Determinants of acute irreversible electroporation lesion characteristics after pulsed field ablation: the role of voltage, contact, and adipose interference.

AIMS: Pulsed field ablation (PFA) is a non-thermal ablative approach in which cardiomyocyte death is obtained through irreversible electroporation (IRE). Data correlating the biophysical characteristics of IRE and lesion characteristics are limited. The aim of this study was to assess the effect of different procedural parameters [voltage, number of cycles (NoCs), and contact] on lesion characteristics in a vegetal and animal model for IRE. METHODS AND RESULTS: Two hundred and four Russet potatoes were used. Pulsed field ablation lesions were delivered on 3 cm cored potato specimens using a multi-electrode circular catheter with its dedicated IRE generator. Different voltage (from 300 to 1200 V) and NoC (from 1 to 5×) protocols were used. The impact of 0.5 and 1 mm catheter-to-specimen distances was tested. A swine animal model was then used to validate the results observed in the vegetable model. The association between voltage, the NoCs, distance, and lesion depth was assessed through linear regression. An almost perfect linear association between lesion depth and voltage was observed (R2 = 0.95; P < 0.001). A similarly linear relationship was observed between the NoCs and the lesion depth (R2 = 0.73; P < 0.001). Compared with controls at full contact, a significant dampening on lesion depth was observed at 0.5 mm distance (1000 V 2×: 2.11 ± 0.12 vs. 0.36 ± 0.04, P < 0.001; 2.63 ± 0.10 vs. 0.43 ± 0.08, P < 0.001). No lesions were observed at 1.0 mm distance. CONCLUSION: In a vegetal and animal model for IRE assessment, PFA lesion characteristics were found to be strongly dependent on voltage settings and the NoCs, with a quasi-linear relationship. The lack of catheter contact was associated with a dampening in lesion depth.

A novel catheter ablation strategy for non-paroxysmal atrial fibrillation combining cryoballoon, radiofrequency, and Marshall-vein ethanol ablations.

BACKGROUNDS: Catheter ablation for non-paroxysmal atrial fibrillation (non-PAF) remains challenging and more effective strategy has been required to reduce postoperative arrhythmia recurrences. This study aims to investigate the efficacy and safety of a novel extensive ablation strategy for non-PAF, that is based on a combination of cryoballoon (CBA), radiofrequency (RFA), and Marshall-vein ethanol ablations (EA-VOM). METHODS: The study was a single-center, retrospective observational study. We enrolled 171 consecutive patients who underwent de-novo catheter ablation for non-PAF under conscious sedation with a novel extensive ablation strategy that included CBA for pulmonary vein isolation (PVI) and left atrial roof ablation (LARA), RFA for mitral isthmus (MI) ablation, superior vena cava isolation, and other linear ablations and EA-VOM. Recurrence of atrial arrhythmias over 1 year, procedure outcomes, and procedure-related complications were investigated. RESULTS: A total of 139 (81.3%) patients remained in sinus rhythm during 1-year follow-up. Of the 139 patients, 51 patients (29.8%) received antiarrhythmic drugs. The mean procedure time was 204 ± 45 min. PVI and LARA ablation by CBA and MI block by RFA and EA-VOM were completed in 171 (100%) and 166 (97.1%) patients, respectively. No serious procedure-related complications were observed except for one case of delayed pericardial effusion. CONCLUSION: Approximately 80% of the study patients were AF-free during 1-year follow-up period after a single procedure based on the novel extensive ablation strategy combining CBA, RFA, and EA-VOM. This strategy for non-PAF may be preferred in terms of maintenance of sinus rhythm, safety even in high-risk patients, and relatively short procedure time.

Algorithm for Mobile Platform-Based Real-Time QRS Detection.

