Exercise-induced ventricular tachycardia in a case with hypertrophic cardiomyopathy taking cibenzoline.

We report a 17-year-old woman with hypertrophic cardiomyopathy (HCM) successfully resuscitated from ventricular fibrillation while taking cibenzoline. During exercise-stress testing before implanting an implantable cardioverter-defibrillator, ventricular tachycardia was induced and thought to be a proarrhythmia due to the use-dependent effect of the Na channel blockade with cibenzoline. In patients with arrhythmogenic substrates such as HCM, it is critical to pay attention to the proarrhythmic effects of class I antiarrhythmic drugs while increasing heart rate.

Safety and Efficacy of Transvenous Lead Extraction With a High-Frequency Excimer Laser　- A Single Center Experience.

BACKGROUND: Transvenous lead extractions have been performed using 40-Hz laser sheaths. Recently, a new 80-Hz laser sheath became available, but only a few reports have compared the effectiveness of the 40- and 80-Hz laser sheaths. Methods and Results: This study included 215 patients. Lead extractions using only laser sheaths were analyzed. The clinical characteristics, extraction parameters, and extraction tools were evaluated. The procedures were performed with 40-Hz sheaths in 150 patients (group 1: 270 leads) and 80-Hz sheaths in 65 (group 2: 99 leads). No statistically significant differences were observed in the clinical parameters except for sex. The mean implant duration was 95.3±86.0 and 78.2±56.8 months in groups 1 and 2, respectively (P=0.07). The respective mean laser time and number of laser pulses were 48.5±52.1 and 48.1±56.1 s (P=0.96) and 2,035.0±2,384.0 and 3,955.1±2,339.3 pulses (P<0.0001). Complete removal was achieved for 97.4% of the leads and in 98.0% in both groups (P=0.38). Major complications occurred in 2.0% and 3.1% of the patients in groups 1 and 2, respectively (P=0.94). CONCLUSIONS: Transvenous lead extraction using high-frequency laser sheaths was as highly successful as with low-frequency laser sheaths in Japanese patients.

Candidacy for a Subcutaneous Implantable Cardioverter Defibrillator in Patients with Cardiac Resynchronization Therapy.

In patients requiring an implantable cardioverter defibrillator (ICD), the combined use of a prior pacemaker and a subcutaneous ICD (S-ICD) could be an alternative treatment option to implantation of new leads or upgrading of pacemakers to an ICD if vascular access is limited. Here, we assessed the prevalence of S-ICD's eligibility according to surface electrogram screening in those receiving cardiac resynchronization therapy (CRT). S-ICD's eligibility was assessed in patients with a CRT pacemaker or a CRT defibrillator using the S-ICD template screening tool. Eligibility was defined as fulfillment of the template in both supine and upright positions in one or more leads during biventricular pacing. Among 44 patients (34 men, age: 67 ± 12), 36 (82%) were found to be eligible. The T/QRS amplitude ratio in lead II was significantly lower in those who were eligible (0.31 ± 0.16 versus 0.44 ± 0.18 in the ineligible group, P = 0.04). The lead position, underlying disease, and other electrocardiographic findings were not different between those who were eligible and those who were not. The majority of patients with biventricular pacing were eligible for S-ICD based on current screening tests and may benefit from this treatment. Further study is required.

Left Atrial Appendage Thrombi Formation in Japanese Non-Valvular Atrial Fibrillation Patients During Anticoagulation Therapy　- Warfarin vs. Direct Oral Anticoagulants.

