Management of Atrial Tachycardias in Patients with Congenital Heart Disease

Stychynskyi A. S., Almiz P. A., Topchii A. V., Plyska N. V., Pokanevitch A. V., Lozovyi O. A.

National Amosov Institute of Cardiovascular Surgery, Kyiv, Ukraine

Abstract. Atrial tachyarrhythmia is observed in 10% to 20% of adult congenital heart disease (CHD) and is associated with high morbidity, impaired quality of life and mortality.

The purpose of the study is to describe atrial tachycardia (AT) type, ablation success and follow-up.

Material and methods. A total of 50 ablations in 44 CHD patients were reviewed.

Results. Cavotricuspid isthmus – dependent flutter (CTI-F) was found in 30 patients, other types of reentrant AT mostly scar-related (Non CTI-F) – in 14 patients. In patients with CTI-F, as a result of ablation, sinus rhythm was restored in 23 of 30; in 7 patients CTI-F was transformed into another type of atrial reentry. Of 23 patients with restored sinus rhythm, 6 patients experienced another type of atrial reentry induced by rapid pacing. Non CTI-F terminated during ablation and was non-inducible in 13 of 14 patients; in 3 patients rapid pacing induced non-sustained atrial fibrillation and in one – CTI-F, which was successfully eliminated. Overall, acute success rate was 98%, with 100% for CTI-F and 96% for non CTI-F. There were 6 recurrences during the follow-up: in 3 cases it was AT previously ablated; in 3 cases – a different type of AT. All of them were successfully ablated after the second procedure. AT catheter ablation in patients with CHD is feasible, safe, with high success rate.

Keywords: atrial tachycardia, congenital heart disease, catheter ablation.

Thanks to the successes in cardiac surgery over the past decades, the number of survivors with congenital heart diseases (CHD) in the general population is increasing every year. Supraventricular tachycardia (SVT) is detected in individuals with CHD with a frequency of 10–20%, depending on the complexity of CHD included in the study and the length of the observation period [1]. The occurrence of these arrhythmias increases the risk of circulatory failure, strokes, sudden cardiac death. The most common types of SVT in CHD are atrial tachycardia (AT) with the macro-re-entry mechanism [1, 4]. The 2014 survey data indicate that the direct efficacy of catheter removal of atrial tachycardia is in the range of 65–96% (81% on average), and the recurrence rate of arrhythmias over a 5-year period is 34–54% [4]. Thus, we see that both the immediate and long-term results of AT catheter treatment in individuals with CHD are worse than in the treatment of other types of SVT in the absence of concomitant structural heart diseases.

The purpose of the work is to analyse the existing experience of catheter treatment of atrial macro-re-entry in adult patients with CHD.

Materials and methods. We used the data of 50 procedures for AT catheter removal in 44 patients with CHD, performed between January 01, 2008 and July 01, 2018. 26 patients had persistent arrhythmia with P wave morphology characteristic of cavo-tricuspid isthmus-dependent atrial flutter (CTI-F) with re-entry counter clockwise; in 18 – various morphology of the atrial wave. At the time of the procedure, 4 patients had a sinus rhythm, their arrhythmia was induced by stimulation.

The elimination of arrhythmias was preceded by the stage of electrophysiological diagnostics, which determined the mechanism of arrhythmia, the location of the substrate of arrhythmogenesis, as well as areas for radio frequency exposure. The methods of activation and substrate mapping were used in combination with various stimulation modes (pace mapping, determination of the post-stimulation interval, etc.).

Results and their discussion. In endocardial mapping, AT with re-entry through the cavotricuspid isthmus was detected in all patients with P-wave morphology characteristic of typical CTI-F, and in 4 with uncharacteristic morphology. As a result of applications in the cavotricuspid isthmus, the sinus rhythm was restored in 23 of 30 cases; in 7 cases there was a change in the cycle of tachycardia and morphology of the P wave. Further mapping showed a change in the re-entry front: in 6 cases, circulation occurred around the scar after atriotomy, in one – around the extensive zone with low-amplitude electrograms in the anterolateral zone of the right atrium. Drawing a line of applications between the scar and the tricuspid valve ring led to the cessation of arrhythmia. In 6 of 23 patients whose sinus rhythm was restored after applications in the cavotricuspid isthmus, tachycardia with a different P wave morphology and with re-entry around the scar after atriotomy was subsequently induced by frequent stimulation, and in one – focal tachycardia from the coronary sinus ostium. Of the 14 patients who were initially diagnosed with non CTI-F, in 12 cases the re-entry occurred around the scar after atriotomy, in one case – around the extensive area with low electrical activity and in one case around the patch on the interatrial septum. Ablation eliminated tachycardia in 13 of 14 patients of this subgroup. After restoration of the sinus rhythm by frequent stimulation, it was possible to induce unstable atrial fibrillation in 3 cases and in one case –CTI-F. In this patient, conduction block through the cavotricuspid isthmus was formed.

The catheter procedure eliminated arrhythmia in 43 (98%) of 44 patients. It should be noted that with applications in the cavotricuspid isthmus, in 7 (23%) of 31 cases it was possible to create conduction block only with the use of catheters with external cooling; when eliminating non CTI-F, the use of cooling catheters was required in 6 (22%) of 27 cases.

In all cases, pre- and postoperative complications were absent.

In the long term, recurrence of arrhythmias was observed in 6 (15%) patients. In 3 cases, it was recurrent arrhythmia, which was eliminated (isthmus-dependent CTI-F – 2, AT with circulation around the postoperative scar – 1), in 3 – arrhythmia with a different pattern of the re-entry. All these arrhythmias were finally eliminated during repeated procedures.

The analysis of the data shows that the most common type of AT in people with CHD is CTI-F. This trend is also noted by other researchers [3, 5]. The combination of different types of re-entry found in 32% of our patients is characteristic of CTI-F after correction of CHD [3-5]. The immediate efficacy of catheter removal of atrial macro-re-entry in CHD is quite high. It was 100% for CTI-F and 96% – for non CTI-F. At the same time, the relapse rate in the long term is also high. Therefore, after the elimination of the initial arrhythmia, a thorough check of the possibility of another arrhythmia is necessary. The question of the appropriateness of the prevention of potentially possible arrhythmias (for example, the creation of a block in the cavotricuspid isthmus in those patients who had only AT with circulation around the scar after atriotomy) needs to be considered.

Conclusions

1. Catheter treatment of AT in individuals who underwent surgical treatment of CHD is an effective and safe method.

2. After surgical correction of CHD, a combination of several variants for atrial macro-re-entries may occur.

References

1. 2015 ACC/AHA/HRS Guideline for the management of adult patients with supraventricular tachycardia: Executive summary. J. Am. Coll. Cardiol. 2015.

2. PACES/HRS Expert consensus statement on the recognition and management of arrhythmias in adult congenital heart disease. Canadian J. Cardiol. 2014;30:e1–e 63.

3. Wasmer K, Kцbe J, Dechering VG et al. Isthmus-dependent right atrial flutter as the leading cause of atrial tachycardias fter surgical atrial septal defect repair. Int.J.Cardiol. 2013;168:2447–52.

4. Lobo RG, Griffith M, De Bono J. Ablation of arrhythmias in patients with adult congenital heart disease. Arrhythm. Electrophysiol. Rev. 2014;3:36–39.

5. Arrhythmias in congenital heart disease: a positional paper of the EHRA, AEPCC, ESC, working group on congenital heart disease, endorsed by HRS,PACES, APHRS and SOLAECE. Europace. 2018;20:1719–20.

Published: March 2019