presents a case of general anesthesia management in a patient with WPW syndrome. We think that it is appropriate to use sugammadex to reverse rocuronium for the prevention of sudden hemodynamic changes in patients with WPW who underwent general anesthesia.

Effectiveness of the Valsalva Manoeuvre for reversion of supraventricular tachycardia.

People with the cardiac arrhythmia supraventricular tachycardia (SVT) frequently present to clinicians in the prehospital and emergency medicine settings. Restoring sinus rhythm by terminating the SVT involves increasing the refractoriness of atrioventricular nodal tissue within the myocardium by means of vagal manoeuvres, pharmacological agents, or electrical cardioversion. A commonly used first-line technique to restore the normal sinus rhythm (reversion) is the Valsalva Manoeuvre (VM). This is a non-invasive means of increasing myocardial refractoriness by increasing intrathoracic pressure for a brief period, thus stimulating baroreceptor activity in the aortic arch and carotid bodies, resulting in increased parasympathetic (vagus nerve) tone. To assess the evidence of effectiveness of the VM in terminating SVT. We updated the electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 7); MEDLINE Ovid (1946 to August week 3, 2014); EMBASE Classic and EMBASE Ovid (1947 to 27 August 2014); Web of Science (1970 to 27 August 2014); and BIOSIS Previews (1969 to 22 August 2014). We also checked trials registries, the Index to Theses, and the bibliographies of all relevant publications identified by these strategies. We included all randomised controlled trials (RCTs) that examined the effectiveness of VM in terminating SVT. Two review authors independently extracted the data using a standardised form. We assessed each trial for internal validity, resolving any differences by discussion. We then extracted and entered data into Review Manager 5. In this update, we did not identify any new RCT studies for inclusion. We identified two RCT studies as ongoing that we are likely to include in future updates. Accordingly, our results are unchanged and include three RCTs with a total of 316 participants. All three studies compared the effectiveness of VM in reverting SVT with that of other vagal manoeuvres in a cross-over design. Two studies induced SVT within a controlled laboratory environment. Participants had ceased all medications prior to engaging in these studies. The third study reported on people presenting to a hospital emergency department with an episode of SVT. These participants were not controlled for medications or other factors prior to intervention.The two laboratory studies demonstrated reversion rates of 45.9% and 54.3%, whilst the clinical study demonstrated reversion success of 19.4%. This discrepancy may be due to methodological differences between studies, the effect of induced SVT versus spontaneous episodic SVT, and participant factors such as medications and comorbidities. We were unable to assess any of these factors, or adverse effects, further, since they were either not described in enough detail or not reported at all.Statistical pooling was not possible due to heterogeneity between the included studies. We did not find sufficient evidence to support or refute the effectiveness of VM for termination of SVT. Further research is needed, and this research should include a standardised approach to performance technique and methodology.

Significance of ST-segment Depression during Paroxysmal Supraventricular Tachycardia

Background: ST-segment depression in ECG is a common finding during paroxysmal supraventricular tachycardia. The exact mechanism and etiology of this ST-segment depression is not always evident. In this study we have tried to evaluate the significance of ST-segment depression during supraventricular tachycardia. Methods: Hospitalized patients for elective electrophysiological study with previous (EPS) history of supraventricular tachycardia with or without ST-segment depression were evaluated clinically, by coronary angiogram and EPS. Data were analyzed by appropriate statistical methods and comparison made between groups with ST-segment depression (Group A) and without ST-segment depression (Group B). Results: Total number of patients was 66. Equal number of patients (33) was in each group. The mean age of patients was 43.8 years. There was female predominance (M:F ratio 2:3). The mean heart rate during supraventricular tachycardia was 161 beats/min. Age, sex, coronary artery disease risk factors and heart rate during an episode of supraventricular tachycardia did not have any significant influence on ST-segment depression. Significant coronary artery disease was found in two patients in Group A and one patient in Group B. Electrophysiological study revealed that Atrio ventricular reentry tachycardia (AVRT) and AV nodal reentry tachycardia (AVNRT) were present in 28 (42.4%) and 38 (57.6%) cases respectively. Patients of group A exhibit AVRT significantly more than patients of group B.The sensitivity of ST-segment depression in correctly diagnosing coronary artery disease (CAD) was 66.7% while the specificity was 50.8%. The sensitivity of ST-segment depression in correctly differentiating AVRT was 83.3% while the specificity was 66.7%. The positive predictive value (PPV) and Negative predictive value (NPV) of the test were 75% and 76.9% respectively. Conclusion: ST-segment depression during episode of supraventricular tachycardia is a poor indicator of coronary artery disease. Presence of ST-segment depression can differentiate AVRT from AVNRT. However, >2 mm ST-segment depression was proved to be an excellent predictor of AVRT. DOI: http://dx.doi.org/10.3329/cardio.v7i2.22249 Cardiovasc. j. 2015; 7(2): 93-97

Utilization of Intraoperative TEE to Assess Supraventricular Tachycardia-Inducing Right-Sided Cardiac Compression by the Liver, Post-Liver-Transplantation Status.

