Pulsed field ablation for paroxysmal atrial fibrillation with mitral and cavotricuspid isthmus­dependent atrial flutter: A case report.

Pulsed field ablation (PFA), a nonthermal ablative mechanism, has been proven to be effective and safe in clinical application. To date, PFA has been used for only atrial fibrillation (AF) ablation in limited clinical trials. The present study describes a case of paroxysmal AF in which mitral and cavotricuspid isthmus (CTI)-dependent atrial flutter was discovered incidentally during PFA operation and successfully ablated with PFA. This is the first medical record of PFA for AF combined with mitral and CTI atrial flutter. The present case report revealed that PFA can be independently used to treat complex arrhythmias, similar to radiofrequency (RF) ablation, without the need for assistance from other ablation methods. Concurrently, the present study, to the best of the authors' knowledge is the first to report a case using a point-to-point PFA ablation strategy for isthmus ablation. This highlights the potential of PFA in treating diverse arrhythmias across different regions, such as the mitral isthmus and other intricate areas, utilizing a point-to-point PFA ablation strategy.

Sinoatrial node function and the role of sinoatrial conduction in the typical atrial flutter substrate.

BACKGROUND: Sinoatrial node (SAN) activation and sinoatrial conduction pathways (SACPs) have been assessed in animals, but not humans. OBJECTIVES: We used ultra-high density (UHD) mapping and simulated models to characterise the SAN and investigate whether slowed SAN conduction may contribute to the atrial flutter (AFL) substrate. METHODS: Twenty-seven patients undergoing electrophysiological procedures underwent right atrial (RA) mapping. SAN activation patterns and conduction block were analysed. The interaction between the SAN and the intercaval line of block (LOB) was analysed, and RA simulations with different degrees of block were created to investigate arrhythmia mechanisms. RESULTS: Fifteen AFL and 12 reference patients were enrolled. SACPs were identified in all patients with sinus rhythm maps. An SAN-adjacent LOB was observed in AFL patients. SAN conduction velocity (CV) was slower in AFL vs reference (0.60m/s [0.56-0.78m/s] vs 1.13m/s [1.00-1.21m/s], p=0.0021). Coronary sinus paced maps displayed an intercaval LOB in AFL patients but not reference, which was completed superiorly by the SAN-adjacent LOB. Corrected sinus node recovery time (cSNRT) was longer in AFL patients (552.3±182.9ms vs 325.4±138.3ms, p<0.0060) and correlated with degree of intercaval block (r=0.7236, p=0.0003). Computer modelling supported an important role of SAN-associated block in the flutter substrate. CONCLUSIONS: UHD mapping accurately identifies SAN activation and SACPs. The LOB important for typical AFL was longer in AFL patients, and when partial, always present inferiorly, and completed superiorly due to slowed conduction across the SAN. cSNRT correlated with intercaval block, suggesting a role for SAN disease in the genesis of the typical AFL substrate.

Two distinct stages and mechanisms of ST-elevation during cryothermal cavotricuspid isthmus ablation guided by intracardiac echocardiography: A case report.

Radiofrequency (RF) catheter ablation is the primary treatment for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), with cryothermal energy as an alternative. While cryoablation offers comparable effectiveness and safety to RF ablation, it poses a risk of coronary artery spasm leading to ST-elevation. This case report presents a 65-year-old man with drug-refractory atrial fibrillation (AF) and AFL undergoing cryothermal CTI ablation guided by intracardiac echocardiography (ICE). During the procedure, two distinct ST-elevation episodes were observed. The first episode coincided with the pull-down of the cryoablation catheter, potentially resulting in coronary compression, as indicated by ICE, and was rapidly resolved by discontinuing the freezing process. The second episode, occurring without active freezing, was attributed to coronary artery spasm and resolved with intracoronary nitroglycerin administration. During the second episode, emergent right coronary angiography confirmed total occlusion in the segment 4 AV adjacent to the region where cryoablation was performed, which fully resolved post-nitroglycerin. This report underscores the dual mechanisms of ST-elevation-coronary artery compression and spasm-during cryothermal CTI ablation, highlighting the critical role of ICE in enhancing procedural safety.

