Cardiac resynchronization therapy guided by interventricular conduction delay: How to choose between biventricular pacing or conduction system pacing.

BACKGROUND: Biventricular pacing (BIV) is the gold standard for cardiac resynchronization therapy (CRT). Thirty percent of patients do not respond to CRT. Conduction system pacing (CSP) represents a viable alternative. Interventricular conduction delay (IVCD), as electrical desynchrony marker, is a CRT response predictor. The aim of this study was to determine the incidence of CRT responders by selecting the best approach between BIV and CPS based on intraoperative IVCD measurement in patients with HFrEF and LBBB. METHODS: Ninety-six patients were randomly assigned in a 1:1 ratio to either a standard BIV group(control group, CG) or a group where the CRT approach was determined based on IVCD evaluation(study group, SG). If the right ventricular sensed electrogram (RVs)-left ventricular sensed electrogram (LVs) interval was ≥100 ms, the lead was left in its original position; otherwise, the LV lead was removed, and CSP was performed instead. Clinical, EKG, and echocardiographic features have been assessed pre- and 6 months post-implant. Echocardiographic and clinical responder were evaluated. RESULTS: Thirty-seven percent of patients in the SG underwent CSP, as the operative algorithm. The incidence of CRT responders was significantly higher in the SG (echocardiographic criterion: 92.5% vs. 69.8%, p:.009; clinical criterion 87.5% vs. 62.8%, p:.014). The SG showed a significantly greater difference in EF between pre- and post-implant as well as reduced end-diastolic and systolic volumes. Univariate and multivariate regression analysis indicated that enrollment in the SG was the only factor associated with CRT response. CONCLUSION: Intraoperative assessment of IVCD could help determine the optimal CRT approach between BIV and CSP, leading to a significant improvement in the rate of CRT responders.

The interventricular conduction delays guide best cardiac resynchronization therapy: A tailored-patient approach to perform a CRT through Conduction System Pacing.

Evaluation of conduction intervals to predict success of resynchronization in biventricular pacing(BiVP) or Conduction System Pacing(CSP) is not spread in clinical practice. A right ventricle-to-left ventricle intrinsic conduction interval (RVs-LVs) > 70 ms or prolonged RVpaced - LVs(RVp-LVs)interval can predict Cardiac Resynchronization Therapy (CRT)response.This paper describes a case of cardiac resynchronization guided by spontaneous and paced interventricular conduction delays (IVCD) obtained in BiVP that led to changing intraoperative approach. A strategy for cardiac resynchronization based on the CSP/BiVP approach according to the IVCD could represent a viable and reliable solution to obtain a narrow paced QRS and to improve the CRT response.

Safety, efficacy, and reproducibility of cavotricuspid isthmus ablation guided by the ablation index: acute results of the FLAI study.

AIMS: Ablation index (AI) is a marker of lesion quality during catheter ablation that incorporates contact force, time, and power in a weighted formula. This index was originally developed for pulmonary vein isolation as well as other left atrial procedures. The aim of our study is to evaluate the feasibility and efficacy of the AI for the ablation of the cavotricuspid isthmus (CTI) in patients presenting with typical atrial flutter (AFL). METHODS AND RESULTS: This prospective multicentre non-randomized study enrolled 412 consecutive patients with typical AFL undergoing AI-guided cavotricuspid isthmus ablation. The procedure was performed targeting an AI of 500 and an inter-lesion distance measurement of ≤6 mm. The primary endpoints were CTI 'first-pass' block and persistent block after a 20-min waiting time. Secondary endpoints included procedural and radiofrequency duration and fluoroscopic time. A total of 412 consecutive patients were enrolled in 31 centres (mean age 64.9 ± 9.8; 72.1% males and 27.7% with structural heart disease). The CTI bidirectional 'first-pass' block was reached in 355 patients (88.3%), whereas CTI block at the end of the waiting time was achieved in 405 patients (98.3%). Mean procedural, radiofrequency, and fluoroscopic time were 56.5 ± 28.1, 7.8 ± 4.8, and 1.9 ± 4.8 min, respectively. There were no major procedural complications. There was no significant inter-operator variability in the ability to achieve any of the primary endpoints. CONCLUSION: AI-guided ablation with an inter-lesion distance ≤6 mm represents an effective, safe, and highly reproducible strategy to achieve bidirectional block in the treatment of typical AFL.

