New generation implantable cardiac rhythm devices allow safe radiotherapy treatments: A large single centre study

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Electrophysiological findings and long-term outcomes of percutaneous ablation of atrial arrhythmias after surgical ablation for atrial fibrillation

OBJECTIVES: Percutaneous ablation (PA) for relapsing atrial tachyarrhythmias after surgical ablation is an emerging therapy. The aim of this study is to report the electrophysiological findings and the procedural long-term outcomes of reablation, in this particular clinical setting. METHODS: We retrospectively analysed all patients who were readmitted to our centre for relapsing atrial arrhythmias after surgical ablation for atrial fibrillation (AF). RESULTS: From 2000 to 2011, 36 patients with previous surgical ablation of AF received additional percutaneous management. Seven patients had had biatrial Maze, 18 left atrial ablation lesion set and 11 pulmonary vein isolation. Energy sources involved were unipolar radiofrequency (RF) (n = 13), bipolar RF (n = 19), combined bipolar RF and cryoenergy (n = 2), cryoenergy (n = 1) and high intensity focused ultrasound (n = 1). The median time to reablation was 34 months (interquartile range: 10-66). The relapsing arrhythmias were left atrial tachycardia (n = 17), AF (n = 15), right atrial flutter (n = 2), right atrial tachycardia (n = 1) and biatrial atrial tachycardia (n = 1). Origin of re-entrant circuits was perimitral (n = 27), around pulmonary veins (PV) including posterior left atrium (n = 15) and cavotricuspid isthmus (n = 3). Twenty-seven (75%) patients had left isthmus catheter ablation and 11 (30%) reablation of PV. Eighteen out of the 27 perimitral circuits were in patients with previous left-atrial Maze; in 17 patients the mitral line was performed with bipolar RF only, without the addition of cryoenergy. The importance of an appropriate energy source is also underlined by the prevalence of gaps in PV isolation that occurred for two-thirds of patients treated using unipolar RF only, which has been discontinued since 2001. Ten patients (27%) needed more than 1 PA for relapsing arrhythmia. At the last follow-up of 97 ± 42 months, freedom from arrhythmias was 53% after single PAs and 67% after more than one procedure. No morbidity, mortality or strokes were recorded during the follow-up. CONCLUSIONS: Percutaneous treatment of highly symptomatic patients with unsuccessful previous surgical ablation is feasible, and relatively effective at the late follow-up. A multidisciplinary approach significantly improves the outcomes in these challenging patients

Long-term results of thoracoscopic ablation of paroxysmal atrial fibrillation: is the glass half full or half empty?

Previous series showed the outcomes of thoracoscopic ablation of stand-alone symptomatic paroxysmal atrial fibrillation (AF) for up to 7 years of follow-up. The goal of this study was to assess the long-term durability of surgical pulmonary vein isolation (PVI) beyond 7 years

Patients with Cardiac Implantable Electronic Device Undergoing Radiation Therapy: Insights from a Ten-Year Tertiary Center Experience

Background: The number of patients with cardiac implantable electronic devices (CIEDs) receiving radiotherapy (RT) is increasing. The management of CIED-carriers undergoing RT is challenging and requires a collaborative multidisciplinary approach. Aim: The aim of the study is to report the real-world, ten-year experience of a tertiary multidisciplinary teaching hospital. Methods: We conducted an observational, real-world, retrospective, single-center study, enrolling all CIED-carriers who underwent RT at the San Raffaele University Hospital, between June 2010 and December 2021. All devices were MRI-conditional. The devices were programmed to an asynchronous pacing mode for patients who had an intrinsic heart rate of less than 40 beats per minute. An inhibited pacing mode was used for all other patients. All tachyarrhythmia device functions were temporarily disabled. After each RT session, the CIED were reprogrammed to the original settings. Outcomes included adverse events and changes in the variables that indicate lead and device functions. Results: Between June 2010 and December 2021, 107 patients were enrolled, among which 63 (58.9%) were pacemaker carriers and 44 (41.1%) were ICD carriers. Patients were subjected to a mean of 16.4 (±10.7) RT sessions. The most represented tumors in our cohort were prostate cancer (12; 11%), breast cancer (10; 9%) and lung cancer (28; 26%). No statistically significant changes in device parameters were recorded before and after radiotherapy. Generator failures, power-on resets, changes in pacing threshold or sensing requiring system revision or programming changes, battery depletions, pacing inhibitions and inappropriate therapies did not occur in our cohort of patients during a ten-year time span period. Atrial arrhythmias were recorded during RT session in 14 patients (13.1%) and ventricular arrhythmias were observed at device interrogation in 10 patients (9.9%). Conclusions: Changes in device parameters and arrhythmia occurrence were infrequent, and none resulted in a clinically significant adverse event

Electrogram fractionation during sinus rhythm occurs in normal voltage atrial tissue in patients with atrial fibrillation

