Does the same lesion index mean the same efficacy and safety profile: influence of the differential power, time, and contact force on the lesion size and steam pops under the same lesion index.

BACKGROUND: The lesion index (LSI) helps predict the lesion size and is widely used in ablation of various types of arrhythmias. However, the influence of the ablation settings on the lesion formation and incidence of steam pops under the same LSI value remains unclear. METHODS: Using a contact force (CF) sensing catheter (TactiCath™) in an ex vivo swine left ventricle model, RF lesions were created with a combination of various power steps (30 W, 40 W, 50 W) and CFs (10 g, 20 g, 30 g, 40 g, 50 g) under the same LSI values (5.2 and 7.0). The correlation between the lesion formation and ablation parameters was evaluated. RESULTS: Ninety RF lesions were created under a target LSI value of 5.2, and eighty-four were developed under a target LSI value of 7.0. In the LSI 5.2 group, the resultant lesion size widely varied according to the ablation power, and a multiple regression analysis indicated that the ablation energy delivered was the best predictor of the lesion formation. To create a lesion depth > 4 mm, an ablation energy of 393 J is the best cutoff value, suggesting a possibility that ablation energy may be used as a supplemental marker that better monitors the progress of the lesion formation in an LSI 5.2 ablation. In contrast, such inconsistency was not obvious in the LSI 7.0 group. Compared with 30 W, the 50-W ablation exhibited a higher incidence of steam pops in both the LSI 5.2 and 7.0 groups. CONCLUSIONS: The LSI-lesion size relationship was not necessarily consistent, especially for an LSI of 5.2. To avoid any unintentional, weak ablation, the ablation energy may be a useful supportive parameter (393 J as a cutoff value for a 4-mm depth) during ablation with an LSI around 5.2. Thanks to a prolonged ablation time, the LSI-lesion size relationship is consistent for an LSI of 7.0. However, it is accompanied by a high incidence of steam pops. Care should be given to the ablation settings even when the same LSI value is used.

Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans.

Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41-78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the "signatures" of the ANS and intrinsic mechanisms and also the anesthesia "signature". In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.

Detailed investigation of the lesion formation with a novel contact force sensing catheter with a mesh-shaped irrigation tip.

Background: Recently, a novel contact force (CF) sensing catheter with mesh-shaped irrigation tip (TactiFlex SE, Abbott) was invented and is expected to be useful for safe and effective radiofrequency ablation. However, this catheter's detailed characteristics of the lesion formation are unknown. Methods: With an in vitro model, TactiFlex SE and its predecessor, FlexAbility SE, were used. A cross-sectional analysis of 60 s lesions (combination of various energy power settings [30, 40, and 50 W], and CFs [10, 30, and 50 g]) and longitudinal analysis (combination of various powers [40 or 50 W], CFs [10, 30, and 50 g] and ablation times [10, 20, 30, 40, 50, and 60 s]) of both catheters were analyzed and compared. Results: One hundred eighty RF lesions were created in protocol 1 and 300 in protocol 2. The lesion formation, impedance changes, and steam pops characteristics were similar between the two catheters. Higher CFs were related to higher incidences of steam pops. A nonlinear, time-dependent increase in the lesion depth and diameter was observed for all power and CF settings, and linear, positive correlations between the RF delivery time and lesion volume were observed for all power settings. Compared with 40 W, a 50 W ablation created greater lesions. Longer durations with higher CF settings had a higher steam pop incidence. Conclusions: The lesion formation and incidence of steam pops with TactiFlex SE and FlexAbility SE were similar. A 40 or 50 W ablation with careful CF control not to exceed 30 g in addition to monitoring impedance drops was required to safely create transmural lesions.

Impact of long-term optimizing atrioventricular delay using device-based algorithms on cardiac resynchronization therapy.

