Extraction of lumenless pacing leads from the His bundle and left bundle branch area: outcomes of the high-volume centre.

AIMS: The application of conduction system pacing (CSP) in clinical practice is growing, and the need for lead extraction will also increase. The data on outcomes and safety of CSP lead extraction are limited. The aim of this study was to assess procedural outcomes and safety of CSP lead removal. METHODS AND RESULTS: Forty-seven patients from the EXTRACT Registry with the indication for CSP lead removal were enrolled in the study conducted at the Department of Electrocardiology in Katowice, Poland. Extraction technique, outcomes, safety, and complication were evaluated. Forty-three (91.5%) leads were successfully removed, and 41 (87.2%) were removed with traction only. The dwelling time of 28 extracted leads was longer than 1 year, and the oldest extracted lead was implanted for 89 months. Seven (14.9%) leads were removed from the left bundle branch (LBB) area and 36 from the His bundle (HB). Transient complete atrioventricular block occurred during the procedure in two patients. In 27 out of 31 attempts (87.1%), new CSP leads were implanted: nine (33.3%) HB pacing leads and 18 (66.7%) LBB area pacing leads. CONCLUSION: The CSP lead extraction is safe and feasible with a low complication rate and high rate of CSP lead reimplantation.

Effect of Sleep-Disordered Breathing on Exercise Capacity after Myocardial Infarction - A Cross-Sectional Study.

Background: Exercise capacity reflects the cardiovascular risk after myocardial infarction (MI). The study aims to evaluate the impact of sleep-disordered breathing (SDB) on exercise capacity after MI. Methods: Consecutive patients referring to outpatient cardiac rehabilitation up to 28 days after MI and participating in the Polish Managed Care after Acute Myocardial Infarction (MC-AMI) program were included. On admission, we assessed the presence and the severity of SDB using the home sleep apnea test (HSAT), patients' maximum exercise capacity on a treadmill exercise stress test (EST), and a 6-minute walk test (6MWT), as well as the effect of SDB on the results obtained. In the multivariate analysis, we verified the strength of the observed associations concerning age, anthropometric parameters, and left ventricular ejection fraction (LVEF). Results: A total of 254 patients aged 60.00 (interquartile range 51.00-67.00), including 39 (15.4%) women, with technically adequate HSAT, constituted the study group. Mild SDB was found in 82 (32.3%), moderate in 54 (21.3%), and severe in 51 (20.1%) patients. Among those diagnosed with SDB, obstructive sleep apnea (OSA) was dominant in 167 (89.8%). With the worsening of SDB, the distance in 6MWT and the maximum physical exertion achieved in EST, expressed in metabolic equivalents (METs) and maximal heart rate (MHR), decreased. The linear regression analysis confirmed the following: (1) inversely proportional relationship between the respiratory event index and METs, MHR, and 6MWT distance (p = 0.005, p = 0.008, and p = 0.004), and the maximum apnea duration and MET and 6MWT distance (p = 0.042 and p = 0.002); and (2) directly proportional relationship between mean arterial oxygen saturation ( SpO 2 ) during sleep and MET, MHR, and 6MWT distance (p = 0.019, p = 0.006, and p = 0.013), and minimum SpO 2 and MET and MHR (p = 0.040 and p < 0.001). However, the independent risk factors for impaired exercise capacity, determined using multivariable regression analysis, were age, female sex, higher body mass index (BMI), and decreased LVEF, but not SDB parameters. Conclusions: SDB negatively impacts exercise capacity after MI. However, the strength of this association may be less pronounced due to the interaction of risk factors common for SDB and impaired exercise capacity, e.g., sex, age, BMI, and LVEF.

Survival of patients with pacing-induced cardiomyopathy upgraded to CRT does not depend on defibrillation therapy.

