Mortality after transvenous lead extraction: A risk prediction model for sustainable care delivery.

BACKGROUND AND AIMS: Transvenous lead extraction (TLE) has become a pivotal part of a comprehensive lead management strategy, dealing with a continuously increasing demand. Nonetheless, the literature about the long-term impact of TLE on survivals is still lacking. Given these knowledge gaps, the aim of our study was to analyse very long-term mortality in patients undergoing TLE in public health perspective. METHODS: This prospective, single-centre, observational study enrolled consecutive patients with cardiac implantable electronic device (CIED) who underwent TLE, from January 2005 to January 2021. The main goal was to establish the independent predictors of very long-term mortality after TLE. We also aimed at assessing procedural and hospitalization-related costs. RESULTS: We enrolled 435 patients (mean age 70 ± 12 years, with mean lead dwelling time 6.8 ± 16.7 years), with prevalent infective indication to TLE (92%). Initial success of TLE was achieved in 98% of population. After a median follow-up of 4.5 years (range: 1 month-15.5 years), 150 of the 435 enrolled patients (34%) died. At multivariate analysis, death was predicted by: age (≥77 years, OR: 2.55, CI: 1.8-3.6, p < 0.001), chronic kidney disease (CKD) defined as severe reduction of estimated glomerular filtration rate (eGFR <30 mL/min/1.73 m2 , OR: 1.75, CI: 1.24-2.4, p = 0.001) and systolic dysfunction assessed before TLE defined as left ventricular ejection fraction (LVEF) <40%, OR: 1.78, CI 1.26-2.5, p = 0.001. Mean extraction cost was €5011 per patient without reimplantation and €6336 per patient with reimplantation respectively. CONCLUSIONS: Our study identified three predictors of long-term mortality in a high-risk cohort of patients with a cardiac device infection, undergoing successful TLE. The future development of a mortality risk score before might impact on public health strategy.

Leadless pacemaker technology: clinical evidence of new paradigm of pacing.

Despite continuous technological developments, transvenous pacemakers (PM) are still associated with significant immediate and long-term complications, mostly lead or pocket-related. Recent technological advances brought to the introduction in clinical practice of leadless PM for selected cohort of patients. These miniaturize devices are implanted through the femoral vein and advanced to the right ventricle, without leaving leads in place. Lack of upper extremity vascular access and/or high infective risk in patients requiring VVI pacing are the most common indications to leadless PM. The recently introduced MICRA AV leadless PM also allows ventricular synchronization through mechanical sensing of atrial contraction waves, thus solving the problem of AV synchronization. This review will discuss and summarize available clinical evidence on leadless PM, their performance compared to transvenous devices, current applications and future perspectives.

Powered sheaths for lead extraction.

Transvenous lead extraction (TLE) has seen a rapid expansion in the past 20 years. The procedure has changed from early techniques involving simple manual traction that frequently proved themselves ineffective for chronically implanted leads, and carried significant periprocedural risks including death, to the availability of a wide range of more efficacious techniques and tools, providing the skilled extractor with a well-equipped armamentarium. The reduction in morbidity and mortality associated with these new extraction techniques has widened indications to TLE from prevalent use in life-threatening situations, such as infection and sepsis, to a more widespread use even in noninfectious situations such as malfunctioning leads. Powered sheaths have been a remarkable step forward in this improvement in TLE procedures and recent registries at high-volume centers report high success rates with exceedingly low complication rates. This review is aimed at describing technical features of powered sheaths as well as reported performance during TLE procedures.

Severity of spleep apnea syndrome and life-threatening tachyarrhythmias in patients with implantable cardioverter defibrillator.