Recurrent atrial flutter after radiofrequency ablation for atrial fibrillation in a patient with hypertrophic obstructive cardiomyopathy undergoing repetitive transcoronary ablation of septal hypertrophy.

INTRODUCTION: We described the clinical characteristics of a patient with hypertrophic obstructive cardiomyopathy (HOCM) who had undergone transcoronary ablation of septal hypertrophy (TASH) twice and developed atrial flutter after radiofrequency ablation for atrial fibrillation (AF) due to pulmonary vein reconnection. This case of HOCM is unique because of its complex complications and multiple complex atrial arrhythmias. The treatment of HOCM was successful and the postoperative follow-up results was good. METHODS AND RESULTS: A 71-year-oldfemale, developed exertional dyspnea with palpitations 12 years ago, with a valid diagnosis of HOCM according to the echocardiography which showed an absolute increase in the interventricular septum thickness (22.8 mm). She underwent two rounds of TASH and only the second round was successful. During a visit due to recurrent palpitations, the patient was diagnosed with AF based on electrocardiographic examination. Circumferential pulmonary vein isolation (CPVI) was performed to treat AF. However, the recurrence of atrial flutter was detected on her electrocardiograms (ECGs) three years after the operation. Since the patient had an interstitial lung injury, there were relative contraindications for antiarrhythmic drugs. Due to restrictive use of antiarrhythmic drugs and continuous palpitation, the patient agreed to receive a second radiofrequency ablation. Left-sided macroreentrant circuits were identified via high-density mapping and successful ablation was performed at the isthmus. CONCLUSIONS: Performing catheter ablation and TASH respectively in patients with HOCM associated with AF would be tricky. But taking such a comprehensive and respective clinical treatment would be beneficial to patients in the long term.

Evaluation of posterior mitral isthmus ablation in the absence of a vein of Marshall.

BACKGROUND AND AIMS: Achieving acute and durable mitral isthmus (MI) block remains challenging using radio frequency (RF)-catheter ablation alone. Vein of Marshall (VoM) ethanolisation results in chemical damage along the mitral isthmus resulting in the creation of a durable transmural lesion with a very high rate of procedural block. However, no studies have systematically assessed the efficacy of MI ablation alone when no anatomical VoM is present. METHODS: Thirty seven patients without VoM evidenced after careful angiographic examination were included. Ablation parameters and result were compared to a matched control group in whom the posterior MI line was performed without assessing the presence of the VoM. RESULTS: MI block was achieved in 36 out of 37 patients without VoM (97%), with endocardial ablation only in 5/37 (14%) and combined endocardial and CS ablation in 32/37 patients (86%). There was a significant difference in occurrence of block between patients without a VoM and the control group (97,3% vs. 65% respectively, p<0,01), with a trend towards less needed RF (26 (IQR 20-38) vs 29 (IQR 19-40) tags (p=0.8), 611 (IQR 443-805) vs 746 (IQR 484-1193) seconds (p=0.08)). CONCLUSION: The absence of a Vein of Marshall is associated with a very high rate of procedural block during posterior mitral isthmus ablation. The higher rate of MI block in this specific population would also suggest the crucial role of the Vein of Marshall (when present) in resistant MI block.

Multielectrode Catheter-Based Pulsed Field Ablation of Persistent and Long-Standing Persistent Atrial Fibrillation.

