Active Arrhythmia Pattern: A Novel Predictor of ICD Shocks-A Subanalysis From the PARTITA Study.

BACKGROUND: In the PARTITA trial (Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator?), antitachycardia pacing (ATP) predicted the occurrence of implantable cardioverter defibrillator (ICD) shocks. Catheter ablation of ventricular tachycardia after the first shock reduced the risk of death or worsening heart failure. A threshold of ATPs that might warrant an ablation procedure before ICD shocks is unknown. Our aim was to identify a threshold of ATPs and clinical features that predict the occurrence of shocks and cardiovascular events. METHODS: We analyzed data from 517 patients in phase A of the PARTITA study. We used classification and regression tree analysis to develop and test a risk stratification model based on arrhythmia patterns and clinical data to predict ICD shocks. Secondary end points were worsening heart failure and cardiovascular hospitalization. RESULTS: Classification and regression tree classified patients into 6 leaves by increasing shock probability. Patients treated with ≥5 ATPs in 6 months (active arrhythmia pattern) had the highest risk of ICD shocks (93% and 86%, training and testing samples, respectively). Patients without ATPs had the lowest (1% and 2%). Other predictors included left ventricle ejection fraction<35%, age of <60 years, and obesity. Survival analysis revealed a higher risk of worsening heart failure (hazard ratio, 5.45 [95% CI, 1.62-18.4]; P=0.006) and cardiovascular hospitalization (hazard ratio, 7.29 [95% CI, 3.66-14.5]; P<0.001) for patients with an active arrhythmia pattern compared with those without ATPs. CONCLUSIONS: Patients with an active arrhythmia pattern (≥5 ATPs in 6 months) are associated with an increased risk of ICD shocks, as well as heart failure hospitalization and cardiovascular hospitalization. These data suggest that additional treatments may be helpful to this high-risk group as a preventive strategy to reduce the incidence of major events. Further prospective randomized trials are needed to confirm the benefits of early ventricular tachycardia ablation in this setting.

The PhysioVP-AF study, a randomized controlled trial to assess the clinical benefit of physiological ventricular pacing vs. managed ventricular pacing for persistent atrial fibrillation prevention in patients with prolonged atrioventricular conduction: design and rationale.

AIMS: In patients with prolonged atrioventricular (AV) conduction and pacemaker (PM) indication due to sinus node disease (SND) or intermittent AV-block who do not need continuous ventricular pacing (VP), it may be difficult to determine which strategy to adopt. Currently, the standard of care is to minimize unnecessary VP by specific VP avoidance (VPA) algorithms. The superiority of this strategy over standard DDD or DDD rate-responsive (DDD/DDDR) in improving clinical outcomes is controversial, probably owing to the prolongation of the atrialventricular conduction (PR interval) caused by the algorithms. Conduction system pacing (CSP) may offer the most physiological-VP approach, providing appropriate AV conduction and preventing pacing-induced dyssynchrony. METHODS AND RESULTS: PhysioVP-AF is a prospective, controlled, randomized, single-blind trial designed to determine whether atrial-synchronized conduction system pacing (DDD-CSP) is superior to standard DDD-VPA pacing in terms of 3-year reduction of persistent-AF occurrence. Cardiovascular hospitalization, quality-of-life, and safety will be evaluated. Patients with indication for permanent DDD pacing for SND or intermittent AV-block and prolonged AV conduction (PR interval > 180 ms) will be randomized (1:1 ratio) to DDD-VPA (VPA-algorithms ON, septal/apex position) or to DDD-CSP (His bundle or left bundle branch area pacing, AV-delay setting to control PR interval, VPA-algorithms OFF). Approximately 400 patients will be randomized in 24 months in 13 Italian centres. CONCLUSION: The PhysioVP-AF study will provide an essential contribution to patient management with prolonged AV conduction and PM indication for sinus nodal disease or paroxysmal 2nd-degree AV-block by determining whether CSP combined with a controlled PR interval is superior to standard management that minimizes unnecessary VP in terms of reducing clinical outcomes.

Electrocardiographic findings in patients with arrhythmogenic cardiomyopathy and right bundle branch block ventricular tachycardia.