BACKGROUND: Sleep apnea syndrome (SAS) has been reported to be associated with a higher incidence of ventricular arrhythmias. The aim of this study was twofold: (1) to investigate whether in SAS patients receiving an implantable cardioverter defibrillator (ICD) the severity of SAS was associated with the occurrence of ventricular arrhythmias; (2) to assess whether changes in nocturnal apnoic/hypopnoic episodes may favor the occurrence of life-threatening arrhythmias, that is, sustained ventricular tachycardia (VT)/fibrillation (VF), requiring ICD intervention. METHODS: We enrolled 46 patients with documented SAS at polysomnography (apnea/hypopnea index [AHI] > 5) who also had a left ventricle ejection fraction (LVEF) < 35% and, according to primary prevention indications, implanted an ICD (Boston Scientific Incepta) able to daily monitor apnoic/hypopnoic episodes occurring during sleep. Patients were followed at 3-month intervals. RESULTS: At a mean follow-up of 18 months, 21 episodes of sustained VT/FV requiring ICD intervention were documented in eight patients (17.4%). Baseline AHI was significantly higher in patients with compared to those without ICD intervention. ICD interventions, however, were not preceded by any worsening of apnoic/hypopnoic episodes. The respiratory disturbance index (RDI) of the week during the event, indeed, was not different from that recorded during the previous 2 weeks (25.4 ± 11, 25.6 ± 10 and 25.1 ± 10, respectively; p = .9). CONCLUSIONS: In patients with SAS who received an ICD for primary prevention of sudden death, those with ICD interventions showed a more severe form of the disease at baseline. ICD interventions, however, were not preceded by any significant changes in SAS severity.

Diagnostic Workflow in Competitive Athletes with Ventricular Arrhythmias and Suspected Concealed Cardiomyopathies.

The diagnosis of structural heart disease in athletes with ventricular arrhythmias (VAs) and an apparently normal heart can be very challenging. Several pieces of evidence demonstrate the importance of an extensive diagnostic work-up in apparently healthy young patients for the characterization of concealed cardiomyopathies. This study shows the various diagnostic levels and tools to help identify which athletes need deeper investigation in order to unmask possible underlying heart disease.

Presence of 'ghosts' and mortality after transvenous lead extraction.

AIMS: The number of cardiovascular implantable electronic devices has increased progressively, leading to an increased need for transvenous lead extraction (TLE) due to device infections. Previous studies described 'ghost' as a post-removal, new, tubular, mobile mass detected by echocardiography following the lead's intracardiac route in the right-sided heart chambers, associated with diagnosis of cardiac device-related infective endocarditis. We aimed to analyse the association between 'ghosts' assessed by transesophageal echocardiography (TEE) and intracardiac echocardiography (ICE) and mortality in patients undergoing TLE. METHODS AND RESULTS: We prospectively enrolled 217 patients (70 ± 13 years; 164 males) undergoing TLE for systemic infection (139), local device infection (67), and lead malfunction (11). All patients underwent TEE before and 48 h after TLE and ICE during TLE. Patients were allocated to two groups: either with (Group 1) or without (Group 2) post-procedural 'ghost'. Mid-term clinical follow-up was obtained in all patients (11 months, IQR 1-34 months). We identified 30 (14%) patients with 'ghost', after TLE. The significant predictors of 'ghost' were Charlson co-morbidity index (HR = 1.24, 95% CI 1.04-1.48, P = 0.03) and diagnosis of endocarditis assessed by ICE (HR = 1.82, 95% CI 1.01-3.29, P = 0.04). Mortality was higher in Group 1 than in Group 2 (28 vs. 5%; log-rank P < 0.001). Independent predictors of mid-term mortality were the presence of 'ghost' and systemic infection as the clinical presentation of device infection (HR = 3.47, 95% CI 1.18-10.18, P = 0.002; HR = 3.39, 95% CI 1.15-9.95, P = 0.001, respectively). CONCLUSION: The presence of 'ghost' could be an independent predictor of mortality after TLE, thus identifying a subgroup of patients who need closer clinical surveillance to promptly detect any complications.

Near zerO fluoroscopic exPosure during catheter ablAtion of supRavenTricular arrhYthmias: the NO-PARTY multicentre randomized trial.

