Mechanism of Atrial Flutter Occurring Late After Orthotopic Heart Transplantation with Atrio-atrial Anastomosis

Frequency, Risk Factors, and Clinical Outcomes of Late-Onset Atrial Flutter in Patients after Heart Transplantation

Aims: Atrial flutter (AFL) is a common late-onset complication after heart transplantation (HTX) and is associated with worse clinical outcomes. Methods: This study investigated the frequency, risk factors, and outcomes of late-onset post-transplant AFL. We analyzed 639 adult patients undergoing HTX at the Heidelberg Heart Center between 1989 and 2019. Patients were stratified by diagnosis and type of late-onset post-transplant AFL (>90 days after HTX). Results: A total of 55 patients (8.6%) were diagnosed with late-onset post-transplant AFL, 30 had typical AFL (54.5%) and 25 had atypical AFL (45.5%). Patients with AFL were younger at HTX (p = 0.028), received more biatrial anastomosis (p = 0.001), and presented with moderate or severe tricuspid regurgitation (56.4%). Typical AFL was associated with graft rejection (p = 0.016), whereas atypical AFL was associated with coronary artery disease (p = 0.028) and stent implantation (p = 0.042). Patients with atypical AFL showed a higher all-cause 1-year mortality (p = 0.010) along with a higher rate of graft failure after diagnosis of AFL (p = 0.023). Recurrence of AFL was high (83.6%). Patients with catheter ablation after AFL recurrence had a higher 1-year freedom from AFL (p = 0.003). Conclusions: Patients with late-onset post-transplant AFL were younger at HTX, received more biatrial anastomosis, and showed a higher rate of moderate or severe tricuspid regurgitation. Typical AFL was associated with graft rejection, whereas atypical AFL was associated with myocardial ischemia, graft failure, and mortality. Catheter ablation represents a viable option to avoid further episodes of late-onset AFL after HTX.

Catheter ablation of organized atrial arrhythmias in orthotopic heart transplantation

BACKGROUND

Organized atrial arrhythmias (OAAs) are common after orthotopic heart transplantation (OHT). Some controversies remain about their clinical presentation, relationship with atrial anastomosis and electrophysiologic features. The objectives of this retrospective study were to determine the mechanisms of OAAs after OHT and describe the outcomes of radiofrequency catheter ablation (RFCA).

METHODS

Thirty consecutive transplanted patients (mean age 48 ± 17 years, 86.6% male) underwent 3-dimensional electroanatomic mapping and RFCA of their OAA from 2004 to 2012 at our center.

RESULTS

Twenty-two patients had biatrial anastomosis and 8 had bicaval anastomosis. Macro-reentry was the arrhythmia mechanism for 96% of patients. The electrophysiologic diagnoses were: cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) in 93% of patients (n = 28); perimitral AFL in 3% (n = 1); and focal atrial tachycardia (FAT) in 3% (n = 1). In 5 patients with biatrial anastomosis, a right FAT was inducible. Primary RFCA success was obtained in 93% of patients. Mean follow-up time was 39 ± 26.8 months. Electrical repermeation between recipient and donor atria, present in 20% of patients (n = 6), did not account for any of the OAAs observed. Survival without OAA relapse at 12, 24 and 60 months was 93%, 89% and 79%, respectively.

CONCLUSIONS

CTI-dependent AFL accounted for most instances of OAA after OHT, regardless of anastomosis type. Time from transplantation to OAA was shorter with bicaval than with biatrial anastomosis. RFCA was safe and provided good long-term results.

Supraventricular arrhythmias late after orthotopic cardiac transplantation: electrocardiographic and electrophysiological characterization and radiofrequency ablation

AIMS

Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrhythmias are increasingly recognized and associated with significant morbidity and mortality. We aim to describe the clinical and electrophysiological characteristics of patients with atrial arrhythmias occurring late after CTX.

