Activation pattern of the coronary sinus facilitates the differentiation for ventricular outflow tract arrhythmias.

INTRODUCTION: The accuracy of surface ECG algorithms for predicting the origin of outflow tract ventricular arrhythmias (OT-VAs) might be questioned. Intracardiac electrograms recorded at anatomic landmarks could provide new predictive insights. We aim to evaluate the efficacy of a novel criterion utilizing the activation pattern of the coronary sinus (CS) in localizing OT-VAs, including VAs originating from the right ventricular outflow tract (RVOT), endocardial left ventricular outflow tract (Endo-LVOT), and epicardial left ventricular outflow tract (Epi-LVOT). METHODS: We measured the ventricular activation time of the mitral annulus (MA) from the onset of the earliest QRS complex of VAs to the initial deflection over the isoelectric line at local signals, namely the QRS-MA interval. The activation at 3 and 12 o'clock of the MA was recorded as the QRS-MA3 and QRS-MA12 intervals, respectively. Their predictive values were compared to previous ECG algorithms. RESULTS: A total of 68 patients with OT-VAs were enrolled (51 for development and 17 for validation). From early to late, the ventricular activation sequences at MA12 were as follows: Epi-LVOT, Endo-LVOT, and RVOT. In LBBB morphology OT-VAs, the QRS-MA12 interval was significantly earlier for LVOT origins than RVOT origins. In the combined cohort of development and validation cohort, a cut-off value of ≤10 ms predicted the LVOT origin with a sensitivity of 100% and specificity of 78%. The QRS-MA12 interval ≤ -24 ms additionally predicted epicardial LVOT sites of origin. CONCLUSIONS: The QRS-MA interval could accurately differentiate the OT-VAs localization.

Venous anatomy of the left ventricular summit region: Insights from high-speed rotational retrograde angiography.

INTRODUCTION: Mapping and ablation through the coronary venous system (CVS) have shown potential for ventricular arrhythmias originating from the left ventricular summit (LVS). Multielectrode catheters and balloons are frequently used for mapping and venous ethanol ablation (VEA). However, there is limited data on the venous size and drainage condition in the LVS region. This study aimed to investigate the morphology, angiographic size, and drainage condition of LV summit veins via high-speed rotational angiography (RA). METHODS: We measured and analyzed the size of the great cardiac vein (GCV), the anterior interventricular vein (AIV), veins near to the LVS, and other main tributaries of CVS in 102 patients undergoing electrophysiology study. RESULTS: Rotational retrograde angiography of LVS was successfully performed in 81 patients. The diameter of GCV at the level of the Vieussens valve and the distal end of GCV (junction of GCV-AIV) was larger in males than females (6.8 ± 1.1 vs. 5.6 ± 1.2 mm, p < .001; 5.2 ± 0.9 vs. 4.6 ± 0.8, p = .002, respectively) while no significant gender differences were observed in other tributaries. The LV summit veins presented downward drainage direction in half of the patients, indicating potential anatomic adjacency with His bundle. Left anterior oblique (LAO) 45° projection might provide the practical and optimal view of the LV summit veins. CONCLUSIONS: The coronary veins of the LVS region present various anatomical morphologies and ostium sizes. We provide a systematic description and angiographic size spectrum of CVS. RA could facilitate assessing the feature of CVS comprehensively.

A novel approach for developing left bundle branch pacing and left bundle branch block in a canine model.

BACKGROUND AND OBJECTIVE: Left bundle branch pacing (LBBP) has shown the benefits in the treatment of dyssynchronous heart failure (HF). The purpose of this study was to develop a novel approach for LBBP and left bundle branch block (LBBB) in a canine model. METHODS: A "triangle-center" method by tricuspid valve annulus angiography for LBBP implantation was performed in 6 canines. A catheter was then applied for retrograde His potential recording and left bundle branch (LBB) ablation simultaneously. The conduction system was stained to verify the "triangle-center" method for LBBP and assess the locations of the LBB ablation site in relation to the left septal fascicle (LSF). RESULTS: The mean LBB potential to ventricular interval and stimulus-peak left ventricular activation time were 11.8 ± 1.2 and 35.7 ± 3.1 ms, respectively. The average intrinsic QRS duration was 44.7 ± 4.7 ms. LBB ablation significantly prolonged the QRS duration (106.3 ± 8.3 ms, p < .001) while LBBP significantly shortened the LBBB-QRS duration to 62.5 ± 5.3 ms (p < .001). After 6 weeks of follow-up, both paced QRS duration (63.0 ± 5.4 ms; p = .203) and LBBB-QRS duration (107.3 ± 7.4 ms; p = .144) were unchanged when comparing to the acute phase, respectively. Anatomical analysis of 6 canine hearts showed that the LBBP lead-tip was all placed in LSF area. CONCLUSION: The new approach for LBBP and LBBB canine model was stable and feasible to simulate the clinical dyssynchrony and resynchronization. It provided a useful tool to investigate the basic mechanisms of underlying physiological pacing benefits.