This unique and interesting case report involves a patient who recently underwent a combined liver and kidney transplant (due to autosomal dominant polycystic kidney disease) and subsequently suffered from episodes of supraventricular tachycardia (SVT) secondary to the new liver graft compressing the right atrium and ventricle. After this was diagnosed, the patient underwent operative plication of the right hemidiaphragm. Intraoperative transesophageal echocardiography was used to demonstrate cardiac compression from the liver and demonstrate resolution of compression after plication of the hemidiaphragm.

Supraventricular tachycardia during pediatric anesthesia: a case series and qualitative analysis

Study ObjectiveTo perform a qualitative analysis of noncardiac patients who developed suspected intraoperative supraventricular tachycardia (SVT) during general anesthesia. DesignRetrospective database analysis and chart review. SettingOperating room of a university-affiliated children’s hospital. MeasurementsThe records of children without cardiac disease who received general anesthesia at The Children’s Hospital of Philadelphia from July 1998 through June 2011 were reviewed. Patients with heart rate values above 180 beats per minute were identified, as were specific medications or key words in the free-text fields of the anesthesia records that would be indicative of a tachyarrhythmia. Each case was reviewed by at least two authors; each patient was assigned a diagnosis classification of “highly suspicious” or “unlikely” SVT. The highly suspicious SVT cases were examined in detail to determine the specific aims. Main Results36 subjects out of a total of 285,353 anesthetics administered during the study period were suspected by the anesthesia care team to have had an episode of intraoperative SVT: 22 were “highly suspicious” events, and 14 were “unlikely” events. The highly suspicious SVT events occurred in all phases of anesthesia, and none led to any hemodynamic instability. Effective treatments included vagal maneuvers, pharmacologic antiarrhythmics, or no treatment if the event resolved spontaneously before treatment. Six patients had outpatient follow-up and three received antiarrhythmic medications to control ongoing SVT. ConclusionsSVT during the intraoperative period in noncardiac pediatric patients was uncommon. When it occurred, it was not associated with clinically significant patient morbidity. For some patients, the anesthesia unmasked a predisposition for re-entrant SVT and those patients remained on maintenance antiarrhythmic therapy following discharge home.

Use of adenosine in the treatment of supraventricular tachycardia in a pediatric emergency department.

Supraventricular tachycardia (SVT) is the most frequent arrhythmia requiring treatment in childhood, with an estimated incidence of 1/100 to 1/250 children. The treatment of choice of the acute event is intravenous adenosine. This study aimed to determine if doses of adenosine higher than previously described are needed to successfully revert SVT in children. This is a retrospective study of SVT cases in a tertiary hospital from January 2007 to December 2011. A total of 44 episodes of SVT were recorded in 26 patients. Mean age was 3.1 years. In 39 patients (89%), adenosine was administered, reverting to stable sinus rhythm in 29 episodes, which represents an effectiveness of 75%. In relation to the number of doses administered, 12 patients (30%) received a single dose, with a mean (SD) response dose of 112 (35) µg/kg; 16 (41%) received 2 doses, with a mean (SD) response dose of 188 (55) µg/kg; and 9 (24%) received 3 doses, with a mean (SD) response dose of 249 (108) µg/kg. Finally, in 2 patients (4%), 4 doses of adenosine were administered, with only 1 of them responding to a dose of 300 µg/kg. The mean (SD) dose that reverted the SVT to normal sinus rhythm was 173 (84) µg/kg, and the mean (SD) number of doses administered was 1.7 (0.8) (range, 1-4). Sixty-six percent were discharged home, without the need to be transferred to pediatric intensive care unit or pediatric ward. Most of the patients with SVT episodes require treatment with more than 1 dose of adenosine. Doses higher than the usually described in the guidelines are necessary to revert SVT. Most patients can be discharged home from the emergency department, without the need of hospital admission.