AIMS: Little is known about patients with right bundle branch block (RBBB)-ventricular tachycardia (VT) and arrhythmogenic cardiomyopathy (ACM). Our aims were: (i) to describe electrocardiogram (ECG) characteristics of sinus rhythm (SR) and VT; (ii) to correlate SR with RBBB-VT ECGs; and (iii) to compare VT ECGs with electro-anatomic mapping (EAM) data. METHODS AND RESULTS: From the European Survey on ACM, 70 patients with spontaneous RBBB-VT were included. Putative left ventricular (LV) sites of origin (SOOs) were estimated with a VT-axis-derived methodology and confirmed by EAM data when available. Overall, 49 (70%) patients met definite Task Force Criteria. Low QRS voltage predominated in lateral leads (n = 37, 55%), but QRS fragmentation was more frequent in inferior leads (n = 15, 23%). T-wave inversion (TWI) was equally frequent in inferior (n = 28, 42%) and lateral (n = 27, 40%) leads. TWI in inferior leads was associated with reduced LV ejection fraction (LVEF; 46 ± 10 vs. 53 ± 8, P = 0.02). Regarding SOOs, the inferior wall harboured 31 (46%) SOOs, followed by the lateral wall (n = 17, 25%), the anterior wall (n = 15, 22%), and the septum (n = 4, 6%). EAM data were available for 16 patients and showed good concordance with the putative SOOs. In all patients with superior-axis RBBB-VT who underwent endo-epicardial VT activation mapping, VT originated from the LV. CONCLUSIONS: In patients with ACM and RBBB-VT, RBBB-VTs originated mainly from the inferior and lateral LV walls. SR depolarization and repolarization abnormalities were frequent and associated with underlying variants.

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.

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.

Step by Step through the Years-High vs. Low Energy Lead Extraction Using Advanced Extraction Techniques.

Background: Limited data is available about the outcome of TLE in patients with vs. without high energy leads in the last decade. Methods: This is an analysis of consecutive patients undergoing TLE at a high-volume TLE centre from 2001 to 2021 using the stepwise approach. Baseline characteristics, procedural details and outcome of patients with high energy lead (ICD group) vs. without high energy lead (non-ICD group) were compared. Results: Out of 667 extractions, 991 leads were extracted in 405 procedures (60.7%) in the ICD group and 439 leads in 262 procedures (39.3%) in the non-ICD group. ICD patients were significantly younger (median 67 vs. 74 years) and were significantly less often female (18.1% vs. 27.7%, p < 0.005 for both). Advanced extraction tools were used significantly more often in the ICD group (73.2% vs. 37.5%, p < 0.001), but there were no significant differences in the successful removal (98.8% vs. 99.2%) or complications (4.7% vs. 3.1%) between the groups (p > 0.2 for both). Discussion: Using the stepwise approach, overall procedural success was high and complication rate was low in a high-volume centre. In patients with a high energy lead, the TLE procedure was more complex, but outcome was similar to comparator patients.

Significance of abnormal and late ventricular signals in ventricular tachycardia ablation of ischemic and nonischemic cardiomyopathies.

BACKGROUND: Abnormal ventricular signals (AVS) are the cornerstone of substrate-based ventricular tachycardia (VT) ablation in sinus rhythm. Signal characterization of AVS in ischemic and nonischemic cardiomyopathies has never been performed. OBJECTIVE: The purpose of this study was to describe ventricular signal abnormalities in 3 different pathologies and examine their association with the diastolic component of VT circuits. METHODS: A total of 45 patients (15 ischemic cardiomyopathy [ICM], 15 arrhythmogenic cardiomyopathy [ACM], 15 dilated cardiomyopathy [DCM]) who had undergone VT ablation with >50% of the diastolic pathway of the VT circuit recorded were studied. AVS were classified into late potentials (LPs) and continuous fractionated ventricular signals (CFVS), and their characteristics and correlation with the diastolic pathway of VT circuits were analyzed. RESULTS: Seventy-five VT circuits were analyzed. Bipolar scars were greatest in ICM endocardially (53 cm2 ICM vs 36 cm2 ACM vs 25 cm2 DCM; P = .010) and in ACM epicardially (98 cm2 ACM vs 25 cm2 ICM vs 24 cm2 DCM; P = .005). Location of the VT diastolic interval coincided with AVS location in 54% of VTs in ICM, 89% in ACM, and 72% in DCM (P = .036). There was a trend toward a greater association of diastolic intervals coinciding with LPs than with CFVS (78% vs 57%; P = .052) (69% diastolic intervals in ICM coincided with LPs, 33% with CFVS; P = .063). All patients (100%) with CFVS in ACM had VT diastolic components arising from CFVS (33% ICM, 64% DCM; P = .049). Positive predictive value for LPs vs CFVS was 77.8% vs 56.7%, and sensitivity was 67.3% vs 32.7%, respectively. CONCLUSION: The nature of abnormal signals in different cardiomyopathies reflects underlying pathology. LPs rather than CFVS seem to be more linked to diastolic components of VT circuits, especially in ICM. LPs have greater sensitivity and specificity for VT; however, CFVS may be of more relevance in ACM.