Sub-optimal atrioventricular delay (AVD) is one of the main causes of non-responder for cardiac resynchronization therapy (CRT). Recently, device-based algorithms (DBAs) that provide optimal AVD based on intracardiac electrograms, have been developed. However, their long-term effectiveness is still unknown. This study aims to investigate the effect of optimizing AVD using DBAs over a long period, on the prognosis of patients undergoing CRT. A total of 118 patients who underwent CRT at our hospital between April 2008 and March 2018, were retrospectively reviewed; 61 of them with optimizing AVD using DBAs were classified into the treated group (group 1), and the remaining 57 were classified into the control group (group 2). The median follow-up period was 46.0 months. The responder and survival rate in group 1 were significantly better than those in group 2 (group 1 vs. group 2: responder rate = 64% vs. 46%, p = 0.046; survival rate: 85.2% vs. 64.9%, p = 0.02). Moreover, investigating only the non-responder population showed that group 1 had an improved survival rate compared to group 2 (group 1 vs. group 2 = 72.7% vs. 45.1%, p = 0.02). Optimizing AVD using DBAs was a significant contributor to the improved survival rate in CRT non-responders in multivariate analysis (HR 3.6, p = 0.01). In conclusion, the long-term optimizing AVD using DBAs improved the survival rate in CRT and the prognosis of CRT non-responders, as well.

Ablation characteristics and incidence of steam pops with a novel, surface temperature-controlled ablation system in an ex vivo experimental model.

BACKGROUND: A novel irrigation catheter (QDOT MICRO™) has been introduced, which enables a surface temperature-controlled ablation combined with tip cooling. However, the detailed description of its complex behavior and effect on the incidence of pops and lesion formation remains elusive. This study aimed to systematically investigate the ablation characteristics, feedback behavior, and incidence of steam pops in a simplified ex vivo swine model. METHODS: Using swine ventricular tissue perfused with saline at 37°C, we systematically created lesions with 4×3 combinations of the wattage (20, 30, 40, and 50 W) and contact force (CF, 10, 30, and 50 g). Ablation was continued for either 120 s or until a steam pop occurred and repeated 10 times with each setting. The lesion geometry, ablation index, feedback dynamics, and conditions underlying the steam pops were measured and analyzed. RESULTS: Steam pops occurred particularly frequently in combinations of a low CF and high power (10 g vs. 30 g+50 g [p < .0001]; 40 W+50 W vs. 20 W+30 W [p < .0001]). Failure to activate a feedback process was associated with a 5.1 times higher incidence of steam pops (21/109 vs.11/11, [95% CI 3.499-7.716], p < .0001). The wattage feedback was particularly evident with a high CF (30 and 50 g) and high initial wattage (40 and 50 W). The average delivered wattage at 27 W predicted the occurrence of steam pops. CONCLUSION: The temperature-controlled ablation with the QDOT MICRO™ demonstrated a complex feedback behavior, which contributed to a reduced incidence of steam pops and prolonged lead time to the pops.

Chest computer tomography is safe without additional interrogation or monitoring for modern cardiac implantable electrical devices.

INTRODUCTION: Whether diagnostic computed tomography (CT) scans to cardiac implantable electronic devices (CIED) is safe in recent models remains unknown. METHODS: A two-centers observational study. Over 14 years, consecutive 2362 chest CT scans (1666 pacemakers [PMs], 145 cardiac resynchronization therapy PM, 316 implantable cardioverter-defibrillator, and 233 cardiac resynchronization therapy defibrillator) were interrogated and monitored upon imaging. RESULTS: Electromagnetic interference occurred only in a few old models: InSync 8040 (n = 14), InSync III Marquis (n = 1), and Kappa (n = 4), which resulted no adverse events. CONCLUSION: CIEDs, especially recent ones, are confirmed safe on chest CT.

The Efficacy and Safety of Dexmedetomidine for Procedural Sedation in Patients Receiving Local Anesthesia Outside the Intensive Care Unit: A Prospective, Double-Blind, Randomized Clinical Phase III Trial in Japan.

