Catheter ablation of atrial arrhythmias in cardiac amyloidosis: Impact on heart failure and mortality.

BACKGROUND: Atrial arrhythmias (AA) commonly affect patients with cardiac amyloidosis (CA) and are a contributing risk factor for the development of heart failure (HF). This study sought to investigate the long-term efficacy and impact of catheter ablation on HF progression in patients with CA and AA. METHODS: Thirty-one patients with CA and AA undergoing catheter ablation were retrospectively included (transthyretin-ATTR CA 61% and light chain-AL CA 39%). AA subtypes included atrial fibrillation (AFib) in 22 (paroxysmal in 10 and persistent in 12), atrial flutter (AFl) in 17 and atrial tachycardia (AT) in 11 patients. Long-term AA recurrence rates were evaluated along with the impact of sinus rhythm (SR) maintenance on HF and mortality. RESULTS: AA recurrence was observed in 14 patients (45%) at a median of 3.5 months (AFib n = 8, AT n = 6, AFl = 0). Post-cardioversion, medical therapy or catheter ablation, 10 patients (32%) remained in permanent AA. Over a median follow-up of 19 months, all-cause mortality was 39% (n = 12): 3 with end-stage HF, 5 due to late complications of CA, 1 sudden cardiac death, 1 stroke, 1 COVID 19 (and one unknown). With maintenance of SR following catheter ablation, significant reductions in serum creatinine and natriuretic peptide levels were observed with improvements in NYHA class. Two patients required hospitalization for HF in the SR maintenance cohort compared to 5 patients in the AA recurrence cohort (p = 0.1). All 3 patients with deaths secondary to HF had AA recurrence compared to 11 out of the 28 patients whom were long-term survivors or deaths not related to HF (p = 0.04). All-cause mortality was not associated with AA recurrence. CONCLUSION: This study demonstrates moderate long-term efficacy of SR maintenance with catheter ablation for AA in patients with CA. Improvements in clinical and biological status with positive trends in HF mortality are observed if SR can be maintained.

Pulsed field ablation of spatiotemporal electrogram dispersion following pulmonary vein isolation and left atrial linear lesions for persistent atrial fibrillation: a case report.

Background: Ablation of persistent atrial fibrillation (AF) remains challenging, with atrial substrate modification often being performed as an adjunct to pulmonary vein isolation (PVI). Pulsed field ablation (PFA) is a novel ablation modality that carries a favourable safety profile, which could facilitate complex procedures. Case summary: We present the case of a 60-year-old male undergoing catheter ablation for symptomatic persistent AF. The procedure was performed with the Farapulse™ PFA system in a stepwise manner, including PVI and linear lesions for the isolation of the posterior left atrial wall and the ablation of the mitral isthmus. The final step of the procedure included the ablation of areas exhibiting spatiotemporal electrogram dispersion, identified with the help of artificial intelligence-based software (VX1, Volta Medical) in both atria. Sinus rhythm was restored after the abolition of an electrogram dispersion zone in the right atrium. The procedure was carried out without any complications. Discussion: Complex ablation procedures for persistent AF can be successfully performed with PFA. In the context of such extensive ablation strategies, PFA is an attractive energy source, given its non-thermal nature that is known to prevent damage to surrounding tissue and result in less chronic fibrosis. However, caution should be exercised to avoid excessive ablation when using the currently available multispline PFA catheter, as it may inadvertently target adjacent areas of healthy myocardium.

Case Report: A leadless and endovascular pacemaker teamwork.