AIMS: Aim of this study was to compare a minimally fluoroscopic radiofrequency catheter ablation with conventional fluoroscopy-guided ablation for supraventricular tachycardias (SVTs) in terms of ionizing radiation exposure for patient and operator and to estimate patients' lifetime attributable risks associated with such exposure. METHODS AND RESULTS: We performed a prospective, multicentre, randomized controlled trial in six electrophysiology (EP) laboratories in Italy. A total of 262 patients undergoing EP studies for SVT were randomized to perform a minimally fluoroscopic approach (MFA) procedure with the EnSiteTMNavXTM navigation system or a conventional approach (ConvA) procedure. The MFA was associated with a significant reduction in patients' radiation dose (0 mSv, iqr 0-0.08 vs. 8.87 mSv, iqr 3.67-22.01; P < 0.00001), total fluoroscopy time (0 s, iqr 0-12 vs. 859 s, iqr 545-1346; P < 0.00001), and operator radiation dose (1.55 vs. 25.33 µS per procedure; P < 0.001). In the MFA group, X-ray was not used at all in 72% (96/134) of cases. The acute success and complication rates were not different between the two groups (P = ns). The reduction in patients' exposure shows a 96% reduction in the estimated risks of cancer incidence and mortality and an important reduction in estimated years of life lost and years of life affected. Based on economic considerations, the benefits of MFA for patients and professionals are likely to justify its additional costs. CONCLUSION: This is the first multicentre randomized trial showing that a MFA in the ablation of SVTs dramatically reduces patients' exposure, risks of cancer incidence and mortality, and years of life affected and lost, keeping safety and efficacy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01132274.

Outcome of Patients Treated by Cardiac Resynchronization Therapy Using a Quadripolar Left Ventricular Lead.

BACKGROUND: Not all heart failure (HF) patients benefit from cardiac resynchronization therapy (CRT). We assessed whether choosing the site of left ventricular (LV) pacing by a quadripolar lead may improve response to CRT. METHODS AND RESULTS: We prospectively randomized 23 patients with HF (67±11 years; 21 males) to CRT with a quadripolar LV lead (group 1, with the LV pacing site chosen on the basis of QRS shortening using simultaneous biventricular pacing), and 20 patients (71±6 years; 16 males) to a bipolar LV lead (group 2, with devices programmed with a conventional tip-to-ring configuration). New York Heart Association (NYHA) class and LV ejection fraction (EF) by 2D echocardiography were assessed at baseline and after 3 months. The baseline EF was not different between the 2 groups (25±6% group 1 vs. 27±3% group 2; P=0.22), but after 3 months EF was higher in group 1 (35±13% group 1 vs. 31±4% group 2; P<0.001). A reduction in at least 1 NYHA class at 3 months was observed in 22 (96%) and 12 (60%) of group 1 and group 2 patients, respectively (P<0.05). CONCLUSIONS: CRT with a quadripolar LV lead was associated with an improvement of EF greater than that observed in patients receiving a bipolar LV lead. In devices with a quadripolar lead, CRT programming based on the best QRS shortening is reliable and effective. (Circ J 2016; 80: 613-618).

Effect of remote ischemic preconditioning on platelet activation and reactivity induced by ablation for atrial fibrillation.

BACKGROUND: Radiofrequency ablation of atrial fibrillation has been associated with some risk of thromboembolic events. Previous studies showed that preventive short episodes of forearm ischemia (remote ischemic preconditioning [IPC]) reduce exercise-induced platelet reactivity. In this study, we assessed whether remote IPC has any effect on platelet activation induced by radiofrequency ablation of atrial fibrillation. METHODS AND RESULTS: We randomized 19 patients (age, 54.7±11 years; 17 male) undergoing radiofrequency catheter ablation of paroxysmal atrial fibrillation to receive remote IPC or sham intermittent forearm ischemia (control subjects) before the procedure. Blood venous samples were collected before and after remote IPC/sham ischemia, at the end of the ablation procedure, and 24 hours later. Platelet activation and reactivity were assessed by flow cytometry by measuring monocyte-platelet aggregate formation, platelet CD41 in the monocyte-platelet aggregate gate, and platelet CD41 and CD62 in the platelet gate in the absence and presence of ADP stimulation. At baseline, there were no differences between groups in platelet variables. Radiofrequency ablation induced platelet activation in both groups, which persisted after 24 hours. However, compared with control subjects, remote IPC patients showed a lower increase in all platelet variables, including monocyte-platelet aggregate formation (P<0.0001), CD41 in the monocyte-platelet aggregate gate (P=0.002), and CD41 (P<0.0001) and CD62 (P=0.002) in the platelet gate. Compared with control subjects, remote IPC was also associated with a significantly lower ADP-induced increase in all platelet markers. CONCLUSIONS: Our data show that remote IPC before radiofrequency catheter ablation for paroxysmal atrial fibrillation significantly reduces the increased platelet activation and reactivity associated with the procedure.