BACKGROUND: Few studies (in other countries than the US) have reported on the efficacy and safety of dexmedetomidine for sedation of patients undergoing surgical or medical procedures under local anesthesia without intubation outside the intensive care unit. We performed a randomized, double-blind study in Japan. METHODS: Adult patients were randomly allocated to receive placebo, dexmedetomidine 0.5 µg/kg (DEX 0.5 group), or dexmedetomidine 1.0 µg/kg (DEX 1.0 group) over 10 min. Then, both dexmedetomidine groups received dexmedetomidine 0.2-0.7 µg/kg/h for maintaining an Observer's Assessment of Alertness/Sedation Scale (OAA/S) score of ≤ 4; however, propofol was administered to rescue patients whose score exceeded this value. The primary endpoint was the percentage of patients who did not require rescue propofol to achieve and maintain an OAA/S score of ≤ 4. RESULTS: In total, 162 patients were included in the placebo (n = 53), DEX 0.5 (n = 53), and DEX 1.0 (n = 56) groups. Propofol was not required in significantly more patients in the dexmedetomidine 0.5 and 1.0 µg/kg groups (52.8% and 57.1%, respectively) compared with the placebo group (1.9%) (P < 0.001 for both). Common adverse events were protocol-defined hypotension, respiratory depression and bradycardia. The incidence of bradycardia was significantly higher in the DEX 0.5 (26.4%) and DEX 1.0 (30.4%) groups than in the placebo group (9.4%) (P = 0.041 and P = 0.008, respectively). CONCLUSION: We concluded that a loading dose of 0.5 or 1.0 µg/kg dexmedetomidine followed by infusion at a rate of 0.2-0.7 µg/kg/h provided effective and well-tolerated sedation in patients undergoing surgical or medical procedures under local anesthesia without intubation.Clinical trials.gov identifier: NCT01438931.

The target ablation index values for electrical isolation of the superior vena cava.

PURPOSE: The ablation index (AI), developed as a radiofrequency (RF) catheter ablation composite component endpoint, which incorporates contact force (CF), time, and power in a weighted formula, has been reported to be useful for a durable pulmonary vein isolation (PVI) to treat atrial fibrillation (AF). No study has reported the target AI value for the SVC isolation (SVCI). In this study, we aimed to investigate the target AI for the SVCI. METHODS: Thirty-six AF patients who underwent an initial SVCI were enrolled. Ablation was performed at 556 points. The sites where dormant conduction was induced or additional ablation was needed were defined as touch up sites (n = 36). We compared the energy deliver time, power, generator impedance (GI) drop, local bipolar voltage, contact force (CF), force-time integral (FTI), and AI between the touch up sites and the no touch up sites (n = 520). RESULTS: The FTI and AI were significantly lower at the touch up sites (touch up sites vs. no touch up sites; FTI, 126.5 [99.3-208.8] vs. 244 [184-340.8], p < 0.0001; AI, 350.1 ± 43.6 vs. 277.2 ± 21.8, p < 0.0001). The median value of the AI at the no touch up sites was 350, and no reconnections were seen where the minimum AI value was more than 308. Most of the touch up sites were located in the anterior wall and lateral wall (anterior wall, 20/36 sites [55.6%]; lateral wall, 10/36 sites [27.8%]; septal wall, 6/36 sites [16.7%]; posterior wall, 0/36sites [0.0%]). CONCLUSION: The target AI value for the SVCI should be 350, and at least 308 would be needed.

Effects of uninterrupted dabigatran on the intensity of anticoagulation during atrial fibrillation ablation.