The prevalence and characteristics of intra-atrial right coronary artery anomaly in 9,284 patients referred for coronary computed tomography angiography

ObjectiveTo determine the prevalence, radiologic patterns and clinical characteristics of intra-atrial right coronary artery (IARCA) among adult coronary computed tomography angiography (CCTA) population. MethodsWe included 9,284 consecutive subjects who underwent CCTA at a single high-volume center. The presence of IARCA including the number, length and diameter of IARCA segments with accompanying atherosclerosis and coronary anomalies were evaluated. Additionally, clinical characteristics and midterm follow-up of IARCA patients were recorded. ResultsThe IARCA prevalence was 0.15% (14/9,284) with 15 intra-atrial segments. The intra-atrial segment length ranged from 14 to 53mm, and the mean diameter proximal to the entry site was 3.3±0.7mm. IARCA was more often associated with intramuscular course of the left anterior descending coronary artery (29% vs. 4%, p=0.001) and anomalous origin of the left circumflex artery from the right aortic sinus (14% vs. 0.3%, p=0.001) compared with non-IARCA cases. The majority of IARCA patients were women (86%) presenting with supraventricular arrhythmia (71%). Compared with computed tomographic population without IARCA, IARCA subjects were younger (60±12 vs. 54±14 years, p=0.037) and more often women (51% vs. 86%, p=0.013). At a mean of 20 months follow-up of IARCA patients there were no adverse cardiac events except for supraventricular tachycardia episodes occurring in 36% of subjects. ConclusionsIARCA occurs rarely and is often associated with additional coronary anomalies. The clinical profile of IARCA patients is most often represented by middle-aged women with supraventricular arrhythmia showing favorable midterm prognosis.

Longitudinal follow-up of 32 to 39 years after Mustard correction of transposition of the great arteries

Purpose: To describe mortality and morbidity in the total cohort of patients who underwent a Mustard operation for transposition of the great arteries (TGA) between 1971-1980 in our center and were followed prospectively every 10 years. Methods: Survival status was obtained from the Dutch National Population Registry. Patients who participated in one or both of the previous studies were invited for thorough in-hospital clinical investigation. Patients who could or would not participate were asked to fulfill a written questionnaire. Events were defined as death or heart transplantation, re-intervention, arrhythmia, heart failure, pacemaker or ICD implantation and endocarditis. Results: Information on survival status was obtained in 86 patients (95%). Mean follow-up was 35±2 years, with a range of 32-39 years. Cumulative survival was 80% after 20 years, 77% after 30 years and 68% after 37 years. Event free survival was 36%, 25% and 19% after 20, 30 and 37 years respectively. In the last 10 years 2 patients died due to ventricular fibrillation and 1 patient underwent heart transplantation, three patients (6%) underwent re-interventions for baffle stenosis, 5 (10%) had their first episode of supraventricular tachycardia, three (6%) needed a pacemaker (1 for sick sinus syndrome and 2 for AV-blok) and 3 (6%) received an ICD (1 for secondary and 2 for primary prevention), 5 patients (10%) were treated for de novo heart failure. ![Figure][1] Survival after Mustard operation for TGA Conclusion: Long-term outcome of Mustard patients is clearly hampered, with 68% survival and only 19% event-free survival after 37 years. [1]: pending:yes

The response of the pumping function of the heart to the orthostatic test and monoamines plasma level may serve as markers of early-stage Parkinson's disease

arrhythmia with the help of mobile telemonitoring, which is an uncomplicated technology that facilitates the continuous monitoring and recording of arrhythmias. Methods: We investigated 54 outpatients in the Republic of Georgia with different types of arrhythmia (32 male, 22 female, age range – 12– 80 years). Among them were patients with unexplained syncope, epilepsy, and asymptomatic patients who underwent radiofrequency catheter ablation. In addition, there were asymptomatic patients after aorto-coronary bypass graft surgery and 10 healthy sportsmen. Investigations were made by 3-lead electrocardiograph-ECG loop recorder in automatic recording/transmitting mode. Results: Arrhythmias were registered during 7–68 hours of observation. 52% of arrhythmia episodes were asymptomatic. Arrhythmia relapse was detected in 3/6 patients who underwent radiofrequency catheter ablation for SVT or SVPCs, but mostly they were asymptomatic. Asymptomatic episodes of ventricular premature complexes were detected in patients who underwent aorto-coronary bypass graft surgery. In 10 patients with epilepsy, there were 3 patients with supraventricular tachycardia (SVT) and 2 patients with sinus tachycardia. Among 10 patients with unexplained syncope, there were 2 patients with sinus tachycardia, 2 patients with SVT and 1 patient with sick-sinus syndrome. Asymptomatic episodes of supraventricular tachycardia were detected in 1 sportsman. Asymptomatic episodes were detected in the majority of cases (p = 0.001). No difference between genders in the frequency of arrhythmias was found (p = 0.05). Conclusions: Mobile telecardiology offers a feasible methodology for monitoring arrhythmia outpatients in Georgia. It is also a useful tool for detecting a relapse, or symptomatic and asymptomatic episodes of life-threatening arrhythmia.