Introduction Electrogram (EGM) fractionation is often associated with diseased atrial tissue; however, mechanisms for fractionation occurring above an established threshold of 0.5 mV have never been characterized. We sought to investigate during sinus rhythm (SR) the mechanisms underlying bipolar EGM fractionation with high-density mapping in patients with atrial fibrillation (AF). Methods Forty-five patients undergoing AF ablation (73% paroxysmal, 27% persistent) were mapped at high density (18562 +/- 2551 points) during SR (Rhythmia). Only bipolar EGMs with voltages above 0.5 mV were considered for analysis. When fractionation (> 40 ms and >4 deflections) was detected, we classified the mechanisms as slow conduction, wave-front collision, or a pivot point. The relationship between EGM duration and amplitude, and tissue anisotropy and slow conduction, was then studied using a computational model. Results Of the 45 left atria analyzed, 133 sites of EGM fragmentation were identified with voltages above 0.5 mV. The most frequent mechanism (64%) was slow conduction (velocity 0.45 m/s +/- 0.2) with mean EGM voltage of 1.1 +/- 0.5 mV and duration of 54.9 +/- 9.4 ms. Wavefront collision was the second most frequent (19%), characterized by higher voltage (1.6 +/- 0.9 mV) and shorter duration (51.3 +/- 11.3 ms). Pivot points (9%) were associated with the highest degree of fractionation with 70.7 +/- 6.6 ms and 1.8 +/- 1 mV. In 10 sites (8%) fractionation was unexplained. The EGM duration was significantly different among the 3 mechanisms (p = .0351). Conclusion In patients with a history of AF, EGM fractionation can occur at amplitudes > 0.5 mV when in SR in areas often considered not to be diseased tissue. The main mechanism of EGM fractionation is slow conduction, followed by wavefront collision and pivot sites.CMC

Long-Term Follow-Up of Catheter Ablation for Premature Ventricular Complexes in the Modern Era: The Importance of Localization and Substrate

Background: Large-scale studies evaluating long-term recurrence rates in both idiopathic and non-idiopathic PVC catheter ablation (CA) patients have not been reported. Objective: To evaluate the efficacy and safety of idiopathic and non-idiopathic PVC CA, investigating the predictors of acute and long-term efficacy. Methods: This retrospective multicentric study included 439 patients who underwent PVC CA at three institutions from April-2015 to December-2021. Clinical success at 6 months’ follow-up, defined as a reduction of at least 80% of the pre-procedural PVC burden, was deemed the primary outcome. The secondary aims of the study were: clinical success at the last available follow-up, predictors of arrhythmic recurrences at long-term follow-up, and safety outcomes. Results: The median age was 51 years, with 24.9% patients being affected suffering from structural heart disease. The median pre-procedural PVC burden was 20.1%. PVCs originating from the RVOT were the most common index PVC observed (29.1%), followed by coronary cusp (CC) and non-outflow tract (OT) LV PVCs (23.1% and 19.0%). The primary outcome at 6 months was reached in 85.1% cases, with a significant reduction in the 24 h% PVC burden (−91.4% [−83.4; −96.7], p < 0.001); long-term efficacy was observed in 82.1% of cases at almost 3-year follow-up. The presence of underlying structural heart disease and non-OT LV region origin (aHR 1.77 [1.07–2.93], p = 0.027 and aHR = 1.96 [1.22–3.14], p = 0.005) was independently associated with recurrences. Conclusion: CA of both idiopathic and non-idiopathic PVCs showed a very good acute and long-term procedural success rate, with an overall low complication. Predictors of arrhythmic recurrence at follow-up were underlying structural heart disease and non-OT LV origin

Electrical Storm Induced by Cardiac Resynchronization Therapy Is Determined by Pacing on Epicardial Scar and Can be Successfully Managed by Catheter Ablation

Background— The mechanism of cardiac resynchronization therapy (CRT)–induced proarrhythmia remains unknown. We postulated that pacing from a left ventricular (LV) lead positioned on epicardial scar can facilitate re-entrant ventricular tachycardia. The aim of this study was to investigate the relationship between CRT-induced proarrhythmia and LV lead location within scar. Methods and Results— Twenty-eight epicardial and 63 endocardial maps, obtained from 64 CRT patients undergoing ventricular tachycardia ablation, were analyzed. A positive LV lead/scar relationship, defined as a lead tip positioned on scar/border zone, was determined by overlaying fluoroscopic projections with LV electroanatomical maps. CRT-induced proarrhythmia occurred in 8 patients (12.5%). They all presented early with electrical storm (100% versus 39% of patients with no proarrhythmia; P <0.01), requiring temporary biventricular pacing discontinuation in half of cases. They more frequently presented with heart failure/cardiogenic shock (50% versus 7%; P <0.01), requiring intensive care management. Ventricular tachycardia was re-entrant in all. The LV lead location within epicardial scar was significantly more frequent in the proarrhythmia group (60% versus 9% P =0.03 on epicardial bipolar scar, 80% versus 17% P =0.02 on epicardial unipolar scar, and 80% versus 17% P =0.02 on any-epicardial scar). Ablation was performed within epicardial scar, close to the LV lead, and allowed CRT reactivation in all patients. Conclusions— CRT-induced proarrhythmia presented early with electrical storm and was associated with an LV lead positioning within epicardial scar. Catheter ablation allowed for resumption of biventricular stimulation in all patients