Recent advancements in smart, wearable technologies have allowed the detection of various medical conditions. In particular, continuous collection and real-time analysis of electrocardiogram data have enabled the early identification of pathologic cardiac rhythms. Various algorithms to assess cardiac rhythms have been developed, but these utilize excessive computational power. Therefore, adoption to mobile platforms requires more computationally efficient algorithms that do not sacrifice correctness. This study presents a modified QRS detection algorithm, the AccYouRate Modified Pan-Tompkins (AMPT), which is a simplified version of the well-established Pan-Tompkins algorithm. Using archived ECG data from a variety of publicly available datasets, relative to the Pan-Tompkins, the AMPT algorithm demonstrated improved computational efficiency by 5-20×, while also universally enhancing correctness, both of which favor translation to a mobile platform for continuous, real-time QRS detection.

Implantable Defibrillator System Shock Function, Mortality, and Cause of Death After Magnetic Resonance Imaging.

BACKGROUND: Studies have shown that magnetic resonance imaging (MRI) does not have clinically important effects on the device parameters of non-MRI-conditional implantable cardioverter-defibrillators (ICDs). However, data on non-MRI-conditional ICD detection and treatment of arrhythmias after MRI are limited. OBJECTIVE: To examine if non-MRI-conditional ICDs have preserved shock function of arrhythmias after MRI. DESIGN: Prospective cohort study. (ClinicalTrials.gov: NCT01130896). SETTING: 1 center in the United States. PATIENTS: 629 patients with non-MRI-conditional ICDs enrolled consecutively between February 2003 and January 2015. INTERVENTIONS: 813 total MRI examinations at a magnetic field strength of 1.5 Tesla using a prespecified safety protocol. MEASUREMENTS: Implantable cardioverter-defibrillator interrogations were collected after MRI. Clinical outcomes included arrhythmia detection and treatment, generator or lead exchanges, adverse events, and death. RESULTS: During a median follow-up of 2.2 years from MRI to latest available ICD interrogation before generator or lead exchange in 536 patients, 4177 arrhythmia episodes were detected, and 97 patients received ICD shocks. Sixty-one patients (10% of total) had 130 spontaneous ventricular tachycardia or fibrillation events terminated by ICD shocks. A total of 210 patients (33% of total) are known to have died (median, 1.7 years from MRI to death); 3 had cardiac arrhythmia deaths where shocks were indicated without direct evidence of device dysfunction. LIMITATIONS: Data were acquired at a single center and may not be generalizable to other clinical settings and MRI facilities. Implantable cardioverter-defibrillator interrogations were not available for a subset of patients; adjudication of cause of death relied solely on death certificate data in a subset. CONCLUSION: Non-MRI-conditional ICDs appropriately treated detected tachyarrhythmias after MRI. No serious adverse effects on device function were reported after MRI. PRIMARY FUNDING SOURCE: Johns Hopkins University and National Institutes of Health.

Magnetic resonance imaging safety in patients with cardiac implantable electronic devices.

High strength magnetic and electric fields used in magnetic resonance imaging (MRI) render images with unmatched soft tissue contrast. These imaging attributes have made MRI an increasingly preferred diagnostic tool in many medical conditions. Initially there was substantial concern regarding the safety of performing these imaging studies in patients with cardiac implantable electronic devices (CIEDs), which have the potential to be affected by the intense electric and magnetic fields of the MRI. More recently, there has been increasing evidence that MRI can be performed safely in patients with devices that have not been specifically labelled by regulatory agencies for use in an MRI environment (MRI nonconditional devices), which has allowed the Centers for Medicare and Medicaid Services (CMS) to start providing reimbursement for MRIs of patients with MRI nonconditional devices. For CMS to reimburse scans, a rigorous protocol must be followed, which recognizes that there are still potential adverse effects that can be mitigated by appropriate procedures. In this review we will survey the initial experiences and efforts to understand the magnitude of risk for device malfunction and harm, as well as current efforts to minimize the potential risks of MRI effects on devices and leads (heating, device movement, lead dislodgement, and device malfunction, the latter including inhibition of pacing and generation of arrhythmias).

Left ventricular lead placement using inner guiding catheter alone in cardiac resynchronization therapy device implantation.