Double-wire technique to facilitate vein of Marshall cannulation and ethanol infusion in atrial fibrillation: a case series.

BACKGROUND: The vein of Marshall (VOM) ethanol infusion is increasingly performed in combination with catheter ablation in atrial fibrillation (AF). The cannulation of the VOM can sometimes be challenging. This study aimed to evaluate the double-wire technique in cases of difficult cannulation of the VOM. CASE PRESENTATION: Patients with AF scheduled for combined catheter ablation and VOM ethanol infusion were consecutively enrolled. The procedure was performed via the femoral vein. If the regular cannulation technique with one angioplasty wire failed or took more than 20 min, the double-wire technique using a stabilizing wire and a cannulation wire was performed. The unique technique was used mainly in two scenarios, when the Eustachian ridge was too prominent as a barrier for catheter manipulation or when the VOM ostium was close to the coronary sinus ostium. Of 162 patients scheduled for VOM ethanol infusion, the double-wire technique was applied in 6 (3.7%) patients and led to a 100% successful cannulation rate of the VOM. Of the six patients, two had a prominent Eustachian ridge, and four had a VOM ostium close to the coronary sinus ostium. The mean cannulation time was 33.3 ± 7.3 min. The ethanol infusion was successfully performed in 5 patients. One patient had a collateral circulation in the distal VOM, and ethanol infusion was not performed. CONCLUSIONS: The double-wire technique can facilitate VOM cannulation and ethanol infusion in challenging cases. WORD COUNT: 231.

Noninvasive assessment of myocardial work during left ventricular isovolumic relaxation in patients with diastolic dysfunction.

BACKGROUND: This study aims to investigate the value of myocardial work (MW) parameters during the isovolumic relaxation (IVR) period in patients with left ventricular diastolic dysfunction (LVDD). METHODS: This study prospectively recruited 448 patients with risks for LVDD and 95 healthy subjects. An additional 42 patients with invasive measurements of left ventricular (LV) diastolic function were prospectively included. The MW parameters during IVR were noninvasively measured using EchoPAC. RESULTS: The total myocardial work during IVR (MWIVR), myocardial constructive work during IVR (MCWIVR), myocardial wasted work during IVR (MWWIVR), and myocardial work efficiency during IVR (MWEIVR) of these patients were 122.5 ± 60.1 mmHg%, 85.7 ± 47.8 mmHg%, 36.7 ± 30.6 mmHg%, and 69.4 ± 17.8%, respectively. The MW during IVR was significantly different between patients and healthy subjects. For patients, MWEIVR and MCWIVR were significantly correlated with the LV E/e' ratio and left atrial volume index, MWEIVR exhibited a significant correlation with the maximal rate of decrease in LV pressure (dp/dt per min) and tau, and the MWEIVR corrected by IVRT also exhibited a significant correlation with tau. CONCLUSIONS: MW during IVR significantly changes in patients with risks for LVDD, and is correlated to LV conventional diastolic indices, including dp/dt min and tau. Noninvasive MW during IVR may be a promising tool to evaluate the LV diastolic function.

Safety and effectiveness of a novel dielectric mapping system: one-year, two chinese centers experiences.