BACKGROUND: Permanent right ventricular pacing (RVP) results in cardiac dyssynchrony that may lead to heart failure and may be an indication for the use of cardiac resynchronization therapy (CRT). The study aimed to evaluate predictors of outcomes in patients with pacing-induced cardiomyopathy (PICM) if upgraded to CRT. METHODS: One hundred fifteen patients, 75.0 years old (IQR 67.0-80.0), were upgraded to CRT due to the decline in left ventricle ejection fraction (LVEF) caused by the long-term RVP. A retrospective analysis was performed using data from hospital and outpatient clinic records and survival data from the National Health System. RESULTS: The prior percentage of RVP was 100.0% (IQR 97.0-100.0), with a QRS duration of 180.0 ms (IQR 160.0-200.0). LVEF at the time of the upgrade procedure was 27.0% (IQR 21.0-32.75). The mean follow-up was 980 ± 522 days. The primary endpoint, death from any cause, was met by 26 (22%) patients. Age > 82 years (HR 5.96; 95% CI 2.24-15.89; P = .0004) and pre-CRT implantation LVEF < 20% (HR 5.63; 95%CI 2.19-14.47; P = .0003), but neither the cardioverter-defibrillator (ICD) implantation (HR 1.00; 95%CI 0.45-2.22; P = 1.00), nor the presence of atrial fibrillation (HR 1.22; 95%CI 0.56-2.64; P = .62), were independently associated with all-cause mortality. CONCLUSION: Advanced age and an extremely low LVEF, but neither the presence of atrial fibrillation nor implanting an additional high voltage lead, influence the all-cause mortality in patients after long-term RVP, when upgraded to CRT.

His bundle pacing is continually relevant for patients with atrial fibrillation and bradycardia without prior atrioventricular nodal ablation, data from mid-term follow-up.

BACKGROUND: In patients with atrial fibrillation (AF) and symptomatic bradycardia, His Bundle pacing (HBP) is used to achieve an appropriate heart rate and physiological depolarization of the left ventricle (LV). AIMS: We aimed to evaluate the impact of HBP on LV function in two different populations: normal LV ejection fraction (LVEF) and low LVEF (<50%). METHODS: Patients who received HBP as de novo therapy or as an upgrade were divided into two groups based on initial LVEF, followed by echocardiographic and device monitoring. RESULTS: One hundred and twenty three patients (aged 76.0 [69.2-79.8] years, 74.0% men) with AF and bradycardia received HBP and completed follow-up with a median of 6.2 months (6.0-8.0). LV function remained unchanged in initially normal LV function patients (65 participants, LVEF 59.0% [55.0 - 62.0] vs. 58.0% [55.0-63.0]). In patients with low LVEF (58 participants), there was an increase in LVEF (37.5% [30.0-43.0] vs. 44.0% [35.0-50.0]; p < 0.0001), reduction of indexed LV end-systolic volume (62.4 [20.7] ml vs. 51.5 [21.5] ml; p = 0.001) and indexed LV end-diastolic volume (97.5 [26.2] ml vs. 88.1 [25.1] ml; p = 0.009), and improvement in the New York Heart Association class (2.3 [0.71] to 1.6 [0.9]; p < 0.0001). CONCLUSION: With permanent HBP, patients with AF and bradycardia and without prior atrioventricular nodal ablation did not experience LV systolic function deterioration. Those with reduced baseline LVEF experienced improvements in LV function and its reverse remodeling at the mid-term follow-up.

His Bundle Pacing: Predicting Mortality and Major Complications in Mid-Term Follow-Up.

Introduction: His bundle pacing (HBP) is suitable for 80% of patients with any indication for permanent pacemaker implantation, with a clinical benefit compared to right ventricular pacing (RVP). Although complications and mortality related to RVP are widely reported in the literature, data on HBP are limited. This study aimed to analyze HBP complications and outcomes in the short-term (up to 30 days) and long-term (up to the following 24 months) follow-up (F/U). Materials and Methods: The study includes 373 patients aged ≥ 18, enrolled from October 2015 to May 2019 in a single-center HBP prospective registry conducted in the Department of Electrocardiology, Upper Silesian Medical Centre of the Medical University of Silesia in Katowice, Poland. Mortality and HBP complications were used as end-points: during hospitalization and up to 30 days (short-term F/U), and for each F/U point-six months, 12 months, and 24 months after the procedure (long-term F/U). Results: Successful HBP was achieved in 252 patients (68%), with an increasing success rate during consecutive years: 57% in 2015-2016 and 73% in 2017-2019. Complications were found in 8.4% of patients (21/252) in short-term F/U and 5.8% (13/224), 5.5% (11/201), and 6.9% (12/174) at six months, 12 months, and 24 months, respectively. There were no deaths during the first 30 days. However, 26 patients (10.3%) died within 24 months. A left ventricular ejection fraction (LVEF) ≤ 34% was the only independent predictor of all-cause mortality or any major complication in the 24-month F/U. Conclusions: This single-center study reported a low risk of mortality and complications associated with HBP at the short-term F/U. However, during the long-term F/U, we observed a higher but acceptable risk of major complications, with a lower LVEF being an independent predictor of the composite end-point of all-cause mortality or any major complication.