BACKGROUND: Subselection inner catheters (Inner-Cath) are used adjunctively with outer guiding catheters (Outer-Cath) during cardiac resynchronization therapy (CRT) device implantation. This study aims to investigate the feasibility and efficacy of left ventricular lead placement (LV-LP) guided by Inner-Cath alone. METHODS: A total of 74 patients undergoing de novo CRT implantation were investigated. LV-LP was initially guided by Inner-Cath in 42 patients (Inner-Cath group) and Outer-Cath in 32 patients (Outer-Cath group). In the Inner-Cath group, a 7Fr Inner-Cath was advanced to the coronary sinus through a 7 Fr sheath inserted in a subclavian vein. In the Outer-Cath group, 9Fr or 10Fr Outer-Caths were used. Success rate of LV-LP, additional use of inner or outer catheters and procedure-related complications were compared between groups. RESULTS: LV-LP was successful in all patients in the Inner-Cath group, while LV-LP had to be abandoned in two patients (6.3%) of the Outer-Cath group due to CS perforation caused by Outer-Cath manipulation. Procedure time was significantly shorter in the Inner-Cath group (148 vs. 168 min; p = .024). Deployment of both an inner and outer cath became necessary less frequently for the Inner-Cath group (4.8% vs. 56.3%; p < .001). Mechanical CS injuries due to guiding catheter manipulation were only observed in the Outer-Cath group (0% vs. 15.6%, p = .013). CONCLUSION: LV-LP guided by Inner-Cath alone was feasible in over 95% of the patients without severe complications. This methodology for LV-LP may be preferable in CRT candidates with severe LV dysfunction in terms of shorter procedure time, smaller guiding sheath, and less procedure-related complications.

[Renal Artery Stenting for Spontaneous Renal Artery Dissection with Renal Infarction].

Spontaneous renal artery dissection (SRAD) is extremely rare and the management procedures have not been established. We report a case of endovascular stent placement for SRAD with renal infarction. A 53-year-old man visited a hospital with the complaint of lumbago. Contrast enhanced computed tomography images showed right renal artery dissection and renal infarction. He was transferred to our hospital for further treatment. We consulted our department of endovascular surgery. As 16 hours had passed from the onset, stent placement was performed on the next day as a wait and see procedure. He was discharged 11 days after the stenting. At 14 months after the procedure, he is free from lumbago and his serum creatine levels are within the normal range.

Predictors of non-pulmonary vein foci in paroxysmal atrial fibrillation.

PURPOSE: Progress of balloon devices for pulmonary vein (PV) isolation in atrial fibrillation (AF) has been remarkable. However, these techniques were specialized in pulmonary vein treatment; predicting non-PV foci in advance is important to decide the treatment strategy. In this study, we investigate the predictors for paroxysmal AF. METHODS: Subjects were consecutive paroxysmal AF patients who underwent high-dose isoproterenol provocation after PV isolation in the first session. The PV group (n = 102) and non-PV group (n = 222) were defined as the patients with and without non-PV ablation, respectively. Non-PV ablation was performed when frequent repetitive premature atrial contractions or triggered AF occurred spontaneously or by isoproterenol provocation. Predictors of non-PV origin in paroxysmal AF patients were examined using clinical characteristics and preoperative echocardiography. RESULTS: In the multivariate logistic regression analysis, female sex, body mass index (BMI < 23.8), absence of hypertension, and higher ratio of mitral early diastolic peak (E-wave) to early diastolic mitral annulus peak (e') velocity (E/e' > 8.44) were significant independent predictors of non-PV foci (hazard ratio 2.04, 1.88, 3.63, and 2.33; 95% confidence interval 1.17-3.55, 1.05-3.39, 1.72-7.67, and 1.34-4.05; p = 0.011, 0.035, < 0.001, and 0.003, respectively). If a patient had these four factors, non-PV was detected with 96.8% specificity. CONCLUSION: Female sex, lower BMI, absence of hypertension, and higher E/e' were significant indicators of non-PV foci in patients with paroxysmal AF. Reviewing these factors in advance may be useful for selecting a device to perform pulmonary vein isolation.

Effect of Endovascular Treatment on Systemic Vascular Resistance in Patients with Lower-Limb Peripheral Artery Disease.

