Shortening of the atrial-His bundle interval during atrial pacing as a predictor of successful ablation for typical atrioventricular nodal re-entrant tachycardia.

Aims: Shortening of the atrial-His bundle (AH) interval during the sinus rhythm is occasionally observed after slow pathway ablation for atrioventricular nodal re-entrant tachycardia (AVNRT). In addition, high-rate atrial pacing is useful for avoiding atrioventricular block. We hypothesized that shortening of the AH interval during slow pathway ablation under high-rate atrial pacing would lead to successful ablation of typical AVNRT. Methods and results: This retrospective study included 37 patients in whom successful ablation of typical AVNRT was performed under atrial pacing. The AH interval was measured immediately before the first radiofrequency (RF) application and immediately after the last RF application, prior to the first induction. Twenty-five of 37 patients achieved procedural success at the first induction (i.e. successful group). No patients developed a prolonged AH interval or atrioventricular block. The AH interval was shortened by an average of 14.6 ± 7.7 and 1.8 ± 1.2 ms in the successful and other patient groups, respectively (P < 0.01). An AH interval decrease of > 10 ms was observed in 23 of 27 (85%) patients in the successful group, whereas all other patients had an AH interval decrease of < 5 ms. Conclusion: Shortening of the AH interval during high-rate atrial pacing is a predictor of the successful ablation for typical AVNRT.

Prospective survey of implantable defibrillator shock anxiety in Japanese patients: Results from the DEF-Chiba study.

BACKGROUND: Patient-reported outcomes of implantable cardioverter defibrillator (ICD), such as those with shock anxiety, have emerged as important endpoints that are related to quality of life (QOL), but they have not been well studied in a sample of the Japanese population. Therefore, we prospectively examined changes in shock anxiety in a large sample of Japanese patients with an ICD. METHODS: We recruited 214 consecutive patients with an ICD who visited the outpatient clinic. At registration and 12 months later, all patients completed the Florida Shock Anxiety Scale (FSAS) questionnaire to allow us to examine changes in shock anxiety over the course of the first year after registration. RESULTS: During the 12-month follow-up period, 10.5% of the patients received ICD shock therapy. Female sex, secondary prevention, and experience of ICD shock therapy were associated with high FSAS scores at registration. The FSAS scores in both patients with appropriate and inappropriate shock were significantly higher at the 12-month follow-up interval than at registration, and there was no significant difference in the extent of changes in FSAS scores (Δ = 5.2 ± 5.1 and Δ = 6.3 ± 9.9, respectively, P = 0.62). CONCLUSIONS: Female sex, secondary prevention, and experience of ICD shock therapy are important risk factors affecting shock anxiety in Japanese patients. Attention should be paid to the after-effects of ICD shock in these patients, regardless of the shock type, with particular attention to women and patients who require secondary prevention.

Comparison of ICD shock rates in Japanese and non-Japanese patients in the PainFree SST study.

BACKGROUND: The PainFree Smart Shock Technology (SST) study showed a low implantable cardioverter-defibrillator (ICD) inappropriate shock rate. However, the majority of patients were from Western countries with patient characteristics different from those in Japan. ICD shock rates using the novel SST algorithms in Japanese patients are still unknown. METHODS: All 2,770 patients in the PainFree SST study (Japan [JPN]: N = 181, other geographies [OJPN]: N = 2,589) were included in this analysis. RESULTS: Japanese patients had higher average left ventricular ejection fraction (P < 0.0001), higher prevalence of secondary prevention indications (P < 0.0001), nonischemic cardiomyopathy (P < 0.0001), and permanent atrial fibrillation (P < 0.0001). The appropriate shock rate at 12 months was not different between JPN and OJPN: 6.4% and 6.3%, respectively (P = 0.95). The inappropriate shock rate at 12 months was significantly higher in Japanese patients (2.9% vs 1.7%, P = 0.017). However, after propensity score matching to adjust for the difference in baseline characteristics, the difference in inappropriate shock rate was not statistically significant (P = 0.51). CONCLUSIONS: There was no difference in the appropriate shock rate between Japan and other geographies. The inappropriate shock rate in Japan was low, although it was slightly higher compared to other geographies due to baseline characteristics, including a higher prevalence of permanent AF. There was not a statistically significant difference after adjusting for baseline characteristics.