The association between ICD interventions and mortality is independent of their modality: clinical implications.

BACKGROUND: Patients with severe structural heart disease have increased mortality after implantable cardioverter-defibrillator (ICD) shocks. Whether this is limited to ICD shock therapy only or extends also to no-shock therapies, such as antitachycardia pacing (ATP), is unclear. We investigated the impact of different ICD therapies on long-term mortality. METHODS: We enrolled 573 patients who underwent ICD implantation at our institution from 2004 to 2011. The population was divided into 3 groups: no device interventions (group 1), ATP interventions (group 2), and shock interventions (group 3). The endpoint was the all-cause mortality. RESULTS: Over a follow-up period of 48 months (range 1-110), 447 (78%) had no device interventions, 71 (12%) had ATP therapy only, and 55 (10%) had at least one shock intervention. All-cause mortality occurred in 94 patients in group 1 (21%), 23 patients (43%) in group 2, and 21 patients (38%) in group 3. At multivariable Cox regression analysis, ATP intervention (HR: 1.8; 95% CI 1.1-3; P < 0.001), shock intervention (HR: 1.39; 95% CI 1.09-1.77; P = 0.008), age (HR: 1.05; 95% CI 1.02-1.07; P < 0.001), and LVEF (HR: 0.95; 95% CI 0.93-0.98; P = 0.001) were predictors of all-cause mortality. No significant difference in mortality was found between group 2 and 3. CONCLUSION: Patients with ICDs who receive appropriate interventions are at increased risk of mortality. Such risk is not dependent on different types of ICD therapy, such as shocks or ATP. Our data suggest that sustained ventricular arrhythmias per se have a negative impact on prognosis rather than modality of ICD therapy.

Cardiovascular implantable electronic device infection: delayed vs standard FDG PET-CT imaging.

BACKGROUND: Positron emission tomography-computed tomography (PET-CT) with (18)F-fluorodeoxyglucose (FDG) has emerged as a rapidly evolving diagnostic tool for infectious diseases. However, the optimal imaging time in this clinical setting is not clear yet. The aim of this study is to investigate whether delayed (3 hours) FDG PET-CT could increase the diagnostic accuracy of this technique compared to standard (1 hour) imaging in the detection of septic foci involving the pocket and/or pacing leads in patients with suspected cardiovascular implantable electronic device (CIED) infection scheduled for device removal. METHODS AND RESULTS: Twenty-seven patients underwent standard and delayed imaging. PET-CT results were compared to bacteriological cultures after CIED removal. Fifteen controls free of infection underwent PET-CT imaging as part of investigation of malignancy. The diagnostic accuracy of delayed imaging was significantly higher than 1-hour scan for lead infection (70% vs 51%, P = .024). No significant difference was found between standard and delayed diagnostic accuracy for pocket or device infection. Semi-quantitative analysis showed that mean pocket and lead target-to-background ratio were significantly higher on delayed compared to standard imaging (3.7 ± 1.9 vs 1.6 ± 1.1, P = .0002; 3.0 ± 1.3 vs 0.7 ± 1.0, P = .01). CONCLUSIONS: Delayed FDG PET-CT imaging should be considered at least in patients with negative 1-hour scan and founded suspicion of pacing lead infection.

Safety of transvenous lead extraction according to centre volume: a systematic review and meta-analysis.