Transvenous lead extraction safety and efficacy in infected and noninfected patients using mechanical-only tools: Prospective registry from a high-volume center.

BACKGROUND: Transvenous lead extraction (TLE) is a well-established treatment option for patients with cardiac implantable electronic devices (CIED) complications. OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of TLE in CIED infection and non-CIED infection patients. METHODS: Consecutive patients who underwent TLE between 2016 and 2022 entered the EXTRACT Registry. Models of prediction were constructed for periprocedural clinical and procedural success and the incidence of major complications, including death in 30 days. RESULTS: The registry enrolled 504 patients (mean age 66.6 ± 12.8 years; 65.7% male). Complete procedural success was achieved in 474 patients (94.0%) and clinical success in 492 patients (97.6%). The total number of major and minor complications was 16 (3.2%) and 51 (10%), respectively. Three patients (0.6%) died during the procedure. New York Heart Association functional class IV and C-reactive protein levels defined before the procedure were independent predictors of any major complication, including death in 30 days in CIED infection patients. The time since the last preceding procedure and platelet count before the procedure were independent predictors of any major complication, including death in 30 days in non-CIED infection patients. CONCLUSIONS: TLE is safe and successfully performed in most patients, with a low major complication rate. CIED infection patients demonstrate better periprocedural clinical success and complete procedural success. However, CIED infection predicts higher 30-day mortality compared with non-CIED infection patients. Predictors of any major complication, including death in 30 days, differ between CIED infection and non-CIED infection patients.

Multicenter Hemodynamic Assessment of the LOT-CRT Strategy: When Does Combining Left Bundle Branch Pacing and Coronary Venous Pacing Enhance Resynchronization?: Primary Results of the CSPOT Study.

BACKGROUND: Left bundle branch area pacing (LBBAP) may be an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We sought to compare the acute hemodynamic and ECG effects of LBBAP, BVP, and left bundle-optimized therapy CRT (LOT-CRT) in CRT candidates with advanced conduction disease. METHODS: In this multicenter study, 48 patients with either nonspecific interventricular conduction delay (n=29) or left bundle branch block (n=19) underwent acute hemodynamic testing to determine the change in left ventricular pressure maximal first derivative (LV dP/dtmax) from baseline atrial pacing to BVP, LBBAP, or LOT-CRT. RESULTS: Atrioventricular-optimized increases in LV dP/dtmax for LOT-CRT (mean, 25.8% [95% CI, 20.9%-30.7%]) and BVP (26.4% [95% CI, 20.2%-32.6%]) were greater than unipolar LBBAP (19.3% [95% CI, 15.0%-23.7%]) or bipolar LBBAP (16.4% [95% CI, 12.7%-20.0%]; P≤0.005). QRS shortening was greater in LOT-CRT (29.5 [95% CI, 23.4-35.6] ms) than unipolar LBBAP (11.9 [95% CI, 6.1-17.7] ms), bipolar LBBAP (11.7 ms [95% CI, 6.4-17.0]), or BVP (18.5 [95% CI, 11.0-25.9] ms), all P≤0.005. Compared with patients with left bundle branch block, patients with interventricular conduction delay experienced less QRS reduction (P=0.026) but similar improvements in LV dP/dtmax (P=0.29). Bipolar LBBAP caused anodal capture in 54% of patients and resulted in less LV dP/dtmax improvement than unipolar LBBAP (18.6% versus 23.7%; P<0.001). Subclassification of LBBAP capture (EHRA criteria) indicated LBBAP or LV septal pacing in 27 patients (56%) and deep septal pacing in 21 patients (44%). The hemodynamic benefit of adding left ventricular coronary vein pacing to LBBAP depended on baseline QRS duration (P=0.031) and success of LBBAP (P<0.004): LOT-CRT provided 14.5% (5.0%-24.1%) greater LV dP/dtmax improvement and 20.8 (12.8-28.8) ms greater QRS shortening than LBBAP in subjects with QRS ≥171 ms and deep septal pacing capture type. CONCLUSIONS: In a CRT cohort with advanced conduction disease, LOT-CRT and BVP provided greater acute hemodynamic benefit than LBBAP. Subjects with wider QRS or deep septal pacing are more likely to benefit from the addition of a left ventricular coronary vein lead to implement LOT-CRT. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04905290.