BACKGROUND: Uninterrupted dabigatran during atrial fibrillation (AF) ablation is now established as the standard therapy. However, there are few reports on the effects of uninterrupted dabigatran on the intensity of anticoagulation during AF ablation. METHODS: We retrospectively analyzed 247 consecutive patients who underwent AF ablation in our hospital from January 2017 to December 2018. Patients who took warfarin or uninterrupted direct oral anticoagulants (DOACs) except for dabigatran were excluded. 89 patients underwent ablation with uninterrupted dabigatran (uninterrupted group, male 71, mean age 59.6 ± 14.0) and 124 with interrupted DOACs (interrupted group, male 105, mean age 56.9 ± 12.9) during AF ablation. The initial ACT level, proportion of ACT levels of more than 300 s, and total amount of heparin were compared. Furthermore, the incidence of procedure complications was also evaluated. RESULTS: The initial ACT levels were significantly higher in the uninterrupted group, and the total number of ACTs of more than 300 s was significantly higher in the uninterrupted group (uninterrupted vs. interrupted; initial ACT level, 315.6 ± 59.8 vs. 264.5 ± 48.6, p < .001; total number of ACTs ≧300, n [%], 304/ 484 [62.8 %] vs. 372/745 [49.9%], p < .001). The total amount of heparin during procedure was significantly lower in the uninterrupted group (uninterrupted group vs. interrupted group; 12966 ± 4773 vs. 16371 ± 5212, p < .001). There was no significant difference in the incidence of complications between the two groups. CONCLUSIONS: In the catheter ablation of AF, uninterrupted dabigatran would be useful to obtain a stable anticoagulation status during the entire procedure.

Characteristics and optimal ablation settings of a novel, contact-force sensing and local impedance-enabled catheter in an ex vivo perfused swine ventricle model.

BACKGROUND: Local impedance (LI) has emerged as a new technology that informs on electrical catheter-tissue coupling during radiofrequency (RF) ablation. Recently, IntellaNav StablePoint, a novel LI-enabled catheter that equips contact force (CF) sensing, has been introduced. Although StablePoint and its predecessor IntellaNav MiFi OI share the common technology that reports LI, distinct mechanics for LI sensing between the two products raise a concern that the LI-RF lesion formation relationship may differ. METHODS: In an ex vivo swine cardiac tissue model, we investigated the initial level and range of a reduction in LI during a 60-s RF ablation and the resultant lesion characteristics at nine combinations of three energy power (30, 40, and 50 W) and CF (10, 30, and 50 g) steps. Correlations and interactions between CF, LI, wattage, and formed lesions were analyzed. Incidence of achieving LI drop plateau and that of a steam pop were also determined. RESULTS: Positive correlations existed between CF and initial LI, CF and absolute/relative LI drop, CF and lesion volume, and LI drop and lesion volume. At the same LI drop, wattage-dependent gain in lesion volume was observed. Steam pops occurred in all CF steps and the prevalence was highest at 50 W. LI drop predicted a steam pop with a cutoff value at 89Ω. CONCLUSION: In StablePoint, wattage crucially affects LI drop and lesion volume. Because 30 W ablation may by underpowered for intramural lesion formation and 50 W often resulted in a steam pop, 40 W appears to achieve the balance between the safety and efficacy.

The optimal ablation setting for a local impedance guided catheter in an in vitro experimental model.

BACKGROUND: The local impedance (LI) reflects the electrical catheter-tissue coupling and correlates with the local tissue temperature. However, there have been few clinical studies showing the recommended method for LI monitoring catheters. This study aimed to investigate the optimal ablation setting for this catheter in an in vitro experimental model. METHODS: LI monitoring catheters were used in an excised swine heart experimental model. The tissue contact force (CF) was directly monitored from an external weight scale. Radiofrequency ablation was performed with a combination of various energy power settings (30, 40, and 50 W), and various CFs (10, 30, and 50 g) for 60 s. The correlation between the LI-related indexes, power, and CF with the lesion formation was statistically analyzed. RESULTS: A positive correlation between the LI or lesion formation and CF was observed under all powers. Although the LI drop always correlated with the maximum lesion depth, lesion diameter, and lesion volume, the coefficient of the correlation value was lower under a high CF (lesion depth, diameter, and volume; 10 g, r = 0.8064, r = 0.8389, r = 0.8477; 30 g, r = 0.7590, r = 0.8063, r = 0.8060; 50 g r = 0.5555, r = 0.5701, and r = 0.5678, respectively). Steam pops occurred only under a 50 W ablation and the LI drop cutoff value for steam pops was 46 Ω. CONCLUSION: The same LI drop did not always lead to the same lesion size when the CF differed. Monitoring the LI and not exceeding 46 Ω would be useful for a safe ablation.