BACKGROUND: Transvenous lead extraction (TLE) is a complex invasive procedure and the experience of the operator and the team is a major determinant of procedural outcomes. AIM: Because of very limited data available on minimum procedural volumes to enable training and ongoing competency for TLEs, we performed a meta-analysis aimed at assessing the outcomes of TLE in the centres with low, medium, and high volume of procedures. METHODS: Of the 280 papers initially retrieved until February 2013, 66 observational studies met inclusion criteria and were included in at least one stratified meta-analysis: 17 were prospective studies; 47 had a retrospective design; and 2 were defined 'experience studies'. We included only articles published after the introduction of laser technique (year 1999). We divided the studies in low, medium, and high volume centres utilizing either the European Heart Rhythm Association (EHRA) or Lexicon classification criteria. RESULTS: When meta-analyses were carried out separately for the studies with larger and smaller sample sizes, either using EHRA or Lexicon classification criteria, no clear differences emerged in the combined rate of major complications or intraoperative deaths. In contrast, both minor complications and mortality at 30 days decreased as centre volume increased. CONCLUSIONS: In our meta-analysis of observational studies, patients who have been treated in higher volume centres have a lower probability of minor complications and death at 30 days regardless of the infection rate, length of lead duration, type of device, and type of extraction.

Acute myocardial infarction revealed by recurrent ventricular tachyarrhythmias detected by remote monitoring.

Remote monitoring (RM) of cardiac implantable electronic devices (CIED) represented a major improvement in clinical practice and has been used with multiple indications. Many parameters monitored on a daily basis by current CIED can indeed assist in clinical practice (eg, decompensated heart failure) by providing the patient with optimal timing for anticipated outpatient visit or urgent medical care. Recognition of acute myocardial infarction (AMI) is not usually considered among the capabilities of RM. We present the case of an AMI occurring without any ischaemic symptoms but associated with recurrent ventricular tachyarrhythmias effectively treated by multiple interventions of the implantable cardioverter defibrillator and promptly detected by RM personnel, who recommended the patient to quickly access to the emergency department where diagnosis and revascularization of an otherwise untreated myocardial infarction was performed.

Characteristics and Outcome of Patients with or without Previous Implantable Cardioverter Defibrillator Interventions Undergoing Ablation for Ventricular Tachycardia.

Background: Catheter ablation (CA) is a well-established treatment in patients with ventricular tachycardia and appropriate implantable cardioverter defibrillator (ICD) therapies. Methods: We enrolled 57 consecutive carriers of ICD undergoing CA for electrical storm (ES). Our aim was to investigate differences in clinical, device-related, and electroanatomic features among patients who had history of appropriate ICD interventions before the ES compared to those who had not. The primary endpoint was a composite of death from any cause and recurrences of sustained VT, ventricular fibrillation, appropriate ICD therapy, or ES. Results: During a median follow up of 39 months, 28 patients (49%) met the primary endpoint. Those with previous ICD interventions had a higher prevalence of late potentials and a greater unipolar low-voltage area at electroanatomic mapping. Patients who met the primary endpoint had a higher prevalence of ATP/shock episodes preceding the ES event. At Cox regression analysis, non-ischemic dilated cardiomyopathy (NIDCM), QRS duration, and previous ATP and/or shock before the ES were associated with arrhythmic recurrences and/or death. At multivariate analysis, NIDCM and previous shock were associated with arrhythmic recurrences and/or death. Conclusions: A history of recurrent ICD therapies predicts worse outcomes when CA is needed because of ES. Although more studies are needed to definitively address this question, our data speak in support of an early referral for CA of ES.

Prognostic value of electroanatomic-guided endomyocardial biopsy in patients with myocarditis, arrhythmogenic cardiomyopathy and non dilated left ventricular cardiomyopathy.