Mitral Valve Injury After Radiofrequency Ablation for Wolff-Parkinson-White Syndrome

A 39-year-old athletic female with symptomatic Wolff-Parkinson-White syndrome underwent an electrophysiological study and subsequent ablation of orthodromic reentrant tachycardias using left lateral, posterolateral, and posteroseptal accessory pathways. Ablation was performed with 7F medium- and large-curl Safire catheters using the retrograde aortic approach. Eighteen radiofrequency lesions were delivered at the mitral valve annulus (50 W, 60°, 10–60 seconds), and 8 were delivered in the coronary sinus, with weak persistence of antegrade conduction through the posteroseptal pathway. Two weeks later, she presented to the emergency room with a new episode of supraventricular tachycardia, She had been having dyspnea since the ablation procedure. A transthoracic echocardiogram revealed severe mitral regurgitation with a regurgitant volume of 66 ml and estimated regurgitant orifice of 39 mm2 (Figure [C, F, and G]); the left atrium was enlarged with a volume index of 36 ml/m2. Transesophageal echocardiogram revealed a ruptured chord to the anterior leaflet adjacent to the posteromedial commissure (Figure [E]). Given the symptoms and severity of the mitral valve regurgitation, the decision …

Long-Term Follow-Up of a Pediatric Cohort With Short QT Syndrome

The purpose of this study was to define the clinical characteristics and long-term follow-up of pediatric patients with short QT syndrome (SQTS). SQTS is associated with sudden cardiac death. The clinical characteristics and long-term prognosis in young patients have not been reported. This was an international case series involving 15 centers. Patients were analyzed for electrocardiography characteristics, genotype, clinical events, Gollob score, and efficacy of medical or defibrillator (implantable cardioverter-defibrillator [ICD]) therapy. To assess the possible prognostic value of the Gollob score, we devised a modified Gollob score that excluded clinical events from the original score. Twenty-five patients 21 years of age or younger (84% males, median age: 15 years, interquartile range: 9 to 18 years) were followed up for 5.9 years (interquartile range: 4 to 7.1 years). Median corrected QT interval for heart rate was 312 ms (range: 194 to 355 ms). Symptoms occurred in 14 (56%) of 25 patients and included aborted sudden cardiac death in 6 patients (24%) and syncope in 4 patients (16%). Arrhythmias were common and included atrial fibrillation (n = 4), ventricular fibrillation (n = 6), supraventricular tachycardia (n = 1), and polymorphic ventricular tachycardia (n = 1). Sixteen patients (84%) had a familial or personal history of cardiac arrest. A gene mutation associated with SQTS was identified in 5 (24%) of 21 probands. Symptomatic patients had a higher median modified Gollob score (excluding points for clinical events) compared with asymptomatic patients (5 vs. 4, p = 0.044). Ten patients received medical treatment, mainly with quinidine. Eleven of 25 index cases underwent ICD implantation. Two patients had appropriate ICD shocks. Inappropriate ICD shocks were observed in 64% of patients. SQTS is associated with aborted sudden cardiac death among the pediatric population. Asymptomatic patients with a Gollob score of <5 remained event free, except for an isolated episode of supraventricular tachycardia, over an average 6-year follow-up. A higher modified Gollob score of 5 or more was associated with the likelihood of clinical events. Young SQTS patients have a high rate of inappropriate ICD shocks.

Necrotizing enterocolitis after recurrent supraventricular tachycardia

Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency that primarily affects premature infants. In the last decade, there have been significant advances to our understanding of neonatal NEC. The exact etiology of NEC remains unclear, but it is widely considered a multifactorial disease; prematurity, enteral feeding, intestinal hypoxia-ischemia, and bacterial colonization are considered major risk factors. We report a case of a 35 week preterm infant with recurrent episodes of supraventricular tachycardia who developed NEC in the second week of life. This case underscores the importance of being appropriately cautious in the feeding of these high-risk premature infants.