Relationship of Non-Invasive Arterial Stiffness Parameters with 10-Year Atherosclerotic Cardiovascular Disease Risk Score in Post-COVID-19 Patients-The Results of a Cross-Sectional Study.

This study evaluated the relationship of non-invasive arterial stiffness parameters with an individual 10-year risk of fatal and non-fatal atherosclerotic cardiovascular disease (ASCVD) events in the cohort post-coronavirus disease 2019 (COVID-19). The study group included 203 convalescents aged 60.0 (55.0-63.0) and 115 (56.7%) women. The ASCVD risk was assessed as low to moderate to very high based on medical history (for 62 participants with pre-existing ASCVD/diabetes/chronic kidney disease in the entire cohort) or calculated in percentages using the Systemic Coronary Risk Evaluation 2 (SCORE2) algorithm based on age, sex, smoking status, systolic blood pressure (BP), and non-high-density lipoprotein cholesterol (for 141 healthy participants). The stiffness index (SI) and reflection index (RI) measured by photoplethysmography, as well as pulse pressure (PP), calculated as the difference between systolic and diastolic BP, were markers of arterial stiffness. Stiffness parameters increased significantly with the increase in ASCVD risk in the entire cohort. In 30 (14.8%) patients in the low- to moderate-risk group, the median SI was 8.07 m/s (7.10-8.73), RI 51.40% (39.40-65.60), and PP 45.50 mmHg (40.00-57.00); in 111 (54.7%) patients in the high-risk group, the median SI was 8.70 m/s (7.40-10.03), RI 57.20% (43.65-68.40), and PP 54.00 mmHg (46.00-60.75); and in 62 (30.5%) patients in the very-high-risk group, the median was SI 9.27 m/s (7.57-10.44), RI 59.00% (50.40-72.40), and PP 60.00 mmHg (51.00-67.00). In healthy participants, the SI ≤ 9.0 m/s (sensitivity of 92.31%, area under the curve [AUC] 0.686, p < 0.001) based on the receiver operating characteristics was the most sensitive variable for discriminating low to moderate risk, and PP > 56.0 mmHg (sensitivity of 74.36%, AUC 0.736, p < 0.001) was used for discriminating very high risk. In multivariate logistic regression, younger age, female sex, PP ≤ 50 mmHg, SI ≤ 9.0 m/s, and triglycerides < 150 mg/dL had the best relationship with low to moderate SCORE2 risk. In turn, older age, currently smoking, PP > 56.0 mmHg, RI > 68.6%, and diastolic BP ≥ 90 mmHg were related to very high SCORE2 risk. In conclusion, arterial stiffness is significantly related to ASCVD risk in post-COVID-19 patients and can be helpful as a single risk marker in everyday practice. Cut-off points for arterial stiffness parameters determined based on SCORE2 may help make individual decisions about implementing lifestyle changes or pharmacological treatment of ASCVD risk factors.

Relationships between Heart Chamber Morphology or Function and Respiratory Parameters in Patients with HFrEF and Various Types of Sleep-Disordered Breathing.

Sleep-disordered breathing (SDB), i.e., central sleep apnea (CSA) and obstructive sleep apnea (OSA), affects the prognosis of patients with heart failure with reduced ejection fraction (HFrEF). The study assessed the relationships between heart chamber size or function and respiratory parameters in patients with HFrEF and various types of SDB. The 84 participants were patients aged 68.3 ± 8.4 years (80% men) with an average left ventricular ejection fraction (LVEF) of 25.5 ± 6.85% who qualified for cardioverter-defibrillator implantation with or without cardiac resynchronization therapy. SDB, defined by an apnea-hypopnea index (AHI) ≥ five events/hour, was diagnosed in 76 patients (90.5%); SDB was severe in 31 (36.9%), moderate in 26 (31.0%), and mild in 19 (22.6%). CSA was the most common type of SDB (64 patients, 76.2%). A direct proportional relationship existed only in the CSA group between LVEF or stroke volume (SV) and AHI (p = 0.02 and p = 0.07), and between LVEF or SV and the percentage of total sleep time spent with hemoglobin oxygen saturation < 90% (p = 0.06 and p = 0.07). In contrast, the OSA group was the only group in which right ventricle size showed a positive relationship with AHI (for basal linear dimension [RVD1] p = 0.06), mean duration of the respiratory event (for RVD1 p = 0.03, for proximal outflow diameter [RVOT proximal] p = 0.009), and maximum duration of respiratory event (for RVD1 p = 0.049, for RVOT proximal p = 0.006). We concluded that in HFrEF patients, SDB severity is related to LV systolic function and SV only in CSA, whereas RV size correlates primarily with apnea/hypopnea episode duration in OSA.

