Anatomic obstacles in cavotricuspid isthmus detected by modified 2D transthoracic echocardiography and long-term outcomes in radiofrequency ablation of typical atrial flutter.

BACKGROUND: Although radiofrequency ablation of the cavotricuspid isthmus (CTI), responsible for sustaining atrial flutter, is a highly effective procedure, in extended patients' observations following this procedure, more than every tenth becomes unsuccessful. Therefore, this study aimed to provide helpful information about the anatomy of the CTI in transthoracic echocardiography, which can aid in better planning of the CTI radiofrequency ablation in patients with typical atrial flutter. MATERIALS AND METHODS: 56 patients with typical atrial flutter after radiofrequency ablation were evaluated at the end of the 24-month observation period. With substernal modified transthoracic echocardiographic (mTTE) evaluation, we identified four main anatomical obstacles impeding radiofrequency ablation. These obstacles were tricuspid annular plane systolic excursion, cavotricuspid isthmus length, cavotricuspid isthmus morphology, and the presence of a prominent Eustachian ridge/Eustachian valve. All intraprocedural radiofrequency ablation data were collected for analysis and correlated with anatomical data. RESULTS: In the 24-month observation period, freedom from atrial flutter was 67.86%. The mean length of the isthmus was 30.34 ± 6.67 mm. The isthmus morphology in 56 patients was categorized as flat (n = 27; 48.2%), concave (n = 10; 17.85%), and pouch (n = 19, 33.9%). A prominent Eustachian ridge was observed in 23 patients (41.1%). Lack of anatomical obstacles in mTTE evaluation resulted in 100% efficacy, while the presence of at least two obstacles significantly increased the risk of unsuccessful ablation with more than two (OR 12.31 p = 0.01). Generally, 8 mm electrodes were the most effective for non-difficult CTI, while 3.5 mm electrodes used with a 3D system had highest performance for complex CTI. Notably, aging was the only factor that worsened the long-term outcome (OR 1.07 p = 0.044). CONCLUSIONS: Preoperative usage of mTTE evaluation helps predict difficulty in cavotricuspid isthmus radiofrequency ablation, thus allowing better planning of the radiofrequency ablation strategy using the most accurate radiofrequency ablation electrode.

Endocardial lead insulation wear in a scanning and optical microscope.

BACKGROUND: The path and interaction of leads within the cardiovascular system are influenced by various factors, including the implantation technique. Furthermore, the multifaceted composition of these leads, often comprising multiple materials, can contribute to their potential degradation and wear over time. OBJECTIVES: Our aim was to investigate the wear of lead insulation following the removal of transvenous leads and pinpoint the regions of the lead most vulnerable to damage. MATERIAL AND METHODS: We undertook a prospective analysis of patients from a single tertiary center who underwent transvenous lead explantation (TLE) between October 1, 2013, and July 31, 2015. Specifically, our examination focused on endocardial leads removed using simple screw-out and gentle traction techniques. Subsequent lead evaluations were conducted utilizing scanning electron and optical microscopes. RESULTS: Among the 86 patients who underwent the TLE procedure, 26 patients (30%) required the removal of 39 leads through simple traction. Inspection using scanning electron microscopy consistently indicated insulation damage across all leads. A total of 347 damaged sites were identified: 261 without lead unsealing and 86 exhibiting unsealing. Notably, the sections of the leads located within the intra-pocket area demonstrated the highest vulnerability to damage (odds ratio (OR): = 9.112, 95% confidence interval (95% CI): 3.326-24.960), whereas the intravenous regions displayed the lowest susceptibility (OR: 0.323, 95% CI: 0.151-0.694). CONCLUSIONS: Our study reveals that all evaluated leads exhibited insulation damage, with the intra-pocket segments manifesting a notably higher prevalence of damage than the intravenous segments.

Importance of Comprehensive Assessment in Brugada Syndrome. Reply to Kataoka, N.; Imamura, T. How to Diagnose and Risk Stratify Brugada Syndrome. Comment on "Matusik et al. Twelve-Lead ECG, Holter Monitoring Parameters, and Genetic Testing in Brugada Syndrome: Insights from Analysis of Multigenerational Family with a History of Sudden Cardiac Arrest during Physical Activity. J. Clin. Med. 2023, 12, 6581".