Working on the dirty side-the ipsilateral subclavian access for temporary pacing after lead extraction.

Background: Temporary pacing is necessary in pacemaker-dependent patients after transvenous lead extraction (TLE) for cardiac implantable electronic device infection. In case of unavailability of other accesses, we propose to use the ipsilateral subclavian access (ISA) combined with a standard permanent active fixation lead for the temporary pacemaker and present preliminary data. Methods: We consecutively enrolled patients undergoing TLE who received a temporary pacemaker using the ISA between August 2016 and April 2020 at our centre. Results: During the observation period, 36 patients undergoing TLE for pocket infection (72.2%), endocarditis (25.0%) or other causes received a temporary pacemaker over the ISA. Their mean age was 77.0 ± 10.7 years, and 13.9% were female. Complete TLE was achieved in 94.4%. There were no major periprocedural complications. Intra-hospital mortality was 11.1%. Pocket revision was performed in 19.4%. During long-term follow-up (23 ± 13 months), 8.3% had a relapse of local pocket infection and 2.8% needed rehospitalization for reintervention. Conclusions: Temporary pacing using a standard permanent active fixation lead using the ISA is a convenient alternative to conventional venous accesses. However, risks of implanting a lead into a previously infected area have to be taken into account.

Bi-atrial characterization of the electrical substrate in patients with atrial fibrillation.

BACKGROUND: Little is known regarding the characterization of electrical substrate in both atria in patients with atrial fibrillation (AF). METHODS: Eight consecutive patients undergoing AF ablation (five paroxysmal, three persistent) underwent electrical substrate characterization during sinus rhythm. Mapping of the left (LA) and right atrium (RA) was performed with the use of the HD Grid catheter (Abbott). Bipolar voltage maps were analyzed to search for low voltage areas (LVA), the following electrophysiological phenomena were assessed: (1) slow conduction corridors, and (2) lines of block. EGMs were characterized to search for fractionation. Electrical characteristics were compared between atria and between paroxysmal versus persistent AF patients. RESULTS: In the RA, LVAs were present in 60% of patients with paroxysmal AF and 100% of patients with persistent AF. In the LA, LVAs were present in 40% of patients with paroxysmal AF and 66% of patients with persistent AF. The areas of LVA in the RA and LA were 4.8±7.3 cm2 and 7.8±13.6 cm2 in patients with paroxysmal AF versus 11.7±3.0 cm2 and 2.1±1.8 cm2 in patients with persistent AF. In the RA, slow conduction corridors were present in 40.0% (paroxysmal AF) versus 66.7% (persistent AF) whereas in the LA, slow conduction corridors occurred in 20.0% versus 33.3% respectively (p = ns). EGM analysis showed more fractionation in persistent AF patients than paroxysmal (RA: persistent AF 10.8 vs. paroxysmal AF 4.7%, p = .036, LA: 10.3 vs. 4.1%, p = .108). CONCLUSION: Bi-atrial involvement is present in patients with paroxysmal and persistent AF. This is expressed by low voltage areas and slow conduction corridors whose extension progresses as the arrhythmia becomes persistent. This electrophysiological substrate demonstrates the important interplay with the pulmonary vein triggers to constitute the substrate for persistent arrhythmia.

The prevalence of left and right bundle branch block morphology ventricular tachycardia amongst patients with arrhythmogenic cardiomyopathy and sustained ventricular tachycardia: insights from the European Survey on Arrhythmogenic Cardiomyopathy.