Objective: Endovascular treatment (EVT) for lower-limb peripheral artery disease patients reduces blood pressure (BP) and improves prognosis. This study retrospectively examined hemodynamics during EVT to clarify the mechanism. Materials and Methods: Systemic vascular resistance (SVR) was measured using a noninvasive continuous cardiac output monitoring system during EVT. Furthermore, ankle brachial index was measured before and after EVT. Results: The study included 88 lesions of 56 patients (hypertension in 98%). SVR significantly decreased from 2409.1±746.8 dynes·s·cm-5 to 2033.7±635.0 dynes·s·cm-5 (p<0.0001). The difference in SVR before and after EVT was significantly greater in the Fontaine IV group than in the Fontaine IIa group (554.7±406.6 dynes·s·cm-5 vs. 312.9±245.7 dynes·s·cm-5, p=0.0151). The change in SVR was correlated with a change in mean BP in the upper limb (p=0.0026). When the change in pressure gradient between the upper limb and the diseased lower limb was large, mean BP of the upper limb significantly decreased (p=0.0022). Conclusion: EVT can reduce SVR and BP by canceling the pressure gradient between central BP and diseased lower-limb BP.

Utility of a ripple map for the interpretation of atrial propagation during atrial tachycardia.

PURPOSE: Ripple map (RM) is a novel method for displaying activation pattern on the surface of a cardiac chamber. The aim of this study was to determine the utility of the RM in interpreting the atrial propagation in atrial tachycardia (AT) in comparison with a conventional local activation (LAT) map. METHODS: Three-dimensional electroanatomical mapping and ablation of AT were performed using multielectrode catheters and the CARTO3 ConfiDENSE Module (Biosense Webster). LAT maps and RMs were retrospectively reviewed by two independent observers who were blinded to the ablation results. RESULTS: High-density maps (1683 ± 1362 points) of 45 ATs (274 ± 64 ms; macroreentry 28, focal 17) were obtained in 39 patients. Of the 45 ATs, 41 (91%) were terminated by catheter ablation. A retrospective review of the LAT map alone by two observers resulted in correct diagnosis in 27% (12 ATs), whereas additional reviews of the RMs improved the diagnostic accuracy to 80% (36 ATs, P < 0.001). The diagnostic accuracy using the RM was equally high for macroreentrant (79%) and focal ATs (82%, P = 1.000). Of the 33 LAT maps in disagreement with the observers, adjusting the window-of-interest (WOI) after reviewing the RMs achieved diagnostic agreement of 91% (30 ATs). CONCLUSION: RMs allow us to have precise understanding of the atrial propagation on high-density CARTO maps for both focal and macroreentrant ATs, which is particularly useful for cases with difficult-to-interpret LAT maps.

Efficacy of catheter ablation of focal sources in persistent atrial fibrillation.

INTRODUCTION: Recent studies suggest that atrial fibrillation (AF) is maintained by electrical activity arising from focal sources. We sought to test whether catheter ablation that targets focal sources can improve on current ablation protocols for persistent AF. METHODS AND RESULTS: In patients with persistent AF whose AF did not terminate with pulmonary vein (PV) isolation, the left atrium was mapped with a 20-pole high-density mapping catheter using CARTO® 3 navigation. If a site demonstrated centrifugal activation over at least three consecutive cycles, it was deemed a focal source and ablated. If AF remained, defragmentation was performed until AF was terminated. Freedom from atrial tachyarrhythmia was compared between the study patients and propensity score matched historical controls who had undergone conventional stepwise ablation. Of the 68 study patients, 2.9 ± 1.9 focal sources were identified in 60 patients. Focal sources displayed transient centrifugal activation patterns for a median of six consecutive cycles. Total radiofrequency duration was shorter in the study group (62 ± 16 minutes vs. 75 ± 24 minutes, P = 0.0003). During a 1-year follow-up period, 39 (57%) and 26 (38%) patients were free from atrial tachyarrhythmias in the absence of antiarrhythmic drugs in the study and control groups, respectively (hazard ratio: 1.85, 95% confidence interval: 1.17-2.96, P = 0.009). Improvement of clinical outcome was mainly driven by a decrease in recurrence of atrial tachycardia in the study patients (22% vs. 40%, P = 0.047). CONCLUSION: The results of this study suggest that focal sources are appropriate ablation targets in addition to the PVs in persistent AF.