A novel technique for ligation of the cephalic vein reduces hemorrhaging during a two-in-one insertion of dual cardiac device leads.

The cutdown technique for the cephalic vein is a common access route for transvenous cardiac device leads (TVLs), and sometimes one cephalic vein can accomodate two TVLs. We examined a novel ligation technique to balance the hemostasis and lead maneuverability for this two-in-one insertion. A total of 22 patients scheduled for cardiac device implantations with two or more leads were enrolled. The ipsilateral cephalic vein was identified for inserting the TVLs with a cutdown. If two TVLs could be introduced into one cephalic vein, hemostasis was established by ligating the venous wall between the TVLs. We measured the amount of hemorrhaging per minute and the operators assessed the lead maneuverability before and after the ligation. We successfully implanted cardiac devices in 15 patients (68%) with this novel method, whereas only one TVL could be introduced via the cephalic vein in 7 patients. As for the successful patients, hemorrhaging from the gap was significantly reduced (5.6 ±â€¯7.3 to 0.41 ±â€¯0.36g/min, p = 0.016) after the novel ligation. The lead maneuverability was well maintained so there was no difficulty placing the leads into the cardiac chambers in all cases. No major complications were observed. In the present study, the novel ligation method provided significant hemostasis as well as a preserved maneuverability. It could be an optional choice for insertion of multiple TVLs.

A novel KCNQ1 nonsense variant in the isoform-specific first exon causes both jervell and Lange-Nielsen syndrome 1 and long QT syndrome 1: a case report.

BACKGROUND: According to previous KCNQ1 (potassium channel, voltage gated, KQT-like subfamily, member 1) gene screening studies, missense variants, but not nonsense or frame-shift variants, cause the majority of long QT syndrome (LQTS; Romano-Ward syndrome [RWS]) 1 cases. Several missense variants are reported to cause RWS by a dominant-negative mechanism, and some KCNQ1 variants can cause both Jervell and Lange-Nielsen Syndrome (JLNS; in an autosomal recessive manner) and LQTS1 (in an autosomal dominant manner), while other KCNQ1 variants cause only JLNS. The human KCNQ1 gene is known to have two transcript isoforms (kidney isoform and pancreas isoform), and both isoforms can form a functional cardiac potassium channel. CASE PRESENTATION: Here, we report a novel nonsense KCNQ1 variant causing not only JLNS, but also significant QTc prolongation identical to RWS in an autosomal dominant manner. Our case study supports that haploinsufficiency in the KCNQ1 gene is causative of significant QTc prolongation identical to RWS. Interestingly, the nonsense variant (NM_000218.2:c.115G > T [p.Glu39X]) locates in exon 1a of KCNQ1, which is a kidney-isoform specific exon. The variant is located closer to the N-terminus than previously identified nonsense or frame-shift variants. CONCLUSION: To the best of our knowledge, this is the first report showing that a nonsense variant in exon 1a of KCNQ1, which is the kidney-isoform specific exon, causes JLNS. Our findings may be informative to the genetic pathogenesis of RWS and JLNS caused by KCNQ1 variants.

Estimation of the origin of ventricular outflow tract arrhythmia using synthesized right-sided chest leads.

AIMS: For successful ablation of ventricular outflow tract arrhythmia, estimation of its origin prior to the procedure can be useful. Morphology and lead placement in the right thoracic area may be useful for this purpose. Electrocardiography using synthesized right-sided chest leads (Syn-V3R, Syn-V4R, and Syn-V5R) is performed using standard leads without any additional leads. This study evaluated the usefulness of synthesized right-sided chest leads in estimating the origin of ventricular outflow tract arrhythmia. METHODS AND RESULTS: This retrospective study included 63 patients in whom successful ablation of ventricular outflow tract arrhythmia was performed. Numbers of arrhythmias originating from the left ventricle, the septum of the right ventricle, and the free wall of the right ventricle were 11, 40, and 13, respectively. In one patient, two different left ventricular outflow tract origins were found. Electrocardiographic recordings from right-sided chest leads were divided into three types as follows: those in which an R > S concordance, a transitional zone, or an R < S concordance were detected. In all left arrhythmia cases, R > S concordance was observed. A transitional zone was evident in 34 of 40 cases of right ventricular outflow tract arrhythmia originating in the ventricular septum, and an R < S concordance was observed in 6 of the 40 cases. However, an R < S concordance was found in all cases of right ventricular outflow tract arrhythmia originating in the free wall. CONCLUSION: Synthesized right-sided chest lead electrocardiography may be useful for estimating the origin of ventricular outflow tract arrhythmia.