BACKGROUND: The KODEX-EPD system is a novel, dielectric three-dimensional mapping system. We aim to illustrate the feasibility, safety, and outcomes of ablation using the KODEX-EPD system. METHODS: A total of 272 patients with supraventricular arrhythmias were enrolled and underwent catheter ablation using the KODEX-EPD system from October 2020 to July 2021. The feasibility, safety, and ablation outcomes were analyzed. RESULTS: Of the enrolled patients, 15 (5.4%) had atrial tachycardia (AT), 88 (31.4%) had atrioventricular reentrant tachycardia (AVRT), 141 (50.4%) had atrioventricular nodal reentrant tachycardia (AVNRT), 34 (12.1%) had atrial fibrillation (AF), and 9 (3.2%) had atrial flutter (AFL). All AF patients included were first-do-pulmonary vein isolation (PVI); there were 26 paroxysmal AF and 8 persistent AF. All patients achieved immediate success of ablation. The mean follow-up duration was 11.8 ± 2.4 months. One patient (1.1%) in the AVRT subgroup and two patients (1.4%) in the AVNRT subgroup experienced recurrence. When considering a three-month blanking time, the estimated freedom of AF at one-year post-ablation with and without AADs was 75.7% and 70.4%, respectively. The Kaplan-Meier analysis showed no significant difference in the overall AF recurrence (log-rank; P = 0.931) or AAD-free AF recurrence (log-rank; P = 0.841) between RFCA and cryoablation. One patient had mild pulmonary embolism. None of the patients died or had a cerebrovascular event in the periprocedural period. CONCLUSIONS: This retrospective, two-center study demonstrated that catheter ablation of supraventricular arrhythmias using the KODEX-EPD system is feasible, safe, and effective. Trial registration Retrospectively registered.

Occluding morphologically complicated left atrial appendage using the small-umbrella LAmbre device.

BACKGROUND: Percutaneous left atrial appendage (LAA) occlusion is effective for stroke prevention in patients with atrial fibrillation. LAA can have a complex anatomy, such as multiple lobes or a large orifice, which may render it unsuitable for occlusion using regular devices. We aimed to investigate the feasibility, safety, and short-term efficacy of the small-umbrella LAmbre device for morphologically complicated LAA. METHODS: We retrospectively enrolled 129 consecutive patients who underwent LAA occlusion using the LAmbre device; the small-umbrella LAmbre device was used in 30 of these patients. We analyzed patients' characteristics, procedural details, and outcomes. RESULTS: Twenty-two patients (73.3%) had multilobed (≥ 2) LAA. The umbrella of the occluder was anchored in the branch in 9 patients and in the common trunks of branches in 13 patients. The landing zone and orifice diameters were 19.0 ± 4.39 mm and 27.4 ± 3.95 mm, respectively. The sizes of the umbrella and occluder cover were 22.0 ± 3.42 mm and 34.3 ± 2.75 mm, respectively. At 3-month follow-up transesophageal echocardiography in 24 patients, no peri-device residual flow was reported. Device thrombosis was detected in one patient at 3 months and disappeared after 3 months of anticoagulation. Ischemic stroke occurred in one patient; no other adverse events were reported. CONCLUSIONS: Occlusion of morphologically complicated LAA using the small-umbrella LAmbre device was feasible, safe, and effective in patients with atrial fibrillation in this study. This occluder provides an alternative for patients who cannot be treated with regular-sized LAA occlusion devices.

Supraventricular tachycardia in patients with coronary sinus stenosis/atresia: Prevalence, anatomical features, and ablation outcomes.

BACKGROUND: Supraventricular tachycardia (SVT) with coronary sinus (CS) ostial atresia (CSA) or coronary sinus stenosis (CSS) causes difficulty in electrophysiological procedures, but its characteristics are poorly understood. OBJECTIVE: Study the anatomical and clinical features of SVT patients with CSA/CSS. METHODS: Of 6128 patients with SVT undergoing electrophysiological procedures, consecutive patients with CSA/CSS were enrolled, and the baseline characteristics, imaging materials, intraoperative data, and follow-up outcomes were analyzed. RESULTS: Thirteen patients, seven with CSA and six with CSS, underwent the electrophysiological procedure. Decapolar catheters were placed into the proximal CS in three cases, while the rest were placed at the free wall of the right atrium. Fourteen arrhythmias were confirmed: four atrioventricular nodal reentrant tachycardias, five left-sided accessory pathways, three paroxysmal atrial fibrillations, and two atrial flutters (AFLs). In addition to three patients who underwent only an electrophysiological study, the acute ablation success rate was 100% in 10 cases, with no procedure-related complications. After a median follow-up period of 59.6 months, only one case of atypical AFL recurred. For those cases (seven CSA and two CSS) with a total of 10 anomalous types of CS drainage, three types were classified: from the CS to the persistent left superior vena cava (n = 3), from an unroofed CS (n = 3), and from the CS to the small cardiac vein (n = 3) or Thebesian vein (n = 1). CONCLUSION: Patients with CSA/CSS may develop different kinds of SVT. Electrophysiological procedures for such patients are feasible and effective. An individualized mapping strategy based on the three types of CS drainage will be helpful.

