Pulsed field ablation for atrial fibrillation: acute procedural efficacy and safety of an initial German multicenter experience

Background

Pulsed field ablation (PFA) is a novel non-thermal energy source to conduct catheter ablation of atrial fibrillation (AF). However, real-world multi-center data regarding acute procedural efficacy and safety is sparse.

Purpose

To study acute procedural success and safety in patients undergoing PFA for catheter ablation of AF in a multicenter registry.

Methods

Consecutive paroxysmal and persistent AF patients undergoing PFA-based catheter ablation using a multispline catheter were enrolled. The cohort included first and repeat ablation procedures. Procedural parameters, acute success and in-hospital safety were evaluated. A follow-up of all patients was conducted.

Results

Five German centers enrolled a total of 154 patients undergoing PFA in this study. Mean age was 68±12 years, median CHA2DS2-VASc Score was 3 (Q1-Q3: 2–4).

Patients suffered from paroxysmal AF (n=55; 36%), persistent AF (n=93; 60%) and consecutive atrial tachycardias (AT) due to previous CA (n=6; 4%).

The median left atrial (LA) PFA and total procedure times were 33 (Q1-Q3: 24–53) and 90 (Q1-Q3: 73–116) minutes, respectively. Mean LA PFA fluoroscopy and total fluoroscopy times were 12.1±5.5 and 20.2±8.7 minutes. Of all 154 procedures, 130 (84%) were index ablation procedures with isolation of pulmonary veins (PVI) only and 24 (16%) were repeat procedures (including re-PVI and ablation of consecutive AT).

Acute PV reconnection following primary PVI and the initial set of PFA-applications was found in 20/130 (15%) patients, necessitating additional PFA ablation. Finally, successful PFA-guided PVI was achieved in all patients.

Additional PFA lesion sets (including LA posterior wall isolation, anterior ablation, mitral isthmus ablation) were applied in 17/154 (11%) patients.

Complications occurred in a total of 6/154 (3.8%) patients (including three groin site complications, two pericardial tamponades, one transient coronary spasm without sequela). The follow up data is still being assessed and will be provided by the time of the ESC 2022 meeting.

Conclusion

PFA performed in patients with atrial fibrillation demonstrates high acute procedural success rates and a favorable safety profile in this first real-world multicenter registry.

Funding Acknowledgement

Type of funding sources: None.

Prognosis of patients with and without septal substrate after VT ablation due to electrical storm

Funding Acknowledgements

Type of funding sources: None.

Background

Data about VT ablation in patients with electrical storm (ES) is limited. This study sought to compare the prognostic outcome of patients undergoing VT ablation after electrical storm with and without a septal substrate on mortality, VT recurrence rates, rehospitalization rates and major adverse cardiac events (MACE).

Methods

In this large single-centre study patients presenting with ES and undergoing VT ablation were included from June 2018 to April 2021. Patients with septal substrate were compared to patients without septal substrate. The primary prognostic outcome was cardiovascular mortality, secondary endpoints were VT recurrence rates, rehospitalization rates and MACE all after a median follow-up of 22 months.

Results

A total of 108 patients underwent a first VT ablation due to electrical storm and were included (65 ± 13 years; 86% male; 45% ischemic cardiomyopathy). Cardiovascular risk factors were equally distributed among both groups (all p>0.05). Major complications occurred in 11% of all patients with increased postinterventional third degree AV blocks among patients with septal substrate (9% vs 0%; p=0.062). Noninducibility of the clinical VT was achieved in 98% of all patients without a septal substrate and in 91% of all patients with a septal substrate (p=0.136). Noninducibility of any VT was achieved in 88% without a septal substrate and in 66% with a septal substrate (p=0.011). However, in non-invasive programmed stimulation before hospital discharge VT inducibility did not differ among both groups (p>0.05). After 1 year and a median of 22 months follow-up, patients with septal substrate died significantly more often due to cardiovascular causes (25% vs. 7%; log-rank p=0.021). In univariate analysis cardiovascular mortality for ES patients with septal substrate was 3.9 fold higher (HR 3.979; CI 95% 1.124 – 14.092; p=0.032). Independent predictors of adverse outcome in multivariable regression analysis were presence of septal substrate (HR 4.836; p=0.026) and increased numbers of VTs inducible during VT ablation (HR 1.635; p=0.007). VT recurrence during follow-up was 59% and equally distributed among both groups (log rank p=0.911). Rehospitalization rates (log rank p=0.532) and rates of MACE (log rank p=0.463) were equal.

