Voltage and propagation mapping: New tools to improve successful ablation of atrioventricular nodal reentry tachycardia.

INTRODUCTION: Mapping system is useful in ablation of atrioventricular nodal reentry tachycardia (AVNRT) and localization of anatomic variances. Voltage mapping identifies a low voltage area in the Koch triangle called low-voltage-bridge (LVB); propagation mapping identifies the collision point (CP) of atrial wavefront convergence. We conducted a prospective study to evaluate the relationship between LVB and CP with successful site of ablation and identify standard value for LVB. MATERIALS AND METHODS: Three-dimensional (3D) maps of the right atria were constructed from intracardiac recordings using the ablation catheter. Cut-off values on voltage map were adjusted until LVB was observed. On propagation map, atrial wavefronts during sinus rhythm collide in the site representing CP, indicating the area of slow pathway conduction. Ablation site was selected targeting LVB and CP site, confirmed by anatomic position on fluoroscopy and atrioventricular ratio. RESULTS: Twenty-seven consecutive patients were included. LVB and CP were present in all patients. Postprocedural evaluation identified standard cut-off of 0.3-1 mV useful for LVB identification. An overlap between LVB and CP was observed in 23 (85%) patients. Procedure success was achieved in all patient with effective site at first application in 22 (81%) patients. There was a significant correlation between LVB, CP, and the site of effective ablation (p = .001). CONCLUSION: We found correlation between LVB and CP with the site of effective ablation, identifying a voltage range useful for standardized LVB identification. These techniques could be useful to identify ablation site and minimize radiation exposure.

Evaluation of Pulmonary Vein Fibrosis Following Cryoballoon Ablation of Atrial Fibrillation: A Semi-Automatic MRI Analysis.

Current guidelines recommend the use of cardiac magnetic resonance imaging (MRI) for the management of atrial fibrillation (AF). However, the widespread use of cardiac MRI in clinical practice is difficult to achieve. The aim of the present study is to assess whether cardiac MRI can be adopted to identify ablation-induced fibrosis, and its relationship with AF recurrences. Fifty patients undergoing AF cryoballoon ablation were prospectively enrolled. Cardiac MRI was performed before and 30 days after the index ablation. Commercially available software and a specifically designed image processing workflow were used to quantify left atrium (LA) fibroses. Thirty-six patients were finally included in the analysis; twenty-eight were analyzed with the dedicated workflow. Acute electrical isolation was achieved in 98% of the treated pulmonary veins (PVs). After a median follow-up of 16 months, AF recurrences occurred in 12 patients (33%). In both analyses, no differences were found between the subgroups of patients with and without recurrence in the variation of either LA fibrosis or fibrosis at the ostium of the PV, before and after ablation. The ability to predict arrhythmic recurrences evaluated via the ROC curve of the variations in both LA fibrosis (AUC 0.566) and PV fibrosis (AUC 0.600) was low. Cardiac MRI holds the potential to provide clinically significant information on LA disease and AF progression; however, LA fibrosis cannot be easily identified, either by currently available commercial programs or custom tools.

Proarrhythmic effect of bipolar epicardial left ventricular stimulation in CRT resolved maintaining biventricular pacing with unipolar-cathodical configuration: A peculiar case report.

Background: The effect of cardiac resynchronization therapy (CRT) on the risk of ventricular arrhythmias is controversial. Several studies reported a decreased risk, but some studies reported a potential proarrhythmic effect of epicardial left ventricular pacing resolved upon discontinuation of biventricular pacing (BiVp). Case Summary: A 67-year-old woman with a history of heart failure due to nonischemic cardiomyopathy and left bundle branch block was hospitalized for CRT device implantation. Unpredictably, as soon as the leads have been connected to the generator, an electrical storm (ES) occurred with relapsing self-resolving polymorphic ventricular tachycardia (PVT) triggered by ventricular extra beats with short-long-short sequences. The ES was resolved without interrupting BiVp switching to unipolar left ventricular (LV) pacing. This allowed to keep CRT active with extreme clinical benefit for the patient and to demonstrate that the cause of the PVT was the anodic capture of bipolar LV stimulation. Reverse electrical remodeling was also demonstrated after 3 months of effective BiVp. Discussion: Proarrhythmic effect of CRT is a rare but significant complication of CRT, and it may compel to discontinuation of the BiVp. The reversal of the physiological transmural activation sequence of epicardial LV pacing and subsequent prolonging of corrected QT interval have been speculated as the most probable explanation, but our case highlights the possibility that the anodic capture may play a relevant role in PVT genesis.

