Yasuhiro Tanabe

Prophylactic catheter ablation for induced monomorphic ventricular tachycardia in patients with implantable cardioverter defibrillators as primary prevention.

AIMS Prophylactic catheter ablation (CA) has been established to reduce the incidence of appropriate implantable cardioverter-defibrillator (ICD) therapy (anti-tachycardia pacing or shock) in secondary prevention patients. The aim of this study was to determine whether prophylactic CA for induced ventricular tachycardia (VT) reduces the incidence of appropriate ICD therapy in primary prevention patients. METHODS AND RESULTS We retrospectively investigated 66 consecutive patients with structural heart disease who had undergone ICD implantation as primary prevention and electrophysiological study. Patients with hypertrophic cardiomyopathy or no inducible monomorphic VT had been excluded, and the remaining 38 patients were divided into two groups; those who had undergone prophylactic CA for induced monomorphic VT (the CA group, n = 18), and those who had not undergone CA (the non-CA group, n = 20). During a mean follow-up of 50 ± 38 months, 1 patient (5%) received appropriate ICD therapy in the CA group and 13 (65%) in the non-CA group. Kaplan-Meier survival analysis revealed a significantly higher event-free survival rates for appropriate ICD therapy in the CA group compared with the non-CA group (P = 0.003). Among the patients, one patient (5%) in the CA group and nine patients (45%) in the non-CA group suffered appropriate shock (P = 0.018). CONCLUSIONS Prophylactic CA for induced monomorphic VT reduces the incidence of appropriate ICD therapy including shock in primary prevention patients. These results indicate that prophylactic CA may be considered for structural heart disease patients who are candidates for ICD implantation as primary prevention.

Current status of the use of inferior vena cava filters in cases of pulmonary embolism in CCUs: From the Tokyo CCU Network

OBJECTIVE To elucidate the current status of use of inferior vena cava filters (IVCFs) in cases of pulmonary embolism at institutions belonging to the Tokyo CCU Network. METHODS We conducted a retrospective investigation of 832 consecutive cases of pulmonary embolism reported on survey forms to the Tokyo CCU Network between 2005 and 2010. RESULTS Of 832 cases of pulmonary embolism, IVCFs were used in 338 (40.6%) and not used in 415 (49.9%). Their use was unclear in 79 (9.5%) cases. The use rate gradually increased each year from 2005 until 2008 but decreased from 2009 onward. Moreover, 68.9% of the IVCFs used in cases were non-permanent types. In terms of pulmonary embolism severity, the rate of use was 37.2% in non-massive cases, 49.4% in sub-massive cases, 46.9% in massive cases, and 31.9% in collapse cases. Thirty-day mortality in cases of collapse in which IVCFs were not used was extremely high at 75.8%, suggesting that in many cases, rapid deterioration may occur with insufficient time for IVCF insertion. The differences in IVCF usage rate among institutions were large in the range of 12.5-90% from 2005 to 2008, which slightly declined to the range of 25.0-72.2% from 2009 to 2010. CONCLUSIONS We elucidated the current IVCF use status in cases of pulmonary embolism at institutions belonging to the Tokyo CCU Network. Since the status of use differed among institutions, future studies of effective methods of use are required.

Prevalence and electrophysiological characteristics of typical atrial flutter in patients with atrial fibrillation and chronic obstructive pulmonary disease.

AIMS Chronic obstructive pulmonary disease (COPD) is one of the important underlying diseases of atrial fibrillation (AF). However, the prevalence and electrophysiological characteristics of typical atrial flutter (AFL) in patients with AF and COPD remain unknown. The purpose of the present study was to investigate those characteristics. METHODS AND RESULTS We investigated 181 consecutive patients who underwent catheter ablation of AF. Twenty-eight patients were diagnosed with COPD according to the Global Initiatives for Chronic Obstructive Lung Disease (GOLD) criteria. Forty patients with no lung disease served as a control group. We analysed the electrophysiological characteristics in these groups. Typical AFL was more common in the COPD group (19/28, 68%) than in the non-COPD group (13/40, 33%; P = 0.006). The prevalence of AFL increased with the severity of COPD: 4 (50%) of 8 patients with GOLD1, 13 (72%) of 18 patients with GOLD2, and 2 (100%) of 2 patients with GOLD3. Atrial flutter cycle length and conduction time from the coronary sinus (CS) ostium to the low lateral right atrium (RA) during CS ostium pacing before and after the cavotricuspid isthmus ablation were significantly longer in the COPD group than in the non-COPD group (285 vs. 236, 71 vs. 53, 164 vs. 134 ms; P = 0.009, 0.03, 0.002, respectively). CONCLUSION In COPD patients with AF, conduction time of RA was prolonged and typical AFL was commonly observed.

