Incessant Tachycardia Research Articles

Characterization of focal right atrial appendage tachycardia

Though right atrial appendage tachycardia (RAAT) has been described, no studies to date have focused on its clinical characterization. The aim of the present study was to analyze its clinical, electrocardiographic (ECG), and electrophysiologic (EP) characteristics and the results of radiofrequency ablation (RFA) in RAAT. Out of 186 consecutive patients undergoing RFA for AT, 15 (8%) had focal RAAT. Mapping was performed using conventional catheters or a 3D electroanatomic mapping system. Patients with RAAT were more likely to be male (66 vs. 38%; P= 0.013) and younger (32 +/- 12.6 vs. 55 +/- 13.2 years; P < 0.001) than patients with AT originating elsewhere. They were also more likely to have dyspnea (27 vs. 7.6%; P = 0.03), incessant tachycardia (53 vs. 16%; P < 0.001), and left ventricular systolic dysfunction (27 vs. 5%; P = 0.018). RFA was effective in all patients (100 vs. 75%; P = 0.022) and no recurrences (0 vs. 8%; P = 0.31) were observed during a mean follow-up of 37 +/- 36 months. A specific ECG pattern was identified, consisting of negative P-waves in leads V1-V2 and a transition to positivity in the rest of the precordial leads. This ECG pattern correctly identified RAAT with a sensitivity of 100%, a specificity of 98%, a positive predictive value of 88%, and a negative predictive value of 100%. Right atrial appendage tachycardia is more prevalent in young male patients and is commonly associated with tachycardiomyopathy. RFA is effective over long-term follow-up. A characteristic ECG pattern identifies RAAT with a very high sensitivity and specificity.

Dual tachycardia in the setting of amiodarone-induced hyperthyroidism

A 65-year-old male with dilated cardiomyopathy (left ventricular ejection fraction 30%) presented with incessant wide complex tachycardia (WCT). His history included paroxysmal atrial fibrillation treated chronically with amiodarone. WCT was refractory to intravenous amiodarone and required multiple cardioversions. …

Low Exposure Radiation with Conventional Guided Radiofrequency Catheter Ablation in Pregnant Women

Cardiac arrhythmias in pregnant women are a common entity and often drug-refractory. The major concern about using radiofrequency (RF) catheter ablation guided by fluoroscopy to treat arrhythmias during pregnancy is the potential consequences of exposing the fetus to radiation. We present two pregnant patients with incessant and life-threatening supraventricular tachycardias successfully treated by conventional RF ablation under strict radioactive dosimeter surveillance. The availability of better fluoroscopy and lead shielding techniques allows to perform RF ablation of drug-refractory and poorly tolerated supraventricular arrhythmias at any stage of pregnancy, with an appropriate tracking of the radiation dose received by both mother and fetus.

Computed tomography image–guided catheter ablation of a focal atrial tachycardia from the noncoronary sinus of Valsalva

A 69-year-old woman underwent catheter ablation of requent episodes of paroxysmal supraventricular tachycaria. Electrophysiological study demonstrated an incessant ocal atrial tachycardia (AT) with a cycle length of 420 ms. iatrial electroanatomical mapping using the CARTO sysem (Biosense-Webster, Diamond Bar, CA) located the arly sites of activation on the interatrial septum just poserior to the His bundle region. Attempts at ablation from oth the right and left atrial aspects of the septum were nsuccessful. By registration of the right atrium (RA) and the aorta, a reprocedural computed tomography (CT) image was suerimposed on the electroanatomic maps. A 4-mm-tip Naistar ablation catheter (Biosense-Webster) was passed rom the right femoral artery to the aortic root and was ositioned in the noncoronary sinus of Valsalva, just oppo-

The Results of Radiofrequency Catheter Ablation of Supraventricular Tachycardia in Children