Detection of oesophageal course during left atrial catheter ablation.

BACKGROUND: Oesophageal changes and injuries were recorded after atrial fibrillation(AF) ablation procedures. The reduction of power in the posterior left atrial(LA) wall(closest to the oesophagus) and the monitoring of temperature in the oesophagus(OE) reduced oesophageal injuries. The intracardiac-echocardiography(ICE) with a Cartosound module provides two-dimensional imaging (2D) to assess detailed cardiac anatomy and its relationship with the OE. The aim of this study was to highlight the safety and feasibility of 3D-reconstruction of the oesophageal course in left atrial catheter ablation(CA) procedures without OE temperature probe or quadripolar catheter to guide ICE OE reconstruction. METHODS: 180 patients(PT) underwent left atrial ablation. AF ablation were 125(69.5%); incisional left atrial tachycardias(IAFL) were 37(20.6%); left atrial tachycardias(LAT) were 19(10.6%). The LA and pulmonary vein anatomies were rendered by traditional electroanatomic mapping(EAM) and merged with an ICE anatomic map. In 109 PT ICE imaging was used to create a geometry of the OE(group A). A quadripolar catheter was used in 71 PT to show OE course associated to ICE(group B). RESULTS: Ablation energy delivery was performed outside the broadest OE anatomy borders. The duration of procedures was longer in group B vs group A Fluoroscopy time was lower in Group A than Group B(Group A 7 ± 3.2 vs 19.2 ± 2.4 min; p < 0.01). CONCLUSIONS: OE monitoring with ICE is safe and feasible. Oesophageal anatomy is complex and variable. Many PT will have a broad oesophageal boundary, which increases the risk of untoward thermal injury during posterior LA ablation. ICE with 3D construction of the OE enhances border detection of the OE, and as such, should decrease the risk of oesophageal injury by improving avoidance strategies without intra-oesophageal catheter visualization.

From near-zero to zero fluoroscopy catheter ablation procedures.

AIMS: The use of electroanatomical mapping (EAM) systems can reduce radiation exposure (RX) and it can also completely eliminate the use of RX. Radiation exposure related to conventional radiofrequency ablation procedures can have a stochastic and deterministic effect on health. The main aim of this study was to evaluate the safety and feasibility of an entirely nonfluoroscopic approach to catheter ablation (CA) using EAM CARTO3. METHODS: In 2011 we started an RX-minimization programme in all procedures using the CARTO system with the deliberate intention to not resort to the aid of RX unless strictly necessary. We divided procedures into two groups (group 1: from 2011 to 2013; group 2: from 2014 to 2017). The only exclusion criteria were the need for transseptal puncture, and nonidiopathic ventricular tachycardia (VT). RESULTS: From a total of 525 procedures, we performed CA entirely without RX in 78.5% of cases. From 2011 to 2013, we performed CA without RX in 38.5% of cases; from 2014 to 2017, we performed 96.2% of cases with zero RX. The use of RX was significantly reduced in group 2 (group 2: 1.4 ± 19.6 seconds vs group 1: 556.92 ± 520.76 seconds; P < .001). These differences were irrespective of arrhythmia treatment. There were no differences between the two groups in acute success, complications, or duration of procedures. CONCLUSION: CA of supraventricular tachycardia and VT entirely without RX, guided by the CARTO system, is safe, feasible, and effective. After an adequate learning curve, CA can be performed entirely without RX.