Background: Cardiac Implantable Electronic Device infections increase short- and long-term mortality, along with healthcare costs. Leadless pacemakers (PM) were developed to overcome pocket- and minimize lead-related complications in selected high-risk patients. Recent advancements enable leadless devices to mechanically detect atrial activity, facilitating atrioventricular (AV) synchronous stimulation. Case summary: A 90-year-old woman, implanted with a dual-chamber pacemaker eight years ago due to sinus node dysfunction, presented with syncope. A diagnosis of complete AV block, in the setting of ventricular lead dysfunction was made. Due to a high risk of infection, the patient was implanted with a leadless PM capable of maintaining AV synchrony in VDD mode (MICRA™ model MC1AVR1). The transvenous PM was programmed to AAI-R mode to drive the atria, which, in turn, triggered the leadless PM to stimulate the ventricles. At six month follow-up, the AV synchrony rate was 85%. Conclusion: The combination of classic atrial pacing with leadless ventricular stimulation can be used in high-risk patients to reduce the risk of complications, in the setting of ventricular lead dysfunction. In this manner, AV synchrony can be maintained, improving hemodynamic parameters and quality of life. Low sinus rate variability at rest is essential to achieve a high AV synchrony rate in such cases.

Systematic use of half normal saline during ablation of ventricular tachycardia in structural heart disease.

BACKGROUND: Efficiency and safety of ablation using half normal saline (HNS) has been shown in refractory ventricular tachycardia (VT), but no evaluation in unselected larger populations has been made. OBJECTIVE: To evaluate the efficiency and safety of systematic HNS ablation in VT ablation. METHODS: All successive VT ablations in patients with structural heart disease from 2018 to 2021 used HNS in our center and were retrospectively included. RESULTS: One hundred seventy-seven successive VT ablation procedures using HNS have been performed in 148 patients (91% males, mean 64 ± 12 years, ischemic cardiomyopathy 64%, left ventricular ejection fraction 38 ± 13%). A mean of 19 ± 7.5 min of RF was delivered, with a mean power of 44 ± 7 W. Relevant complications happened in 9% (strokes 2%, tamponades 3%, atrioventricular block during septal ablations 5%). Over a mean follow-up of 15 ± 9 months, VT recurred in 46%. Final recurrence rate after one or several procedures was 36% (18 months follow-up). Number of VT episodes decreased from 14 ± 35 before to 2.5 ± 10 after ablation (p < .0001) and number of ICD shocks decreased from 4.8 ± 6.8 to 1.5 ± 0.8 (p = .027). CONCLUSION: Systematic use of HNS during VT ablations in patients with structural heart disease leads to long-term recurrences rates and complications in the range of what is reported using normal saline. Although controlled studies are needed for demonstrating the superiority of such attitude, the use of HNS in every scar-related VT ablation seems safe for standard cases and may be furthermore useful in case of refractory arrhythmias due to difficult-to-ablate substrates.

Pulsed-Field Ablation on Mitral Isthmus in Persistent Atrial Fibrillation: Preliminary Data on Efficacy and Safety.

BACKGROUND: Pulsed-field ablation (PFA) is a new and promising modality of ablation that has been shown to specifically ablate cardiac tissue while sparing other anatomic structures, thus avoiding thermal ablation-related complications. Recent studies have certified safety and efficacy of PFA for pulmonary vein isolation (PVI) in the setting of paroxysmal atrial fibrillation (AF). However, there are very limited data assessing the feasibility and safety of PFA ablation of different substrates within the left atrium in the setting of persistent AF. OBJECTIVES: The purpose of this study was to evaluate the feasibility and safety of mitral isthmus (MI) ablation in addition to PVI and posterior wall (PW) ablation with PFA in patients with persistent AF. METHODS: We prospectively included all consecutive patients with persistent AF who underwent a first ablation procedure with PFA. We performed in all these patients a substrate ablation strategy comprising PVI, PW, and MI ablation with the use of PFA only. The primary feasibility endpoint was obtaining a persistent MI block at the end of the procedure. The safety endpoint was a composite of major safety events. RESULTS: From November 2021 to September 2022, we included 45 patients. Complete MI block was achieved in all 45 (100%). Three patients presented with complications, among them 2 cases (4.4%) of reversible and nonfatal coronary spasm. During a mean follow-up time of 107.8 ± 59.5 days, a 20% recurrence rate was observed. CONCLUSIONS: PFA is a feasible and safe ablation approach for mitral isthmus ablation in addition to PVI in patients with persistent AF.