Predictive value of biomarkers for the prognosis of acute pulmonary embolism in Japanese patients: Results of the Tokyo CCU Network registry

BACKGROUND Several studies from Western countries have reported associations between cardiac troponin and B-type natriuretic peptide (BNP) levels and acute pulmonary embolism prognosis; however, the number of such reports from Asian countries, including Japan, is limited. Thus, we evaluated the relationship between blood biochemical findings and acute-phase pulmonary embolism prognosis in Japanese patients. METHODS The subjects included 441 patients with acute pulmonary embolism (191 men, 250 women; average age, 65.8±16.0 years) treated at Tokyo CCU Network Institutions from 2009 to 2011 and registered via survey forms. The association between blood biochemical findings at admission and 30-day mortality was investigated. RESULTS The median BNP value was 186.5pg/mL (25th to 75th interquartile range: 49.8-500pg/mL) of 210 cases. No deaths were recorded among those with BNP levels <90pg/mL (n=70), whereas significantly higher mortality (10 deaths/140 cases, 7.1%; p=0.033) was observed among those with BNP levels ≥90pg/mL. A qualitative cardiac troponin test was positive in 58 of the 204 cases (28.4%), with a significantly higher mortality incidence (p=0.017) among the troponin-positive cases [6 (10.3%) versus 3 (2.1%) deaths among the 146 troponin-negative cases]. The overall mean blood glucose level at admission of 331 cases was 152.0±74.0mg/dL, and 30-day mortality significantly increased with blood glucose values (p=0.048). CONCLUSIONS Troponin, BNP, and blood glucose levels are useful prognostic biomarkers for acute pulmonary embolism in Japanese patients.

Ablation of swallowing-induced atrial tachycardia affects heart rate variability: a case report.

A 47-year-old man underwent slow pathway ablation for slow-fast atrioventricular nodal reentrant tachycardia. Following the procedure, he felt palpitations while swallowing, and swallowing-induced atrial tachycardia was diagnosed. Swallowing-induced atrial tachycardia arose from the right atrium-superior vena cava junction and was cured by catheter ablation. After the procedure, the patient’s heart rate variability changed significantly, indicating suppression of parasympathetic nerve activity. In this case, swallowing-induced atrial tachycardia was related to the vagal nerve reflex. Analysis of heart rate variability may be helpful in elucidating the mechanism of swallowing-induced atrial tachycardia.

Effect of Cigarette Smoking on the Risk of Atrial Fibrillation Recurrence after Pulmonary Vein Isolation

Introduction: Previous studies have shown that atrial fibrillation (AF) recurrence after pulmonary vein (PV) isolation depends on various factors; however, the effect of cigarette smoking on AF recurrence after PV isolation has not been investigated.

Pulmonary Embolism Severity Index and Simplified Pulmonary Embolism Severity Index Risk Scores Are Useful to Predict Mortality in Japanese Patients With Pulmonary Embolism

BACKGROUND The Pulmonary Embolism Severity Index (PESI) and simplified PESI (sPESI) have not been fully evaluated in Japan, so the present study aimed to evaluate these risk stratification models in the prediction of mortality of affected patients in Japan. METHODS AND RESULTS We retrospectively analysed 302 PE patients (63.9±17.2 years of age; 42.4% male) from January 2011 to December 2012 using data from the Tokyo CCU Network. The areas under the receiver-operating characteristic curves were 0.92 (95% confidence interval (CI): 0.88-0.97) for the PESI and 0.88 (95% CI: 0.77-0.98) for the sPESI. CONCLUSIONS Both scores can be used to predict PE mortality in Japan.

Improving the understanding of Takotsubo syndrome: consequences of diagnosis and treatment

ABSTRACT Takotsubo syndrome was first described in Japan in 1990. Although it has gained worldwide recognition in the last 25 years, the pathophysiology of Takotsubo syndrome remains controversial. This syndrome is often reported in elderly postmenopausal women suffering from sudden, unexpected emotional and physical stress. Its clinical presentation resembles that of acute myocardial infarction. The prognosis of Takotsubo syndrome was initially considered favorable compared with that of myocardial infarction; however, subsequent studies have demonstrated that the mortality was higher than previously reported. Prompt diagnosis followed by appropriate management for acute complications such as heart failure, arrhythmia, intraventricular thrombus, and left ventricular outflow tract obstruction is required. We discuss the current knowledge on Takotsubo syndrome to facilitate optimal diagnosis and treatment.

Prominent J-wave and T-wave alternans associated with mechanical alternans in a patient with takotsubo cardiomyopathy

A 74‐year‐old woman with takotsubo cardiomyopathy developed polymorphic ventricular tachycardia during the acute phase. She exhibited prominent J‐wave and T‐wave alternans preceding ventricular tachycardia. These abnormalities disappeared after recovery from myocardial stunning.

A case of coronary microvascular spasm with slow flow induced by the intracoronary acetylcholine provocation test

Microvascular angina is a rare condition in which myocardial ischemia is caused by microvascular dysfunction without any abnormalities of the epicardial coronary arteries. In clinical practice, it is difficult to diagnose because the microvascular alterations cannot be detected by conventional angiography. Herein we present a rare case of a 67-year-old woman with unstable angina pectoris in whom considerably slow coronary flow was induced by the acetylcholine provocation test with mild epicardial arterial spasm, suggesting the presence of microvascular spasm. Moreover, we show that β-methyl-p-[123I]-iodophenyl-pentadecanoic (123I-BMIPP) single-photon emission computed tomography imaging is useful for proving myocardial ischemia.