Refractory Atrial Tachycardia Research Articles

Emergent Zero-Fluoroscopy Mapping and Thoracoscopic Ectomy of Appendage in Pregnant Women with Life-Threatening Atrial Tachycardia: A Case Report and Literature Review

Background: Focal atrial tachycardia (AT) originating from the right atrial appendage (RAA), often persistent and refractory, is clinically rare in pregnant woman, and the therapy is much more challenging. We report that a pregnant woman presented with hypotension due to persistent and refractory atrial tachycardia and was successfully cured by a multidisciplinary treatment (MDT) approach, consisting of a combination of zero-fluoroscopy mapping and thoracoscopic atrial appendectomy. We also carried out a literature review of this topic. Methods and Results: A 26-year-old woman in pregnancy at 21 weeks presented with severe palpitation and hypotension due to persistent rapid supraventricular tachycardia (SVT). Since adenosine triphosphate could not terminate the tachycardia, a catheter ablation procedure was planned and finally canceled when the zero-fluoroscopy mapping using Carto 3TM system revealed an atrial tachycardia originating from the RAA. Thoracoscopic RAA ectomy was recommended after multidisciplinary consultation and successfully performed without fluoroscopy. EnsiteTM velocity mapping system was used for accurately locating the origin of the arrhythmia during ectomy. The woman finally produced a healthy baby during follow-up. Conclusions: Focal AT originating from appendage in pregnant patients can be persistent, refractory, and life-threatening; traditional strategies, such as medicine or catheter ablation, are limited in this situation. MDT measures, using a thoracoscopic ectomy and zero-fluoroscopy three-dimensional electroanatomical mapping technique, is minimally invasive and a promising strategy.

Ivabradine Use in a Pediatric Heart Transplant Recipient with Refractory Atrial Tachycardia

<h3>Introduction</h3> Ivabradine, an oral I_f channel antagonist, has been used in pediatric and adult heart failure patients for heart rate control, and in adult heart transplant (HT) recipients with sinus tachycardia secondary to cardiac graft denervation. There are little data describing the use of ivabradine in pediatric HT patients. We describe the use of ivabradine in a pediatric HT recipient with refractory ectopic atrial tachycardia (EAT) causing hemodynamic instability. <h3>Case Report</h3> A 3 year old male underwent HT for restrictive cardiomyopathy. Post-transplant course was complicated by pulmonary hypertensive crisis and cardiac arrest, followed by the development of EAT at a rate of >200 bpm and periods of atrial flutter 2 weeks post-transplant. Steroids were started for suspected clinical rejection, but endomyocardial biopsy was reassuring (ACR grade 1R/1A, pAMR0). Hypotension was noted when EAT rate was >170 bpm. Patient was refractory to esmolol, sotalol, and amiodarone. He underwent EP study with ablation of a posterolateral atrial focus, with recurrence of EAT several hours later. Given ongoing hemodynamic instability with EAT, repeat ablation was performed 1 week later with termination of EAT. However, periodic EAT recurred 3 weeks later and he was again symptomatic with recurrent emesis with rates >170 bpm. Ivabradine 0.05 mg/kg twice daily was initiated. After a single dose, the duration and frequency of EAT periods decreased. Rhythm was mostly sinus (SR) with a rate of 90-100 bpm with premature atrial contractions (PACs), few atrial couplets and blocked PACs. No hypotension, bradycardia, or hemodynamic instability was noted. He was discharged home and dose was up-titrated as an outpatient to 0.2 mg/kg twice daily. Six weeks later, a 72 hour Holter monitor showed predominately SR with short bursts of EAT with variable AV conduction, atrial ectopy overall making up <10% of beats, and rare premature ventricular contractions (PVCs). All subsequent clinic ECGs with follow up to 3 months demonstrated SR. Repeat Holter 3 months after initiation of ivabradine showed SR with rare, isolated PACs and PVCs with no EAT. <h3>Summary</h3> Ivabradine can be considered for EAT treatment in pediatric patients post-HT, with no identified side effects.

Launching minimally invasive stand-alone maze procedure for atrial fibrillation

Minimally invasive Maze procedure via right mini-thoracotomy approach is reportedly a promising option for paroxysmal and non-paroxysmal atrial fibrillation (AF), although it is not widely performed. This study aimed to validate feasibility and safety of minimally invasive stand-alone Maze procedure in an institutional first case series. This study enrolled an institutional consecutive series of 20 cases who underwent minimally invasive Maze procedure between November 2018 and January 2021. Concomitant tricuspid annuloplasty was performed in five cases who showed moderate tricuspid regurgitation preoperatively. Minimally invasive Maze procedure using cryo-energy source was successfully accomplished with sinus rhythm being restored at the intensive care unit entry in all cases without conversion to the sternotomy approach. All cases were discharged home, while one case was complicated with stroke postoperatively. Nineteen cases (95%) showed sinus rhythm at the last follow-up, whereas one case, who had large left atrium, showed recurrent persistent AF despite optimum medical therapy. Catheter ablations were performed for residual conductions at box lesions and/or mitral/tricuspid isthmus in three cases, who showed medically refractory atrial tachycardia post-Maze procedure. Consequently, these three cases showed sinus rhythm restoration at the last follow-up Conclusions: Minimally invasive stand-alone Maze procedure with or without tricuspid annuloplasty was feasible and safe for AF in the institutional first case series. Catheter ablations for recurrent AF post-Maze procedure would be warranted.