BACKGROUND AND AIMS: Rhythm control of non-paroxysmal atrial fibrillation (AF) is significantly more challenging, as a result of arrhythmia perpetuation promoting atrial substrate changes and AF maintenance. We describe a tailored ablation strategy targeting multiple left atrial (LA) sites via a pentaspline pulsed field ablation (PFA) catheter in persistent AF sustained beyond 6 months (PerAF>6m) and long-standing persistent AF (LSPAF). METHODS: The ablation protocol included the following stages: pulmonary vein antral and posterior wall isolation plus anterior roof line ablation (Stage 1); electrogram-guided substrate ablation (Stage 2); atrial tachyarrhythmia regionalization and ablation (Stage 3). RESULTS: Seventy-two [age:68±10years, 61.1%males; AF history: 25 (18-45) months] patients with PerAF>6m (52.8%) and LSPAF (47.2%) underwent their first PFA via the FarapulseTM system. LA substrate ablation (Stage 1 and 2) led to AF termination in 95.8% of patients. AF organized into a left-sided atrial flutter (AFlu) in 46 (74.2%) patients. The PFA catheter was used to identify LA sites showing diastolic, low-voltage electrograms and entrainment from its splines was performed to confirm the pacing site was inside the AFlu circuit. Left AFlu termination was achieved in all cases via PFA delivery. Total procedural and LA dwell times were 112±25min and 59±22 min, respectively. Major complications occurred in 2 (2.8%) patients. Single-procedure success rate was 74.6% after 14.9±2.7 months of follow-up; AF-free survival was 89.2%. CONCLUSIONS: In our cohort, PFA-based AF substrate ablation led to AF termination in 95.8% of cases. Very favorable clinical outcomes were observed during >1year of follow-up.

Post-cardiac Injury Syndrome Following Catheter Ablation of Atrial Flutter: A Case Report.

A woman in her 70s presented to accident and emergency (A&E) with shortness of breath and fever following atrial flutter ablation. Initial investigations revealed a new onset of pleural and pericardial effusion with raised inflammatory markers. After systematically ruling out chest infection and heart failure, a diagnosis of post-cardiac injury syndrome (PCIS) was made. After a short course of steroids and colchicine, she showed significant improvement in her symptoms, and subsequent follow-up showed resolution of her pleural and pericardial effusion.

Lessons from ablation responses to preferential wavefront in typical atrial flutter.

BACKGROUND: The heterogeneous conduction properties through the cavotricuspid isthmus (CTI) in typical atrial flutter (AFL) have not yet been well elucidated. OBJECTIVE: We sought to investigate preferential conduction through the CTI and the efficacy of ablation targeting preferential wavefront (PW) guided by ultra-high-resolution mapping. METHODS: In retrospective study, 28 patients were enrolled. Wavefront propagation patterns through the CTI and ablation responses at the location of PW were evaluated. In the following prospective study, 23 patients with predominant PW across the CTI were enrolled and assigned to the arm of PW prior ablation and the arm of conventional ablation. RESULTS: Five activation patterns were noticed in the retrospective study. The termination sites were exactly located at the PW in 18 of 28 patients (64.3%). The width of the PW in direct termination group was significantly narrower than that in the CL prolongation before termination group (16.6 ± 1.0 mm vs. 23.3 ± 3.4 mm, respectively, p = 0.025). In the prospective study, the voltage of PW region was significantly higher than non-PW regions both from unipolar and bipolar mapping. 21 of 23 patients (91.3%) were terminated at PW. AFL could no longer be induced immediately after termination. The time from radiofrequency application to AFL termination and to achieve bidirectional conduction block was significantly shorter in PW prior ablation arm than that in conventional ablation group (p < 0.05). CONCLUSIONS: Ablation targeting the PW first could be more efficient to terminate typical AFL and to achieve the endpoint of bidirectional conduction block.

Emergence of Atrial Fibrillation and Flutter in COVID-19 Patients: A Retrospective Cohort Study.

COVID-19 is associated with various cardiovascular complications, including arrhythmias. This study investigated the incidence of new-onset atrial fibrillation (AFB) and atrial flutter (AFL) in COVID-19 patients and identified potential risk factors. We conducted a retrospective cohort study at a tertiary-care safety-net community hospital including 647 patients diagnosed with COVID-19 from March 2020 to March 2021. Patients with a prior history of AFB or AFL were excluded. Data on demographics, clinical characteristics, and outcomes were collected and analyzed using chi-square tests, t-tests, and binary logistic regression. We found that 69 patients (10.66%) developed AFB or AFL, with 41 patients (6.34%) experiencing new-onset arrhythmias. The incidence rates for new-onset AFB and AFL were 5.4% and 0.9%, respectively. Older age (≥65 years) was significantly associated with new-onset AFB/AFL (OR: 5.43; 95% CI: 2.31-12.77; p < 0.001), as was the development of sepsis (OR: 2.73; 95% CI: 1.31-5.70; p = 0.008). No significant association was found with patient sex. Our findings indicate that new-onset atrial arrhythmias are a significant complication in COVID-19 patients, particularly among the elderly and those with sepsis. This highlights the need for targeted monitoring and management strategies to mitigate the burden of atrial arrhythmias in high-risk populations during COVID-19 infection.