Access to magnetic resonance imaging of patients with magnetic resonance-conditional pacemaker and implantable cardioverter-defibrillator systems: results from the Really ProMRI study.

Aims: The Really ProMRI study evaluates magnetic resonance imaging (MRI) access for patients with cardiac implantable electronic devices (CIEDs) as well as the performance of magnetic resonance (MR)-conditional leads when undergoing MRI. Methods and results: Patients either with an MR-conditional pacemaker or implantable defibrillator (ICD) system or with at least a component (device or one or more leads) from an MR-conditional system, were asked to fill in a questionnaire when they were referred to a MR scan. The rate of prescription, denial, or execution of MR examinations was evaluated in a 1-year follow-up visit. In total, 555 patients [median age (interquartile range) 72.2 (62.2-78.6); 72% male] were enrolled, 49% (270) with a pacemaker, 51% (285) with an ICD system. Five-hundred and ten patients completed the follow-up period. A total of 37 MRI referrals were reported in 35 patients, with a consequent event rate of 7.0/100 patient-years (CI, 4.9-9.7). Fourteen were denied, while 23 [66%; (CI, 48-81%)] were performed. The number of patients with MR referrals was not statistically different between pacemaker and ICD groups (21 vs. 14; P = 0.178). The rate of scans performed was higher in the pacemaker subjects (19/23 vs. 4/14, P = 0.003), while it was similar between patients with or without a complete MR-conditional system (19/30 vs. 4/7, P = 0.606). Conclusion: In this study, we reported a 7.0/100 patient-year's event rate of MR prescriptions in CIED patients. Many examinations were denied, despite MR-conditional systems, especially in ICD patients. Regulatory and cultural changes are needed to allow wider access to MR imaging in CIED patients with MR-conditional systems.

Left Ventricular Lead Placement for Biventricular Pacing in a Left Lateral Vein in a Patient with Congenital Atresia of the Coronary Sinus Ostium.

Coronary sinus ostial atresia (CSOA) is a rare kind of congenital heart anomaly. This creates a new drainage pathway for the cardiac venous flow, with the most common being a persistent left superior vena cava (PLSVC). During the implantation of a cardiac resynchronization therapy defibrillator, we discovered a case of CSOA in a patient who underwent aortic valve and ascending aorta replacement. CSOA led to the research and subsequent identification of a PLSVC, which drained in the CS. The left ventricular pacing lead was appropriately placed in a left lateral vein. This case report highlights the technical aspects and procedural difficulties that characterize this specific anatomical variant.

Moderator Band and Ventricular Tachycardia: Structural or Functional Substrate?

The moderator band (MB) is an intracavitary structure of the right ventricle composed of muscular fibers encompassing specialized Purkinje fibers, separated each other by collagen and adipose tissue. In the last decades, premature ventricular complexes originating within the Purkinje network have been implicated in the genesis of life-threatening arrhythmias. However, right Purkinje network arrhythmias have been much less reported in the literature compared to the left counterpart. The MB has unique anatomical and electrophysiological properties, which may account for its arrhythmogenicity and may be responsible for a significant portion of idiopathic ventricular fibrillation. MB embodies autonomic nervous system cells, with important implications in arrhythmogenesis. Some idiopathic ventricular arrhythmias, defined as the absence of any identifiable structural heart disorder, can begin from this site. Due to these complex structural and functional peculiarities strictly interplayed each other, it is arduous to determine the precise mechanism underlying MB arrhythmias. MB-related arrhythmias should be differentiated from other right Purkinje fibers arrhythmias because of the opportunity for intervention and the unusual site for the ablation poorly described in the literature. In the current paper, we report the characteristics and electrical properties of the MB, their involvement in arrhythmogenesis, clinical and electrophysiological peculiarities of MB-related arrhythmias, and current treatment options.