Exercise-induced cardiac troponin elevations and cardiac ventricular dysfunction assessed by tissue Doppler echocardiography and speckle tracking among non-elite runners in Beijing marathon.

OBJECTIVES: We aimed to identify the major determinants of cardiac troponin changes response to exercise among non-elite runners participating in the Beijing 2022 marathon, with a particular focus on the associations with the cardiac function assessed by tissue Doppler echocardiography and speckle tracking. DESIGN: A prospective study. METHODS: A total of 33 non-elite participants in the 2022 Beijing Marathon were included in the study. Echocardiographic assessment and blood sample collection were conducted before, immediately after, and two weeks after the marathon. Blood samples were analyzed using the same Abbot high-sensitivity cTnI STAT assay. Echocardiography included tissue Doppler and speckle tracking echocardiography. RESULTS: Following the marathon, significant increases were observed in cardiac biomarkers, with hs-cTnI elevating from 3.1 [2.3-6.7] to 49.6 [32.5-76.9] ng/L (P < 0.0001). Over 72 % of participants had post-race hs-TnI levels surpassing the 99th percentile upper reference limit. There was a notable correlation between pre-marathon hs-cTnI levels (ß coefficient, 0.56 [0.05, 1.07]; P = 0.042), weekly average training (ß coefficient, -1.15 [-1.95, -0.35]; P = 0.009), and hs-cTnI rise post-marathon. Echocardiography revealed significant post-race cardiac function changes, including decreased E/A ratio (P < 0.0001), GWI (P < 0.0001), and GCW (P < 0.0001), with LVEF (ß coefficients, 0.112 [0.01, 0.21]; P = 0.042) and RV GLS (ß coefficients, 0.124 [0.01, 0.23]; P = 0.035) changes significantly associated with hs-TnI alterations. All echocardiographic and laboratory indicators reverted to baseline levels within two weeks. CONCLUSIONS: Baseline hs-cTnI levels and weekly average training influence exercise-induced hs-cTnI elevation in non-elite runners. Echocardiography revealed post-race changes in cardiac function, with LVEF and RV GLS significantly associated with hs-TnI alterations. These findings contribute to understanding the cardiac response to exercise and could guide training and recovery strategies.

Dyssynchronous heart failure models in canines: New insights into electrocardiographic, echocardiographic and histological features.

BACKGROUND: We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines. METHODS: A total of eight dogs were included in the experiment, four were tachy-paced in right ventricle apex (RVAP) and 4 were paced in right atrium after the ablation of left bundle branch to achieve left bundle branch block (RAP+LBBB). Three weeks of follow-up were conducted to observe the changes in cardiac function and myocardial staining was performed at the end of the experiment. RESULTS: Both experimental approaches successfully established heart failure with reduced ejection fraction models, with similar trends in declining cardiac function. The RAP+LBBB group exhibited a prolonged overall ventricular activation time, delayed left ventricular activation, and lesser impact on the right ventricle. The RVAP approach led to a reduction in overall right ventricular compliance and right ventricular enlargement. The RAP+LBBB group exhibited significant reductions in left heart compliance (LVGLS, %: RAP+LBBB -12.60 ± 0.12 to -5.93 ± 1.25; RVAP -13.28 ± 0.62 to -8.05 ± 0.63, p = 0.023; LASct, %: RAP+LBBB -15.75 ± 6.85 to -1.50 ± 1.00; RVAP -15.75 ± 2.87 to -10.05 ± 6.16, p = 0.035). Histological examination revealed more pronounced fibrosis in the left ventricular wall and left atrium in the RAP+LBBB group while the RVAP group showed more prominent fibrosis in the right ventricular myocardium. CONCLUSION: Both approaches establish HFrEF models with comparable trends. The RVAP group shows impaired right ventricular function, while the RAP+LBBB group exhibits more severe decreased compliance and fibrosis in left ventricle.

A self-powered intracardiac pacemaker in swine model.