A Case of Refractory Atrial Tachycardia Inducible Only by Head-up Tilt Test

A Case of Refractory Atrial Tachycardia Inducible Only by Head-up Tilt Test

56-20: Radiofrequency ablation safety and efficacy in early childhood

The use of radiofrequency ablation (RFA) for the management of supraventricular tachycardia (SVT) in infants and small children remains controversial. Although arrhythmias in the majority of small children can be managed medically and can spontaneously resolve within 18 months, RFA is occasionally necessary for patients with drug-refractory tachycardias complicated by hemodynamic compromise. However, a limited number of centers have experience with RFA in small children worldwide. Our clinic is among those in which catheter ablation procedures are performed in small children. The main purpose of this abstract is to share our experience with the use of RFA in this cohort of patients. Purpose: To assess safety and efficacy of RFA of tachyarrhythmias in patients under 5 years old. Methods: This retrospective study involved 101 patients under 5 years old inclusive that underwent RFA, 25 of them were under one year old. Drug refractory atrial tachycardia was present in 28 patients, 55 patients had WPW syndrome with frequent reciprocating tachycardia, 6 patients suffered AV-nodal tachycardia and 12 patients had ventricular arrhythmias. The indication for RFA was symptomatic drug refractory arrhythmia accompanied by arrhythmogenic cardiomyopathy and heart failure. Femoral approach was routinely used with single 5Fr introducer on each side. If tachycardia substrate was located in the left heart, the transseptal approach or femoral artery puncture was used in the absence of a patent foramen ovale (PFO). In cases with femoral approach difficulties a reference electrode was placed in esophagus. The temperature limit was set at 50-55 C and power was titrated up to 30 watts. Procedures were performed under intravenous general anesthesia. Three patients under one year old with severe heart failure and high risk of respiratory failure required mechanical ventilation for RFA procedure. Results: There was no mortality in study population. Only one patient had major complication – damage of mitral valve leaflet resulted with mitral regurgitation. Later it became a reason for mitral valve repair. In 10 patients a transient His-Purkinje conduction disturbances were noted and were related to RFA in parahisian locations or bumping during procedure. There were two cases of haemopericardium. In 19 patients after effective RFA an arrhythmia recurrence were noted and procedure was repeated and showed long term success in 14 patients, but third intervention due to recurrence was needed in 5 patients. The regression analysis showed that major predictor for arrhythmia recurrence after successful RFA was minimal power applied to prevent possible complication (OR 0,894 (0,804-0,994, p = 0,039). The total RFA success rate, considering recurrences and retreatment, was 95%. Heart failure disappeared within 5–7 days after RFA. Reverse remodeling of cardiomyopathy was documented within 1 month after effective RFA. Conclusion: Our study suggested that RFA may be considered as the method of choice for SVT treatment in small children when drug therapy is ineffective and arrhythmogenic cardiomyopathy progresses. Taking into account technical aspects of catheter interventions in small children, RFA of tachyarrhythmias should be performed in specialized clinics with relevant experience.

Clot Through the Heart

We present the case of a 67-year-old man with concomitant stroke and pulmonary embolism 1 day after radiofrequency catheter ablation for refractory atrial tachycardia. A chest computed tomographic angiogram revealed "thrombus-in-transit" across a patent foramen ovale, confirming the diagnosis of paradoxical embolism. Paradoxical embolism is a rare definitive diagnosis. Our case is a key demonstration of the even rarer instance where such a diagnosis is confirmed at multidetector computed tomography.