Identification of left atrial ganglionated plexi by dense epicardial mapping as ablation targets for the treatment of concomitant atrial fibrillation.

BACKGROUND: Autonomic ganglionated plexi (GPs) play a significant role in the initiation and maintenance of atrial fibrillation (AF). GPs are key targets for a maze procedure. The purpose of this study was to identify the location of the left atrial GPs based on dense epicardial mapping during a maze procedure in patients with concomitant AF. METHODS: Sixteen patients (age, 68 ± 10 years; 11 males, 69%) with heart failure and concomitant AF (duration 55 ± 86 months) underwent intraoperative epicardial electrophysiological mapping and a GP ablation using the maze procedure at our institution. Twenty-four-site, high-frequency stimulation (1,000/min; output, 18 V; pulse width, 0.75 ms) was performed by placing tweezers directly onto the potential GP sites on the left atrial epicardium. RESULTS: Active GPs were found in 13 (81%) of the 16 patients, and 12 (92%) of 13 patients had active GPs between the right pulmonary veins (PVs) and the interatrial groove. For those patients with active locations, a 7-day event-loop recording demonstrated that 12 (92%) of 13 patients were maintained in sinus rhythm 3 months after the operation. CONCLUSION: Dense epicardial mapping in the potential GP areas identified active GP locations in a high percentage of patients. GPs between the PVs and interatrial groove have a high potential as ablation targets for treatment of concomitant AF.

Comparison of 2-year outcomes between primary and secondary prophylactic use of defibrillators in patients with coronary artery disease: A prospective propensity score-matched analysis from the Nippon Storm Study.

BACKGROUND: The Nippon Storm Study was a prospective observational study designed to gather clinical data on implantable cardioverter-defibrillator (ICD) therapy in Japanese patients. OBJECTIVE: The purpose of this subanalysis was to compare the incidence of ICD therapy in patients with left ventricular dysfunction owing to coronary artery disease (CAD) for primary and secondary prophylaxis of sudden cardiac death. METHODS: We analyzed data of 493 patients with CAD and ICDs (men, 87%; age, 68 ± 10 years; left ventricular ejection fraction, 36% ± 13%; primary prophylaxis, 36%). All patients were followed up for at least 2 years. Propensity score matching was used to select patient subgroups for comparison: 133 patients with ICD for primary prophylaxis and 133 with ICD for secondary indications. RESULTS: There were no significant differences between primary and secondary prophylaxis groups with respect to the incidence of appropriate ICD therapy within 2 years (0.153 vs 0.239; hazard ratio, 1.565 [95% confidence interval (CI), 0.898-2.727]; P = .114). Two-year electrical storm risks were 3.3% and 9.6% with HR = 3.236 (95% CI, 1.058-9.896; P = .039) in patients with primary and secondary prophylaxis, respectively. CONCLUSION: The incidence of ICD therapy received by patients with CAD for primary and secondary prophylaxis was not significantly different based on our propensity score-matched analysis. However, secondary-prophylaxis ICD therapy seems to be associated with a significantly higher risk for electrical storm than primary-prophylaxis ICD therapy.

Remote Management of Pacemaker Patients With Biennial In-Clinic Evaluation: Continuous Home Monitoring in the Japanese At-Home Study: A Randomized Clinical Trial.