METHODS AND RESULTS

Sixteen patients with prior CTX who presented with late atrial arrhythmias for electrophysiological studies (EPS) were identified at two cardiac transplant centres. Among 859 patients, 16 (mean age 52 ± 14 years, 11 of 16 were men) patients underwent EPS for atrial arrhythmias presenting 8.6 ± 5.7 years following CTX. Among 16 patients, 14 underwent cardiac alone and 2 included lung transplantation. There were no cases of cardiac rejection. Arrhythmias were due to counterclockwise cavotricuspid-dependent atrial flutter (AFL) in 10 of 16, atrial tachycardia (AT) in 6 (1 patient had AFL and AT), and 1 due to atrioventricular nodal re-entrant tachycardia. Recipient-donor atrial electrical connection was seen in two of six AT and in no cases of AFL. In two cases, a focal AT was mapped to the remnant atrium conducting 2 : 1 or at variable block to the donor atrium. In four cases a focal/micro re-entrant AT originated within the vicinity of the interatrial suture scar. All cases were successfully ablated with radiofrequency energy; however, one case of AFL required a repeat ablation. Patients remained free of arrhythmia at 34 ± 15 months post-ablation.

CONCLUSION

Typical AFL and AT are the most frequent supraventricular arrhythmias occurring late following CTX. Focal ATs may originate in low-voltage or border zones immediately adjacent to the atrio-atrial anastomosis. Radiofrequency ablation is an effective treatment strategy with high long-term success.

Atrial flutter after heart transplantation: mechanism and catheter ablation

BACKGROUND

Atrial flutter is a frequent arrhythmia after heart transplantation, but little is known about its mechanism and treatment. We report the results of an electrophysiologic study in patients with atrial flutter after orthotopic heart transplantation, describing its mechanism and demonstrating the acute and long-term efficacy of catheter ablation for treating this arrhythmia.

METHODS

We included 14 patients with symptomatic atrial flutter after orthotopic heart transplantation. All of them underwent an electrophysiologic study to determine the mechanism of the arrhythmia and catheter ablation when possible.

RESULTS

Counterclockwise right atrial circuit around the tricuspid annulus involving the cavotricuspid isthmus was demonstrated in 13 patients (86%). Catheter ablation of the isthmus was performed with good acute results in all but 1. During a mean follow-up of 24 ± 17 months, recurrent atrial flutter was documented in 3 patients and atrial fibrillation in 2. In another patient, we demonstrated a left atrial origin.

CONCLUSIONS

The most common mechanism of atrial flutter in heart transplant recipients is a counterclockwise circuit around the tricuspid annulus involving the cavotricuspid isthmus. Catheter ablation of the isthmus between tricuspid annulus and posterior atrial suture line represents an effective treatment in these patients. This condition may be avoided by changing the surgical technique to a bicaval anastomosis.

Supraventricular tachycardia after orthotopic cardiac transplantation

OBJECTIVES

The purpose of this study was to define the incidence, mechanisms, and management, including catheter ablation, of supraventricular tachycardia (SVT) in a large series of patients after orthotopic heart transplantation (OHT).

BACKGROUND

Supraventricular arrhythmias are frequently encountered after OHT, but their characteristics in this population have not been well established.

METHODS

We analyzed the incidence, clinical course, and management of SVTs in a cohort of 729 adult patients who underwent OHT. Furthermore, the mechanisms of arrhythmias among the patients referred for electrophysiological study (EPS) and ablation were also characterized.

RESULTS

The most common arrhythmia was atrial flutter, which occurred in 9% of this cohort. Persistent or paroxysmal atrial fibrillation occurred in 7%, the majority (57%) in the perioperative period. Persistent or paroxysmal atrial fibrillation was observed in OHT patients, beyond the post-operative period, only in the presence of rejection or transplant vasculopathy. Other persistent or paroxysmal SVTs were seen in 47 stable OHT patients (7%). Of these, 24 patients (4%) underwent EPS. Accessory and dual atrioventricular nodal pathways in the donor heart caused SVT in 3 patients. Macro-reentrant atrial tachycardia was seen in 7 patients, and isthmus-dependent atrial flutter occurred in 14 patients.

CONCLUSIONS

The majority of SVTs in stable OHT patients can be attributed to macro-reentrant tachycardias (flutter and scar reentry). Catheter ablation is effective in management of these SVTs. Atrial fibrillation was never encountered in stable patients in our series, and its occurrence should prompt an evaluation for acute rejection and/or vasculopathy.