Stereotactic management of arrhythmia - radiosurgery in treatment of ventricular tachycardia (SMART-VT). Results of a prospective safety trial.

BACKGROUND AND PURPOSE: Despite its increasing popularity, there are limited prospective data on stereotactic arrhythmia radioablation (STAR). In this trial, we assessed the safety and efficacy of STAR in patients with ventricular tachycardia (VT), focusing on early treatment-related grade ≥ 3 adverse events (AE). MATERIALS AND METHODS: This prospective trial was designed for adults with VT recurrence following catheter ablation (CA) despite adequate pharmacotherapy, or contraindications to CA. A single dose of 25 Gy was delivered to the arrhythmia substrate defined on electro-anatomic mapping and cardiac-gated CT. The primary endpoint was safety, defined as two or fewer treatment-related grade ≥ 3 AEs during the first three months in 11 patients. Additional endpoints included treatment efficacy, clinical and biological markers of cardiac injury, and quality of life. RESULTS: Eleven patients with a median age of 67 years, structural heart disease, and a clinically significant recurrence of VT despite adequate pharmacotherapy and 1-4 previous CAs were enrolled between 2020/09 and 2022/10. Following the treatment, one patient developed a possibly treatment-related grade ≥ 3 AE, a grade 4 heart failure exacerbation at 87 days, which resolved after conservative treatment. There was a total 84.3% reduction in VT burden in 10 evaluable patients; however, VT recurrence was eventually observed in eight, and three patients required additional CAs. Three deaths due to unrelated causes were recorded. CONCLUSIONS: STAR appears to be safe and efficient. It is a promising treatment for selected patients; however, long-term outcomes remain to be evaluated, and controlled trials comparing STAR with standards of care are missing.

The Effects of His Bundle Pacing Compared to Classic Resynchronization Therapy in Patients with Pacing-Induced Cardiomyopathy.

Pacing-induced cardiomyopathy (PICM) is among the most common right ventricular pacing complications. Upgrading to cardiac resynchronization therapy (CRT) is the recommended treatment option. Conduction system pacing with His bundle pacing (HBP) has the potential to restore synchronous ventricular activation and can be an alternative to biventricular pacing (BVP). Patients with PICM scheduled for a system upgrade to CRT were included in the prospective cohort study. Either HBP or BVP was used for CRT. Electrocardiographic, clinical, and echocardiographic measurements were recorded at baseline and six-month follow-up. HBP was successful in 44 of 53 patients (83%). Thirty-nine patients with HBP and 22 with BVP completed a 6-month follow-up. HBP led to a higher reduction in QRS duration than BVP, 118.3 ± 14.20 ms vs. 150.5 ± 18.64 ms, p < 0.0001. The improvement in New York Heart Association (NYHA) class by one or two was more common in patients with HBP than those with BiV (p = 0.04). Left ventricular ejection fraction (LVEF) improved in BVP patients from 32.9 ± 7.93% to 43.9 ± 8.07%, p < 0.0001, and in HBP patients from 34.9 ± 6.45% to 48.6 ± 7.73%, p < 0.0001. The improvement in LVEF was more considerable in HBP patients than in BVP patients, p = 0.019. The improvement in clinical outcomes and left ventricle reverse remodeling was more significant with HBP than BVP. HBP can be a valid alternative to BVP for upgrade procedures in PICM patients.

The usefulness of His bundle pacing in a heterogeneous population of patients with impaired left ventricular systolic function.