AIMS: In arrhythmogenic cardiomyopathy (ACM), sustained ventricular tachycardia (VT) typically displays a left bundle branch block (LBBB) morphology while a right bundle branch block (RBBB) morphology is rare. The present study assesses the VT morphology in ACM patients with sustained VT and their clinical and genetic characteristics. METHODS AND RESULTS: Twenty-six centres from 11 European countries provided information on 954 ACM patients who had ≥1 episode of sustained VT spontaneously documented during patients' clinical course. Arrhythmogenic cardiomyopathy was defined according to the 2010 Task Force Criteria, and VT morphology according to the QRS pattern in V1. Overall, 882 (92.5%) patients displayed LBBB-VT alone and 72 (7.5%) RBBB-VT [alone in 42 (4.4%) or in combination with LBBB-VT in 30 (3.1%)]. Male sex prevalence was 79.3%, 88.1%, and 56.7% in the LBBB-VT, RBBB-VT, and LBBB + RBBB-VT groups, respectively (P = 0.007). First RBBB-VT occurred 5 years after the first LBBB-VT (46.5 ± 14.4 vs 41.1 ± 15.8 years, P = 0.011). An implanted cardioverter-defibrillator was more frequently implanted in the RBBB-VT (92.9%) and the LBBB + RBBB-VT groups (90%) than in the LBBB-VT group (68.1%) (P < 0.001). Mutations in PKP2 predominated in the LBBB-VT (65.2%) and the LBBB + RBBB-VT (41.7%) groups while DSP mutations predominated in the RBBB-VT group (45.5%). By multivariable analysis, female sex was associated with LBBB + RBBB-VT (P = 0.011) while DSP mutations were associated with RBBB-VT (P < 0.001). After a median follow-up of 103 (51-185) months, death occurred in 106 (11.1%) patients with no intergroup difference (P = 0.176). CONCLUSION: RBBB-VT accounts for a significant proportion of sustained VTs in ACM. Sex and type of pathogenic mutations were associated with VT type, female sex with LBBB + RBBB-VT, and DSP mutation with RBBB-VT.

Continuous Electrical Monitoring in Patients with Arrhythmic Myocarditis: Insights from a Referral Center.

BACKGROUND: The incidence and burden of arrhythmias in myocarditis are under-reported. OBJECTIVE: We aimed to assess the diagnostic yield and clinical impact of continuous arrhythmia monitoring (CAM) in patients with arrhythmic myocarditis. METHODS: We enrolled consecutive adult patients (n = 104; 71% males, age 47 ± 11 year, mean LVEF 50 ± 13%) with biopsy-proven active myocarditis and de novo ventricular arrhythmias (VAs). All patients underwent prospective monitoring by both sequential 24-h Holter ECGs and CAM, including either ICD (n = 62; 60%) or loop recorder (n = 42; 40%). RESULTS: By 3.7 ± 1.6 year follow up, 45 patients (43%) had VT, 67 (64%) NSVT and 102 (98%) premature ventricular complexes (PVC). As compared to the Holter ECG (average 9.5 exams per patient), CAM identified more patients with VA (VT: 45 vs. 4; NSVT: 64 vs. 45; both p < 0.001), more VA episodes (VT: 100 vs. 4%; NSVT: 91 vs. 12%) and earlier NSVT timing (median 6 vs. 24 months, p < 0.001). The extensive ICD implantation strategy was proven beneficial in 80% of the population. Histological signs of chronically active myocarditis (n = 73, 70%) and anteroseptal late gadolinium enhancement (n = 26, 25%) were significantly associated with the occurrence of VTs during follow up, even in the primary prevention subgroup. CONCLUSION: In patients with arrhythmic myocarditis, CAM allowed accurate arrhythmia detection and showed a considerable clinical impact.

Long-term outcome of left atrial appendage occlusion with multiple devices.