A new mapping method to estimate exit sites of ventricular arrhythmias using intracardiac echocardiography and M-mode for catheter ablation.

BACKGROUND: Catheter ablation of premature ventricular complexes (PVCs) has been used as a curative therapy in many cases. Intracardiac ultrasound with a magnetic sensor probe has recently become available for catheter ablation. In this study, we assessed a new mapping method, contraction mapping, for determining the optimal ablation sites using intracardiac ultrasound and M-mode. This study sought to assess the accuracy of the new mapping method using intracardiac echocardiography. METHODS: Eighteen patients (10 males and eight females; mean age, 63±12 years) with 104 mapping points diagnosed as idiopathic PVCs were included in this study. At the mapping points, the time interval from the onset of the QRS to the onset of the contraction (QRS-c-time) and the local activation time were measured using M-mode with an intracardiac echo probe and using the conventional method. The correlation between the QRS-c-time and local activation time were studied. RESULTS: The QRS-c-time was significantly correlated with the local activation time (activation time=-66.8+0.882 * QRS-c-time, R2=0.728, p<0.0001). CONCLUSIONS: Contraction mapping could help determine the local activation time without the delivery of a catheter to the mapping points.

Association of the Clinical and Genetic Factors With Superior Vena Cava Arrhythmogenicity in Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) can be initiated from arrhythmogenic foci within the muscular sleeves that extend not only into the pulmonary veins but also into both vena cavae. The superior vena cava (SVC) is a key target site for catheter ablation. Patients with SVC-derived AF often lack the clinical risk factors of AF.Methods and Results:We conducted a meta-analysis of the clinical and genetic factors of 2,170 AF patients with and without SVC arrhythmogenicity. In agreement with previous reports, the left atrial diameter was smaller in AF patients with SVC arrhythmogenicity. Among 6 variants identified in a previous genome-wide association study in Japanese patients, rs2634073 and rs6584555 were associated with SVC arrhythmogenicity. This finding was confirmed in our meta-analysis using independent cohorts. We also found that SVC arrhythmogenicity was conditionally dependent on age, body mass index, and left ventricular ejection fraction. CONCLUSIONS: Both clinical and genetic factors are associated with SVC arrhythmogenicity.

Mechanisms of Diuresis for Acute Decompensated Heart Failure by Tolvaptan.

Tolvaptan, a vasopressin type 2 receptor antagonist, does not affect kidney circulation or cause worsening of renal function (WRF) in patients with acute decompensated heart failure (ADHF). Bioelectrical impedance analysis (BIA) can be used to evaluate intravascular volume by calculating the ratio of extracellular water (ECW) to intracellular water (ICW). There have been no reports examining the mechanisms of tolvaptan-induced diuresis using BIA. We investigated whether tolvaptan decreases excess volume while maintaining intravascular volume in ADHF patients.Study patients included 29 ADHF patients (age 48-95, men 69%) diagnosed between April 2013 and May 2016 and who underwent BIA before and after treatment. Fifteen patients were treated with tolvaptan in addition to conventional diuresis therapy (tolvaptan group), and 14 patients were treated with conventional diuresis therapy only (control group). In the control group, the numerical value of serum creatinine (Cre) significantly increased from 0.89 ± 0.22 mg/ dL to 1.07 ± 0.29 mg/dL (P = 0.004), and the ECW/ICW significantly decreased from 0.696 ± 0.036 to 0.673 ± 0.032 (P = 0.004). These values were not significantly different from those obtained for the tolvaptan group. Furthermore, regression analysis showed a negative correlation between ΔCre and ΔECW/ICW, which are the differences between values before and after treatment (ΔCre = -0.002-5.668 × ΔECW/ICW, r2 = 0.306, P = 0.002).Our findings suggest that WRF is caused by a reduction in intravascular volume and that tolvaptan treatment can decrease the excess volume while maintaining intravascular volume.