Harvesting biomechanical energy from cardiac motion is an attractive power source for implantable bioelectronic devices. Here, we report a battery-free, transcatheter, self-powered intracardiac pacemaker based on the coupled effect of triboelectrification and electrostatic induction for the treatment of arrhythmia in large animal models. We show that the capsule-shaped device (1.75 g, 1.52 cc) can be integrated with a delivery catheter for implanting in the right ventricle of a swine through the intravenous route, which effectively converts cardiac motion energy to electricity and maintains endocardial pacing function during the three-week follow-up period. We measure in vivo open circuit voltage and short circuit current of the self-powered intracardiac pacemaker of about 6.0 V and 0.2 µA, respectively. This approach exhibits up-to-date progress in self-powered medical devices and it may overcome the inherent energy shortcomings of implantable pacemakers and other bioelectronic devices for therapy and sensing.

Bias-Free Cardiac Monitoring Capsule.

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Patients often fail to recognize the early signs of CVDs, which display irregularities in cardiac contractility and may ultimately lead to heart failure. Therefore, continuously monitoring the abnormal changes in cardiac contractility may represent a novel approach to long-term CVD surveillance. Here, a zero-power consumption and implantable bias-free cardiac monitoring capsule (BCMC) is introduced based on the triboelectric effect for cardiac contractility monitoring in situ. The output performance of BCMC is improved over 10 times with nanoparticle self-adsorption method. This device can be implanted into the right ventricle of swine using catheter intervention to detect the change of cardiac contractility and the corresponding CVDs. The physiological signals can be wirelessly transmitted to a mobile terminal for analysis through the acquisition and transmission module. This work contributes to a new option for precise monitoring and early diagnosis of CVDs.

Left Bundle Branch Area Pacing With or Without Conduction System Capture in Heart Failure Models.

BACKGROUND: Left bundle branch area pacing includes left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP), which is effective in patients with dyssynchronous heart failure (DHF). However, the basic mechanisms are unknown. OBJECTIVES: This study aimed to compare LBBP with LVSP and explore potential mechanisms underlying the better clinical outcomes of LBBP. METHODS: A total of 24 beagles were assigned to the following groups: 1) control group; 2) DHF group, left bundle branch ablation followed by 6 weeks of AOO pacing at 200 ppm; 3) LBBP group, DHF for 3 weeks followed by 3 weeks of DOO pacing at 200 ppm; and 4) LVSP with the same interventions in the LBBP group. Metrics of electrocardiogram, echocardiography, hemodynamics, and expression of left ventricular proteins were evaluated. RESULTS: Compared with LVSP, LBBP had better peak strain dispersion (44.67 ± 1.75 ms vs 55.50 ± 4.85 ms; P < 0.001) and hemodynamic effect (dP/dtmax improvement: 27.16% ± 7.79% vs 11.37% ± 4.73%; P < 0.001), whereas no significant differences in cardiac function were shown. The altered expressions of proteins in the lateral wall vs septum in the DHF group were partially reversed by LBBP and LVSP, which was associated with the contraction and adhesion process, separately. CONCLUSIONS: The animal study demonstrated that LBBP offered better mechanical synchrony and improved hemodynamics than LVSP, which might be explained by the reversed expression of contraction proteins. These results supported the potential superiority of left bundle branch area pacing with the capture of the conduction system in DHF model.

The predictive value of tissue response viewer for lesion transmurality in a porcine model.

BACKGROUND: The tissue response viewer (TRV) is a multiparametric index that incorporates time, power, tissue pressure, impedance, and wall thickness data during radiofrequency catheter ablation (RFCA) and is used to predict the transmurality of lesions. This study aimed to evaluate the feasibility and accuracy of the TRV in a porcine model. METHODS: Twelve pigs underwent preablation high-density voltage and activation mapping of two atria, and both were repeated after linear RFCA. Intentional gaps were kept in the left atrium (LA) and were touched up in the right atrium (RA). Standard and high powers were, respectively, performed in the LA ablation. Six pigs were immediately sacrificed for pathological examination after the mapping and ablation procedure (acute study). Another six pigs were kept for 4 weeks before remapping and pathological examination (chronic study). RESULTS: All animals completed the planned procedure. The TRV function showed a sensitivity of 97.1% and a specificity of 76.9% in the acute study, and a sensitivity of 95.9% and a specificity of 72.5% in the chronic study to predict the transmural lesion. All positive and negative predictive values were over 80%. In addition, the TRV achieved higher sensitivity (92.3% vs. 85.0%) and specificity (88.2% vs. 78.9%) to predict the transmural lesion in LA ablation with high power compared with standard ablation. CONCLUSIONS: This study presents the histopathological validation of TRV to predict transmural lesions. The use of TRV may guide a more individual ablation and a more precise touch-up of gaps for atrial arrhythmias.