Idiopathic Right Atrial Scar

Right atrial scars participating in macro reentrant tachycardia circuits are generally seen in patients following cardiac surgery for congenital heart disease. Right and left atrial scars without any prior cardiac surgery have been reported but are rare [1,2]. A 65 year old farmer had recurrent drug refractory atrial tachycardia for which he underwent an EP study with three dimensional mapping and radiofrequency ablation. He was not a diabetic or hypertensive, had a structurally normal heart with preserved biventricular function, and normal coronaries. He had not undergone any cardiac surgery prior. Three dimensional mapping was done using CARTO 3 (Biosence, Webster). Sinus rhythm mapping of the right atrium (RA) showed a large atrial scar, defined as electrically silent areas with no recordable activity or bipolar voltage amplitude < 0.25 V. The scar was distributed over posterior, anterior and anterolateral areas near the tricuspid annulus (TA). Mapping during tachycardia showed macro reentrant tachycardia (cycle length =370 msec) propagating around RA scar. Figure 1 shows the sinus rhythm bipolar voltage map of the right atrium (RA) shows the large extent of the RA scar. Figure 2 shows the split atrial potentials mapped at the scar borders. Figure 3 shows activation map of atrial tachycardia, demonstrating Early meets late at the upper scar border.

Ebstein’s anomaly with refractory atrial tachycardia

The incidence of accessory pathways in patients with Ebstein’s anomaly is high, ranging from 20% to 30%, with right and multiple pathways being more commonly encountered. Radiofrequency ablation can eliminate the accessory pathway, but success rates of ablation treatment and the chances of recurrence are generally less satisfactory as compared to those observed when the procedure is performed on structurally normal hearts. We report the case of a 56-year-old man with Ebstein’s anomaly and refractory atrial tachycardia. The special abnormality of the tricuspid valve led to the failure of preoperative electrophysiological mapping and radiofrequency ablation treatment. Finally, the anomalies observed in this patient were corrected with simultaneous surgery and pathway resection.

Ablate and pace as bail-out therapy in a patient with Fontan correction and malignant atrial tachycardia

Atrial tachyarhthmias complicating Fontan correction may have a 'malignant' clinical presentation seriously impairing the patient haemodynamic. Current strategies are surgical total cavopulmonary connection with or without antiarrhythmic surgery or transcatheter ablation. We describe the case of a patient who previously underwent atriocaval Fontan correction and later presented with refractory atrial tachycardia responsible for relapsing syncope. After a failed attempt at surgical conversion, and while waiting for heart transplantation, he was submitted to ablation of the atrioventricular node through an aortic retrograde approach and ventricular pacing through the coronary sinus tree. One year later, the patient is doing well, displaying a stable functional recovery and excellent pacing lead performances. An ablate and pace approach may deserve consideration in selected Fontan patients experiencing life-threatening atrial arrhythmias.

Minimally Invasive Epicardial Left Atrial Ablation and Appendectomy for Refractory Atrial Tachycardia

Surgical removal or epicardial radiofrequency ablation of the left atrial appendage (LAA) is occasionally required when endocardial ablations fail. We report a modified minimally invasive surgical approach for elimination of recurrent atrial arrhythmias arising from the LAA, including both radiofrequency ablation and appendectomy. Ablation of the LAA base was performed using the Medtronic Cardioblate bipolar radiofrequency device (Medtronic, Minneapolis, MN), and left atrial appendectomy was then completed using the EndoGIA stapling system (US Surgical, Norwalk, CT). This procedure successfully isolated and removed the tachycardia focus, and normal sinus rhythm was restored. Elimination of LAA arrhythmias using a combination of epicardial radiofrequency ablation and appendectomy ensures electrical isolation while minimizing surgical invasiveness.

Atrioventricular Nodal Ablation and Biventricular Pacing Therapy with Coronary Venoplasty for Severe Heart Failure with Drug Refractory Atrial Tachycardia

A 53-year-old man was admitted to our hospital for dyspnea, associated with atrial tachycardia. He underwent mitral valve replacement and Maze operation for mitral regurgitation and atrial fibrillation and since then he suffered from drug refractory atrial tachycardia followed by cardiogenic shock with systolic heart failure. Atrial tachycardia with rapid ventricular response was medically refractory, and radical catheter ablation was thought to be very difficult due to post Maze operation, mitral mechanical valve replacement and unstable hemodynamics. Thus, atrioventricular nodal ablation, which was s safe procedure compared to the radical ablation for this patient, and biventricular pacemaker implantation, which required coronary venoplasty, were performed. Combination therapy may be one of the treatments for heart failure patients with drug refractory tachyarrhythmias.

Impact of arrhythmia circuit cryoablation during Fontan conversion for refractory atrial tachycardia