Radiofrequency (RF) catheter ablation represents a major advance in the management of children with cardiac arrhythmias and has rapidly become the standard of care for the first-ling therapy of supraventricular tachycardias (SVTs). The purpose of this study was to investigate the results of the RF catheter ablation of SVTs in pediatric patients. From December 1989 to August 2005, a total of 228 pediatric patients (age: 9 +/- 7 years, range: 5-18 years; male:female = 117:111) with clinically documented SVT underwent an electrophysiologic study and RF catheter ablation at our institution. The arrhythmias included atrioventricular reentrant tachycardia (AVRT; n = 140, 61%), atrioventricular nodal reentrant tachycardia (AVNRT; n = 66, 29%), atrial tachycardia (AT; n = 11, 5%), and atrial flutter (AFL; n = 11, 5%). The success rate of the RF catheter ablation was 92% for AVRT, 97% for AVNRT, 82% for AT, and 91% for AFL, respectively. Procedure-related complications were infrequent (8.7%; major complications: high grade AV block (2/231, 0.9%); minor complications: first degree AV block (6/231, 2.6%), reversible brachial plexus injury (2/231, 0.9%), and local hematomas or bruises (10/231, 4.3%)). The recurrence rate was 4.7% (10/212) during a follow-up period of 86 +/- 38 months (0.5-185 months). The RF catheter ablation was a safe and effective method to manage children with paroxysmal and incessant tachycardia. The substrates of the arrhythmias differed between the pediatric and adult patients. However, the success rate of the ablation, complications, and recurrence during childhood were similar to those of adults.

Epicardial catheter ablation of ventricular tachycardia using surgical subxyphoid approach

We report the case of a patient presenting with a previous inferior myocardial infarction complicated by incessant monomorphic ventricular tachycardia resistant to antiarrhythmic drugs. Because endocardial catheter ablation failed and because of focal endocardial activation arising from the left ventricular inferior wall, an epicardial location of the reentry circuit was suspected. Catheter mapping of the pericardial space through a surgical subxyphoid approach performed in the electrophysiological laboratory confirmed the epicardial location of the arrhythmogenic substrate and allowed us successfully to ablate and cure the patient. Surgical subxyphoid approach can be performed in the electrophysiological laboratory when epicardial ablation is needed in case of inadvisable, difficult, or failed non-surgical percutaneous access.

Pivotal role of integrated electroanatomic mapping with three-dimensional multislice computed tomography scan in the ablation of a left atrial ectopic focus

A 25-year-old woman without structural heart disease was referred to our centre for ablation of incessant left atrial tachycardia ( Figure 1 ). An automatic ectopic focus was located to the left atrial appendage by conventional electroanatomic mapping (CARTO®, Biosense Webster Inc., Diamond Bar, CA, USA). Twenty-five radiofrequency applications were delivered at the area of earliest atrial activation (−25 ms from the P wave onset) through a 3.5 mm irrigated tip ablation catheter (Navi-Star® Thermo-Cool®, Biosense Webster Inc., Diamond Bar, CA, USA), using a power limit of 35 W, but tachycardia was not interrupted. Epicardial mapping via the coronary sinus did not provide better …

AB2-3: The use of percutaneous lVAD to facilitate ablation of incessent unstable VT in a patient with previous myocardial infarction

VT storm is serious complication in patients with ischemic cardiomyopathy. In patients unresponsive to medical therapy, catheter ablation is a viable option but can be limited due to the unstable nature of the “unmappable” ventricular arrhythmia. We report a 63 yo man with a history of ischemic cardiomyopathy, EF 15%, who presented 6 months post ICD implantation with multiple ICD shocks and incessant wide QRS tachycardia unresponsive to antiarrhythmic drugs & IABP. Due to acute cardiogenic shock, a percutaneous left ventricular assist device (Tandem Heart™ - pVAD) was placed.

Slow and wide QRS complex tachycardia as a unique complication following radiofrequency catheter ablation of a left-sided accessory pathway in a child

Radiofrequency lesions can, theoretically, be the substrate for new persistent arrhythmias. As far as we know, this has never previously been encountered after transcatheter ablation of accessory pathways. A child with Wolff-Parkinson-White syndrome was referred for radiofrequency catheter ablation of a left-sided accessory pathway. After successful ablation of the accessory pathway using a retrograde transaortic approach, the child developed an incessant wide QRS complex tachycardia at slow rate that was resistant to pharmacologic interventions. The focus of the tachycardia was identical to the ventricular site of insertion of the eliminated accessory pathway.