BACKGROUND: His bundle pacing (HBP) maintains a physiological activation pattern of ventricular activation, and in patients with intraventricular conduction delay (IVCD) it can normalize wide QRS duration. METHODS: A total of 181 patients from the HBP registry were enrolled into a the study, which was conducted at the Department of Electrocardiology in Katowice, Poland. The patients had left ventricular ejection fraction (LVEF) < 50% and were implanted between November 2015 and April 2019. The HBP indications were as follows: 1) bradycardia and atrioventricular conduction disturbances with expected high pacing burden, 2) IVCD, LVEF ≤ 35%, with an indication for resynchronization therapy, 3) the need to upgrade to resynchronization therapy due to pacing-induced cardiomyopathy. Pacing parameters and echocardiographic and clinical data were assessed for up to 2 years of follow-up (FU). RESULTS: His bundle pacing was successful in 154 (85.1%) patients. Eighty-two patients completed a 6-month FU. The mean age was 70.6 ± 9.23 years, and 79% were males. At 6 months FU LVEF improved from 35.3 ± 8.22% to 43.1 ± 10.14% (p < 0.0001), and indexed left ventricular end-systolic volume (LVESVi) decreased from 63.1 ± 25.21 mL/m² to 51.9 ± 22.79 mL/m² (p < 0.0001). In 53.1%, the LVESVi reduction was greater than 15%. The improvement in LVEF and LVESVi was also observed after 24 months of FU. CONCLUSIONS: His bundle pacing in permanently paced patients when LVEF is reduced below 50% is associated with improvement in LVEF and reverse left ventricle remodeling.

Radiosurgery in Treatment of Ventricular Tachycardia - Initial Experience Within the Polish SMART-VT Trial.

Background: Stereotactic Arrhythmia Radioablation (STAR) is an emerging treatment modality for patients with sustained ventricular tachycardia (VT) and refractory to treatment with drugs and radiofrequency catheter ablation (RFA). It is believed that up to 12-17% of patients experience recurrence of VT within 1 year of follow-up; thus, novel therapeutic options are needed. The aim of this article is to present initial experience within a novel treatment modality for VT. Case Summary: Two patients with a medical history of coronary artery disease and heart failure with reduced left ventricle (LV) ejection fraction, after implantation of cardioverter-defibrillator (ICD) and previous unsuccessful RFAs owing to sustained VT were admitted to the cardiology department due to recurrence of sustained VT episodes. With electroanatomical mapping (EAM), the VT substrate in LV has been confirmed and specified. In order to determine the target volume for radioablation, contrast-enhanced computed tomography was performed and the arrhythmia substrate was contoured using EAM data. Using the Volumetric Modulated Arc Therapy technique and three 6 MeV flattening filter-free photon beam fields, a single dose of 25 Gy was delivered to the target volume structure located in the apex and anterior apical segments of LV in the first patient and in the apex, anterolateral and inferior apical segments of the second patient. In both cases, volumes of the target structures were comparable. Interrogation of the implanted ICD at follow-up visits throughout 6 months after the treatment revealed no VT episodes in the first patient and sudden periprocedural increase in VT burden with a subsequent gradual decrease of ventricular arrhythmia to only two non-sustained episodes at the end of the follow-up period in case of the second patient. A significant reduction in premature ventricular contractions burden was observed compared to the pre-treatment period. No noticeable deterioration in LV function was noted, nor any adverse effects of radiosurgery associated with the implanted device. Conclusion: The early response to STAR can be unpredictable and probably does not reflect the final outcome of irradiation. Close monitoring of patients, especially in the early period after irradiation is crucial to properly handle potentially harmful early reactions to STAR.

Two-point left ventricle pacing and cardiac computed tomography.

Endocardial leads can potentially cause problems during coronary vessels visualization in multislice computed tomography (MSCT) due to a large number of artifacts. Based on presented case, we conclude that it is possible to perform MSCT of coronary arteries and leads visualization despite coexistence of four endocardial leads.

Role of multi-slice computed tomography in the recognition of pericardial cyst.

A pericardial cyst is, according to the definition, a collection of fluid or blood in the pericardial space (inside the pericardial sac) around the heart. New visualization methods can help in the non-invasive diagnosis of pericardial cysts. Based on a presented case, we conclude that multi-slice computed tomography can have a great impact on the detection of pericardium diseases such as a pericardial cyst.

Lead interaction: rare cause of oversensing during implantation procedure of implantable cardioverter-defibrillator system.

A variety of etiologies can cause erroneous detection in patients with implantable cardioverter defibrillator (ICDs). Interaction between two endocardial leads is rare and uncommon in causing electrical noise. During a reimplantation procedure of an ICD system in a 68-year-old man, additional electrical signals could be detected. The interaction between two endocardial defibrillation leads was identified as the cause of sensing problems. When it is not possible to extract the nonfunctional endocardial lead during implantation of the new electrode, it should be implanted away and not in parallel from the old one to avoid interaction between them. A variety of etiologies can cause erroneous detection in patiens with ICD. Interaction between two endocardial leads is rare and uncommon to cause electrical noise.