BACKGROUND: Current expert consensus recommends remote monitoring for cardiac implantable electronic devices, with at least annual in-office follow-up. We studied safety and resource consumption of exclusive remote follow-up (RFU) in pacemaker patients for 2 years. METHODS: In Japan, consecutive pacemaker patients committed to remote monitoring were randomized to either RFU or conventional in-office follow-up (conventional follow-up) at twice yearly intervals. RFU patients were only seen if indicated by remote monitoring. All returned to hospital after 2 years. The primary end point was a composite of death, stroke, or cardiovascular events requiring surgery, and the primary hypothesis was noninferiority with 5% margin. RESULTS: Of 1274 randomized patients (50.4% female, age 77±10 years), 558 (RFU) and 550 (Conventional follow-up) patients reached either the primary end point or 24 months follow-up. The primary end point occurred in 10.9% and 11.8%, respectively (P=0.0012 for noninferiority). The median (interquartile range) number of in-office follow-ups was 0.50 (0.50-0.63) in RFU and 2.01 (1.93-2.05) in conventional follow-up per patient-year (P<0.001). Insurance claims for follow-ups and directly related diagnostic procedures were 18 800 Yen (16 500-20 700 Yen) in RFU and 21 400 Yen (16 700-25 900 Yen) in conventional follow-up (P<0.001). Only 1.4% of remote follow-ups triggered an unscheduled in-office follow-up, and only 1.5% of scheduled in-office follow-ups were considered actionable. CONCLUSIONS: Replacing periodic in-office follow-ups with remote follow-ups for 2 years in pacemaker patients committed to remote monitoring does not increase the occurrence of major cardiovascular events and reduces resource consumption. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT01523704.

Catheter ablation of atrial tachyarrhythmias after a Maze procedure: A single center experience.

Significant recurrence of atrial tachyarrhythmias are observed after the surgical Cox Maze procedure (CMP). We retrospectively enrolled 11 consecutive patients who had atrial tachyarrhythmias (ATAs) that recurred after a biatrial CMP and underwent catheter ablation. Information including the site of any incomplete lesions and the etiology of the clinical ATAs was shared with the surgical team as feedback. In a total of 11 patients, 12 clinical ATAs were identified. They consisted of 2 atrial fibrillations and 10 atrial tachycardias (ATs). In 6 patients, the CMP was performed after the beginning of this investigation. In a total of 10 ATs, we diagnosed 5 mitral annular flutters, 2 roof-dependent flutters, 1 pulmonary vein (PV)-reentrant AT, and 1 localized reentrant AT. A total of 6 patients had reconnected perimitral block lines. PV reconnections were observed in 3 and posterior wall (PW) residual conduction was also observed in 3 cases. However, no residual conduction of the pulmonary vein isolation (PVI) and only 1 residual conduction of the PW were observed in 5 patients who underwent their index surgery after the beginning of this investigation. This fact may implicate that sharing the information from the electrophysiological study of postsurgical ATAs with the surgical team may contribute to the refinement of the CMP in each facility. .

Successful intermuscular implantation of subcutaneous implantable cardioverter defibrillator in a Japanese patient with pectus excavatum.

The entirely subcutaneous implantable cardioverter-defibrillator (ICD) system was developed to provide a life-saving defibrillation therapy that does not affect the heart and vasculature. The subcutaneous ICD is preferred over the transvenous ICD for patients with a history of recurrent infection presenting major life-threatening rhythms. In this case report, we describe the first successful intermuscular implantation of a completely subcutaneous ICD in a Japanese patient with pectus excavatum. There were no associated complications with the device implantation or lead positioning. Further, the defibrillation threshold testing did not pose any problem with the abnormal anatomy of the patient.

Computed tomography is important in appropriately diagnosing patients with third-degree atrioventricular block and second-degree atrioventricular block but not Wenckebach type.

PURPOSE: To evaluate CT utility for detection of cardiac or lung abnormalities in the diagnosis of organic cardiac disease in subjects with second- or third-degree atrioventricular block (AVB) excepting Wenckebach type. MATERIALS AND METHODS: A total of 50 consecutive patients (25 male; 64±15years) with de novo third- or second-degree AVB underwent both TTE and a combination of cardiac and chest 320 slice CT (Aquilion one, Toshiba Medical) and were retrospectively analyzed. The presence of focal left ventricular (LV) wall thinning and thickening was evaluated on both TTE and cardiac CT. We evaluated the presence of significant coronary artery stenosis, focal late enhancement (LE) in LV myocardium, significant-sized (>10mm) lymph nodes in hialus or mediastinum and/or typical lung nodules for sarcoidosis on CT. RESULTS: Abnormalities for 26%, 30%, and 36% of patients were demonstrated on TTE, cardiac CT, and a combination of cardiac and chest CT, respectively. 12% and 18% patients who did not exhibit cardiac abnormalities on TTE, revealed abnormalities on cardiac CT, or a combination of cardiac and chest CT, respectively. 36% patients had organic cardiac diseases. Sensitivities for detection of organic cardiac disease were significantly greater when cardiac and chest CT were combined than TTE alone (P<0.01). CONCLUSIONS: Approximately one third of patients with third- or second-degree AVB had organic cardiac diseases. For detection of cardiac and chest abnormality and correct diagnosis of organic cardiac disease in patients with third- or second-degree AVB, TTE is not sufficient on its own. CT or a combination of TTE and CT are required.