Ectopic dominant pacemakers originating from the atrial appendages

Introduction: Incessant atrial tachycardia is an uncommon arrhythmia. The diagnosis is suspected in patients with unexplained rapid resting heart rates and P waves inconsistent with a sinus origin. The diagnosis may be difficult if the ectopic rhythm is located close to the sinus node. Moreover, the anatomical substrate of this arrhythmia has not been defined.

Incessant tachycardia following catheter ablation of an accessory pathway: What is the mechanism?

A 16-year-old male with a history of symptomatic supraventricular tachycardia refractory to medical therapy and evidence of preexcitation on surface ECG was referred for catheter ablation. Baseline 12-lead ECG and the induced tachycardia are shown in Figure 1. AH interval was 45 ms, HV interval was 0 ms, and QRS duration was 134 ms. Retrograde activation of the atria during orthodromic tachycardia was believed to be utilizing two right-sided accessory pathways (APs). His-refractory premature ventricular complexes delivered in the right ventricle during tachycardia advanced the subsequent atrial activation, showing participation of at least one of the pathways in the retrograde limb of the tachycardia. Ventricular burst pacing always terminated the tachycardia. Catheter ablation of the manifest AP was performed, and the postablation intervals were AH: 118 ms, HV: 45 ms, and QRS duration: 84 ms. Following ablation, the tachycardia utilizing the second (concealed) AP became incessant (Figure 2). What is the mechanism of the incessant tachycardia? Why did the tachycardia become incessant after the ablation of the first pathway? Figure 2Intracardiac recording after ablation of the manifest accessory pathway showing a sinus beat reinitiating tachycardia (arrow). HRA = right atrial catheter; His p = His-bundle proximal; His m = His-bundle mid; His d = His-bundle distal; CS OS = coronary sinus ostium; CS DIST = coronary sinus distal; RVa = right ventricular apex. View Large Image Figure Viewer

Radiofrequency catheter ablation for incessant atrioventricular nodal reentrant tachycardia normalized H-V block associated with tachycardia-induced cardiomyopathy

A 30-year-old man was admitted for treatment of tachycardia-induced cardiomyopathy caused by incessant atrioventricular nodal reentrant tachycardia (AVNRT). An echocardiogram revealed dilatation of all cardiac chambers with severe globally depressed biventricular systolic function. During an electrophysiologic study, HV interval was prolonged to 118 ms by atrial extrastimulus and 2:1 HV block was documented during AVNRT. Four weeks after catheter ablation for AVNRT, an echocardiogram demonstrated regression of the wall motion abnormality of both ventricles and of their dimensions. In the electrophysiologic study, the HV conduction disturbance disappeared. So far, this is the first case in which tachycardia-induced cardiomyopathy was accompanied by transient His-Purkinje conduction abnormality.

Taquicardia recíproca de la unión auriculoventricular: características electrofisiológicas en un paciente con la variedad paroxística. Caso clínico

Junctional reciprocating tachycardia is an atrioventricular reentrant tachycardia whose anterograde conduction occurs via the His Purkinje and the retrograde conduction via an accessory pathway with slow conduction. The most common form is incessant tachycardia but a paroxysmal form also exists. We report a 35 years old female with recurrent paroxysmal tachycardia, that underwent electrophysiological evaluation. A left posterolateral accessory pathway was documented. Reciprocating paroxysmal tachycardia was induced by electrical stimulation and a successful pathway ablation was performed.

Association of angiotensin converting enzyme gene polymorphism with tachycardia cardiomyopathy

Despite incessant tachycardia, not all patients develop tachycardia-mediated cardiomyopathy. The cardiac renin-angiotensin system may be involved in cardiac remodelling and fibrosis. The level of angiotension-converting enzyme (ACE) in the serum is associated with a 287 bp insertion (I)/deletion (D) polymorphism in intron 16 of the ACE gene. The DD genotype is associated with increased serum ACE levels and a higher incidence of idiopathic dilated and ischemic cardiomyopathy. The objective of this study was to assess whether the ACE gene I/D polymorphism is responsible for development of tachycardia-mediated cardiomyopathy. We identified 20 consecutive patients with persistent tachycardia and cardiomyopathy who showed significant improvement in ejection fraction after rate control (group A, tachycardia cardiomyopathy group). We compared the I/D genotype frequency of group A with the gene frequency of a separate group of 20 patents who, despite rapid atrial arrhythmias had preserved left ventricular ejection fraction (group B, tachycardia without cardiomyopathy group). These two groups were then compared with 24 healthy normal volunteers (group C). After a mean follow-up of 30 months, group A patients showed improvement in ejection fraction from 20+/-7 to 43+/-9% (p<0.001). Group A had a significantly higher frequency of the DD genotype than groups B and C (p-value <0.035 and <0.009 respectively). The profile of group B patients was intermediate between normal and patients with tachycardia-mediated cardiomyopathy. I/D polymorphism of the ACE gene may account for cardiomyopathy secondary to tachycardia.