We would like to thank Dr. Imamura for their interest in our study and their valuable comments on diagnostics and risk stratification in Brugada syndrome (BrS) [...].

Twelve-Lead ECG, Holter Monitoring Parameters, and Genetic Testing in Brugada Syndrome: Insights from Analysis of Multigenerational Family with a History of Sudden Cardiac Arrest during Physical Activity.

Brugada syndrome (BrS) is an arrhythmogenic disorder increasing the risk of syncopal episodes and sudden cardiac death. BrS usually runs through families with reduced penetrance and variable expression. We analyzed the multigenerational family of a patient who died after sudden cardiac arrest with post-mortem diagnosis of BrS. We analyzed clinical history, comprehensive arrhythmic risk, genetic findings, and additional tests, including electrocardiogram (ECG), detailed 24-hour Holter ECG results, and standard echocardiography findings, and followed up the patients in the ambulatory clinic. We analyzed a pedigree of 33 members of four generations of the family (19 male and 14 female patients). In this family, we identified 7 patients with BrS (median Modified Shanghai Score and Sieira model: 4.5 (4-6) and 1 (0-4) points, respectively), including both parents of the deceased patient, and 8 relatives with negative sodium channel blocker drug challenge test. Genetic testing revealed a novel mutation in sodium voltage-gated channel alpha subunit 5 (SCN5A) c.941A>G, (p.Tyr314Cys) inherited from the father of the proband. Patients with BrS were characterized by longer P-wave duration (120 (102-155) vs. 92.5 (88-110) ms, p = 0.013) and longer PR intervals (211.3 ±26.3 vs. 161.6 ± 18.9 ms, p = 0.001), along with more frequent positive aVR sign, but did not differ in terms of QRS duration or T-wave characteristics in resting ECGs. BrS patients were characterized by lower mean, minimal, and maximal (for all p ≤ 0.01) heart rates obtained from Holter ECG monitoring, while there was no difference in arrhythmias among investigated patients. Moreover, visual diurnal variability of ST segment changes and fragmented QRS complexes were observed in patients with BrS in Holter ECG monitoring. There were no major arrhythmic events during median follow-up of 68.7 months of alive BrS patients. These results suggest ECG features which may be associated with a diagnosis of BrS and indicate a novel SCN5A variant in BrS patients. Twelve-lead Holter ECG monitoring, with modified precordial leads placement, may be useful in BrS diagnostics and risk stratification in personalized medicine.

The usefulness of echo-based hemodynamic parameters in cardiac resynchronization therapy with conduction system pacing for optimal device programing.

BACKGROUND: His bundle pacing (HBP) has proved to be a valuable alternative enabling the physiological activation of cardiac contraction in cardiac resynchronization therapy (CRT). At present, however, little is known about the optimal method of programming of the His bundle-paced CRT systems in terms of achieving the best cardiac output. AIM: The aim of this study was to evaluate the impact of cardiac resynchronization therapy with conduction system pacing (CRT+CSP) on echo-based hemodynamic parameters in the early post-operative measurements. METHODS: The study enrollment criteria included: permanent atrial fibrillation, heart failure and bundle branch block. All patients underwent implantation of CRT + HBP. During the post-operative phase, we aimed to optimize HOT-CRT settings in order to achieve the greatest cardiac output assessed by complex echocardiographic measurements. RESULTS: The study included 21 patients, mean age 71.2 (6.3) years, predominantly men (71.4%) with non-ischemic cardiomyopathy 62%. All patients had heart failure with NYHA functional class III and IV (81%). Mean left ventricular ejection fraction was 27.5 (9.7%). The mean duration of the QRS complex was 148.8 ms. The effects of resynchronization pacing: HBP alone, HBP with left ventricular pacing, HBP with biventricular pacing (BiV) and BiV without HBP ​​were analyzed consecutively. HBP combined with left ventricular pacing demonstrated the best hemodynamic response. CONCLUSION: His bundle pacing coupled with LV pacing proved to be the most advantageous pacing program setting with regard to cardiac output. Moreover, it performed better than biventricular pacing and significantly better than RV pacing.

Permanent single-chamber atrial pacing: an obsolete or viable alternative to dual-chamber pacing in selected patients with sinus node disease?