A wide variety of non-invasive and invasive techniques for SCD risk stratification in non ischemic cardiomyopathy (NICM) have been proposed, including left ventricular (LV) ejection fraction, QRS duration, late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) and invasive electrophysiologic study with or without three-dimensional electroanatomic mapping (3D-EAM), to identify and characterize the arrhythmogenic substrate. There is still no clear consensus on the risk stratification in this clinical setting. The aim of our study is to characterize the 3D-EAM substrate in patients with the same clinical presentation of unexplained complex VAs and NICM using CMR, three-dimensional electranatomic mapping (3D-EAM) in association with endomyocardial biopsy (EMB) and genetic screening, as a more precise and early diagnostic assessment may provide important subsequent prognostic impact. The study was designed as a prospective multi-center observational evaluation and the patient follow-up was scheduled at 6 months interval. We enrolled 125 patients distinct into four different group by complete diagnostic work-up: myocarditis, non-dilated left ventricular cardiomyopathy, arrhythmogenic cardiomyopathy and control group. The four groups were compared in terms of clinical, imaging and 3D-EAM data. At multivariate analysis sustained VT/VF on admission [HR: 3.64 (1.79-7.4), p < 0.001], total bipolar scar area of left and right ventricle detected by 3D-EAM [HR: 2.24 (1.13-4.49), p = 0.02], histological diagnosis of myocarditis by 3D-EAM guided endomyocardial biopsy (EBM) [HR: 2.79 (1.04-7.44), p = 0.01] were independent predictors of complex VAs or death at follow-up. 3D-EAM guided EMB represent not only a valid diagnostic tool to identify the arrhythmogenic substrate in patients with NICM and ventricular arrhythmic phenotype but also an important predictor of complex Vas at long term follow-up.

Remote Monitoring of Cardiac Implantable Electronic Devices in Very Elderly Patients: Advantages and Specific Problems.

Cardiac implantable electronic devices (CIEDs) offer the benefit of remote monitoring and decision making and find particular applications in special populations such as the elderly. Less transportation, reduced costs, prompt diagnosis, a sense of security, and continuous real-time monitoring are the main advantages. On the other hand, less physician-patient interactions and the technology barrier in the elderly pose specific problems in remote monitoring. CIEDs nowadays are abundant and are mostly represented by rhythm control/monitoring devices, whereas hemodynamic remote monitoring devices are gaining popularity and are evolving and becoming refined. Future directions include the involvement of artificial intelligence, yet disparities of availability, lack of follow-up data, and insufficient patient education are still areas to be improved. This review aims to describe the role of CIED in the very elderly and highlight the merits and possible drawbacks.

Novel cryoballoon technology for atrial fibrillation ablation: Impact of pulmonary vein variant anatomy, cooling characteristics, and 1-year outcome from the CHARISMA registry.

BACKGROUND: No data have been reported on cooling characteristics and the impact of variant pulmonary vein (PV) anatomy on atrial fibrillation (AF) recurrences after POLARx cryoballoon (CB) ablation. OBJECTIVE: The purpose of this study was to analyze the impact of PV anatomy variants and cooling characteristics after CB ablation from a large multicenter prospective registry. METHODS: The primary end point was defined as 1-year absence of any atrial tachyarrhythmias (ATAs: AF/atrial flutter/atrial tachycardia). Correlation between ATA recurrences and anatomy variants/cooling characteristics were evaluated. The secondary outcome was the rate of major periprocedural complications. RESULTS: A total of 429 consecutive patients diagnosed with paroxysmal AF (83.4%) or persistent AF (peAF; 16.6%) were enrolled. Twenty-eight patients (6.6%) exhibited an anatomical variant (common ostium: 4.0%; adjunctive PV: 2.6%). Nadir temperature, thaw time, and total deflation time were different between standard PVs and PV variants. After the blanking period, over a mean of 431 ± 99 days of follow-up, 63 patients (14.7%) suffered an ATA recurrence. Patients with recurrences had both a shorter thaw time (18.5 ± 7 seconds vs 19.8 ± 7 seconds; P = .0012) and a shorter total deflation time, whereas time to isolation was longer (57.4 ± 42 seconds vs 49.1 ± 33 seconds; P = .04). Patients with anatomy variants showed a similar ATA recurrence rate (5 of 28 [17.9%]) to the standard anatomy group (58 of 401 [14.5%]) (P = .584), with a hazard ratio (HR) of 1.43 (95% confidence interval [CI] 0.49-4.13; log-rank, P = .4384). After adjusting for confounders, heart failure (HR 4.12; 95% CI 1.75-9.73; P = .0013) and peAF (HR 1.81; 95% CI 1.03-3.18; P = .0433) remained associated with ATA recurrence during follow-up. CONCLUSION: The POLARx CB system demonstrated long-term efficacy, along with a safe profile, in both patients with paroxysmal AF and those with peAF, regardless of the presence PV variants. Time to isolation was longer in patients with ATA recurrences during follow-up. CLINICAL TRIAL REGISTRATION: Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice (CHARISMA). CLINICALTRIALS: gov identifier: NCT03793998. Registration date: January 4, 2019.

