Miyo Nakano

Risk factors for the development of incident atrial fibrillation in patients with cardiac implantable electronic devices

INTRODUCTION Cardiac implantable electronic devices (CIEDs) can detect atrial fibrillation (AF) early and accurately. Risk factors for the development of new-onset AF in patients with CIEDs remains uncertain. METHODS Patients with CIEDs who visited Chiba University Hospital between January 2016 and December 2016 were enrolled. We only included patients without single chamber CIEDs or a known history of AF. RESULTS Of 371 patients with CIEDs, 78 (21.0%; median age 61.0 years, 65.5% male) developed new-onset AF. Multivariate analysis demonstrated that independent predictors for the development of new or incident AF were age ≥65 years (odd ratio [OR] 2.76, 95% confidence interval [CI] 1.54-4.96, P = 0.001), diabetes mellitus (OR 2.24, 95% CI 1.20-4.19, P = 0.011), congestive heart failure (OR 1.94, 95% CI 1.06-3.54, P = 0.031), and left atrial volume index >34 ml/m2 (OR 3.51, 95% CI 1.96-6.25, P < 0.001). Based on these 4 clinical factors (age ≥ 65, diabetes mellitus, congestive heart failure, left atrial volume index > 34 ml/m2) there was a good predictive ability for new AF development (AUC 0.728) and clinically usefulness using decision curve analysis. CONCLUSIONS A substantial number of patients with CIEDs develop new-onset AF. Four clinical factors (age ≥ 65, diabetes mellitus, congestive heart failure, left atrial volume index > 34 ml/m2) independently predicted new-onset AF and may provide an approach to clinically useful risk assessment for incident AF.

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.

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.