INTRODUCTION: Single atrial stimulation (AAI) has been commonly used for permanent pacing in sick sinus syndrome and significant bradycardia. OBJECTIVE: The study aimed to evaluate long­term AAI pacing and to identify timing and reasons for pacing mode change. PATIENTS AND METHODS: Retrospectively, we included 207 patients (60% women) with initial AAI pacing, who were followed­up for an average of 12 years. RESULTS: At the time of death or loss to follow­up, 71 patients (34.3%) had unchanged AAI pacing mode. The reason for an upgrade of the pacing system was development of atrial fibrillation (AF) in 43 patients (20.78%) and atrioventricular block (AVB) in 34 patients (16.4%). The cumulative ratio for a pacemaker upgrade reoperation reached 2.77 per 100 patient­years of the follow­up. Cumulative ventricular pacing below 10% after an upgrade to dual­chamber pacemaker was observed in 28.6% of the patients. Younger age at implant was the leading independent predictor of the change to dual­chamber simulation (hazard ratio, 1.98; 95% CI, 1.976-1.988; P = 0.001). There were 11 (5%) lead malfunctions that required reoperation. Subclavian vein occlusion was noted in 9 upgrade procedures (11%). One cardiac device-related infection was observed. CONCLUSIONS: The reliability of AAI pacing decreases with each year of observation due to development of AF and AVB. However, in the current era of effective AF treatment, the advantages of AAI pacemakers, such as lower incidence of lead malfunction, venous occlusion, and infection, as compared with dual-chamber pacemakers, may make AAI pacemakers a viable option.

Mechanical extraction of implantable cardioverter-defibrillator leads with a dwell time of more than 10 years: insights from a single high-volume centre.

AIMS: To analyze and compare the effectiveness and safety of transvenous lead extraction (TLE) of implantable cardioverter-defibrillator (ICD) leads with a dwell time of >10 years (Group A) vs. younger leads (Group B) using mechanical extraction systems. METHODS AND RESULTS: Between October 2011 and July 2022, we performed TLE in 318 patients. Forty-six (14.4%) extracted ICD leads in 46 (14.5%) patients that had been implanted for >10 years. The median dwell time of all extracted ICD leads was 5.9 years. Cardiovascular implantable electronic device-related infection was an indication for TLE in 31.8% of patients. Complete ICD leads removal and complete procedural success in both groups were similar (95.7% in Group A vs. 99.6% in Group B, P = 0.056% and 95.6% in Group A vs. 99.6% in Group B, P = 0.056, respectively). We did not find a significant difference between major and minor complication rates in both groups (6.5% in Group A vs. 1.5% in Group B and 2.2% in Group A vs. 1.8% in Group B, P = 0.082, respectively). One death associated with the TLE procedure was recorded in Group B. CONCLUSION: The TLE procedures involving the extraction of old ICD leads were effective and safe. The outcomes of ICD lead removal with a dwell time of >10 years did not differ significantly compared with younger ICD leads. However, extraction of older ICD leads required more frequent necessity for utilizing multiple extraction tools, more experience and versatility of the operator, and increased surgery costs.

Radiofrequency catheter ablation of ventricular tachycardia using combined endocardial techniques in patients with structural heart disease improves procedural effectiveness and reduces arrhythmia episodes.

BACKGROUND: Evidence indicates that radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in patients with structural heart disease (SHD) is safe and effective. However, arrhythmia recurrence is still relatively high, and the optimal procedural strategy is unclear. In clinical practice, several combinations of mapping and ablation techniques are used to improve VT ablation efficacy. AIM: The study aimed to evaluate and provide evidence on the efficiency and safety of a systematized combination of VT ablation (mapping) techniques in patients with SHD. METHODS: From 2016 to 2019, 47 patients (54 procedures) with SHD (89% heart failure, 94% ischemic heart disease, 37% VT storm) who underwent RFCA of VT were retrospectively analyzed from a group of 58 consecutive patients. During RFCA of VT, different combinations of three techniques, activation mapping (AM), pace mapping (PM), and substrate-based mapping (SbM), were used. The procedures were performed using the CARTO® 3 (Biosense Webster Inc., Diamond Bar, CA, US) electro-anatomical mapping system. RESULTS: During a median (interquartile range [IQR]) follow-up of 25.5 months (11.75-52.25), VT-free survival after ablation was 68.5% (n = 37/54 procedures). Acute procedural success was achieved in 85% (n = 46/54 procedures). The number of induced VT morphologies, induction of non-clinical or non-sustained VT after ablation, and fewer VT mapping techniques used during the procedure were related to decreasing VT-free survival. CONCLUSIONS: VT ablation strategy based on systemic use of combined techniques is effective and safe in long-term follow-up of patients with SHD.

