Low incidence of significant valvar insufficiency following retrograde aortic radiofrequency catheter ablation in young patients

Complications of catheter ablation for ventricular tachycardia

With the increasing literature demonstrating benefits of catheter ablation for ventricular tachycardia (VT), the number of patients undergoing VT ablation has increased dramatically. As VT ablation is being performed more routinely, operators must be aware of potential complications of VT ablation. This review delves deeper into the practice of VT ablation with a focus on periprocedural complications.

Feasibility of electroanatomic mapping and radiofrequency catheter ablation in Boxer dogs with symptomatic ventricular tachycardia

Background

Treatment for Boxers with ventricular tachycardia (VT) is limited. Electroanatomic mapping (EAM) facilitates identification of arrhythmogenic substrate for radiofrequency catheter ablation (RFCA).

Objective

Describe the use of EAM to guide RFCA in Boxers with VT.

Animals

Five client‐owned Boxers with symptomatic VT or persistent VT despite antiarrhythmic medications.

Methods

Case series evaluating clinical, EAM, and before and after RFCA Holter data.

Results

Sustained VT was inducible in 3 dogs, but required aggressive stimulation protocols. Low‐voltage areas consistent with electroanatomic scar were found in 2 dogs, located at the right ventricular (RV) outflow tract and cranial RV. Two dogs had a focal activation pattern of VT and 1 dog had a reentrant mechanism. After RFCA, all dogs no longer collapsed and had fewer runs of VT, 3 of which had 0 runs of VT. Number of ventricular premature beats increased in 3 dogs and decreased in 2 dogs, 1 of which had nearly complete resolution of all arrhythmias. Procedural complications included ventricular fibrillation (n = 2) with successful defibrillation, bruising or hemorrhage at the vascular access site (n = 4), retroperitoneal hemorrhage (n = 1), aortic and mitral regurgitation (n = 1), onset of frequent supraventricular tachycardia (n = 1), and persistent right pelvic limb lameness (n = 1).

Conclusions and Clinical Importance

Electroanatomic mapping and RFCA are feasible in Boxers with VT. Based on this small cohort, RFCA may help decrease runs of VT and improve clinical signs. The anatomic substrate and electrophysiologic mechanisms are variable and require further study.

Aortic Regurgitation as a Complication of Electrophysiologic Ablation Techniques: A Narrative Review

BACKGROUND

Radiofrequency catheter ablation is a well-established treatment for several cardiac arrhythmias. Arrhythmias originating from the left side of the heart including ventricular and supraventricular tachycardia and ectopy can be successfully ablated through either transseptal or retrograde aortic approach. Although these techniques have a generally low rate of complications, aortic valve injury is a potential complication of ablation at the left cardiac side that warrants more investigation.

OBJECTIVE

The purpose of this review is to evaluate the incidence of iatrogenic aortic valve regurgitation and explore the potential mechanisms and risk factors that might contribute to aortic valve injury during radiofrequency ablation. Additionally, the course and progression of aortic regurgitation in the reported cases will be described.

METHODS

Authors searched PubMed for articles using the keywords "ablation" AND "aortic insufficiency" OR "aortic valve injury" OR "aortic regurgitation". Case reports and series as well as retrospective and prospective studies were included, and relevant review articles and editorial comments were used as a supplementary source of data. A total of 19 references were used and a detailed description of patient characteristics, procedural techniques, and incidence, predictors, and fate of aortic regurgitation were reported by 11 clinical studies.

RESULTS

There is a small risk of significant iatrogenic aortic regurgitation after radiofrequency ablation of left-sided cardiac arrhythmias, especially techniques performed via a retrograde aortic approach.

CONCLUSION

Although the risk is not confined to procedures applying direct energy to the aortic cusp region, a more aggressive ablation applied in the vicinity of the valvular complex seems to be associated with a higher risk. Routine post-procedural surveillance should be adopted to detect de novo aortic valve injury following radiofrequency ablation techniques.