Rapid mapping and differentiation in ventricular outflow tract arrhythmia using non-contact mapping.

PURPOSE: Ventricular outflow tract arrhythmias (VOTAs) can be successfully treated by catheter ablation. However, it is sometimes difficult to differentiate the origin of VOTAs between the right ventricular outflow tract (RVOT) and the other sites, leading to a long fluoroscopy time and unnecessary radiofrequency applications. This study aimed to clarify distinguishable characteristics of the propagation pattern obtained from non-contact mapping (NCM) for VOTA ablation. METHODS: Consecutive 45 patients with VOTAs who underwent catheter ablation using the NCM system were included in this study. We analyzed an isopotential map on three-dimensional geometry of the RVOT obtained from the virtual unipolar electrograms (VUEs) and assessed mapping data of the isopotential area with an initial negative VUE of -1 mV. RESULTS: Successful ablation was achieved from the endocardial RVOT in 34 patients (RVOT group) and the non-RVOT in 11 (non-RVOT group). Major and minor axis diameters of the isopotential area did not significantly differ between the two groups. However, a ratio of major/minor axis diameter was greater in the RVOT group (1.9 ± 0.1 versus 1.3 ± 0.1; P < 0.001). In addition, the propagation velocity defined as an increase of the isopotential area per millisecond was significantly slower in the RVOT group (2.2 ± 0.4 versus 4.2 ± 0.7 mm2/ms; P = 0.02). CONCLUSIONS: The isopotential area of VOTAs originating from the RVOT, as compared to the other sites, spread more elliptically and slowly. The propagation pattern obtained from NCM can provide useful information and efficient strategy for VOTA ablation.

New horizon for infection prevention technology and implantable device.

There has been a significant increase in the number of patients receiving cardiovascular implantable electronic devices (CIED) over the last two decades. CIED infection represents a serious complication after CIED implantation and is associated with significant morbidity and mortality. Recently, newly advanced technologies have offered attractive and suitable therapeutic alternatives. Notably, the leadless pacemaker and anti-bacterial envelope decrease the potential risk of CIED infection and the resulting mortality, when it does occur. A completely subcutaneous implantable cardioverter defibrillator is also an alternative to the transvenous implantable cardioverter defibrillator (ICD), as it does not require implantation of any transvenous or epicardial leads. Among the patients who require ICD removal and subsequent antibiotics secondary to infection, the wearable cardioverter defibrillator represents an alternative approach to inpatient monitoring for the prevention of sudden cardiac death. In this review paper, we aimed to introduce the advanced technologies and devices for prevention of CIED infection.

Evaluation of periesophageal nerve injury after pulmonary vein isolation using the (13)C-acetate breath test.

BACKGROUND: Pulmonary vein isolation (PVI) has become an important option for treating patients with atrial fibrillation (AF). Periesophageal nerve (PEN) injury after PVI causes pyloric spasms and gastric hypomotility. This study aimed to clarify the impact of PVI on gastric motility and assess the prevalence of gastric hypomotility after PVI. METHODS: Thirty consecutive patients with AF underwent PVI under luminal esophageal temperature (LET) monitoring. The (13)C-acetate breath test was conducted before and after the procedure for all patients (PVI group). Gastric emptying was evaluated using the time to peak concentration of (13)CO2 (T max). This test was also conducted in another 20 patients who underwent catheter ablation procedures other than PVI (control group). RESULTS: The number of patients with abnormal T max (≥75 min) increased from seven (23%) to 13 (43%) and from three (15%) to five (25%) after the procedure in the PVI group and control group, respectively. The mean T max was longer after PVI than before PVI (64±14 min vs. 57±15 min, p=0.006), whereas there was no significant difference before and after the procedure in the control group. However, no significant difference in ΔT max was observed between the two groups (p=0.27). No patients suffered from symptomatic gastric hypomotility. CONCLUSIONS: Asymptomatic gastric hypomotility occurred more often after PVI. However, the average impact of PVI on gastric motility was minimal.