Traumatic brain injury is associated with the subsequent risk of atrial fibrillation or atrial flutter.

BACKGROUND: Traumatic brain injury (TBI) is associated with a variety of adverse long-term outcomes and increases sympathetic nervous system activation, which could increase the risk of arrhythmias including atrial fibrillation or atrial flutter (AF/AFL). OBJECTIVE: We examined episodes of TBI and subsequent AF/AFL in a large cohort of post-9/11 servicemembers and veterans. METHODS: The variable of interest was TBI, stratified by severity (mild, moderate/severe, and penetrating). The outcome was a subsequent diagnosis of AF/AFL. We used Fine-Gray competing risks models to evaluate the potential risk imparted by TBI on subsequent AF/AFL. RESULTS: Of the 1,924,900 participants included in the analysis, 369,891 (19.2%) experienced an episode of documented TBI. Most were young (63% <35 years), male (81.7%), and non-Hispanic White (62.7%). AF/AFL was diagnosed in 22,087 patients. On univariate analysis, only penetrating TBI (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.84-2.23; P < .001) was associated with AF/AFL compared with veterans without TBI. After adjustment in the full multivariable model (adjusted for age, sex, race and ethnicity, service branch, rank, component, and comorbidities), mild (HR 1.27, 95% CI 1.22-1.32; P < .001), moderate/severe (HR, 1.34; 95% CI, 1.24-1.44; P < .001), and penetrating TBI (HR, 1.82; 95% CI, 1.65-2.02; P < .001) were significantly associated with AF/AFL compared with no TBI. Post hoc analyses demonstrated that the risk of AF/AFL was concentrated in female and younger patients. CONCLUSION: We found that an episode of TBI, particularly penetrating TBI, significantly increased the risk for AF/AFL. Further work is needed to delineate the long-term risk of arrhythmias after TBI.

Long-term risk of right coronary artery injury after catheter ablation of cavotricuspid isthmus-dependent flutter.

BACKGROUND: Radiofrequency ablation (RFA) of cavotricuspid isthmus (CTI)-dependent atrial flutter requires ablation of the tricuspid annulus overlying the right coronary artery (RCA). Although it is considered safe, reports of acute and subacute RCA injury in human and animal studies raise the possibility of late RCA stenosis. OBJECTIVE: The objective of this study was to compare the incidence and severity of angiographic RCA stenoses in patients who have undergone CTI RFA with a control group to assess the long-term risk of RCA damage. METHODS: A 2-center retrospective case-cohort study was performed including all patients from 2002 to 2018 undergoing atrial fibrillation (AF) with CTI ablation (CTI + AF) or AF ablation alone with subsequent coronary angiography (CAG). The AF alone group served as controls because of anticipated similarity of baseline characteristics. Coronary arteries that are anatomically remote to the CTI were examined as prespecified falsification end points. CAG was scored by a blinded observer. RESULTS: There were 156 patients who underwent pulmonary vein isolation with subsequent CAG (CTI + AF, n = 81; AF alone, n = 75) with no difference in baseline characteristics including age, sex, comorbidities, and medications. Mean time from ablation to CAG was similar (CTI + AF, 5.0 ± 3.7 years; AF alone, 5.4 ± 3.9 years; P = .5). The mid and distal RCA showed no difference in the average number of angiographic stenoses or lesion severity. In regression analysis, CTI ablation was not a predictor of RCA stenosis severity (P = .6). There was no difference in coronary disease at sites remote to the CTI ablation (P = NS for all). CONCLUSION: There was no observed relationship between CTI RFA and the number or severity of angiographically apparent RCA stenoses in long-term follow-up.