Angiographic assessment of vein of Marshall in atrial fibrillation: Implications for identification and cannulation.

Background: The vein of Marshall (VOM) ethanol infusion improves rhythm control in atrial fibrillation (AF). The identification and cannulation of the VOM can be technically challenging. This study aimed to assess the angiographic morphology of the VOM and investigate its value in the VOM ethanol infusion. Methods: Patients with AF (n = 162) scheduled for combined catheter ablation and VOM ethanol infusion were enrolled. The VOM morphologic features in the right anterior oblique (RAO), the left anterior oblique (LAO), and the LAO cranial views were analyzed. The impact of morphology on the identification and cannulation of the VOM was investigated. Results: The VOM was identified in 159 (98.1 %) and cannulated in 150 (92.6 %) patients. The VOM identification rate in the RAO and LAO/LAO cranial view was 97.3 % and 89.3 %, respectively. Of 134 patients with VOM identification in the LAO/LAO cranial view, 104 (77.6 %) had a VOM ostium clock location (VOMoClock) of ≤3 and 3-4 o'clock. The VOM cannulation success rate in the ≤3, 3-4, 4-5, and 5-6 o'clock groups was 100 %, 92.6 %, 88.5 %, and 77.8 %, respectively (p = 0.032). The median (interquartile range) cannulation time in the four groups was 10.5 (6.3), 12.0 (9.0), 13.0 (23.0), and 34.0 (30.0) minutes, respectively (p < 0.001). The diameter of the coronary sinus ostium in the RAO view and the VOMoClock were independent predictors for difficult cannulation. Conclusions: The VOM morphologic features in different angiographic views provide valuable information which could facilitate the identification and cannulation of the VOM.

Slow-Pathway Visualization by Using Panoramic View: A Novel Ablation Technique for Ablation of Atrioventricular Nodal Reentrant Tachycardia.

(1) Background: The panoramic view of a novel wide-band dielectric mapping system could show the individual anatomy. We aimed to compare the feasibility, efficacy and safety of the panoramic view guided approach for ablation of AVNRT with the conventional approach. (2) Methods: Ablation distributions in eight patients were retrospectively analyzed using the panoramic view. The para-slow-pathway (para-SP) region was divided into three regions, and the region that most frequently appeared with the appropriate junctional rhythm or eliminated the slow-pathway was defined as the adaptive slow-pathway (aSP) region. Twenty patients with AVNRT were then ablated in the aSP region under the panoramic view and compared with 40 patients using the conventional approach. (3) Results: Thirty ablation points were analyzed. The majority of effective points (95.0%) were located in the inferior and anterior portions of the para-SP region and defined as the aSP region. Baseline characteristics, fluoroscopic duration, and mean number of ablations were similar among the two groups. The panoramic view group had a significantly higher percentage of appropriate junctional rhythm (81.9% ± 26.0% vs. 55.7% ± 30.5%, p = 0.002) than the conventional group. (4) Conclusions: The use of the panoramic view for AVNRT ablation achieved similar clinical endpoints with higher ablation efficiency than the conventional approach.

Novel tissue-pressure sensing technology using a wide-band dielectric imaging system: An in vivo study.