BACKGROUND: To evaluate long-term efficacy of left atrial appendage occlusion with multiple devices. METHODS: All consecutive patients who underwent left atrial appendage occlusion (LAAO) with a follow-up of at least 4 years, were included in this single center, retrospective registry. No specific exclusion criteria were applied. LAA occlusion was performed with the Watchman, Watchman FLX, Amplatzer Cardiac plug or Amplatzer Amulet occluder devices. RESULTS: A total of 224 consecutive patients underwent LAAO occlusion. Mean age was 72.5 ± 9.0 years. A history of stroke was present in 29%, TIA in 8.5% and a previous episode of bleeding in 64.7% of patients. In 63% there was a contraindication to oral anticoagulants. The average CHADS-VASc was 4.0 ± 1.6 and the average HAS-BLED was 3.4 ± 1.3. There was a reduction of strokes of 72.9%, thromboembolic events of 59.7% and major bleeding events of 70.9% compared to historic data. During follow-up, 48.3% of the ischemic and major bleeding events occurred within the first year. The annual mortality rate of 7.5 deaths/ 100 patients years. There were no significant differences in terms of outcome between the devices used and there were no late events associated with any device. The main antithrombotic regimen in the long term was with single antiplatelet therapy and the second one was no therapy. CONCLUSION: LAAO is a safe and effective procedure, that reduces ischemic and bleeding events in the long-term, regardless of the type of device used, in AF patients at high risk of ischemic stroke and major bleeding, without the need of anticoagulation.

Check the Need-Prevalence and Outcome after Transvenous Cardiac Implantable Electric Device Extraction without Reimplantation.

BACKGROUND: after transvenous lead extraction (TLE) of cardiac implantable electric devices (CIEDs), some patients may not benefit from device reimplantation. This study sought to analyse predictors and long-term outcome of patients after TLE with vs. without reimplantation in a high-volume centre. METHODS: all patients undergoing TLE at our centre between January 2010 and November 2015 were included into this analysis. RESULTS: a total of 223 patients (median age 70 years, 22.0% female) were included into the study. Cardiac resynchronization therapy-defibrillator (CRT-D) was the most common device (40.4%) followed by pacemaker (PM) (31.4%), implantable cardioverter-defibrillator (ICD) (26.9%), and cardiac resynchronization therapy-PM (CRT-P) (1.4%). TLE was performed due to infection (55.6%), malfunction (35.9%), system upgrade (6.7%) or other causes (1.8%). In 14.8%, no reimplantation was performed after TLE. At a median follow-up of 41 months, no preventable arrhythmia-related events were documented in the no-reimplantation group, but 11.8% received a new CIED after 17-84 months. While there was no difference in short-term survival, five-year survival was significantly lower in the no-reimplantation group (78.3% vs. 94.7%, p = 0.014). CONCLUSIONS: in patients undergoing TLE, a re-evaluation of the indication for reimplantation is safe and effective. Reimplantation was not related to preventable arrhythmia events, but all-cause survival was lower.

Etiology is a predictor of recurrence after catheter ablation of ventricular arrhythmias in pediatric patients.

BACKGROUND: Ventricular arrhythmias (VAs) are rare in pediatric patients, especially in absence of structural heart disease (SHD). Few data are available regarding the invasive VAs treatment with catheter ablation (CA) in pediatric patients and predictors of outcomes have not been fully investigated. OBJECTIVE: To describe the clinical presentation, procedural characteristics, and outcomes in pediatric patients undergoing CA for VAs. METHODS: Eighty-one consecutive pediatric patients (58 male [72%], 15.5 ± 2.2 years) treated by CA for ventricular tachycardia (VT) or premature ventricular beats (PVBs) were retrospectively evaluated. Study endpoints were VAs recurrence and mortality for any cause. RESULTS: Ninety-five procedures were performed in 81 patients, 52 (55%) PVBs and 43 (45%) VT ablations. During a follow-up of 35.0 months (interquartile range = 13.0-71.0), 14 patients (14.7%) had a VA recurrence: 11 (33.3%) patients treated with CA for VT and 3 (6.2%) patients treated for PVBs (p < .001). One patient (1%) died 26 months after the procedure during an electrical storm. Patients with SHD had higher VAs recurrence rate, as compared with idiopathic VAs (pairwise log-rank p < .001). Patients treated with CA for VT had higher VA recurrence rate, as compared with PVB patients (pairwise log-rank p = .002). At Cox multivariate analysis only SHD was an independent predictor of VAs recurrence (hazard ratio = 5.56, 95% confidence interval = 2.68-11.54, p < .001). CONCLUSION: CA of VAs is effective and safe in a pediatric population. CA of idiopathic and fascicular VAs are associated with lower recurrence rate, than VAs in the setting of SHD.

Characterization of cardiac electrogram signals in atrial arrhythmias.