Biventricular or Conduction System Pacing for Cardiac Resynchronization Therapy: A Strategy for Cardiac Resynchronization Based on a Hybrid Approach.

BACKGROUND: Cardiac resynchronization therapy (CRT) is usually performed with biventricular pacing (BiVP), but recently, conduction system pacing (CSP) has been proposed as an alternative in case of BiVP failure. The aim of this study is to define an algorithm to choose between BiVP and CSP resynchronization using the interventricular conduction delays (IVCD) as a guide. METHODS: Consecutive patients from January 2018 to December 2020 with an indication for CRT were prospectively enrolled in the study group (delays-guided resynchronization group, DRG). A treatment algorithm based on IVCD was used to decide whether to leave the left ventricular (LV) lead to perform BiVP or pull it out and perform CSP. Outcomes from the DRG group were compared to a historical cohort of CRT patients who underwent CRT procedures between January 2016 and December 2017 (resynchronization standard guide group, SRG). The primary endpoint was a composite of cardiovascular mortality, heart failure (HF) hospitalization, or HF event at 1 year after the date of intervention. RESULTS: The study population consisted of 292 patients, of which 160 (54.8%) were in the DRG and 132 (45.2%) in the SRG. In the DRG, 41 of 160 patients underwent CSP based on the treatment algorithm (25.6%). The primary endpoint was significantly higher in the SRG (48/132, 36.4%) compared to the DRG (35/160, 21.8%) (hazard ratio (HR): 1.72; 95% confidence interval (CI): 1.12-2.65; p = 0.013). CONCLUSIONS: A treatment algorithm based on IVCD shifted one patient out of every four from BiVP to CSP, with consequent reduction in the primary endpoint after implantation. Therefore, its application could be useful to determine whether to perform BiVP or CSP.

Combined Use of Voltage Mapping and Speckle-tracking Analysis for the Characterization of Arrhythmogenic Right Ventricular Cardiomyopathy: A Case Report.

A 38-year-old man was admitted to our hospital after ventricular tachycardia. Endocardial bipolar and unipolar voltage mapping were performed and findings were integrated with data from intracardiac echocardiography (ICE) right ventricular (RV) speckle-tracking analysis. A reduction in the strain analysis was stored in correspondence of the fragmented electrogram area. The definitive diagnosis was arrhythmogenic RV cardiomyopathy (ARVC). The integration of ICE-derived RV strain and voltage mapping could represent a successful strategy to improve the results of ablation in ARVC.

Association Between Device-Detected Sleep-Disordered Breathing and Implantable Defibrillator Therapy in Patients With Heart Failure.

BACKGROUND: Sleep-disordered breathing is highly prevalent in heart failure (HF) and has been suggested as a risk factor for malignant ventricular arrhythmias. The Respiratory Disturbance Index (RDI) computed by an implantable cardioverter-defibrillator (ICD) algorithm accurately identifies severe sleep apnea. OBJECTIVES: In the present analysis, the authors evaluated the association between ICD-detected sleep apnea and the incidence of appropriate ICD therapies in patients with HF. METHODS: We enrolled 411 HF patients who had received an ICD endowed with an algorithm that calculates the RDI each night. In this analysis, the weekly mean RDI value was considered. The endpoint was the first appropriate ICD shock. RESULTS: The median follow-up was 26 months (25th to 75th percentile: 16-35 months). During follow-up, 1 or more ICD shocks were documented in 58 (14%) patients. Patients with shocks were younger (age 66 ± 13 years vs 70 ± 10 years; P = 0.038), and had more frequently undergone implantation for secondary prevention (21% vs 10%; P = 0.026). The maximum RDI value calculated during the entire follow-up period did not differ between patients with and without shocks (55 ± 15 episodes/h vs 54 ± 14 episodes/h; P = 0.539). However, the ICD-detected RDI showed considerable variability during follow-up. The overall median of the weekly RDI was 33 episodes/h (25th to 75th percentile: 24-45 episodes/h). A time-dependent Cox regression model revealed that a continuously measured weekly mean RDI of ≥45 episodes/h was independently associated with shock occurrence (HR: 4.63; 95% CI: 2.54-8.43; P < 0.001), after correction for baseline confounders (age, secondary prevention). CONCLUSIONS: In HF patients, appropriate ICD shocks were more likely to be delivered during periods when patients exhibited more sleep-disordered breathing. (Arrhythmias Detection in a Real World Population [RHYTHM DETECT]; NCT02275637).