Ultrahigh density atrio-ventricular dual-chamber mapping as a next generation tool for ablation of accessory pathways.

INTRODUCTION: Detailed three-dimensional (3D) mapping has been useful for effective radiofrequency catheter ablation. The Rhythmia system can create atrio-ventricular dual-chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of mapping the atrium and ventricle simultaneously with a high-density 3D mapping system for the ablation of accessory pathways (AP). METHODS: From July 2015 to August 2020, 111 patients underwent ablation of APs. Dual-chamber maps were created in 50 patients (median age 15 [10-54], 32 male [64.0%]), while 61 patients underwent radiofrequency (RF) ablation with conventional single-chamber 3D maps. The background characteristics and procedural details were compared between the dual-chamber mapping group and the conventional single-chamber mapping group. RESULTS: The number of RF applications (median [IQR]; 1.0 [1.0-3.0] vs. 3.0 [1.0-6.0], p = .0023), RF time (median [IQR], s; 9.2 [2.0-95.7] vs. 95.6 [4.1-248.7], p = .0107), and RF energy (median [IQR], J; 248.4 [58.7-3328.2] vs. 2867.6 [134.2-7728.4], p = .0115) were significantly lower in the dual-chamber group. The fluoroscopy time (median [IQR], min; 19.9 [14.2-26.1] vs. 26.5 [17.7-43.4], p = .0025) and fluoroscopy dose (median [IQR], mGy; 52.5 [31.3-146.0] vs. 119.0 [43.7-213.5], p = .0249) were also significantly lower in the dual-chamber than single-chamber mapping group. CONCLUSION: The dual-chamber mapping was useful for ablating accessory pathways and reducing the number of RF applications, total RF energy, and radiation exposure as compared with traditional mapping techniques.

Gender Differences in the Circadian and Seasonal Variations in Patients with Takotsubo Syndrome: A Multicenter Registry at Eight University Hospitals in East Japan.

Objective The aim of this study was to clarify the circadian and seasonal variations in addition to identify sex-based differences in Japanese patients with Takotsubo syndrome (TTS). Methods The authors conducted a retrospective observational study to analyse the differences between the groups based on sex. Patients The patients were registered out of each institute registry of the acute coronary syndrome (ACS) which contains a total of 10,622 cases in eight academic hospitals in east Japan. Results Data for 344 consecutive TTS (73 male and 271 female) were extracted from each hospital registry. In-hospital mortality was higher in the male group than in the female group (18% vs. 7%; p=0.005). With regard to the circadian variations in all study patients, TTS events occurred most often in the afternoon and least often during the night. Moreover, the patterns of circadian variations in the female and male groups were the same as that of all study patients. TTS events occurred most frequently in the autumn and least often in the spring in the whole study cohort. Moreover, the seasonal variation in the female group showed the same pattern as that of the whole cohort. However, there were no significant seasonal differences in the incidence of TTS in the male group. Conclusion In a multicenter study in Japan, seasonal variation was observed in the female group but not in the male group. Circadian variation was observed in both groups. These results suggested that the pathogenesis and clinical features of TTS might therefore differ according to sex.

Antegrade slow pathway mapping of typical atrioventricular nodal reentrant tachycardia based on direct slow pathway capture.