Management of symptomatic Wolff–Parkinson–White syndrome in childhood

The term “ventricular preexcitation” or “preexcitation” refers to the presence of a delta wave and short PR interval on electrocardiogram (ECG) during normal sinus rhythm. The Wolff–Parkinson–White (WPW) syndrome refers to preexcitation during sinus rhythm, in association with episodes of supraventricular tachycardia (SVT). The delta wave represents extra-nodal conduction via an accessory connection located along the atrioventricular groove or the septal region, and this substrate can support atrioventricular reentrant tachycardia. Patients with Wolff–Parkinson–White syndrome may experience symptoms of palpitations, dizziness, syncope, or sudden cardiac arrest related to supraventricular tachycardia; infants may present with congestive heart failure. Catastrophic symptoms such as cardiac arrest or sudden death may be triggered from atrial fibrillation with rapid antegrade conduction to the ventricle via the accessory connection, resulting in ventricular fibrillation [1–4]; this risk is likely higher in patients in the first three decades of life [4,5]. Sudden cardiac arrest as the initial symptom may be more common in younger patients [2,4,6]; for this reason, appropriate evaluation and management of the young patient with preexcitation is essential.

Optimal dose of adenosine effective for supraventricular tachycardia in children.

To determine the optimal adenosine dose effective in supraventricular tachycardia (SVT) and underlying conditions affecting the effective dose in children. Experimental study. Department of Cardiology, The Children's Hospital and Institute of Child Health, Lahore, from July 2008 to June 2011. All children presenting with SVT were administered adenosine in rapid boluses according to PALS guidelines using incremental doses of 100, 200 and 300 μg/kg. The response was recorded on 12 lead ECG. Preexcitation was documented and echocardiography performed on all children after attaining sinus rhythm. Mann Whitney test and Kruskal-Wallis test were used as a test of significance to determine any difference in effective adenosine dose between normal heart and various underlying conditions, taking p < 0.05 as significant. Eighty five patients were treated for 110 episodes of SVT with adenosine. M:F ratio was 2.2:1. Their age ranged from 6 days to 14 years with mean age of 27.9 months. Adenosine was effective in reverting 97 episodes of SVT to sinus rhythm (88.2%). A dose of upto 100 μg/kg was only effective in 36.4% episodes of SVT. Two hundred μg/kg was effective in 44.3% of those not responding to 100 μg/kg dose (n = 31/70, cumulative 64.5%). A dose of 300 μg/kg was effective in further 25 patients not responding to lower doses (n = 25/38, 65.8%; cumulative 88.2%). Mean effective dose of adenosine was 185.3 + 81.0 μg/kg with median effective dose of 200 μg/kg. Significantly higher dose of adenosine was required in children with underlying pre-excitation, n = 18/97 (220.8 + 67.6 μg/kg vs. 177.2 + 81.9 μg/kg, p = 0.039). Adenosine is an effective medicine in treating SVT in children. A higher dose of 200 μg/kg may be used as first bolus particularly in children with pre-excitation.

Slow pathway ablation using electro-anatomical mapping in a patient with corrected transposition of the great arteries, dextrocardia, and atrioventricular nodal reentrant tachycardia

We reported a 26-year-old female with congenitally corrected transposition of the great arteries, dextrocardia, cardiac situs inversus, and episodes of supraventricular tachycardia (A). A three-dimensional (3D) reconstruction image was made by computed …

Dexmedetomidine: Therapeutic Use for the Termination of Reentrant Supraventricular Tachycardia

The current drug of choice for reentrant supraventricular tachycardia (SVT) is adenosine followed by verapamil or diltiazem. Although limitations and significant adverse events have been encountered over the years, an alternative effective and safe agent has not been available. Dexmedetomidine has recently been shown to have potential antiarrhythmic effects, and here we describe our experience in the acute termination of reentrant SVT. Retrospective case series. Quaternary University Children's Hospital, Cardiac Intensive Care Unit. Patients who received dexmedetomidine for SVT in the past 5 years. None. SVT episodes terminated with dexmedetomidine were compared with episodes terminated with adenosine. Fifteen patients, median age of 10 days (6-16), were given 27 doses of dexmedetomidine, mean dose 0.7 ± 0.3 mcg/kg, for a total of 27 episodes of SVT. Successful termination occurred in 26 episodes (96%) at a median time of 30 seconds (20-35). Duration of sinus pause was 0.6 ± 0.2 seconds, there was one episode of hypotension and no bradycardia and sedation lasted for 34 ± 8 minutes. Five patients received 27 doses of adenosine, with an overall successful cardioversion in 17 patients (63%) (P= .0017). Transient bradycardia and hypotension was seen in three patients (11%), agitation in 16 patients (59%), and broncospasm in one patient. Median sinus pause was 2.5 seconds (2-9) (P < .001). Dexmedetomidine appears to have novel antiarrhythmic properties for the acute termination of reentrant SVT. Although adenosine is very effective, dexmedetomidine may prove to possess a more favorable therapeutic profile with increased effectiveness and fewer side effects.