Hemodynamical consequences and tolerance of sustained ventricular tachycardia.

AIMS: Factors underlying clinical tolerance and hemodynamic consequences of monomorphic sustained ventricular tachycardia (VT) need to be clarified. METHODS: Intra-arterial pressures (IAP) during VT were collected in patients admitted for VT ablation and correlated to clinical, ECG and baseline echocardiographical parameters. RESULTS: 114 VTs from 58 patients were included (median 67 years old, 81% ischemic heart disease, median left ventricular ejection fraction 30%). 61 VTs were untolerated needing immediate termination (54%). VT tolerance was tightly linked to the evolution of IAPs. Faster VT rates (p<0.0001), presence of resynchronization therapy (p = 0.008), previous anterior myocardial infarction (p = 0.009) and more marginally larger baseline QRS duration (p = 0.1) were independently associated with VT tolerance. Only an inferior myocardial infarction was more often present in patients with only tolerated VTs vs patients with only untolerated VTs in multivariate analysis (OR 3.7, 95% CI 1.4-1000, p = 0.03). In patients with both well-tolerated and untolerated VTs, a higher VT rate was the only variable independently associated with untolerated VT (p = 0.02). Two different patterns of hemodynamic profiles during VT could be observed: a regular 1:1 relationship between electrical (QRS) and mechanical (IAP) events or some dissociation between both. VT with the second pattern were more often untolerated compared to the first pattern (78% vs 29%, p<0.0001). CONCLUSION: This study helps to explain the large variability in clinical tolerance during VT, which is clearly related to IAP. VT tolerance may be linked to resynchronization therapy, VT rate, baseline QRS duration and location of myocardial infarction.

Correlations Between Endocardial Voltage Mapping, Diagnosis, and Genetics in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

The relations between endocardial voltage mapping and the genetic background of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have not been investigated so far. A total of 97 patients with proved or suspected ARVC who underwent 3-dimensional endocardial mapping and genetic testing have been retrospectively included. Presence, localization, and size of scar areas were correlated to ARVC diagnosis and the presence of a pathogenic variant. A total of 78 patients (80%) presented with some bipolar or unipolar scar on endocardial voltage mapping, whereas 43 carried pathogenic variants (44%). Significant associations were observed between presence of endocardial scars on voltage mapping and previous or inducible ventricular tachycardia, right ventricular function and dimensions, or electrocardiogram features of ARVC. A total of 60 of the 78 patients (77%) with an endocardial scar fulfilled the criteria for a definitive arrhythmogenic right ventricular dysplasia diagnosis versus 8 of 19 patients (42%) without scar (p = 0.003). Patients with a definitive diagnosis of ARVC had more scars from any location and the scars were larger in patients with ARVC. In the 68 patients with a definitive diagnosis of ARVC, the presence of any endocardial scar was similar whether an ARVC-causal mutation was present or not. Only scar extent was significantly greater in patients with pathogenic variants. There was no difference in the presence and characteristics of scars in PKP2 mutated versus other mutated patients. The 3-dimensional endocardial mapping could have an important role for refining ARVC diagnosis and may be able to detect minor forms with otherwise insufficient criteria for diagnosis. The trend for larger scar extent were observed in mutated patients, without any difference according to the mutated genes.

Radiation dose during catheter ablation in children using a low fluoroscopy frame rate.