Empirical superior vena cava electrical isolation guided by quantitative ablation index improves outcomes of radiofrequency catheter ablation for paroxysmal atrial fibrillation.

BACKGROUND: The value of empirical superior vena cava isolation (SVCI) following pulmonary vein isolation (PVI) to improve the efficacy of radiofrequency catheter ablation (RFCA) for paroxysmal atrial fibrillation (PAF) remains controversial. OBJECTIVE: To evaluate the efficacy and safety of quantitative ablation index (AI)-guided empirical SVCI, in addition to PVI, for patients with PAF. METHODS: Patients with symptomatic PAF who underwent RFCA between October 2021 and May 2023 were retrospectively analysed. Patients were categorised into PVI-only group and PVI+SVCI group based on the intraoperative ablation strategy. RFCA was guided by quantitative AI in both groups. Regular clinical follow-ups were conducted to detect AF recurrence, defined as any episode of atrial fibrillation, atrial flutter or atrial tachycardia lasting >30 s. RESULTS: A total of 246 patients were enrolled, with 108 patients in the PVI group and 138 patients in the PVI+SVCI group. Compared with the PVI group, patients in the PVI+SVCI group had a higher prevalence of coronary artery disease (p=0.04), stroke (p=0.02) and a smaller left atrial diameter (p<0.01). After a follow-up period of 16±6 months, the ablation success rate was significantly higher in the SVCI+PVI group compared with the PVI group (91.3% vs 81.5%, p=0.02). Multivariable logistic regression analysis indicated that SVCI was an independent predictor of reduced AF recurrence postablation (Relative Risk [RR] 0.4, 95% CI 0.19 to 0.90, p=0.026). No significant difference in complication rates was observed between the groups. CONCLUSION: Quantitative AI-guided empirical SVCI, in addition to PVI, improves the success rate of RFCA for PAF without increasing the risk of complications.

The positive F wave in lead V1 of typical atrial flutter is caused by activation of the right atrial appendage: Insight from mapping during entrainment from the right atrial appendage.

INTRODUCTION: Typical atrial flutter (AFL) is a macroreentrant tachycardia in which intracardiac conduction rotates counterclockwise around the tricuspid annulus. Typical AFL has specific electrocardiographic characteristics, including a negative sawtooth-like wave in the inferior lead and a positive F wave in lead V1. This study aimed to analyze the origin of the positive F wave in lead V1, which has not been completely understood. METHODS: This study enrolled 10 patients who underwent radiofrequency catheter ablation for a typical AFL. Electroanatomical mapping was performed both during typical AFL and entrainment from the right atrial appendage (RAA). The 12-lead electrocardiogram (ECG) and three-dimensional (3D) electroanatomical maps were analyzed. RESULTS: The positive F wave in lead V1 changed during entrainment from the RAA in all the cases. The 3D map during entrainment from the RAA revealed an area of antidromic capture around the RAA, which collided with the orthodromic wave in the anterior right atrium. This area of antidromic capture around the RAA was the only difference from the 3D electroanatomical map of AFL and is considered the cause of the change in the F wave in lead V1 during entrainment. CONCLUSION: The analysis of the differences in the 12-lead ECG and 3D maps between tachycardia and entrainment from the RAA clearly demonstrated that activation around the RAA is responsible for the generation of the positive F wave in lead V1 of typical AFL.

Pericardial hydatid cysts presenting with atrial flutter and mitral regurgitation.

Despite being a rare phenomenon, pericardial hydatid cysts present unique diagnostic challenges and require a multimodality imaging as well as a multidisciplinary approach for a curative management. The authors here present a case of a middle aged man who was referred to them for management of new onset atrial flutter with mitral regurgitation.

Bipolar catheter ablation of a left atrial anteroseptal line in a patient with peri-mitral atrial flutter: a case report.