Endocardial ablation of epicardial ganglionated plexi: history, open questions and future prospects of cardioneuroablation.

Neurocardiogenic syncope is the most common cause of transient loss of consciousness and considerably reduces quality of life. Pharmacological and pacing therapy may not be fully efficacious and complications related to implanted hardware must be considered. In this context, cardioneuroablation (CNA) has been proposed to attenuate the vagal reflex with elimination of cardioinhibition. It has been shown that CNA is able to eliminate recurrences of syncope in over 90% of cases and no major complications are reported in the current literature. Despite these encouraging findings, CNA is only mentioned in current guidelines as a possible alternative treatment and has no real indication class. The diversity of mapping techniques, the absence of direct denervation control, the lack of a precise endpoint, the possible placebo effect, the short follow-up, and the question of the learning curve represent the major limitations of this promising procedure. The aim of this review was to look over the existing literature, analysing the novelties, the limitations, the unresolved issues and the outcome of CNA.

Prevalence and predictors of left atrial thrombosis in atrial fibrillation patients treated with non-vitamin K antagonist oral anticoagulants.

BACKGROUND: Few data are available regarding the prevalence of left atrium (LA) thrombi in atrial fibrillation (AF) patients treated with non-vitamin K antagonist oral anticoagulants (NOACs). Methods: We evaluated the prevalence and predictors of LA/LA appendage (LAA) thrombi in non-valvular AF patients treated with NOACs referring to a single centre for a scheduled electrical cardioversion (ECV) or catheter ablation (CA). Transesophageal echocardiography (TEE) was performed within 12 h prior to the index procedure. RESULTS: A total of 352 consecutive patients with non-valvular AF treated with NOACs were included in this analysis (ECV group n = 176 and CA group n = 176) between 2013 and 2018. 85 patients (24.2%) were on dabigatran, 150 (42.7%) on rivaroxaban, 104 (29.6%) on apixaban and 13 (3.7%) on edoxaban. A LA/LAA thrombus was detected by TEE in 27 (7.7%) patients, 18 in the ECV group and nine in the ablation group; 18 (5.1%) patients presented dense LA/LAA spontaneous echo contrast (SEC). Predictors of LA/LAA thrombi were a CHA2DS2-VASc score > 3 (OR 4.54, 95% CI 1.50 - 13.70, p value = .007) and obesity (OR 6.01, 95% CI 1.95 - 18.50, p value = .001). CONCLUSIONS: Among real-world patients with non-valvular AF treated with NOACs, we found a high incidence of LA/LAA thrombi compared to previous reports. The main predictors of LA/LAA thrombosis were a CHA2DS2-VASc score > 3 and obesity.

Catheter ablation for treatment of bradycardia-tachycardia syndrome: is it time to consider it the therapy of choice? A systematic review and meta-analysis.

BACKGROUND: Atrial fibrillation catheter ablation (AFCA) should be considered as a strategy to avoid pacemaker (PM) implantation for patients with bradycardia-tachycardia syndrome (BTS), but lack of evidence is remarkable. METHODS: Our aim was to conduct a random-effects model meta-analysis on safety and efficacy data from controlled trials and observational studies. We compared atrial fibrillation (AF) recurrence, AF progression, procedural complication, additional procedure, cardiovascular death, cardiovascular hospitalization, heart failure and stroke in patients undergoing AFCA vs. PM implantation. RESULTS: PubMed/MEDLINE, Cochrane Database and Google Scholar were screened, and four retrospective studies were selected. A total of 776 patients (371 in the AFCA group, 405 in the PM group) were included. After a median follow-up of 67.5 months, lower AF recurrence [odds ratio (OR) 0.06, confidence interval (CI) 0.02-0.18, I2 = 82.42%, P < 0.001], AF progression (OR 0.12, CI 0.06-0.26, I2 = 0%, P < 0.001), heart failure (OR 0.12, CI 0.04-0.34, I2 = 0%, P < 0.001), and stroke (OR 0.30, CI 0.15-0.61, I2 = 0%, P = 0.001) were observed in the AFCA group. No differences were observed in cardiovascular death and hospitalization (OR 0.48, CI 0.10-2.28, I2 = 0%, P = 0.358 and OR 0.43, CI 0.14-1.29, I2 = 87.52%, P = 0.134, respectively). Higher need for additional procedures in the AFCA group was highlighted (OR 3.65, CI 1.51-8.84, I2 = 53.75%, P < 0.001). PM implantation was avoided in 91% of BTS patients undergoing AFCA. CONCLUSIONS: AFCA in BTS patients seems to be more effective than PM implantation in reducing AF recurrence and PM implantation may be waived in most BTS patients treated by AFCA. Need for additional procedures in AFCA patients is balanced by long-term benefit in clinical end points.