BACKGROUND: A novel dielectric wide-band imaging system with tissue pressure (TP) technology provides real-time contact force (CF) monitoring using non-CF catheters. This study sought to investigate the feasibility, safety, and efficacy of ablation with TP technology. METHODS: Eighty-five patients with supraventricular tachycardia (SVT) were ablated with real-time monitoring of CF by TP technology and compared with 85 patients who underwent ablation with a conventional non-TP approach. Baseline characteristics, procedural data, and TP data were analyzed in the study. Ablation applications in the TP group were then subdivided into good contact and poor contact groups according to the TP level for analysis. RESULTS: The TP group had a significantly shorter procedural time (16.2 ±â€¯6.9 min vs. 19.9 ±â€¯10.0 min, p = 0.033), shorter ablation time (334.6 ±â€¯166.9 s vs. 391.3 ±â€¯195.7 s, p = 0.049), and fewer mean numbers of radiofrequency catheter ablation (RFCA) deliveries (6.2 ±â€¯3.2 vs. 7.6 ±â€¯5.2, p = 0.047) than the non-TP group. The achieved average percentage of TP >3 g was significantly higher in the good-contact group (97.94% vs. 15.48%, p < 0.001). The median impedance decreases during RFCA in the good contact group and poor contact group were 4.10 (0.30-6.88) Ω and 2.60 (-0.05-4.98) Ω at 10 s, 4.45 (0.58-8.25) Ω and 2.88 (0.23-5.70) Ω at 20 s, and 4.67 (1.95-9.08) Ω and 2.97 (-0.26-6.33) Ω at 30 s, respectively (p < 0.05 for comparisons between categories). All patients achieved acute success, and no complications were observed. Two patients in the TP group and one patient in the non-TP group experienced recurrence during follow-up. CONCLUSION: TP-technology guided ablation of SVT is feasible, efficient, and safe.

Vein of Marshall Collateralization during Ethanol Infusion in Atrial Fibrillation: Solution for Effective Myocardium Staining.

BACKGROUND: The vein of Marshall (VOM) ethanol infusion improves sinus rhythm maintenance in patients with atrial fibrillation (AF). Distal collateral circulation of VOM can be a challenge to effective ethanol infusion. OBJECTIVE: This study aimed to evaluate the feasibility and efficacy of ethanol infusion in VOM with distal collateral circulation. METHODS: Patients with AF scheduled for catheter ablation and VOM ethanol infusion were consecutively enrolled. During the procedure, non-occluded coronary sinus angiography was first performed for VOM identification. After VOM identification, an over-the-wire angioplasty balloon was used for cannulation and occluded angiography of the VOM. Those with distal VOM collateral circulation were included in this study. A method of slower ethanol injection (2 mL over 5 min) plus additional balloon occlusion time for 3 min after each injection was used. RESULTS: Of 162 patients scheduled for VOM ethanol infusion, apparent distal VOM collateral circulation was revealed in seven (4.3%) patients. Five patients had collateral circulation to the left atrium, one to the right superior vena cava, and one to the great cardiac vein. Two patients did not undergo further ethanol infusion because of our inadequate experience during the early stage of the project. Five patients had successful VOM ethanol infusion with manifest localized myocardium staining. CONCLUSIONS: Ethanol infusion in VOM with distal collateral circulation can be solved by slow injection of ethanol and enough balloon occlusion time between multiple injections.

Spatial Distribution of Idiopathic Ventricular Arrhythmias Originating Around the Pulmonary Root: Lessons From Intracardiac Echocardiography.

OBJECTIVES: The purpose of this study was to investigate the spatial distribution of ventricular arrhythmias (VAs) and their relationship with anatomic landmarks in the right ventricular outflow tract (RVOT). BACKGROUND: Although controversy has mainly focused on whether VAs ablated in the RVOT originate above or below the pulmonary sinus, little is known about their actual distribution. METHODS: We performed mapping and ablation in the reconstructed RVOT using intracardiac echocardiography (ICE) and summarized the spatial electroanatomic characteristics of RVOT-VAs. RESULTS: A total of 50 VAs were recruited and were distributed among the 3 subregions: the pulmonary sinuses (19 of 50, 38%), sinus junctions (18 of 50, 36%), and infundibulum (13 of 50, 26%). In total, 70% (35 of 50) of ablation targets were within 10 mm (mean 4.3 ± 2.7 mm) of the pulmonary valve hinge point. An ablation target with both amplitude ≤1.14 mV and duration ≥101.5 milliseconds predicted an origin above the pulmonary sinus with a sensitivity of 84.2% and specificity of 84.4%. For the ablation targets (13 of 50, 26%) located in the infundibulum of the RVOT, 4 were surrounded by trabeculations, whereas only 1 ablation target in the sinus junction abutted the trabeculation (30.8% vs 5.6%). CONCLUSIONS: Ablation targets of RVOT-VAs were mainly distributed around the hinge point of the pulmonary valve and the trabeculation of the infundibulum. ICE can clearly and precisely locate those anatomic landmarks of the RVOT.