Amiodarone therapy for drug-refractory fetal tachycardia.

Fetal tachycardia complicated by ventricular dysfunction and hydrops fetalis carries a significant risk of morbidity and mortality. Transplacental digoxin is effective therapy in a small percentage, but there is no consensus with regard to antiarrhythmic treatment if digoxin fails. This study evaluates the safety, efficacy, and outcome of amiodarone therapy for digoxin-refractory fetal tachycardia with heart failure. Fetuses with incessant tachycardia and either hydrops fetalis (n=24) or ventricular dysfunction (n=2) for whom digoxin monotherapy and secondary antiarrhythmic agents (n=13) were not effective were treated transplacentally with a loading dose of oral amiodarone for 2 to 7 days, followed by daily maintenance therapy for <1 to 15 weeks. Digoxin therapy was continued throughout gestation. Newborns were studied by transesophageal pacing or ECG monitoring to determine the mechanism of tachycardia. Three fetuses were delivered urgently in tachycardia during amiodarone loading, and 3 required additional antiarrhythmic agents for sustained cardioversion. Amiodarone or amiodarone combinations converted 14 of 15 (93%) with reentrant supraventricular tachycardia, 2 of 2 with ventricular or junctional ectopic tachycardia, and 3 of 9 (33%) with atrial flutter. Amiodarone-related adverse effects were transient in 5 infants and 8 mothers. Mean gestational age at delivery was 37 weeks, with 100% survival. Orally administered amiodarone is safe and effective treatment for drug-refractory fetal tachycardia, specifically reentrant supraventricular tachycardia, junctional ectopic, or ventricular tachycardia, even when accompanied by hydrops fetalis or ventricular dysfunction.

Efficacy and safety of intravenous amiodarone for incessant tachycardias in infants.

Amiodarone is an effective anti-arrhythmic agent for the treatment of supraventricular and ventricular tachycardias. The safety and efficacy of intravenous amiodarone has been described in adults and children but only to a limited extent in infants. The purpose of this study was to evaluate the safety and efficacy of intravenous amiodarone in infants. Between February 1994 and June 2001, 23 infants with a median age of 8 days (range 1-300 days) with life-threatening incessant tachycardias (17 supraventricular, 6 ventricular) were treated with intravenous amiodarone as single anti-arrhythmic agent. At presentation, 22 infants were haemodynamically unstable. Amiodarone was given as an intravenous loading dose of 5 mg/kg over 1 h followed by an intravenous maintenance dose of 5 micro g/kg per min with stepwise increase up to 25 micro g/kg per min until arrhythmia control or side-effects occurred. Amiodarone was effective in 19 infants, partially effective in three and ineffective in one infant. The median time until arrhythmia control was 24 h (range 1-96 h) and the median maintenance dosage 15 micro g/kg per min (range 5-26 micro g/kg per min). Electrophysiological side-effects necessitating dose reduction comprised of sinus bradycardia in two patients. Hypotension in one patient resolved after dose diminution. Neurological side-effects consisted of choreatic movements in one infant, which resolved over time. Amiodarone administration was stopped in one patient with elevated liver enzymes. intravenous amiodarone is a safe and effective therapy for life-threatening incessant tachycardias in infants.