Despite significant advancements in 3D cardiac mapping systems utilized in daily electrophysiology practices, the characterization of atrial substrate remains crucial for the comprehension of supraventricular arrhythmias. During mapping, intracardiac electrograms (EGM) provide specific information that the cardiac electrophysiologist is required to rapidly interpret during the course of a procedure in order to perform an effective ablation. In this review, EGM characteristics collected during sinus rhythm (SR) in patients with paroxysmal atrial fibrillation (pAF) are analyzed, focusing on amplitude, duration and fractionation. Additionally, EGMs recorded during atrial fibrillation (AF), including complex fractionated atrial EGMs (CFAE), may also provide precious information. A complete understanding of their significance remains lacking, and as such, we aimed to further explore the role of CFAE in strategies for ablation of persistent AF. Considering focal atrial tachycardias (AT), current cardiac mapping systems provide excellent tools that can guide the operator to the site of earliest activation. However, only careful analysis of the EGM, distinguishing low amplitude high frequency signals, can reliably identify the absolute best site for RF. Evaluating macro-reentrant atrial tachycardia circuits, specific EGM signatures correspond to particular electrophysiological phenomena: the careful recognition of these EGM patterns may in fact reveal the best site of ablation. In the near future, mathematical models, integrating patient-specific data, such as cardiac geometry and electrical conduction properties, may further characterize the substrate and predict future (potential) reentrant circuits.

Relation of Prolonged Pacemaker Dependency After Cardiac Surgery to Mortality.

Permanent pacemaker implantation (PPI) represents a rare complication after cardiac surgery, with no uniform agreement on timing and no information on follow-up. A multicenter retrospective study was designed to assess pacemaker dependency (PMD) and long-term mortality after cardiac surgery procedures. Between 2004 and 2016, PPI-patients from 18 centers were followed. Time-to-event data were evaluated with semiparametric regression Cox models and semiparametric Fine and Gray model for competing risk framework. Of 859 (0.90%) PPI-patients, 30% were pacemaker independent (PMI) at 6 months. PMD showed higher mortality compared with PMI (10-year survival 80.1% ± 2.6% and 92.2% +2.4%, respectively, log-rank p-value < 0.001) with an unadjusted hazard ratio for death of 0.36 (95% CI 0.20 to 0.65, p< 0.001 favoring PMI) and an adjusted hazard ratio of 0.19 (95% CI 0.08 to 0.45, p< 0.001 with PMD as reference). Crude cumulative incidence function of restored PMI rhythm at follow-up at 6 months, 1 year and 12 years were 30.5% (95% CI 27.3% to 33.7%), 33.7% (95% CI 30.4% to 36.9%) and 37.2% (95% CI 33.8% to 40.6%) respectively. PMI was favored by preoperative sinus rhythm with normal conduction (SR) (HR 2.37, 95% CI 1.65 to 3.40, p< 0.001), whereas coronary artery bypass grafting and aortic valve replacement were independently associated with PMD (HR 0.63, 95% CI 0.45 to 0.88, p = 0.006 and HR 0.807, 95% CI 0.65 to 0.99, p = 0.047 respectively). Time-to-implantation was not associated with increased rate of PMI. Although 30% of PPI-patients are PMI after 6 months, PMD is associated with higher mortality at long term.

Pacemaker-Related Complications in Patients Undergoing Transcatheter Aortic Valve Implantation: A Single-Center Experience.

BACKGROUND: The aim of this study was to describe the rate of complications secondary to permanent pacemaker (PPM) implantation after transcatheter aortic valve implantation (TAVI). METHODS: Patients were identified by retrospective review of a dedicated TAVI database at a single center between 2008 and 2015. Clinical and procedural data were collected to determine the incidence and severity of the main adverse events following this procedure. The overall population included 736 patients and 123 (16.7%) underwent PPM implantation. Three patients were excluded from the final analysis due to PPM implantation occurring at other institutions post discharge. The final population consisted of 120 patients (16.3%). RESULTS: Self- and mechanically expandable valves were associated with a higher risk of PPM after TAVI compared with balloon-expandable valves (23.9% vs 27.5% vs 7.6%, respectively; P<.001). Year of procedure and operator's experience did not affect the PPM-related complication rate. A high rate of major bleeding complications (n = 29; 24.1%) was observed. Major bleeding occurred more frequently in patients who received PPM implantation within the first 24 hours post TAVI than in the group of patients who required a PPM >24 hours post TAVI (38.2% vs 12.3%, respectively; P<.01). Patients who experienced a major bleeding event following PPM insertion were more frequently on triple-antithrombotic therapy (51.7% vs 9.9%; P<.001). CONCLUSIONS: PPM-related complications are common in elderly patients after TAVI, and some of these adverse events can be life threatening. Particular attention is required in the periprocedural management of these patients.