Refractory atrial arrhythmias in late postoperative Fontan patients are usually associated with residual hemodynamic abnormalities and result in significant morbidity and mortality. Surgical revision of the Fontan anastomosis may improve hemodynamics without eliminating tachycardia. This study sought to assess the impact of surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion on the clinical recurrence of tachycardia. Sixteen consecutive atriopulmonary Fontan patients with refractory atrial arrhythmias underwent surgical conversion to lateral tunnel total cavopulmonary anastomosis (15) or Fontan revision (1 patient). The initial 4 patients underwent Fontan conversions alone, without specific arrhythmia surgery. The subsequent 12 patients underwent electrophysiologically guided cryoablation of the tachycardia circuits at the time of surgical conversion. The mean age at Fontan revision was 15.6 ± 3.8 years. Cryoablation was directed to 3 identified major tachycardia circuits: the inferomedial right atrium, the superior rim of the prior atrial septal defect patch, and along the lateral right atrial wall. Transmural antitachycardia pacemakers were implanted in 11 of the 16 patients. There was no surgical mortality in either group, and all patients improved in functional classification. All patients not undergoing cryoablation experienced recurrent symptomatic tachycardia requiring antiarrhythmic therapy (median follow-up, 54 months) versus 2 of 12 patients receiving cryoablation (median follow-up, 25 months; p <0.02). Thus, surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion is highly effective in the management of refractory atrial arrhythmias, and is superior to Fontan conversion alone.

An elderly case of tetralogy of Fallot with refractory atrial tachycardia presenting heart failure

An elderly case of tetralogy of Fallot with refractory atrial tachycardia presenting heart failure

Ablación con catéter mediante radiofrecuencia de taquicardias auriculares

Radiofrequency catheter ablation of atrial tachycardia guided by bipolar activation mapping has been reported in the last years. This article reports the use of radiofrequency catheter ablation for the treatment of atrial tachycardia using simultaneous bipolar and unipolar activation mapping at our institution. Nine patients (7 male and 2 female, mean age 37.2 +/- 24.1 years), were selected for radiofrequency catheter ablation of drug refractory atrial tachycardia. Mapping procedure included an investigation of the local earliest bipolar and unipolar activity and unipolar morphology analysis. Atrial tachycardia was successfully ablated in 7 patients (78%) with an average number of 6.8 +/- 3.1 RF pulses. Procedure related complications and tachycardia follow-up recurrences were not observed in any patient. Bipolar local activation time was significantly shorter at successful than at unsuccessful ablation sites (-30 +/- 21.1 ms vs -18.3 +/- 20.6 ms; p = 0.01). No difference was observed in unipolar local activation time between successful and unsuccessful sites (-22.5 +/- 26.2 ms vs -19.8 +/- 21.5 ms; p = 0.56). Accurate localization of the successful ablation site by unipolar electrogram analysis was not feasible because a "QS" pattern was found at both 21 unsuccessful and 2 successful ablation sites. Finally, a fast slope of the negative deflection of the unipolar electrogram was found at 2 out of 45 unsuccessful and 3 out of 6 successful ablation sites. Radiofrequency catheter ablation of atrial tachycardia is feasible without complications in most patients. Bipolar activation mapping accurately localizes the successful ablation site. A "QS" pattern is not predictive of successful radiofrequency application.

Radiofrequency catheter ablation of sustained intra-atrial reentrant tachycardia in adult patients. Identification of electrophysiological characteristics and endocardial mapping techniques.

Information about electrophysiological characteristics and radiofrequency ablation of intra-atrial reentrant tachycardia has not been reported before. We proposed that induction and termination of intra-atrial reentrant tachycardia by atrial extrastimuli or rapid atrial pacing and resetting the response pattern by atrial extrastimuli during intra-atrial reentrant tachycardia could ensure the mechanism of reentry and that the earliest site of endocardial activation and concealed entrainment pace mapping with the shortest stimulus-P wave interval could localize a critical area responsible for intra-atrial reentrant tachycardia and radiofrequency ablation. Seven patients with refractory atrial tachycardia were referred for electrophysiological studies and radiofrequency ablation. Electrophysiological studies and endocardial mapping found (1) 10 atrial foci with atrial tachycardia cycle length of 406 +/- 41 ms; (2) atrial tachycardia had induction and termination by atrial extrastimuli (8 of 10) or rapid atrial pacing (10 of 10); (3) atrial tachycardia had increasing (6 of 10) or mixed (flat and increasing, 4 of 10) resetting response pattern, with resetting interval of 57 +/- 13 ms (14 +/- 4% of atrial tachycardia cycle length); (4) exit sites of atrial tachycardia in right atrial free wall (6 of 10), right atrial septum (3 of 10), and midposterior left atrium (1 of 10); and (5) earliest activation site had timing relative to P wave by -37 +/- 7 ms, and concealed entrainment pace mapping had shortest stimulus-P interval 23 +/- 3 ms. By the endocardial activation pace-mapping technique, radiofrequency energy (8 +/- 1 pulses, 31 +/- 3 W, 101 +/- 11 seconds) successfully eliminated the 10 atrial foci without recurrence (follow-up, 16 +/- 5 months). Mechanism of intra-atrial reentrant tachycardia could be confirmed by the electrophysiological characteristics, and radiofrequency ablation energy delivered to a critical area in the atrial reentrant circuit is safe and effective for the treatment of intra-atrial reentrant tachycardia.