The Efficacy of Isochronal 3D Mapping-Based Ablation of Ventricular Arrhythmia.

Treatment of ventricular arrhythmias (VAs) commonly involves ablating sites showing electrograms with the earliest activity relative to the VA, but there is no threshold value for prematurity guaranteeing success. Ablation of sites with great prematurity can still result in failure.We hypothesized that isochronal map area (ISCA), derived from isochrones indicating electrogram prematurity, could help identify ablation targets in VA patients, as well as predict outcome. Specifically, we hypothesized that smaller ICSA for a given prematurity value would indicate a shallower arrhythmogenic focus leading to a higher likelihood of successful ablation.We studied ICSA in 29 patients (12 males, 57 [17-65] years old) undergoing VA ablation. The VAs originated from the right and left ventricles in 11 and 18 patients, respectively. The earliest activation site of the VAs, ECG morphology of sinus beats and premature ventricular complexes (PVCs), and ISCA of activation preceding PVCs were evaluated.RF ablation at the site showing earliest prematurity resulted in VA elimination in 21 patients (success group). The 5-ms ISCA was smaller in the success group than in the failure group (0.2 [0.1-0.6] versus 1.0 [0.8-1.5] cm2, respectively; P < 0.01). No significant difference was noted in prematurity itself (36 [30-45] versus 30 [29-33] ms, respectively; P = 0.07). The cut-off value of the 5 ms ISCA for successful RF ablation was 0.7 cm2 with 87.5% sensitivity and 85.6% specificity.Isochrones of activity preceding PVCs appear to contain information beyond prematurity values and may help dictate suitable areas for successful ablation of VAs.

Novel Mapping Technique for Localization of Focal and Reentrant Activation During Atrial Fibrillation.

INTRODUCTION: Identification of wavefront propagation pattern during AF remains challenging in ablation procedures. We sought to test a novel combination of a new mapping technology called Ripple Map and high-density mapping to distinguish focal and reentrant activation during atrial fibrillation (AF). METHODS AND RESULTS: Subjects were patients undergoing ablation for persistent AF. If AF remained after isolation of the pulmonary veins, the left atrium (LA) was mapped by a high-density mapping catheter for later analysis, after which ablation was continued using a conventional stepwise approach. After the procedure, electrograms from the high-density mapping catheter were analyzed using Ripple Map, which is a new feature in the CARTO®3, and type of activation on ≥3 consecutive AF cycles was determined. High-density mapping was performed on 569 sites in 45 patients (13 ± 3 sites per patient). AF wavefront propagation determined by Ripple Map was in good agreement with analysis of manual annotation of bipolar electrograms. Ripple Map's representation of wavefront activation pattern, which could include local as well as far-field activity, allowed us to identify focal activation in 64 (11%) sites and 1 (0.2%) reentrant activation site. Radiofrequency delivery in atrial regions with activation sites identified as focal by Ripple Map resulted in termination of AF more often than regions without focal activation (22% vs. 7%, P = 0.015). CONCLUSION: This study demonstrated that Ripple Map enabled quick identification of AF wavefront activation pattern, potentially being helpful for determining ablation targets in persistent AF.

The impact of B-type natriuretic peptide levels on the suppression of accompanying atrial fibrillation in Wolff-Parkinson-White syndrome patients after accessory pathway ablation.