Inflammation as a Predictor of Recurrent Ventricular Tachycardia After Ablation in Patients With Myocarditis.

BACKGROUND: Little is known about the risk stratification of patients with myocarditis undergoing ventricular tachycardia (VT) ablation. OBJECTIVES: This study sought to describe VT ablation results and identify factors associated with arrhythmia recurrences in a cohort of patients with myocarditis. METHODS: The authors enrolled 125 consecutive patients with myocarditis, undergoing VT ablation. Before ablation, disease stage was evaluated, to identify active (AM) versus previous myocarditis (PM). The primary study endpoint was assessment of VT recurrences by 12-month follow-up. Predictors of VT recurrences were retrospectively identified. RESULTS: All patients (age 51 ± 14 years, 91% men, left ventricular ejection fraction 52% ± 9%) had history of myocarditis diagnosed by endomyocardial biopsy (59%) and/or cardiac magnetic resonance (90%). Furthermore, all had multiple episodes of drug-refractory VTs. Multimodal pre-procedural staging identified 47 patients with AM (38%) and 78 patients with PM (62%). All patients showed low-voltage areas (LVA) at electroanatomical map (97% epicardial or endoepicardial); of them, 25 (20%) had wide borderzone (WBZ, constituting >50% of the whole LVA). VT recurrences were documented in 25 patients (20%) by 12 months, and in 43 (34%) by last follow-up (median 63 months; interquartile range: 39 to 87). At multivariable analysis, AM stage was the only predictor of VT recurrences by 12 months (hazard ratio: 9.5; 95% confidence interval: 2.6 to 35.3; p < 0.001), whereas both AM stage and WBZ were associated with arrhythmia recurrences anytime during follow-up. No VT episodes were found after redo ablation was performed in 23 patients during PM stage. CONCLUSION: Our findings suggest that VT ablation should be avoided during AM, but is often of benefit for recurrent VT after the acute phase of myocarditis.

Complete Electroanatomic Imaging of the Diastolic Pathway Is Associated With Improved Freedom From Ventricular Tachycardia Recurrence.

BACKGROUND: The development of multielectrode mapping catheters has expanded the spectrum of mappable ventricular tachycardias (VTs). Full diastolic pathway recording has been associated with a high rate of VT termination during radiofrequency ablation as well as noninducibility at study end. However, the role of diastolic pathway mapping on VT recurrence has yet to be clearly elucidated. We aimed to explore the role of complete diastolic pathway activation mapping on VT recurrence. METHODS: Eighty-five consecutive patients who underwent VT ablation guided by high-density mapping were enrolled. During activation mapping, the presence of electrical activity in all segments of diastole defined the evidence of having had recorded the whole diastolic interval. Patients were categorized as having recorded the full diastolic pathway, partial diastolic pathway, or no diastolic pathway map performed. Recurrences of VT were defined as appropriate implantable cardioverter defibrillator therapies or on the basis of ECG-documented arrhythmia. RESULTS: Eighty-five patients were included. Complete recording of the diastolic pathway was achieved in 36/85 (42.4%) patients. Partial recording of the diastolic pathway of the clinical VT was achieved in 24/85 (28.2%) patients. No recording of the diastolic pathway of the clinical VT was feasible in 25/85 patients (29.4%). At a mean of 12.8 months, freedom from VT recurrence was 67% in the overall cohort. At a mean of 12.8 months, freedom from VT recurrence was 88%, 50%, and 55% in patients who had full diastolic activity recorded, partial diastolic activity recorded, or underwent substrate modification, respectively; the observed differences were statistically significant (P=0.02). CONCLUSIONS: Mapping of the entire diastolic pathway was associated with a higher freedom from VT recurrence as compared with partial diastolic pathway recording and substrate modification. The use of multielectrode mapping catheters in recording diastolic activity may help predict those VTs employing intramural circuits and further optimize ablation strategies.