A case report of long-term successful stereotactic arrhythmia radioablation in a cardiac contractility modulation device carrier with giant left atrium, including a detailed dosimetric analysis.

Introduction: Catheter ablation (CA) is the current standard of care for patients suffering drug-refractory monomorphic ventricular tachycardias (MMVTs). Yet, despite significant technological improvements, recurrences remain common, leading to increased morbidity and mortality. Stereotactic arrhythmia radioablation (STAR) is increasingly being adopted to overcome the limitations of conventional CA, but its safety and efficacy are still under evaluation. Case presentation: We hereby present the case of a 73-year-old patient implanted with a mitral valve prosthesis, a cardiac resynchronization therapy-defibrillator, and a cardiac contractility modulation device, who was successfully treated with STAR for recurrent drug and CA-resistant MMVT in the setting of advanced heart failure and a giant left atrium. We report a 2-year follow-up and a detailed dosimetric analysis. Conclusion: Our case report supports the early as well as the long-term efficacy of 25 Gy single-session STAR. Despite the concomitant severe heart failure, with an overall heart minus planned target volume mean dosage below 5 Gy, no major detrimental cardiac side effects were detected. To the best of our knowledge, our dosimetric analysis is the most accurate reported so far in the setting of STAR, particularly for what concerns cardiac substructures and coronary arteries. A shared dosimetric planning among centers performing STAR will be crucial in the next future to fully disclose its safety profile.

Evidence-based insights on ideal blanking period duration following atrial fibrillation catheter ablation.

AIMS: Despite the general adoption of a 3-month blanking period (BP), increasing scientific evidence suggests an association between early recurrences of atrial tachyarrhythmias (ERAT) and failure of atrial fibrillation catheter ablation (AFCA). The aim of the present study was to perform a diagnostic meta-analysis to derive the ideal BP cut-off following AFCA. METHODS AND RESULTS: PubMed/MEDLINE databases were screened for articles reporting late recurrences of atrial tachyarrhythmias (LRAT) in AFCA patients experiencing an ERAT (with at least one time cut-off). Seventeen studies were finally included in the analysis, encompassing 5837 AF patients experiencing ERAT after AFCA. A random-effect meta-analysis of diagnostic test accuracy studies with multiple cut-offs was performed. The day at which the ERAT occurred was considered the diagnostic 'test', whereas the different time cut-offs reported in the singular studies were treated as cut-offs of interest in the meta-analysis. Overall, a 27.7 day (95% confidence interval: 10.4-45.1 days) cut-off was identified as the optimal BP duration [area under the summary receiver operating characteristic (AUC-SROC) curve: 0.66, 95% CI: 0.56-0.75]. Specificity (95% CI: 63-85%) and positive predictive value were 76%. At subgroup analysis, the optimal BP cut-off was 39.0 days (95% CI: 26.8-51.2 days, AUC-SROC: 0.63) following radiofrequency AFCA and 30.1 days (95% CI: 0-63.4 days, AUC-SROC: 0.76) after cryoballoon ablation. CONCLUSION: The present meta-analysis indicates that a 4-week BP represents the optimal cut-off following AFCA. Altogether, these meta-analytic insights support the need of a revision of the actual 3-month BP duration.

Incidence and Clinical Relevance of COVID-19 in a Population of Young Competitive and Elite Football Players: A Retrospective Observational Study.