Background: Treatment of recurring atrial flutter can be challenging due to anatomical obstacles preventing complete conduction block of linear ablation lesions. Epicardial or bipolar ablation can be used as an alternative to create deeper ablation lesions but is still limitedly used in patients with atrial flutter. Case summary: We describe a case of a 54-year-old patient with recurring peri-mitral flutter treated with ablation of an anteroseptal line using bipolar ablation to achieve a complete conduction block. Discussion: As conventional ablation cannot always achieve, complete conduction block in linear ablation lesions alternatives may be used to create deeper lesions. In this, case bipolar ablation was used successfully for an anteroseptal line in a patient with recurring peri-mitral flutter.

Outcome after ablation of atypical atrial flutter: Is induction a feasible approach?

Background: Atypical atrial flutter (AAF) is an increasingly relevant clinical problem. Despite advancements in mapping and ablation techniques, the general management of these patients remain challenging especially when mapping cannot be performed during ongoing arrhythmia. There are no data whether induction of AAF is a feasible approach in these cases. Methods: We retrospectively analyzed patients who underwent catheter ablation of AAF and compared procedural results between patients with ongoing tachycardia when starting the procedure and patients with induced AAF. Results: We analyzed 97 ablation procedures performed in 76 patients with a mean follow-up of 13.2 ± 12.2 months. In 68 procedures (70.1 %) AAF was ongoing at the beginning of the procedure and in 29 cases (29.9 %) AAF had to be induced.There was no statistically significant difference regarding acute procedural success. The recurrence rate of any arrhythmia during follow-up was significantly higher after ablation of ongoing AAF compared to induced AAF (63.2 % vs. 42.9 %; p = 0.047) driven by a significant higher rate of AAF-recurrence (57.4 % vs. 34.5 %; p = 0.039). The number of ablated tachycardias per patient as well as the number of de-novo tachycardias found during re-ablation showed no significant difference between both groups. Conclusion: Starting a procedure with ongoing arrhythmia did not result in better short- or mid-term outcome in patients undergoing AAF ablation. Furthermore, based on our results inducing AAF seems a legitimate approach for AAF ablation in patients presenting in sinus rhythm.

Updates in Arrhythmia Management in Adult Congenital Heart Disease.

Arrhythmias are highly prevalent in adults with congenital heart disease. For the clinician caring for this population, an understanding of pathophysiology, diagnosis, and management of arrhythmia is essential. Herein we review the latest updates in diagnostics and treatment of tachyarrhythmias and bradyarrhythmias, all in the context of congenital anatomy, hemodynamics, and standard invasive palliations for congenital heart disease.

Prevalence of demoralization and depressive symptoms in a sample of patients with supraventricular tachyarrhythmias: preliminary results.

Introduction: Supraventricular tachyarrhythmias (ST) are the most common cardiac arrhythmias. Little is known about the potential impact of demoralization, which is considered as partially distinct from depression, on the course of ST. A correct assessment of both depressive symptoms and demoralization appears relevant for the treatment of these cardiac diseases, potentially influencing their course. Methods: The sample consisted of 110 subjects affected by different ST, such as atrial fibrillation (AF), atrial flutter (AFL) and paroxysmal supraventricular tachycardia (PSVT). They all underwent a psychiatric evaluation; the Italian version of 9-item Patient Health Questionnaire (PHQ-9) and the Italian version of Demoralization Scale (DS) were administered. Descriptive statistics, pairwise comparisons, and correlational analysis have been implemented. Results: 26 individuals (23.6%) presented high levels of demoralization. Of these, 20 (76.9%) had a diagnosis of AF and six patients (23.1%) received a diagnosis of other ST. No differences in demoralization levels resulted in regard of sex, cardiac diagnoses and anticoagulant therapies. Amongst people with high levels of demoralization, 13 (50%) received no formal psychiatric diagnosis, and 12 (46.2%) showed moderate/severe depressive symptoms. Demoralization levels and PHQ-9 scores showed a significant positive correlation in the whole sample (r=0.550, p<0.001). Discussion: The present study found that in a sample of patients suffering from ST, high levels of demoralization were more frequent than clinically relevant depressive symptoms. We propose that demoralization and depression show partially distinguished psychopathological features, potentially associated with different therapeutic trajectories.