Upgrading from a Dual-chamber Pacemaker to a Cardiac Resynchronization Therapy Defibrillator in Situs Inversus Totalis with Dextrocardia Following Mitral Valve Replacement and Tricuspid Annuloplasty Using a Left-sided Approach.

A 71-year-old female patient was referred to our center to upgrade a dual-chamber pacemaker to a cardiac resynchronization therapy defibrillator (CRT-D) following the detection of worsened systolic function (ejection fraction:25%-30%) via transthoracic echocardiography. The patient had situs inversus totalis with dextrocardia. She had undergone mitral valve replacement and tricuspid annuloplasty in July 2019, with a concomitant left upper pulmonary lobectomy for neoplasm, detected at cardiac tomography incidentally. In January 2020, we performed an upgrade of the preexisting device to a CRT-D system because the patient developed heart failure, reduction in systolic function, and numerous nonsustained ventricular tachycardias. The right ventricular lead that had been previously implanted was extracted. To facilitate the intervention, we decided to flip the fluoroscopic image, obtained with a right-anterior oblique view, by 180° (right-left), creating the optical impression of a levocardial position.

Catheter inversion during cavotricuspid isthmus catheter ablation: The new shaft visualization catheter reduces fluoroscopy use.

AIMS: Catheter ablation (CA) is the choice therapy of cavotricuspid isthmus (CTI) atrial flutter. The aim of this study was to describe our approach to improve the CTI ablation using a zero-fluoroscopy (ZF). The procedural difficulties could be related to anatomical characteristics of the CTI. METHODS: One hundred eighty-eight patients that performed CA of CTI were retrospectively and consecutively evaluated between 2017 and 2019. The studied population was divided into two groups. Eighty-eight patients who were undergone CA using ablation catheter without shaft visualization catheter (NSV) were Group 1. One hundred patients were undergone CA using ablation catheter with a shaft visualization (SV); they were Group 2. The catheter was looped at the Eustachian ridge after 200 seconds of radiofrequencies (RF) without elimination of local electrogram. RESULTS: A conduction line block of CTI was obtained in all patients of Group 2 using a ZF approach. In 16 patients of Group 1, the catheter inversion was obtained using fluoroscopy to avoid damages during its loop. In Group 2, a complete CTI block was obtained with a catheter inversion approach in ten patients without fluoroscopy, visualizing the shaft and the tip of the ablation catheter on the electroanatomic (EAM) map. In the overall population studied the use of SV had a linear correlation with the ZF approach (r = .629; P < .001). The duration of RF was lower in Group 2 than in Group 1 (Group 1: 27.8 ± 6.3 vs Group 2: 15.6 ± 7.2 minutes; P < .01). The procedure time between two groups was lower in Group 2 than in Group 1 (Group 1: 58.4 ± 22.4 vs Group 2: 42.2 ± 15.7 minutes; P < .01). No differences between two groups were documented regarding success and complications. CONCLUSIONS: The visualization of the shaft's catheter on the EAM permitted the catheter inversion safely in order to overcome some complex CTI anatomy and obtain bidirectional block. The SV reduced procedure time, RF applications and fluoroscopy exposition during CTI ablation.

Zero-fluoroscopy catheter ablation of premature ventricular contractions at left coronary cusp near left main coronary artery.