BACKGROUND: The COVID-19 pandemic dramatically changed lifestyle worldwide, including sport. A comprehensive evaluation of the prevalence of cardiac involvement in COVID-19 is essential to finalize a safe protocol for resuming elite sport. The aim of this study is to evaluate incidence of cardiac involvement and COVID-19 impact on athletic performance. MATERIALS AND METHODS: This retrospective observational study analysed the data collected from consecutive competitive athletes who performed medical-sports examinations at the J Medical Center from March 2020 to March 2021. All athletes periodically performed a molecular test using a nasopharyngeal swab to detect COVID-19 infection. Positive athletes performed laboratory (cardiac troponin T-cTnT) and instrumental (echocardiography, stress test, Holter ECG) investigations following recovery to identify any cardiac involvement. Cardiac magnetic resonance imaging (MRI) was performed in case of abnormal findings at first-level evaluation. RESULTS: Among 238 athletes (median age 20 years), 77 contracted COVID-19, mainly males (79%) with a median age of 16 years. Fifty-one athletes (66%) presented mild symptoms, and none required hospitalization. Evaluation for resuming sport was performed after a median of 30 days from the first positive test. Abnormal findings were obtained in 13 cases (5 athletes [6%] with elevated cTnT values; 13 athletes [17%] with arrhythmias on Holter ECG and/or during stress test; 2 athletes [3%] anomalies at echocardiography). Cardiac MRI discovered abnormalities in 9 cases, but none of these was clearly related to COVID-19 and none fulfilled acute myocarditis criteria. No negative impact on athletic performance was observed, and none of the athletes developed persistent COVID-related symptoms. CONCLUSIONS: Our registry confirms the predominantly self-limiting illness in young athlete population. The incidence of clear COVID-19-related structural myocardial injury was very low, but transient exertional ventricular arrhythmias or pericardial effusion was observed without significant impact on athletic performance. Implemented screening for return to activity is likely reasonable only in moderate-to-severe symptomatic athletes.

Prognostic role of left atrial enlargement in patients with implantable cardioverter defibrillators for primary prevention.

PURPOSE: Left atrial volume index (LAVI) is a predictor of heart failure and adverse events, irrespective of left ventricular systolic function. The role of LAVI in the prediction of appropriate implantable cardioverter-defibrillator (ICD) therapies is currently unclear and was the focus of this study. METHODS: Consecutive heart failure patients with ischaemic (ICM) or idiopathic (DCM) aetiology receiving ICD for primary prevention were included. The primary endpoint was the occurrence of appropriate ICD therapies (ATs): shocks or antitachycardia pacing (ATP). Inappropriate ICD shocks were also assessed as secondary endpoint. RESULTS: Among 198 included patients, severe left atrial dilatation (SLAE = LAVI ≥ 60 ml/m2) was present in 54 (27%). SLAE patients had a higher prevalence of NYHA class ≥ III, severe mitral regurgitation and atrial fibrillation history. During a median follow-up of 45 months (IQR 25-68), ATs occurred more frequently in SLAE group (33% vs. 15%, p = .007) as well as appropriate shocks (24% vs. 10%, p = .014). At multivariate analysis SLAE was an independent predictor of ATs (OR 3.19, 95% CI 1.38-7.38, p = .007). Inappropriate shocks were associated with AF during implantation (p = .03), but not with SLAE (p = .009). CONCLUSION: In DCM or ICM patients candidate to receive an ICD for primary prevention, a severely enlarged left atrium is a predictive factor for ATs (shocks or ATP). The risk of inappropriate shocks was increased in patients with atrial fibrillation, rather than SLAE.

S-ICD lead dislodgement in a young isometric athlete: A rare complication.

The subcutaneous implantable cardioverter defibrillator (S-ICD) is an alternative to transvenous ICD in patients who do not need cardiac pacing. We report the case of a young isometric athlete who received S-ICD for primary prevention of sudden death. Lead dislodgement and myopotential noise oversensing during isometric training led to inappropriate shock, and a surgical revision was performed. During the procedure, strong fibrous adhesions were found, requiring polytetrafluoroethylene dilator sheaths. The S-ICD was finally reimplanted. Despite continued isometric training, no more myopotential oversensing occurred after 1-year follow-up. The present case highlights the possible higher risks of lead complication in an isometric athlete and the uncommon effort in removing an old-generation subcutaneous defibrillator lead.