Nonsurgical transthoracic epicardial radiofrequency ablation: An alternative in incessant ventricular tachycardia

ObjectivesThe purpose of this study was to analyze the feasibility, efficacy, and safety of epicardial radiofrequency (RF) ablation in patients with incessant ventricular tachycardia (VT). BackgroundManagement of patients with incessant VT is a difficult clinical problem. Drugs and RF catheter ablation are not always effective. A nonsurgical transthoracic epicardial RF ablation can be an alternative in patients refractory to conventional therapy. MethodsEpicardial RF ablation was performed in 10 patients who presented with incessant VT despite the use of two or more intravenous antiarrhythmic drugs. ResultsIn eight patients, endocardial ablation (EdA) failed to control the tachycardia. In the remaining two patients, epicardial ablation (EpA) was first attempted because of left ventricular thrombus and severe artery disease, respectively. Eight patients had a diagnosis of coronary artery disease with healed myocardial infarction. One patient had dilated cardiomyopathy, and one patient had idiopathic, incessant VT. In patients with structural heart disease, the mean ejection fraction was 0.28 ± 0.10%. Four patients previously received an implantable defibrillator. The EpA effectively terminated the incessant tachycardia in eight patients, which represents a success rate of 80%. In them, after a follow-up of 18 ± 18 months, a single episode of a different VT was documented in one patient. No significant complications occurred related to the procedure. ConclusionsIn patients with incessant VT despite the use of drugs or standard EdA, the epicardial approach was very effective and should be considered as an alternative in this life-threatening situation.

Ablación con éxito de un ritmo automático del haz de His

Automatic junctional tachycardias are rare supraventricular tachyarrhythmias observed mainly in infants and children. This arrhythmia has a high mortality rate. We report the case of a 22-month-old infant in which the electrophysiological study disclosed an incessant junctional tachycardia originating from an automatic focus located in the His bundle region. Radiofrequency pulse delivery to the His bundle with controlled progressive heating of this region resulted in a definitive ablation of the ectopic focus without complications.

Taquicardia auricular incesante y tumoración cerebral

We report the case of an asymptomatic 78-year-old woman in whom incessant atrial tachycardia refractory to many pharmacological treatments appeared. Months after the appearance of atrial tachycardia, clinical neurological symptoms of a cerebral cystic tumor appeared. Treatment of the tumor resolved the rhythm disorder.

Mechanisms whereby rapid RV pacing causes LV dysfunction: perfusion-contraction matching and NO.

Incessant tachycardia induces dilated cardiomyopathy in humans and experimental models; mechanisms are incompletely understood. We hypothesized that excessive chronotropic demands require compensatory contractility reductions to balance metabolic requirements. We studied 24 conscious dogs during rapid right ventricular (RV) pacing over 4 wk. We measured hemodynamic, coronary blood flow (CBF), myocardial O(2) consumption (MVO(2)) responses, myocardial nitric oxide (NO) production, and substrate utilization. Early pacing (6 h) resulted in decreased heart rate (HR)-adjusted coronary blood flow (CBF), MVO(2) (CBF/beat: 0.33 +/- 0.02 to 0.19 +/- 0.01 ml, P < 0.001, MVO(2)/beat: 0.031 +/- 0.002 to 0.016 +/- 0.001 ml O(2), P < 0.001), and contractility [left ventricular (LV) first derivative pressure (dP/dt)/LV end-diastolic diameter (EDD): 65 +/- 4 to 44 +/- 3 mmHg x s(-1) x mm(-1), P < 0.01], consistent with flow-metabolism-function coupling, which persisted over the first 72 h of pacing (CBF/beat: 0.15 +/- 0.01 ml, MVO(2)/beat: 0.013 +/- 0.001 ml O(2), P < 0.001). Thereafter, CBF per beat and MVO(2) per beat increased (CBF/beat: 0.25 +/- 0.01 ml, MVO(2)/beat: 0.021 +/- 0.001 ml O(2) at 28 days, P < 0.01 vs. 72 h). Contractility declined [(LV dP/dt)/LVEDD: 19 +/- 2 mmHg x s(-1) x mm(-1), P < 0.0001], signifying flow-function mismatch. Cardiac NO production, endothelial NO synthase expression, and fatty acid utilization decreased in late phase, whereas glycogen content and lactate uptake increased. Incessant tachycardia induces contractile, metabolic, and flow abnormalities reflecting flow-function matching early, but progresses to LV dysfunction late, despite restoration of flow and metabolism. The shift to flow-function mismatch is associated with impaired myocardial NO production.