Conclusions

Presence of a septal substrate is associated with adverse long-term cardiovascular mortality in patients admitted for VT ablation after electrical storm. Despite decreased ablation success in these patients VT recurrence rates were not increased during follow-up.

Efficacy and safety of VT ablation of electrical storm

Funding Acknowledgements

Type of funding sources: None.

Background

Data about VT ablation in patients with electrical storm (ES) is limited. This study sought to compare the prognostic outcome of patients with ES to those with ventricular tachyarrhythmias but without ES undergoing VT ablation on mortality, VT recurrence rates, rehospitalization rates and major adverse cardiac events (MACE).

Methods

In this large single-centre study patients presenting with ES and undergoing VT ablation from June 2018 to April 2021 were compared to patients undergoing VT ablation due to ventricular tachyarrhythmias but without ES. The primary prognostic outcome was cardiovascular mortality, secondary endpoints were VT recurrence rates, rehospitalization rates and MACE all after a median follow-up of 22 months.

Results

A total of 311 patients underwent a first VT ablation due to ventricular tachyarrhythmias and were included (63 ± 14 years; 86% male). Of them 108 presented with ES. In the ES cohort dilated cardiomyopathy as underlying heart disease was significantly increased (p=0.008), whereas all other cardiomyopathies were equally distributed. Major complications were equal among both groups (p>0.05). Ablation of the clinical VT was achieved in 95% of all patients without ES and in 94% of all patients with ES (p>0.05). Noninducibility of any VT was achieved in 91% without ES and in 76% with ES (p=0.001). This was also reflected in higher VT induction rates in non-invasive programmed stimulation before hospital discharge among ES patients (40% vs. 19%; p=0.031). After a median of 22 months of follow-up, patients with ES revealed slightly increased cardiovascular mortality rates (17% vs. 9%; log-rank p=0.061; HR 1.902; CI 95% 0.961 – 3.765; p=0.061). Furthermore, ES patients suffered from increased VT recurrence rates (59% vs. 40%; log rank p=0.006), rehospitalization rates (73% vs. 49%; log rank p=0.001) and MACE (71% vs. 45%; log rank p=0.001). ES patients displayed a 1.7-fold increased risk for VT recurrence (HR 1.701; CI 95% 1.160 – 2.493; p=0.006), a 1.9-fold increase for rehospitalization (HR 1.885; CI 95% 1.366 – 2.600; p=0.001) and a 1.9-fold increase for occurrence of MACE (HR 1.935; CI 95% 1.398 – 2.679; p=0.001). Presence of ES was the only independent predictors of VT recurrence and occurrence of MACE, whereas ES and decreased LVEF were independent predictors of rehospitalization.

Conclusions

VT ablation in patients with ES is challenging and these patients reveal highest risk for recurrent VTs, rehospitalization and MACE. These patients need close follow-ups and optimal guideline-directed therapy.

Acute safety and efficacy outcome of pulmonary vein isolation using pulsed field ablation technology

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pulsed field ablation (PFA) is a new technology for electrical isolation of pulmonary veins (PVI) using electroporation for irreversible cell death. First data imply a very low complication rate in terms of esophageal lesion, phrenic nerve palsy and pulmonary vein stenosis. We present our datas of our first patients concerning acute safety and efficacy.

Method

38 patients with paroxysmal and persistent atrial fibrillation (AF) consecutively underwent PFA ablation including complete PVI of all pulmonary veins in all cases (including 14 redo cases ), mean age 68,3 year, and a mean ejection fraction of 56 %, mean CHADSVASC Score 3. 19 patients had paroxysmal AF, in 21 patients additional posterior wall isolation was performed. Additional anatomical and voltage characterization with CARTO was performed before and after ablation. Post ablation, all patients underwent endoscopic evaluation of the esophagus and all eligible patients were screened for silent cerebral lesions (SCL) using cerebral magnetic resonance imaging (MRI). All acute procedure data and complications were documented.

Results

In all 38 patients effective PVI using only PFA catheter was achieved (100 %) within a mean procedure time of 81±15 min and a mean fluoroscopy time of 18± 5 min. In 2 patients left atrial macroreentrant tachycardia was effectively terminated with PFA pulses in the PV-mitral-annular isthmus region.