BACKGROUND: Atrial fibrillation (AF) is a common cardiac arrhythmia, associated with increased cardiovascular morbidity and mortality including thromboembolic events. The aims of this study were to assess the prevalence of left atrial appendage (LAA) thrombi in Japanese non-valvular atrial fibrillation (NVAF) patients undergoing preprocedural transesophageal echocardiography (TEE) during anticoagulation therapy, and to compare the efficacy of warfarin and direct oral anticoagulants (DOAC).Methods and Results:This retrospective study reviewed records of 559 consecutive NVAF patients (445 men; age, 62±11 years) undergoing preprocedural TEE following at least 3 weeks of anticoagulation therapy. Of these, 275 patients had non-paroxysmal AF (49%). LAA thrombus was observed in 15 patients (2.7%). The prevalence of LAA thrombi was similar between the DOAC group (2.6%) and the warfarin group (2.8%, P=0.86). No patients with CHA2DS2-VASc score=0, or paroxysmal AF without prior stroke or transient ischemic attack, had LAA thrombi. On univariate analysis, non-paroxysmal AF, structural heart disease, antiplatelet therapy, larger left atrium, higher brain natriuretic peptide (BNP), reduced LAA flow, and higher CHA2DS2-VASc score were all associated with LAA thrombi. On multivariate analysis, BNP ≥173 pg/mL remained the only independent predictor of LAA thrombi. CONCLUSIONS: LAA thrombi were found in 2.7% of Japanese NVAF patients scheduled for procedures despite ongoing oral anticoagulation therapy. Incidence of thrombi was similar for patients on DOAC and on warfarin.

Surface Electrocardiogram Screening for Subcutaneous Implantable Cardioverter-Defibrillators in Japanese Patients With and Without Brugada Syndrome.

BACKGROUND: Subcutaneous implantable cardioverter-defibrillators (S-ICD) could eliminate lead-associated complications. We assessed the prevalence of S-ICD ineligibility in conventional ICD recipients and compared it in patients with and without Brugada syndrome (BrS).Methods and Results:Consecutive patients with a transvenous ICD without an indication for antibradycardia pacing were assessed. A patient was considered eligible for S-ICD if the ECG satisfied the screening template, both supine and standing, in ≥1 lead. Among 130 patients (103 men, age 57±15 years), a total of 18 (13.8%) patients were ineligible. The BrS group (n=33) had a significantly higher prevalence of S-ICD screening failure as compared with the non-BrS group (P=0.003; 30% vs. 8.2%). In the BrS group, the body mass index (BMI) was significantly lower, and T/QRS amplitude in lead I was significantly higher in those who were ineligible than that in the patients who were eligible. Of the 10 BrS patients failing the screening, 4 became eligible in the right parasternal electrode position. CONCLUSIONS: Among current ICD patients, there was a high incidence of patients with BrS who were unsuitable for S-ICD based on the left parasternal screening test. Suitability screening of patients for S-ICDs should be conducted carefully in patients with BrS, particularly if the BMI is low. Right parasternal electrode positioning should also be tested in such BrS patients.

Comparative evaluation of standard maintenance-dose clopidogrel versus low-dose prasugrel in patients with stable coronary artery disease after percutaneous coronary intervention.

BACKGROUND: Treatment with low-dose prasugrel might be more beneficial even in chronic stable coronary artery disease (CAD) patients treated with clopidogrel. We compared platelet reactivity between standard maintenance-dose and low-dose prasugrel in stable CAD patients. METHODS: This multicenter study enrolled 164 stable CAD patients receiving dual antiplatelet therapy with aspirin and clopidogrel. Patients were randomly assigned to continue treatment with 75-mg clopidogrel daily (n = 80) or switch to 3.75-mg prasugrel daily (n = 84). Platelet reactivity was evaluated by measuring P2Y12 reaction unit (PRU) before randomization and at 5 and 30 days thereafter using the VerifyNow® assay. Patients were classified into three groups according to CYP2C19-clopidogrel metabolic phenotype: extensive (without a *2 or *3 allele), intermediate (one *2 or *3 alleles), or poor (two *2 or *3 alleles) metabolizers. RESULTS: The PRU level was comparable between the two groups at baseline but was significantly lower in the prasugrel group than in the clopidogrel group on days 5 (133.0 vs. 156.8 PRU, P = 0.005) and 30 (124.3 vs. 158.0 PRU, P < 0.001). On day 30, the PRU level was lower in the prasugrel group among patients categorized as poor and intermediate metabolizers but not among extensive metabolizers. CONCLUSIONS: Low-dose prasugrel achieves more consistent antiplatelet effects than clopidogrel irrespective of the metabolic phenotype in Japanese patients with stable CAD. Low-dose prasugrel might be also beneficial in the chronic phase without increasing the bleeding risk among stable CAD patients in other countries.