BACKGROUND: Radiofrequency (RF) ablation of typical atrioventricular nodal reentrant tachycardia (tAVNRT) is performed without revealing out the location of antegrade slow pathway (ASp). In this study, we studied a new electrophysiological method of identifying the site of ASp. METHODS: This study included 19 patients. Repeated series of very high-output single extrastimulations (VhoSESts) were delivered at the anatomical slow pathway region during tAVNRT. Tachycardia cycle length (TCL), coupling interval (CI), and return cycle (RC) were measured and the prematurity of VhoSESts [ΔPM (= TCL - CI)] and the prolongation of RCs [ΔPL (= RC - TCL)] were calculated. Pacing sites were classified into two categories: (i) ASp capture sites [DSPC(+) sites], where two different RCs were shown, and ASp non-capture sites [DSPC(-) sites], where only one RC was shown. RF ablation was performed at DSPC(+) sites and/or sites with catheter-induced mechanical trauma (CIMT) to ASp. RESULTS: DSPC(+) sites were shown in 13 patients (68%). RF ablation was successful in all patients without any degree of atrioventricular block nor recurrence. Total number of RF applications was 1.8 ± 1.1. Minimal distance between successful ablation sites and DSPC(+)/CIMT sites and His bundle (HB) electrogram recording sites was 1.9 ± 0.8 mm and 19.8 ± 6.1 mm, respectively. ΔPL of more than 92.5 ms, ΔPL/TCL of more than 0.286, and ΔPL/ΔPM of more than 1.565 could identify ASp with sensitivity of 100%, 91.1%, and 88.9% and specificity of 92.9%, 97.0%, and 97.6%, respectively. CONCLUSIONS: Sites with ASp capture and CIMT were close to successful ablation sites and could be useful indicators of tAVNRT ablation.

Transvenous lead performance of implantable cardioverter-defibrillators and pacemakers.

BACKGROUND: After the reports of recalled leads, several technological improvements have been introduced and the durability of implantable cardioverter defibrillator (ICD) leads has improved. The incidence of lead failures is now less than in the previous studies. However, there are few reports that have shown the long-term durability of ICD leads as compared to pacemaker (PM) leads. This study analyzed the medium to long-term performance of transvenous ICD leads as compared to PM leads. METHODS: We retrospectively studied 1227 cases from April 2007 to December 2017 who underwent an initial transvenous ICD or PM implantation. The number of lead failures and patient background characteristics were analyzed. RESULTS: During a median 3-3.5 years follow up period, 1 (0.3%) ICD lead and 18 (2.4%) PM leads failed. The incidence of lead failures was significantly higher in the PM group than ICD group (p = .019). Males were associated with a higher incidence of lead failures in the PM group. CONCLUSION: Since the era of recalled ICD leads, the durability of ICD leads has remarkably improved and the incidence of lead failures with non-recalled ICD leads has been less than that for PM leads.

Impact of high-density mapping on outcome of the second ablation for atrial fibrillation.

PURPOSE: Identification of a conduction gap between the left atrium and pulmonary vein (LA-PV gap) and the circuit of atrial tachycardia after pulmonary vein isolation (PVI) is an important process during the second ablation for atrial fibrillation (AF). The high-density mapping system RHYTHMIA® is useful for identification of an LA-PV gap and the circuit of atrial tachycardia. Therefore, this study was performed to investigate the effect of RHYTHMIA® in terms of the outcome of the second ablation for AF. METHODS: One hundred patients underwent a second ablation for AF in our institute from April 2015 to December 2018. We retrospectively evaluated 49 patients using RHYTHMIA® (group 1) and 51 patients using the conventional method with additional anatomical guide by CARTO® system. RESULTS: In group 1, we performed redo PVI for 41 patients with 49 LA-PV countable gaps and ablation for other atrial arrhythmias in 7 patients. In group 2, we performed redo PVI in 40 patients with 33 LA-PV countable gaps and ablation for other atrial arrhythmias in 9 patients. Three and two unstable arrhythmias in each group were not ablated. The final recurrence of atrial arrhythmia was significantly lower in group 1 than 2 (8/49 (16%) vs. 17/51 (33%), respectively; P = 0.017). Atrial arrhythmias other than AF after the second ablation occurred in only one patient in group 1 but seven patients in group 2. CONCLUSION: Using high-density mapping for the second ablation of AF was found to be superior to the conventional ablation method in terms of the suppression of atrial events in this study. This technique warrants further investigation.