BACKGROUND: Atrial fibrillation (AF) often coexists with Wolff-Parkinson-White (WPW) syndrome. We compared the efficacy of Kent bundle ablation alone and additional AF ablation on accompanying AF, and examined which patients would still have a risk of AF after successful Kent bundle ablation. METHODS: This retrospective multicenter study included 96 patients (56±15 years, 72 male) with WPW syndrome and AF undergoing Kent bundle ablation. Some patients underwent simultaneous pulmonary vein isolation (PVI) for AF. The incidence of post-procedural AF was examined. RESULTS: Sixty-four patients underwent only Kent bundle ablation (Kent-only group) and 32 also underwent PVI (+PVI group). There was no significant difference in the basic patient characteristics between the groups. Additional PVI did not improve the freedom from residual AF compared to Kent bundle ablation alone (p=0.53). In the Kent-only group, AF episodes remained in 25.0% during the follow-up (709 days). A univariate analysis showed that age ≥60 years, left atrial dimension ≥38mm, B-type natriuretic peptide (BNP) ≥40pg/ml, and concomitant hypertension were predictive factors for residual AF. However, in the multivariate analysis, only BNP ≥40pg/ml remained as an independent predictive factor (HR=17.1 and CI: 2.3-128.2; p=0.006). CONCLUSIONS: Among patients with WPW syndrome and AF, Kent bundle ablation alone may have a sufficient clinical impact of preventing recurrence of AF in select patients. Screening the BNP level would help decide the strategy to manage those patients.

Bleeding events and activated partial thromboplastin time with dabigatran in clinical practice.

BACKGROUND: Dabigatran has demonstrated promising results for the prevention of strokes in patients with non-valvular atrial fibrillation (NVAF). However, there have been episodes of major bleeding, especially in elderly patients or those with renal dysfunction. The purpose of this study was to retrospectively examine the relationship between the bleeding events and activated partial thromboplastin time (APTT) values under dabigatran usage in the everyday clinical practice. Moreover, we investigated which factors would contribute to the APTT values. METHODS AND RESULTS: A total of 139 NVAF patients (112 men, 65 ± 11 years) were included. We evaluated the influence of the putative etiological variables and the bleeding score, HAS-BLED score, on APTT values: age greater than 70 years, renal function, gender, dose of dabigatran, and the concomitant prescription of a P-glycoprotein inhibitor. There were 50 patients with an age of ≥ 70 years (36.0%). A P-glycoprotein inhibitor was administered in 18 patients. During the observation period (median 120 days) there was 1 episode of asymptomatic cerebral infarction. There were no intrinsic major bleeding events, however, 11 patients had minor hemorrhagic events. The results of the APTT measurements exhibited a variety of values both among inter- and intra-individuals. On multivariable analysis, significant associations were found between the following risk factors and the APTT values: creatinine clearance, dose of dabigatran, and concomitant use of a P-glycoprotein inhibitor. The minor bleeding events did not correlate with the APTT values, nor HAS-BLED score. CONCLUSIONS: The APTT values became prolonged under dabigatran usage and exhibited a remarkable diversity. Although major bleeding did not occur unless APTT was prolonged excessively, minor bleeding arose irrespective of the APTT values even within the range of the APTT values not exceeding 80s.

Distribution of the origin of adenosine triphosphatesensitive atrial tachycardias with the earliest activation recorded in the His bundle catheter: are they limited to the immediate vicinity of the His bundle?

BACKGROUND: The aim of this study was to assess the spatial distribution of the origins of adenosine triphosphate (ATP) sensitive focal atrial tachycardias (AT) that have their earliest activation recorded in the His bundle (HB) catheter. METHODS AND RESULTS: Catheters were placed according to the standard fashion for an electrophysiologic study of supraventricular arrhythmia, namely, high right atrium, HB, coronary sinus, and right ventricle. The ATs with their earliest activation recorded in the HB catheter and that were terminated by rapid injection of ATP (4.3 ± 2.5mg), formed the study group (n=12). After catheter ablation of these ATs, the distances between the successful ablation site and the HB area were measured. Only one successful site was near the HB and the other sites were at the noncoronary sinus of Valsalva (n=6), tricuspid annulus (n=3), right atrial septum (n=1), and left atrial septum (n=1). The average distance between the HB catheter and successful site was 10.4 ± 8.8mm. In 5 of the 12 cases (the 3 tricuspid and 2 septal foci), the distances were greater than 10mm. CONCLUSIONS: When ablating ATP-sensitive AT with the earliest activation recorded in the HB catheter, it is important to perform detailed mapping not only around the HB.