A prospective multicenter study of direct comparison of feasibility and safety of pulmonary vein isolation using the minimally interrupted apixaban between second-generation cryoballoon and radiofrequency ablation of paroxysmal atrial fibrillation: J-HIT apixaban.

BACKGROUND: The feasibility and safety of pulmonary vein isolation (PVI) using cryoballoon (CB) for paroxysmal atrial fibrillation (PAF) with minimally interrupted apixaban has not fully explored. METHODS: In this multicenter, randomized prospective study, we enrolled patients with PAF undergoing CB or radiofrequency (RF) ablation with interrupted (holding 1 dose) apixaban. The primary composite end point consisted of bleeding events, including pericardial effusion and major bleeding requiring blood transfusion, or thromboembolic events at 4 weeks after ablation; secondary end points included early recurrence of AF and procedural duration. RESULTS: A total of 250 patients underwent PVI (125 assigned to the RF ablation and 125 assigned to the CB ablation). The primary end point occurred in 1 patient in the CB ablation group (0.8%; 90% confidence interval [CI], 0.04 to 3.70) and 3 patients in the RF group (2.4%, P = .622; risk ratio, 0333; 90% CI, 0.05 to 2.20). All events were pericardial effusion, all of whom recovered after pericardiocentesis. Early recurrence of AF occurred in 4 patients (3.2%) in the RF group and in 6 patients (4.8%) in the CB group (P = .749). The procedural duration was shorter in the CB group than that in the RF group (136.5 ± 39.9 vs 179.5 ± 44.8 min, P < .001). CONCLUSION: CB ablation with minimally interrupted apixaban was feasible and safe in patients with PAF undergoing PVI, which was equivalent to RF ablation.

Transvenous extraction of advisory implantable cardioverter defibrillator leads with a relatively long implant duration.

BACKGROUND: Optimal management of advisory implantable cardioverter defibrillator (ICD) leads has not been established. Several studies were reported concerning the lead extraction of advisory ICD leads, but the implant duration of those studies was short. We estimated the efficacy of lead extractions of advisory ICD leads with a relatively longer duration in Japanese patients. METHODS: We retrospectively analyzed 28 patients who underwent a lead extraction at Kokura Memorial Hospital and Tokyo Medical and Dental University Hospital [Fidelis (Medtronic, Minneapolis, MN, USA): n=19, Riata (St. Jude Medical, Sylmar, CA, USA): n=8, Isoline (SORIN CRM SAS, Clamart, France): n=1]. The mean implant duration was 63.3±19.3 months. The indications were device related infections in 3, electrical lead failures in 18, electrical lead failures and venous obstructions in 3, and prophylactic reasons in 4 patients. Inappropriate shocks because of electrical lead failures were observed in 9 patients. RESULTS: Complete removals were achieved of all 28 advisory leads. In 23 out of 28 patients, new ICD leads were implanted during the same procedure. In one patient, open chest surgery was performed for a hemothorax that occurred during a new ICD lead implantation just after successfully removing the advisory ICD lead. There were no other major or minor complications. CONCLUSION: Transvenous extractions of advisory ICD leads with relatively long implant duration were performed with a high success rate and low complication and mortality rate in Japanese patients.

Vascular hyperpermeability in pulmonary decompression illness: 'the chokes'.

Decompression illness (DCI) develops during or after diving. Pulmonary decompression illness ('Chokes') is rarely seen because the affected individual usually dies in the water. We encountered a rare and interesting case. A 60-year-old man complained of leg pain after diving. Despite rapid transfer to a nearby hospital, advanced respiratory failure and shock had set in. He was then transferred to our hospital for hyperbaric oxygen therapy (HBOT). On account of his poor general condition, we initially treated him in the intensive care unit without HBOT, where he showed extreme hyperpermeability and a high level of serum procalcitonin (PCT; 20.24 ng/mL). Despite large-volume fluid therapy, severe intravascular dehydration and shock status remained. We assume that the injured endothelial cells induced vascular hyperpermeability and increased levels of inflammatory cytokines leading to the high serum PCT level. PCT might be a useful stress marker of endothelial damage and severity in DCI, including Chokes.