QT prolongation and variability: new ECG signs of atrial potentials dispersion before atrial fibrillation onset.

AIMS: QT interval may be considered an indirect marker of atrial repolarization. Aim of our study was to verify if QT interval variations precede the onset of atrial fibrillation (AF). METHODS: We analyzed 21 AF onsets recorded at 24-h Holter ECG. Triggering supraventricular extrabeats (TSVEB) were identified and matched to nontriggering supraventricular extrabeats (NTSVEB) with the same prematurity index. QT and QTc intervals and their variability (max-min QT interval) were measured in the 10 beats preceding TSVEB and NTSVEB. RESULTS: QTc (470.1 ±â€Š56.7 vs. 436.7 ±â€Š25.6 ms; P = 0.006), QT (36.8 ±â€Š13.1 vs. 21.1 ±â€Š10.1 ms; P = 0.001) and QTc variability (41.5 ±â€Š15.8 vs. 23.1 ±â€Š11.9; P = 0.001) significantly varied between TSVEB and NTSVEB. By stratifying AF onsets in vagal (n = 10) and adrenergic (n = 11) according to Heart Rate Variability, significant differences emerged concerning QT (35.20 ±â€Š16.48 vs. 22.70 ±â€Š10.23 ms, P = 0.006) and QTc variability (39.30 ±â€Š18.32 vs. 25.60 ±â€Š12.91 ms, P = 0.029) for vagal onsets and QTc (477.73 ±â€Š57.50 vs. 438.00 ±â€Š28.55 ms, P = 0.045), QT (38.36 ±â€Š9.79 vs. 19.73 ±â€Š10.21 ms, P = 0.005) and QTc variability (43.55 ±â€Š13.72 vs. 20.82 ±â€Š11.01 ms, P = 0.004) for adrenergic onsets. By stratifying AF onsets in type I (n = 7) or II (n = 14) according to a cycle length variation in the 30 s before the onset greater or smaller than 10% respectively, significant differences were noted concerning QTc (477.73 ±â€Š57.50 vs. 438 ±â€Š28.55 ms, P = 0.045), QT (43.55 ±â€Š13.72 vs. 20.82 ±â€Š11.01 ms, P = 0.005) and QTc variability (43.55 ±â€Š13.72 vs. 20.82 ±â€Š11.01 ms, P = 0.004) in type I and QT (35.20 ±â€Š16.48 vs. 22.70 ±â€Š10.23 ms, P = 0.006) and QTc variability (39.30 ±â€Š18.32 vs. 25.60 ±â€Š12.91 ms, P = 0.029) in type II onsets. CONCLUSION: Prolongation and QT variability represent a relevant substrate marker in the genesis of AF, independently of the trigger type.

Autonomic Tone Activity Before the Onset of Atrial Fibrillation.

INTRODUCTION: The autonomic nervous system has been proven to play a major role in the onset of atrial fibrillation (AF), along with a predisposing substrate and a specific trigger event usually consisting of a premature supraventricular ectopic beat (SVEB). By means of heart rate variability (HRV) analysis, we investigated the activity of the autonomic nervous system before SVEBs nontriggering and triggering AF. METHODS AND RESULTS: We evaluated 28 patients with at least 1 episode of sustained AF (>30 seconds) recorded during 24-hour Holter monitorings. We performed HRV analysis during the hour preceding 35 AF onsets and compared these results with the HRV values before nontriggering SVEBs with similar prematurity. According to the low frequency (LF)/high frequency (HF) ratio in the 5 minutes before the onset, AF episodes were classified as either vagal (LF/HF ratio <1.5) or adrenergic (LF/HF ratio ≥1.5).Vagal episodes (16) showed a decrease in LF (from 50.81 ± 1.67 to 32.73 ± 3.54) and an increase in HF (from 36.00 ± 2.30 to 54.7 ± 3.69) throughout the hour preceding the onset. Adrenergic episodes (19) had opposite changes in LF (from 55.4 ± 4.95 to 67.51 ± 5.24) and HF (from 33.78 ± 5.82 to 27.96 ± 3.51) during the same period. No similar trends were observed before the selected nontriggering SVEBs. CONCLUSION: Only SVEBs occurring during a phase of hyperactivity of one of the 2 branches of the autonomic nervous system are able to trigger episodes of AF.