Kota Komiyama

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.

Transient sinus node dysfunction following sinus node artery occlusion due to radiofrequency catheter ablation of the septal superior vena cava-right atrium junction.

We performed catheter ablation to septal superior vena cava (SVC)-right atrium (RA) junction rapid firing in a 57-year-old man with paroxysmal atrial fibrillation. He later experienced transient sinus node dysfunction resulting from injury to the sinus node artery (SNA), which branched only from the proximal region of the left circumflex artery. The direction of the SNA should be considered during catheter ablation at the septal SVC-RA junction, especially if the sinus node is supplied by only one SNA from the right coronary artery or the left circumflex artery.

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.

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.

Long-term efficacy of catheter ablation for paroxysmal atrial fibrillation in patients with Brugada syndrome and an implantable cardioverter-defibrillator to prevent inappropriate shock therapy

BACKGROUND In patients with an implantable cardioverter-defibrillator (ICD) and Brugada syndrome (BrS), the long-term efficacy of catheter ablation for preventing inappropriate shock therapy due to paroxysmal atrial fibrillation (PAF) has not been elucidated. OBJECTIVE To evaluate the efficacy of atrial fibrillation (AF) ablation for PAF for prevention of inappropriate ICD therapy over a longer follow-up period. METHODS We enrolled 76 men with BrS and an ICD, with a mean age of 46.2 ± 16.5 years. Twenty-one patients had AF (19 had PAF, 1 had persistent AF, and 1 had longstanding persistent AF). Fourteen patients with PAF underwent pulmonary vein isolation (PVI) and received follow-up electrophysiological study (EPS) 6 months after the first PVI. If necessary, ablation was performed. RESULTS Over a mean follow-up period of 3.3 ± 1.4 years after the repeat session, 13 of the 14 patients (92.9%) had no recurrence of AF. Six patients with PAF without inappropriate ICD therapy before PVI had no recurrence of AF and no inappropriate therapy during follow-up. Among the 8 patients who had inappropriate therapy because of PAF before PVI, 1 patient who had recurrent AF underwent another ablation session. After this final session, there were no recurrences of AF and no inappropriate therapy (mean follow-up period 3.1± 1.2 years). CONCLUSION Catheter ablation is effective in patients with BrS and an ICD, and prevents inappropriate ICD therapy owing to PAF; thus, catheter ablation is an appropriate first-line therapy for PAF among such patients.

Early repolarization pattern and its day-to-day dynamic change as markers for ventricular fibrillation in patients with vasospastic angina.

AIMS An early repolarization (ER) pattern is a risk factor for ventricular fibrillation (VF) in certain diseases. However, it is unclear whether this association holds for patients with vasospastic angina (VSA). Moreover, the reported long-term follow-up of implantable cardioverter defibrillator (ICD) therapy for VSA patients is limited to 3 years. This study aimed to clarify the relation between ER and VF in patients with VSA and to investigate the long-term outcomes of ICD therapy. METHODS AND RESULTS This retrospective, observational survey evaluated 265 consecutive VSA patients, including 21 with VF. Their electrocardiogram findings and clinical course were analysed over a mean follow-up of 5.5 ± 3.3 years. Early repolarization was observed in 64 patients (24.2%) and was more frequent in patients with VF history than those without (P = 0.001). Early repolarization was independently associated with VF history. During follow-up, four patients had VF recurrences. Ventricular fibrillation recurrence was higher in patients with ER (log-rank, P = 0.018) or VF history (log-rank, P < 0.001) than those without. Among patients with ER, day-to-day variations in ER (P = 0.003) and notching of ER pattern (P = 0.03) were associated with VF history. Cases with day-to-day variation showed a higher incidence of VF recurrence during follow-up (log-rank, P = 0.007). During long-term follow-up, 23.5% of patients with an ICD received appropriate shock therapy. CONCLUSION The presence of ER, especially with day-to-day variation, can help predict VF recurrence in VSA patients. Implantable cardioverter defibrillator implantation is a reasonable approach for the secondary prevention of VF in high-risk VSA patients.

In-hospital mortality analysis of Japanese patients with acute coronary syndrome using the Tokyo CCU Network database: Applicability of the GRACE risk score

BACKGROUND The GRACE risk score was developed to predict in-hospital mortality for acute coronary syndrome (ACS) using multinational registries, but did not include Japanese data. Therefore, GRACE risk scores are not extensively used in Japan. The present study aimed to evaluate the relationship between the GRACE risk score and in-hospital mortality among Japanese patients with ACS using the Tokyo CCU (cardiovascular care unit) Network Database. METHODS AND RESULTS A total of 9460 patients with ACS hospitalized at 67 Tokyo CCUs between January 2011 and December 2013 were retrospectively reviewed and GRACE risk scores were calculated. Patients in the Tokyo CCU Network database had more severe conditions compared to those of the original GRACE study. There was a strong correlation between the GRACE risk score and in-hospital mortality for patients with ST-segment elevation myocardial infarction (STEMI) or non ST-segment elevation myocardial infarction (NSTEMI) (r=0.99, p<0.001); however, the correlation was not significant for patients with unstable angina (r=0.35, p=0.126). For STEMI+NSTEMI patients, the discrimination ability of the GRACE risk score was excellent, with a c statistic of 0.87 (95% confidence interval, 0.86-0.89). CONCLUSIONS The GRACE risk score is a good predictor of in-hospital mortality for Japanese patients with STEMI or NSTEMI, and can help clinicians stratify patients by risk for optimal patient triage and early treatment management.

Hemodynamic correlates of nutritional indexes in heart failure

BACKGROUND Malnutrition in heart failure (HF) is related to altered intestinal function, which could be due to hemodynamic changes. We investigated the usefulness of novel nutritional indexes in relation to hemodynamic parameters. METHODS We retrospectively analyzed 139 HF patients with reduced ejection fraction who underwent right heart catheterization. We investigated correlations between right side pressures and nutritional indexes, which include controlling nutritional (CONUT) score and geriatric nutritional risk index (GNRI). Receiver operating characteristic (ROC) curves were generated to investigate the prognostic accuracy of CONUT score and GNRI for a composite of death or HF hospitalization in 12 months. Logistic regression analysis was performed to investigate whether hemodynamic correlates were associated with malnutrition, which was defined based on CONUT sore or GNRI. RESULTS Higher right side pressures were positively correlated with worse nutritional status according to CONUT score, but were negatively correlated with worse nutritional status according to GNRI. Area under ROC curve for the composite endpoint was 0.746 in CONUT score and 0.576 in GNRI. The composite endpoint occurred in 40% of CONUT score≥3 and in 11% of CONUT score<3 (p<0.001). These relationships were also investigated with GNRI (40% of GNRI<95 vs. 17% of GNRI≥95, p=0.002). In multivariate analysis, higher right atrial pressure was significantly associated with higher CONUT score, while no hemodynamic parameter was related to GNRI. CONCLUSIONS CONUT score was associated with right side congestion, while no association between GNRI and right side congestion was noted. CONUT score had better predictive value than GNRI.

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.