Management of Arrhythmias and Conduction Disorders in Amyloid Cardiomyopathy.

Cardiac amyloidosis, a condition characterized by abnormal protein deposition in the heart, leads to restrictive cardiomyopathy and is notably associated with an increased risk of arrhythmias and conduction disorders. This article reviews the current understanding and management strategies for these cardiac complications, with a focus on recent advancements and clinical challenges. The prevalence and impact of atrial arrhythmias, particularly atrial fibrillation, are examined, along with considerations for stroke risk and anticoagulation therapy. The article also addresses the complexities of managing rate and rhythm control, outlining the utility and limitations of pharmacological agents and interventions such as catheter ablation. Furthermore, it reviews the challenges in the treatment of ventricular arrhythmias, including the contentious use of implantable cardioverter-defibrillators for primary and secondary prevention. Individualized approaches, considering the unique characteristics of cardiac amyloidosis, are paramount. Continuous research and clinical exploration are essential to refine treatment strategies and improve outcomes in this challenging patient population.

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.

Employment of the Evolution RL sheath as a first-choice device shortens transvenous lead extraction time without affecting procedural safety and efficacy compared to its auxiliary use: Insights from the prospective multicenter EVO registry.

BACKGROUND: Transvenous lead extraction (TLE) is recommended in cases of local and systemic infections related to cardiac implantable electronic devices (CIEDs). Additionally, TLE is indicated in the event of lead damage or CIED malfunction. The extraction procedure is associated with a risk of life-threatening complications. OBJECTIVES: The aim of the EVO registry was to assess the safety and efficacy of birotational Evolution tool usage. MATERIAL AND METHODS: This registry study was prospectively conducted in 8 high-volume implantation centers in Poland. The study included 133 patients aged 63.5 ±15.1 years, and 76.69% were male. Indications for the procedure were: local or systemic infection (33.1%) and lead dysfunction (66.9%). The number of leads extracted varied from 1 (39.84%) to 3 (9.77%). RESULTS: Clinical procedural success was achieved in 99.1% of cases. A total of 226 leads were extracted, and 206 used the Evolution system. Two procedural strategies were identified while using the Evolution system: (1) usage of locking stylet, propylene sheaths and the Evolution system (118 leads, 52%) - group A; (2) usage of locking stylet and Evolution (88 leads, 39%) - group B. There were no differences in the number of complications between these 2 groups. The extraction time was significantly shorter (p = 0.02) in group B than in group A. Major complications occurred in 5.2% of cases with 2 intraprocedural deaths. Minor complications occurred in 1.5% of patients. CONCLUSIONS: The registry confirmed the efficacy and relative safety of the birotational Evolution sheath. Using the rotational sheath as a first attempt significantly reduces extraction time without compromising its safety.

Advances in Molecular Imaging in Infective Endocarditis.

Infective endocarditis (IE) is a growing epidemiological challenge. Appropriate diagnosis remains difficult due to heterogenous etiopathogenesis and clinical presentation. The disease may be followed by increased mortality and numerous diverse complications. Developing molecular imaging modalities may provide additional insights into ongoing infection and support an accurate diagnosis. We present the current evidence for the diagnostic performance and indications for utilization in current guidelines of the hybrid modalities: single photon emission tomography with technetium99m-hexamethylpropyleneamine oxime-labeled autologous leukocytes (99mTc-HMPAO-SPECT/CT) along with positron emission tomography with fluorodeoxyglucose (18F-FDG PET/CT). The role of molecular imaging in IE diagnostic work-up has been constantly growing due to technical improvements and the increasing evidence supporting its added diagnostic and prognostic value. The various underlying molecular processes of 99mTc-HMPAO-SPECT/CT as well as 18F-FDG PET/CT translate to different imaging properties, which should be considered in clinical practice. Both techniques provide additional diagnostic value in the assessment of patients at risk of IE. Nuclear imaging should be considered in the IE diagnostic algorithm, not only for the insights gained into ongoing infection at a molecular level, but also for the determination of the optimal clinical therapeutic strategies.

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.

To what extent does prior antimicrobial therapy affect the diagnostic performance of radiolabeled leukocyte scintigraphy in infective endocarditis?