A novel electrocardiographic predictor of clinical response to cardiac resynchronization therapy.

AIMS: A wide QRS with left bundle branch block pattern is usually required for cardiac resynchronization therapy (CRT) in patients with dilated cardiomyopathy. However, ∼30% of patients do not benefit from CRT. We evaluated whether a detailed analysis of QRS complex can improve prediction of CRT success. METHODS AND RESULTS: We studied 51 patients (67.3 + 9.5 years, 36 males) with classical indication to CRT. Twelve-lead electrocardiogram (ECG) (50 mm/s, 0.05 mV/mm) was obtained before and 3 months after CRT. The following ECG intervals were measured in leads V1 and V6: (i) total QRS duration; (ii) QRS onset-R wave peak; (iii) R wave peak-S wave peak (RS-V1 and RS-V6); (iv) S wave peak-QRS end; and (v) difference between QR in V6 and in V1. Patients were considered as responder when left ventricular ejection fraction (LVEF) increased by ≥5% and New York Heart Association class by ≥1 after 3 months of CRT. Of ECG intervals, only basal RS-V1 was longer in responders (n = 36) compared with non-responders (52.9 ± 11.8 vs. 44.0 ± 12.6 ms, P = 0.021). Among patients with RS-V1 ≥45 ms 83% responded to CRT vs. 33% of those with RS-V1 < 45 ms (P < 0.001). RS-V1 ≥ 45 ms was independently associated with response to CRT in multivariable analysis (odds ratio 9.8; P = 0.002). A reduction of RS-V1 ≥ 10 ms by CRT also significantly predicted clinical response. RS-V1 shortening correlated with improvement in LVEF (r = -0.45; P < 0.001) and in MS (r = 0.46; P < 0.001). CONCLUSION: Our data point out that RS-V1 interval and its changes with CRT may help to identify patients who are most likely to benefit from CRT.

Clinical Impact of Cardiac Fibrosis on Arrhythmia Recurrence after Ablation in Adults with Congenital Heart Disease.

BACKGROUND: Adults with congenital heart disease (ACHD) are often affected by cardiac arrhythmias requiring catheter ablation. Catheter ablation in this setting represents the treatment of choice but is flawed by frequent recurrencies. Predictors of arrhythmia relapse have been identified, but the role of cardiac fibrosis in this setting has not been investigated. The aim of this study was to determine the role of the extension of cardiac fibrosis, detected by electroanatomical mapping, in predicting arrhythmia recurrencies after ablation in ACHD. MATERIALS AND METHODS: Consecutive patients with congenital heart disease and atrial or ventricular arrhythmias undergoing catheter ablation were enrolled. An electroanatomical bipolar voltage map was performed during sinus rhythm in each patient and bipolar scar was assessed according to the current literature data. During follow-up, arrhythmia recurrences were recorded. The relationship between the extent of myocardial fibrosis and arrhythmia recurrence was assessed. RESULTS: Twenty patients underwent successful catheter ablation of atrial (14) or ventricular (6) arrhythmias, with no inducible arrhythmia at the end of the procedure. During a median follow-up period of 207 weeks (IQR 80 weeks), eight patients (40%; five atrial and three ventricular arrhythmias) had arrhythmia recurrence. Of the five patients undergoing a second ablation, four showed a new reentrant circuit, while one patient had a conduction gap across a previous ablation line. The extension of the bipolar scar area (HR 1.049, CI 1.011-1.089, p = 0.011) and the presence of a bipolar scar area >20 cm2 (HR 6.101, CI 1.147-32.442, p = 0.034) were identified as predictors of arrhythmia relapse. CONCLUSION: The extension of the bipolar scar area and the presence of a bipolar scar area >20 cm2 can predict arrhythmia relapse in ACHD undergoing catheter ablation of atrial and ventricular arrhythmias. Recurrent arrhythmias are often caused by circuits other than those previously ablated.