BACKGROUND: Catheter ablation (CA) in children using fluoroscopy carries risks inherent to ionizing radiation exposure. AIMS: The objective of this study was to demonstrate the feasibility of using low frames rate during ablation in children to maximally decrease radiation dose. METHODS: Hundred sixty eight successive patients<18 years of age undergoing CA performed under a 3.75 frames/second rate were retrospectively included. Demographics, procedural and dosimetry data were analysed. The effective dose (ED) was evaluated in a subgroup of 14 patients. RESULTS: Median age and weight were 15 years and 54kg, 72% had WPW, 10% AV node reentrant tachycardia, 10% ventricular tachycardia (atrial tachycardia, flutter and atrial fibrillation for the other cases). Acute success was achieved in 98.5% without any complication. Median procedure and fluoroscopy duration were 120 and 16minutes. Median Dose Area Product (DAP) and Air Kerma were 2.46Gy.cm2 and 18 mGy respectively (2Gy.cm2 and 15 mGy for WPW ablation). A significant reduction of median DAP was noted over the years for WPW, from 3.1Gy.cm2 in 2011 to 1.4 in 2019. Median estimated ED was 0.19 mSv (0.03 to 1.64), falling into the range of yearly normal natural irradiation or caused by leasure or professional activity. CONCLUSION: Low frame rate fluoroscopy is a highly effective and safe approach in decreasing radiation exposure during CA in children without altering the success rate of the procedure. ED is low, similar to natural/leisure irradiation. This approach can be considered a good alternative to 3D-based procedures in terms of efficiency and radiation issues, at least for WPW ablations.

Relationships between left ventricular mass and QRS duration in diverse types of left ventricular hypertrophy.

AIMS: Hypertrophic cardiomyopathy (HCM) may be associated with very narrow QRS, while left ventricular hypertrophy (LVH) may increase QRS duration. We investigated the relationships between QRS duration and LV mass (LVM) in subtypes of abnormal LV wall thickness. METHODS AND RESULTS: Automated measurement of LVM on MRI was correlated to automated measurement of QRS duration on ECG in HCM, left ventricular non compaction (LVNC), left ventricular hypertrophy (LVH), and controls with healthy hearts. Uni and multivariate analyses were performed between groups including explanatory variables expected to influence LVM and QRS duration. The relationships between QRS duration and LVM were further studied within each group. Two hundred and twenty-one HCM, 28 LVNC, 16 LVH, and 40 controls were retrospectively included. Mean QRS duration was 92 ms for HCM, 104 for LVNC, 110 for LVH, and 92 for controls (P < 0.01). Mean LVM was 100, 90, 108, and 68 g/m2 (P < 0.01). QRS duration, LVM, hypertension, maximal wall thickness, and late gadolinium enhancement were significantly linked to HCM in multivariate analysis (w/wo bundle branch block). An independent negative correlation was found between LVM and QRS duration in the HCM group, while the relationship was reverse in LVNC, LVH, and controls. CONCLUSION: QRS duration increases with LVM in LVNC, LVH, or in healthy hearts, while reverse relationship is present in HCM. These relationships were independent from other parameters. These results warrant additional investigations for refining diagnosis criteria for HCM in the future.

Premature Ventricular Contractions and Ultra-High-Definition Mapping. Contribution and Limits.

BACKGROUND: The utility of ultra-high definition mapping (UHDM) for ablation of premature ventricular contractions (PVC) remains undetermined. The aim of this study was to investigate UHDM for PVC ablation, and additionally to compare to conventional technique. METHODS: Twenty patients investigated using UHDM were prospectively included and analyzed. Electrophysiological caracteristics and results were compared to 40 patients ablated using fluoroscopy only. RESULTS: 2541±2033 EGMs and 331±240 PVC beats were recorded for each patient. Surfaces of isochronal activations were 2.3±1.7 and 6.9±6.1 cm2 (first 10 and 20 ms). Local scar was present in 40% and local block in 65%. Areas of pace-mapping > 95, 90 and 85% concordance were 1.5±3.4, 2.1±3.9 and 3.3±5 cm2. Mean distance between the ablation site and the site of best pace-mapping or of earliest activation was 8±8 mm and 5±7 mm. Pre-potential was noted in 17% vs 26% controls (ns). QS pattern was present in 83% vs 83% controls (ns), and earliest activation was - 31±50 vs - 25±14 ms in controls (ns). Procedure (100±36 vs 190±51 min, p< 0.0001) and fluoroscopy duration (15±9 vs 24±9 min, p=0.005) were shorter in controls. Acute success was achieved in 65% patients with UHDM and in 72% controls (p=ns) with lower residual PVC burden in the control group. Over a follow-up of 19±12 months, long-term success was similar between groups (65 vs 68%). CONCLUSIONS: UHDM may reveal poorly recognized activation features and PVC mechanism. In this series, conventional mapping was quicker and did clinically as well as UHDM.