The left coronary cusp is the commonest site of origin for coronary cusp PVC. Catheter ablation without fluoroscopy is highly effective, feasible, and safe but it could be related to risks because of proximity to the coronary arteries. The use of ICE integration allowed an improvement in the safety and efficiency of these procedures.

Manufacturer change and risk of system-related complications after implantable cardioverter defibrillator replacement: physicians' survey and data from the Detect Long-term Complications After Implantable Cardioverter Defibrillator Replacement Registry.

AIMS: Some barriers seem to exist in changing implantable cardioverter defibrillator (ICD) manufacturer at the time of device replacement. We sought to understand the obstacles to changing ICD manufacturer within the cohort of patients enrolled in the Detect Long-term Complications After ICD Replacement Registry. METHODS: We analyzed 784 consecutive ICD/cardiac resynchronization therapy defibrillator (CRT-D) device replacements within a 1.5-year time-frame in 36 Italian centers to evaluate potential factors associated with changing manufacturers and system-related complications. RESULTS: Manufacturer change occurred in 191 patients (24%): 72/211 single-chamber ICDs (34%), 52/210 dual-chamber ICDs (25%) and 67/363 CRT-D (18%, P < 0.0001 vs. single-chamber). Replacement-only procedures were associated with a lower rate of manufacturer change than upgrading procedures (23 vs. 32%, P = 0.02). In the single-chamber/dual-chamber cohort, the only variables associated with manufacturer change were the number of available manufacturers (OR = 1.9; P < 0.0001) and an upgrade procedure (OR = 1.7; P = 0.035), whereas the center volume was associated with maintenance of the same manufacturer (OR = 0.5; P = 0.0172). In the CRT-D group, the number of available manufacturers [OR = 2.9; P < 0.0001, service life below the median value (OR = 2.5; P = 0.0026)], and physiological design (OR = 8.4; P = 0.0048) were associated with manufacturer change. At 6-month follow-up, 17 patients (2.2%) experienced a system complication that was lead-related in all cases; upgrade procedure was the only predictor (hazard ratio = 6.7) of complications. CONCLUSION: At the time of ICD replacement, a manufacturer change occurred in 24% of patients and it was less likely in CRT-D devices, which are equipped with more specific technology and less frequently require the addition of features. System-related complications are strongly associated to upgrade procedures rather than to manufacturer change.

Influence of aetiology on long-term effects of resynchronization on cardiac structure and function in patients treated with ß-blockers.

OBJECTIVES: Cardiac resynchronization therapy (CRT) elicits more beneficial effects on left-ventricular (LV) structure and function, and long-term clinical outcomes in nonischemic heart failure patients. Rates of ß-blocker use in recent heart failure trials are higher than in CRT trials and this may influence the response to CRT. This study examined the long-term effects of CRT on LV structure and function in New York Heart Association class III-IV ß-blocker-treated patients. METHODS: One hundred and four (41 ischemic and 63 nonischemic) CRT patients, who were receiving ß-blockers before and throughout 12 months following device implantation, were retrospectively selected. Variations in echocardiographic parameters recorded before, and 6 and 12 months after CRT were analyzed. RESULTS: Selected patients were all stable on ß-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (97%) and diuretics (97%) before implantation. CRT was associated with significant improvements in LV morphological and systo-diastolic functional parameters at 6 months, with further improvements between 6 and 12 months seen in nonischemic patients only. Accordingly, rates of echocardiographic response to CRT were similar at 6 months but significantly higher in nonischemic patients after 1 year. The degree of reduction in LV diameters and volumes, and of increase in ejection fraction, was significantly larger in nonischemic patients at both 6 and 12 months. In addition, a significant reduction in LV mass and severity of mitral regurgitation was more evident in nonischemic patients both 6 and 12 months following CRT. CONCLUSIONS: Ischemic aetiology of heart failure is associated with less favorable long-term effects of CRT on LV structure and function despite the systematic use of ß-blockers.