In no patient an esophageal lesion could be detected (0%). Cerebral MRI was performed in 18 cases and revealed SCLs (47 %) in 5 patients (3 patients with multiple lesions, 2 patiens with 3 lesions, max size of 8 mm). No symptomatic complications including pericardial effusion or access site complications were noted.

Conclusion

PFA is a highly effective method for acute PVI. No relevant symptomatic complications were noted. Of note, no patient had esophageal injury related to the ablation but 40% of patients undergoing post-ablation MRI had documented SCE. Further data have to be collected to discuss these findings properly.

[Epicardial VT ablation : In whom, when, how and why?]

Ventricular tachycardia (VT) is a leading cause of cardiovascular death and remains the main cause of sudden cardiac death. Implanted cardiac defibrillators (ICD) improve survival but the recurrent ICD therapies, mostly ICD shocks, are associated with an increased mortality and deleterious psychological effects. In this regard and based on the results of multicenter studies, the current European guidelines recommend early referral for catheter ablation. The ablation strategy (isolated endocardial approach or combined epi-/endocardial) depends mostly on the underlying myocardial disease. Thus, almost all patients with right ventricular dysplasia and Chagas disease, the majority of those with dilative cardiomyopathy, and some patients with ischemic cardiomyopathy (mostly posterior wall infarction or large transmural anterior wall infarction) have an epicardial scar as the underlying substrate for recurrent VT episodes. Thus, in this group of patients, isolated endocardial VT ablation may be associated with an increased VT recurrence and therefore an epicardial approach is also needed. Cardiac imaging (cardio-CT/MRI with late enhancement[MRI LE]) can reliably identify the distribution and characteristics of the myocardial scar and may be helpful in planning the ablation strategy. When performed in highly specialized centers, epicardial catheter ablation of VT leads to a significant reduction of recurrent VT episodes compared to the endocardial VT ablation alone and with lower complication rates.

[Epicardial ablation of ventricular tachycardias]

Ventricular tachycardias (VT) in patients with structural heart diseases have predominantly a scar-associated reentry mechanism so that substrate-based ablation approaches also have to be used in nearly all procedures. In many VT cases-especially in nonischemic cardiomyopathy (NICM) and arrhythmogenic right ventricular cardiomyopathy-a critical epicardial substrate can be identified as an essential component of the reentry circuit so that for the ablation-based modification of the substrate in these cases an epicardial approach is necessary. In cases of redo-VT ablation procedures in ischemic cardiomyopathy (after a previously endocardial ablation), an epicardial approach should also be considered. There are also cases in whom no endocardial substrate can be identified and an isolated epicardial substrate can be identified. Worldwide epicardial VT ablations are usually performed after gaining epicardial access using subxyphoidal puncture. The results of recent studies show a higher efficiency with stabilization of cardiac rhythm and reduction of recurrent VT episodes (about 70% event-free survival at the 2‑year follow-up) after endo-plus epicardial substrate modification. In electrical storm cases, an early epicardial VT ablation approach also appears to be relevant, especially in NICM. Epicardial instrumentation and ablation represents a complex procedure which should only be performed in experienced centers with cardiac surgery back-up. In these experienced centers, the complications rate is less than 5%.

[Recurrent hemoptysis as initial symptom of a thoracic angiomatosis in an adult patient]

HISTORY

A 24-year-old man presented with recurrent hemoptysis and decreased exercise capacity. DIAGNOSTIC FINDINGS: The chest radiograph demonstrated multiple disseminated pulmonary nodules. In addition the patient developed a hematopericardium with tamponade. The further diagnostic approach revealed an extensive thoracic angiomatosis affecting the lung and the heart.

TREATMENT AND COURSE

Tumor resection could not be performed. A therapy with Interferon alpha-2a was initiated. After 3 month a significant regression of the pulmonary angiomatosis was documented. On the other hand the cardiac tumor showed no therapeutic response.

CONCLUSION

Thoracic angiomatosis should be considered in the differential diagnosis of otherwise unclear hemoptysis or hematopericardium. Diagnosis intra vitamin requires an aggressive and invasive approach. Interferon alpha-2a is effective in palliative treatment of diffuse angiomatous diseases. But not all angiomatous processes respond to that therapy.