Successful Reversal of Severe Tachycardia-Induced Cardiomyopathy with Cardiogenic Shock by Urgent Rhythm or Rate Control: Only Rhythm and Rate Matter.

Background and objectives Severe forms of Tachycardia-induced cardiomyopathy (TIC) with cardiogenic shock are not well described so far, and efficiency of catheter ablation in this setting is unknown. Methods We retrospectively included consecutive patients admitted to the Intensive Cardiac Care Unit for acute heart failure with cardiogenic shock associated with atrial arrhythmia and managed by ablation. Result Fourteen patients were included, each with cardiogenic shock and two needing the use of extracorporeal membrane oxygenation. Successful ablation was performed in the acute setting or over the following weeks. Two patients experienced relapses of arrhythmias and were treated by new ablation procedures. At 7.5 ± 5 months follow-up, all patient were alive with stable sinus rhythm. The left ventricular Ejection Fraction dramatically improved (21 vs. 54%, p = 0.001) as well as the end-diastolic left ventricular diameter (61 vs. 51 mm, p = 0.01) and NYHA class (class IV in all vs. median 1, p = 0.002). Conclusion Restoration and maintenance of sinus rhythm in severe TIC with cardiogenic shock and atrial arrhythmias lead to a major increase or normalization of LVEF, reduction of ventricular dimensions, and improvement in functional status. Ablation is efficient in long-term maintenance of sinus rhythm and may be proposed early in refractory cases.

Creation of sinus rhythm and paced maps using a single acquisition step: the "one acquisition-two maps" technique-a feasibility study.

PURPOSE: Scars and abnormal electrograms may significantly differ according to the activation wavefront. We propose a new fast technique for reliable comparison between sinus rhythm and ventricular pacing using a single map acquisition and the Rhythmia™ 3D mapping system. METHODS: A special programming of the external stimulator was assuring full stable regular paced-beat bigeminy during spontaneous rhythm. A first map was acquired for the spontaneous cardiac beat. Then the window of detection was moved to the following paced beat, and a second map was available after recalculation by the system, depicting activation and voltage of the paced cardiac beat at the same locations, with an exactly the same number of beats in both maps. RESULTS: Thirty patients with structural heart disease referred for ablation of ventricular tachycardia underwent this protocol, who were compared with 19 similar patients undergoing repeated maps. Duration of the mapping was significantly shorter compared to controls (34 ± 12 vs 57 ± 14 min, p < 0.0001) without differences in the number of electrograms (6978 ± 7067 vs 9554 ± 4424 for sinus rhythm map and 6610 ± 7240 vs 7783 ± 3804 for paced map, p = ns for both). The technique cannot be completed in five patients (17%), because of arrhythmogenicity, mechanical right bundle branch block, hemodynamical impairment, or bradycardia. CONCLUSION: We propose a novel technique for performing maps during sinus rhythm and ventricular pacing using a single acquisition. Beside time saving, this will allow more strict comparisons between different activation wavefronts.

Long-Lasting Ventricular Fibrillation in Humans ECG Characteristics and Effect of Radiofrequency Ablation.

BACKGROUND: Studies of ventricular fibrillation (VF) in humans are limited because of the short available duration. We sought to study surface ECG waveforms and effect of ablation in long-lasting VF in patients with left assist devices. METHODS: Continuous 12-lead ECG of 5 episodes of long-lasting VF occurring in 3 patients with left ventricular assist device were analyzed. Spectral analysis (dominant frequency) and quantification of waveform amplitude, regularity (Unbiased Regularity Index), and complexity (Nondipolar Index) were performed over a median of 24 minutes of VF. Radiofrequency ablation was performed during VF in 2 patients. RESULTS: There was a significant increase in dominant frequency between VF onset and termination but none of the other parameters significantly changed. Some VF parameters varied from patient to patient and from lead to lead. Dominant frequency decreased after radiofrequency ablation in both cases and VF terminated spontaneously shortly after ablation in one case. The previously incessant VFs in these 2 patients did not recur afterward. CONCLUSIONS: VF rate increases over time in patients with left ventricular assist devices and is lowered by ablation. Long-lasting VF may be modified or even terminated by ablation.