AIMS: This prospective, single-center study sought to assess to what extent there is interference between the hybrid technique of single-photon emission tomography-computed tomography with technetium99m-hexamethylpropyleneamine oxime-labeled leukocytes (99mTc-HMPAO-SPECT/CT) and antimicrobial therapy in patients with infective endocarditis (IE). METHODS AND RESULTS: During the years 2015-2019, we enrolled 205 consecutive adults with suspected IE, all underwent 99mTc-HMPAO-SPECT/CT. The study population was divided into those who had received antimicrobial therapy up to 30 days prior to 99mTc-HMPAO-SPECT/CT (group 1, n = 96) and those who had not (group 2, n = 109). Patients were prospectively observed for 12 ± 10 months. Group 1 presented higher positive predictive values (91.89% vs. 60.00%, = 0.001), and decreased negative predictive values (77.97% vs. 90.54%, P = 0.04). Patients treated with antimicrobial therapy displayed false-negative 99mTc-HMPAO-SPECT/CT results more often [odds ratio (OR), 4.63; 95% confidence interval (CI), 1.41-15.23, P = .01], particularly when intravenous (OR 5.37; 95% CI 1.73-16.62, P = .004), definite (OR 9.43; 95% CI 2.65-33.51, P = .001), and combination antibiotic regimens (OR 8.1; 95% CI 2.57-25.64, P = .001) had been administered. CONCLUSION: Prior antibiotic therapy affects 99mTc-HMPAO-SPECT/CT diagnostic properties. Patients treated with antimicrobial therapy display false-negative 99mTc-HMPAO-SPECT/CT results more often, especially if intravenous, definite, or combination regimens are administered.

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.

The electrocardiographic interpretation of ventricular pacing suppression algorithms in the pacemaker.

Algorithms designed to reduce the right ventricular (RV) pacing burden are widely available in modern dual-chamber implantable pacing devices. These algorithms allow the atrioventricular delay for sensed ventricular events to be longer than for ventricular paced events. However, since these features are unique to pacemaker manufacturers, they often produce unfamiliar electrocardiographic (ECG) appearances that suggest pacemaker dysfunction. We describe a Vp suppression algorithm used in Biotronik dual-chamber pacemakers and implantable cardioverter-defibrillator devices.

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.

Extracellular volume is an independent predictor of arrhythmic burden in dilated cardiomyopathy.

The current stratification of arrhythmic risk in dilated cardiomyopathy (DCM) is sub-optimal. Cardiac fibrosis is involved in the pathology of arrhythmias; however, the relationship between cardiovascular magnetic resonance (CMR) derived extracellular volume (ECV) and arrhythmic burden (AB) in DCM is unknown. This study sought to evaluate the presence and extent of replacement and interstitial fibrosis in DCM and to compare the degree of fibrosis between DCM patients with and without AB. This is a prospective, single-center, observational study. Between May 2019 and September 2020, 102 DCM patients underwent CMR T1 mapping. 99 DCM patients (88 male, mean age 45.2 ± 11.8 years, mean EF 29.7 ± 10%) composed study population. AB was defined as the presence of VT or a high burden of PVCs. There were 41 (41.4%) patients with AB and 58 (58.6%) without AB. Replacement fibrosis was assessed with late gadolinium enhancement (LGE), whereas interstitial fibrosis with ECV. Overall, LGE was identified in 41% of patients. There was a similar distribution of LGE (without AB 50% vs. with AB 53.7%; p = 0.8) and LGE extent (without AB 4.36 ± 5.77% vs. with AB 4.68 ± 3.98%; p = 0.27) in both groups. ECV at nearly all myocardial segments and a global ECV were higher in patients with AB (global ECV: 27.9 ± 4.9 vs. 30.3 ± 4.2; p < 0.02). Only indexed left ventricular end-diastolic diameter (HR 1.1, 95%CI 1.0-1.2; p < 0.02) and global ECV (HR 1.12, 95%CI 1.0-1.25; p < 0.02) were independently associated with AB. The global ECV cut-off value of 31.05% differentiated both groups (AUC 0.713; 95%CI 0.598-0.827; p < 0.001). Neither qualitative nor quantitative LGE-based assessment of replacement fibrosis allowed for the stratification of DCM patients into low or high AB. Interstitial fibrosis, expressed as ECV, was an independent predictor of AB in DCM. Incorporation of CMR parametric indices into decision-making processes may improve arrhythmic risk stratification in DCM.

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.