Utility of Echocardiography in Detecting Silent Complications After Pediatric Catheter Ablations

Although transcatheter arrhythmia ablation (TCA) has been performed in children for over two decades, guidelines for routine use of post-ablation transthoracic echocardiography (TTE) are absent. We sought to determine the efficacy of TTE after apparently uneventful TCA procedures in detecting adverse findings and identify predisposing factors. A retrospective review of clinical and procedural data on patients who underwent TCA for supraventricular arrhythmias from 2000 to 2015 was performed. Pre- and post-ablation TTE data were reviewed. All patients were followed at 1 week, 6 and 12 months post-TCA. A repeat TTE was performed at 12 months on patients in whom post-TCA abnormalities were found. Patients were divided into two groups: those with and without adverse TTE findings and comparative analysis between variables was performed. Data on 252 patients, 52% males, mean age 14 ± 3 years were analyzed. New onset or worsening atrioventricular valve regurgitation occurred in 17 (6.7%), a small pericardial effusion in 3 (1.2%) and worsened ventricular function in 2 patients (0.8%). Patients in the complication group had higher mean number of ablations (22.6 ± 15.3 vs. 16.8 ± 9.2, p 0.001) and required longer duration of ablation (sec) (254.6 ± 256.4 vs. 180.9 ± 158.9, p < 0.001). TCA location (including coronary sinus), energy source, arrhythmia substrate, and a trans-septal approach were noncontributory to any adverse findings. Routine post-ablation TTE uncovers asymptomatic self-resolving abnormalities that typically do not require any intervention.

Prospective assessment after pediatric cardiac ablation: fate of intracardiac structure and function, as assessed by serial echocardiography

BACKGROUND

Catheter ablation puts cardiac valves at risk of damage, and children are of particular concern.

METHODS

A multicenter prospective study was performed to assess the results and risks associated with radiofrequency (RF) ablation in children. Patients were aged 0 to 16 years with supraventricular tachycardia due to accessory pathway or atrioventricular node reentry, excluding patients with more than trivial congenital heart disease. A total of 481 patients were recruited into the prospective cohort and were followed up at 2, 6 and, 12 months after ablation. Complete echocardiograms were obtained before and at intervals after RF ablation, and they were reviewed by experts who were blinded with respect to diagnosis, outcome, pathway site, and study interval.

RESULTS

Moderate valve insufficiency was quite rare (0.12%), but mild insufficiency was common, both before ablation (42.43%) and at 2 months after ablation (40.49%). Analysis of paired readings failed to demonstrate a tendency toward increased insufficiency of valves adjacent to ablation targets, with the exception of the tricuspid valve after the ablation of right freewall pathways and atrioventricular node reentry, but the degree of change was small. No clear changes in left ventricular systolic or diastolic function were observed, and dyskinesis was rare and not related to the ablation target. No intracardiac thrombosis was observed.

CONCLUSIONS

Serious injury to cardiac valves due to RF ablation is very rare, but the tricuspid valve may be mildly affected in some cases. We identified no clear effect of RF ablation on cardiac wall motion or on left ventricular function.

Radiofrequency catheter ablation of left-sided accessory pathways in pediatric patients

In many cases, radiofrequency catheter ablation has replaced the long-term use of antiarrhythmic medication for symptomatic tachycardia, and has all but eliminated arrhythmia surgery. The most common substrate for radiofrequency catheter ablation in pediatric patients is atrioventricular (AV) reentry tachycardia due to a concealed or manifest accessory pathway. Accessory pathways are distributed unevenly along the right and left atrioventricular valve annuli, and left-sided accessory pathways are most common. Although some centers advocate an abbreviated diagnostic and mapping approach to both concealed and manifest left-sided accessory pathways, most still use a complete electrophysiological evaluation and complex catheter manipulation for mapping, followed by the application of radiofrequency energy. Left-sided accessory pathways may be approached from the transatrial approach, the retrograde aortic approach, or less commonly from within the coronary sinus. Each approach has proven to be associated with success, but also with a distinct set of risks. Possibly because left-sided accessory pathways are most common, catheter ablation of this substrate has proven highly successful and has the lowest risk of recurrence. However, recent data also suggest that this substrate is associated with greater risk of complications than of right-sided accessory pathways or pathways located in the posteroseptal region. The following report reviews some of the recently described diagnostic and mapping techniques, success rates, risks and follow-up data in pediatric patients undergoing radiofrequency catheter ablation of left-sided accessory pathways.