Clinical and procedure characteristics in patients treated with polytetrafluoroethylene-covered stents after coronary perforation: a CIRC-8U multicenter registry and literature review.

This study aimed at identifying the clinical characteristics and in-hospital outcomes of patients treated with polytetrafluorethylene (PTFE)-covered stents after coronary interventions in a multicenter registry. Subjects with coronary artery perforation were selected from 31,262 consecutive patients who underwent coronary interventions in the hospital registries. Subjects were divided into two groups: those with a PTFE-covered stent implantation and those without a PTFE-covered stent implantation. Clinical characteristics and in-hospital outcomes were compared between the two groups. Data for 82 consecutive coronary perforations (15 PTFE-covered stents and 67 non-PTFE-covered stents) were extracted from each hospital registry. The PTFE-covered stent group had a higher prevalence of perforations due to pre-dilatation before stenting or post-dilatation after stenting (80% vs. 10.4%; p < 0.001), more Ellis classification III perforations (66.6% vs. 28.4%; p = 0.019), longer perforation to hemostasis time (74 min vs. 10 min; p < 0.001), lower hemostatic success rates (73.3% vs. 94.0%; p = 0.015), and higher in-hospital mortality (26.7% vs. 6.0%; p = 0.015) than the non-PTFE-covered stent group. Although the prevalence of intravascular ultrasound (IVUS) usage was high during coronary interventions (86.7%), IVUS was performed in less than half the cases just before coronary perforations (47%) in the PTFE-covered stent group. Patients requiring PTFE-covered stents are more likely to be observed after balloon dilatation before or after stenting and have a poor prognosis. Careful coronary intervention is needed when IVUS image acquisition is not achieved in addition to proper evaluation of IVUS. Furthermore, if coronary artery perforation occurs, it is important to determine the need for a prompt PTFE-covered stent.

Myopotential Oversensing Is a Major Cause of Inappropriate Shock in Subcutaneous Implantable Defibrillator in Japan.

Previous study has identified marked differences in patient characteristics and causes of inappropriate shock (IAS) between Japan and the Western societies in terms of subcutaneous implantable cardioverter-defibrillator (S-ICD). However, evidence of IAS in Asian populations including Japan has been limited to one observational study.Thus, we conducted a single-center registry study that tracks the postoperative course of 61 consecutive patients who received S-ICD from February 2016 to January 2020. Our findings showed that IAS occurred in 9.8% of the study population (6/61), which is comparable to the previously reported incidence. Remarkably, T-wave oversensing did not result in an IAS (0/6). Instead, myopotential oversensing was determined to have caused the most IAS events (4/6), while atrial fibrillation ranked second (2/6). A provocation maneuver (e.g., abdominal clench, push-ups, lifting a heavy item) reproduced myopotential noise disguised as R-waves, which should potentially trigger an IAS if uninterrupted. R-wave amplitude of the IAS group appeared relatively low compared to that of the non-IAS group although this finding was not tested significant. Furthermore, no temporal changes were noted in R-wave amplitude between the time of implantation and IAS events, suggesting that it is neither constantly low nor acutely dropped R-wave amplitude but a relatively high noise level that drives IAS. All the myopotential-IAS patients were found to be male. Right-sided lead implantation was associated with a higher incidence of IAS.This study highlights the fact that IAS continues to occur due to myopotential noise oversensing instead of T-wave oversensing. To minimize the risk of IAS, it is desirable to search and secure high R-wave voltage.

Erratum: Differential Atrial Pacing to Detect Reconnection Gaps After Pulmonary Vein Isolation in Atrial Fibrillation.

The errors in the following list appeared in the article entitled "Differential Atrial Pacing to Detect Reconnection Gaps After Pulmonary Vein Isolation in Atrial Fibrillation" by Mai Tahara, Ritsushi Kato, Yoshifumi Ikeda, Koji Goto, So Asano, Hitoshi Mori, Shiro Iwanaga, Toshihiro Muramatsu, and Kazuo Matsumoto (Vol. 61, No. 3, 503-509, 2020).