Continuous positive airway pressure treatment reduces ventricular arrhythmias in obstructive sleep apnea patients with nocturnal dominance of arrhythmias and severe desaturations.

INTRODUCTION: Continuous positive airway pressure (CPAP) treatment is considered effective in reducing ventricular arrhythmias (VAs) in patients with obstructive sleep apnea (OSA). OBJECTIVES: We aimed to assess the influence of this treatment and to identify determinants of antiarrhythmic response. PATIENTS AND METHODS: We included patients with OSA and VAs (corresponding to grades 2-5 in the Lown classification), who underwent CPAP treatment and controls, who refused CPAP therapy. Holter electrocardiographic monitoring was performed at baseline and after 3 months of follow­up. RESULTS: The study consisted of 46 patients in the CPAP group and 30 controls. We observed a significant reduction in premature ventricular contractions (PVCs) and nonsustained ventricular tachycardia events (P = 0.007 and P = 0.03, respectively) in the CPAP group after 3 months, and no difference in controls. The effect of PVC reduction was significant in the patients with nocturnal dominance of PVCs (P = 0.002) and with desaturations equal to or below 80% (P = 0.001). PVC reduction rate (PVC at follow­up / PVC at baseline) correlated inversely with night / day PVC ratio at baseline (R = -0.36; P = 0.02) and the lowest saturation (R = 0.32; P = 0.03) in the CPAP group. After adjustment for clinical data, night / day PVC ratio was an independent predictor of PVC reduction rate (unstandardized coefficient B = -0.19; 95% CI, -0.37 to -0.01; P <0.05). Its value equal to or greater than 1.16 predicted good antiarrhythmic treatment response with sensitivity and specificity of 83% and 70%, respectively. CONCLUSIONS: CPAP treatment decreases VAs in OSA patients, especially those with severe desaturations and nocturnal domination of PVCs. Night / day PVC ratio might be a useful clinical parameter predicting reduction of PVCs in these patients.

Contact Force-Sensing versus Standard Catheters in Non-Fluoroscopic Radiofrequency Catheter Ablation of Idiopathic Outflow Tract Ventricular Arrhythmias.

BACKGROUND: Adequate contact between the catheter tip and tissue is important for optimal lesion formation and, in some procedures, it has been associated with improved effectiveness and safety. We evaluated the potential benefits of contact force-sensing (CFS) catheters during non-fluoroscopic radiofrequency catheter ablation (NF-RFCA) of idiopathic ventricular arrhythmias (VAs) originating from outflow tracts (OTs). METHODS: A group of 102 patients who underwent NF-RFCA (CARTO, Biosense Webster Inc., Irvine, CA, USA) of VAs from OTs between 2014 to 2018 was retrospectively analyzed. RESULTS: We included 52 (50.9%) patients in whom NF-RFCA was performed using CFS catheters and 50 (49.1%) who were ablated using standard catheters. Arrhythmias were localized in the right and left OT in 70 (68.6%) and 32 (31.4%) patients, respectively. The RFCA acute success rate was 96.1% (n = 98) and long-term success during a minimum 12-month follow-up (mean 51.3 ± 21.6 months) was 85.3% (n = 87), with no difference between CFS and standard catheters. There was no difference in complications rate between CFS (n = 1) and standard catheter (n = 2) ablations. CONCLUSIONS: There is no additional advantage of CFS catheters use over standard catheters during NF-RFCA of OT-VAs in terms of procedural effectiveness and safety.

Thoracic impedance measurement in heart stimulation and cardiac arrhythmias.

The electrocardiogram (ECG) interpretation in patients with implantable cardioverter defibrillator (ICD) is often a puzzling problem. The difficulty of the device function evaluation further increases in the presence of unfamiliar timing cycles and additional functions. We present an interesting ECG with a special function of a Biotronik ICD devices called the thoracic impedance monitoring, and demonstrate its behavior in a patient with atrial fibrillation, pacing beats, ventricular ectopic beats, and couple of ventricular beats. This report shows unexceptional occurrence of tricky ECG finding in patient with Biotronik ICDs.