Coagulation and heparin requirements during ablation in patients under oral anticoagulant drugs.

BACKGROUND: Anticoagulation during catheter ablation should be closely monitored with activated clotting time (ACT). However vitamin K antagonists (VKA) or direct oral anticoagulant drugs (DOAC) may act differently on ACT and on heparin needs. The aim of this study was to compare ACT and heparin requirements during catheter ablation under various oral anticoagulant drugs and in controls. METHODS: Sixty consecutive patients referred for ablation were retrospectively included: group I (n = 15, VKA), group 2 (n = 15, uninterrupted rivaroxaban), group 3 (n = 15, uninterrupted apixaban), and group 4 (n = 15, controls). Heparin requirements and ACT were compared throughout the procedure. RESULTS: Heparin requirements during the procedure were significantly lower in patients under VKA compared to DOAC, but similar between DOAC patients and controls.Activated clotting time values were significantly higher in patients under VKA compared to DOAC and similar in DOAC patients versus controls. Furthermore, anticoagulation control as evaluated by the number/proportion of ACT> 300 as well as the time passed over 300 seconds was significantly better in patients under VKA versus DOAC, without significant differences between DOAC and controls. Finally, the number of patients/ACT with excessive ACT values was significantly higher in VKA versus DOAC patients versus controls.There was no significant difference between rivaroxaban and apixaban for ACT or heparin dosing throughout the procedure. CONCLUSION: Vitamin K antagonists allowed less heparin requirement despite reaching higher ACT values and more efficient anticoagulation control (with more excessive values) compared to patients under DOAC therapy and to controls. There was no difference in heparin requirements or ACT between DOAC patients and controls.

Chest pain in Brugada syndrome: Prevalence, correlations, and prognosis role.

BACKGROUND: Brugada syndrome (BrS) is sometimes diagnosed because of chest pain. Prevalence and characteristics of such BrS patients are unknown. METHODS: A total of 200 BrS probands were retrospectively included. BrS diagnosis made because of chest pain (n = 34, 17%) was compared to the other ones. RESULTS: BrS probands with diagnosis because of chest pain had significantly more often smoker habits, increased body mass index, and familial history of coronary artery disease but less frequently previous resuscitated sudden death/syncope or atrial fibrillation. Presence of coronary spasm and familial coronary artery disease were independently associated with BrS diagnosed because of chest pain. They presented more often with spontaneous type 1 ST elevation (59% vs 26%, P = .0004) and higher ST elevation during the episode of chest pain compared to other patients or compared to baseline electrocardiogram after chest pain resumption. ST elevation during chest pain was lower compared to ajmaline test. A total of 20% of them had significant coronary artery disease and four (11%) had coronary spasm, and they experienced more often recurrent chest pain episodes (24% vs 5%, P = .0002). Presence of chest pain at BrS diagnosis was not correlated to future arrhythmic events in univariate analysis. Only previous sudden cardiac death (SD)/syncope and familial SD were still significantly associated with outcome in multivariate analysis. CONCLUSION: Chest pain is a common cause for BrS diagnosis, although major part is not apparently explained by ischemic heart disease. Mechanisms leading to chest main remain unknown in the other ones. ST elevation is higher in this situation but does not seem to carry poor prognosis.

Feasibility of fast ventricular tachycardia mapping using the Rhythmia ™ system in a patient with an Impella ™.

Use of 3D navigation systems may be sometimes impossible in patients with left ventricular assist devices because of major electromagnetical interferences with some 3D systems based on magnetic localization. Mapping with the Rhythmia ™ system in patients implanted with an Impella ™ is described to be non feasible. We relate how to overcome this technical issues in this case.