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Background: Radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) refractory to medical therapy remains controversial in patients with hypertrophic cardiomyopathy (HCM); the acute effects on the direct left atrial (LA) pressure are not completely understood. Methods: We consecutively studied patients with HCM (n=15) and without HCM (NHCM, n=106) who underwent extensive encircling pulmonary vein isolation for drug-refractory AF. We compared clinical parameters, echocardiographic parameters, electrophysiological parameters, LA pressures using hemodynamic catheterization and recurrence rate in both groups. Results: The LA volume index was significantly higher (51.9±13.6 mL/m2 vs. 41.6±12.7 mL/m2, p=0.02) in the HCM group than the NHCM group. The pre-ablation mean LA pressure was significantly higher in the HCM group than the NHCM group. Among the AF patients, the mean LA pressure decreased more significantly in the HCM group than the NHCM group (post-ablation minus pre-ablation pressures: 4.2±3.7 mmHg vs. 0.9±4.1 mmHg, p=0.03). The early recurrence rate (within 30 days after ablation) tended to be higher in the HCM group than the NHCM group (20% vs. 5.7%, p=0.08), but the rates of late recurrences (>30 days after ablation) were similar (13.3% vs. 7.6%, p=0.83). Discontinuation of antiarrhythmic drugs occurred at rates of 13% and 62% in the HCM and NHCM groups, respectively (p

A 41-year-old man with Brugada syndrome, who had been implanted with an ATLAS+DR V-243 (St. Jude Medical, Inc., St. Paul, MN, USA) dual-chamber implantable cardioverter defibrillator (ICD) for secondary prevention of arrhythmia, received an inappropriate shock. The ventricular fibrillation (VF) zone was programmed to deliver maximum output shock therapy at a detection threshold of greater than 214 beats per min, and 12 consecutive instances of crossing the threshold constituted 1 VF. The monitoring zone was programmed to detect heart rates of greater than 160 beats per min with all supraventricular tachycardia (SVT) discriminators in the “ON” mode, and 12 consecutive instances of the heart rate exceeding 160 beats per min constituted 1 SVT. The ICD shock was delivered after an episode of sinus tachycardia that continued for 3 min 15 s. The monitoring zone is effective for detecting asymptomatic ventricular tachycardia or SVT, and therapy is not usually set up in this zone. Here, we report the possibility that in some patients implanted with certain types of ICD devices, the monitoring zone may become a factor in the delivery of an inappropriate shock.

Background: Japan started using the CARELINK® (Medtronic, Inc, Minneapolis, MN, USA) remote monitoring system in April 2009. However, in some cases, the device failed to transmit a message after registration or according to schedule. We investigated the difference between patients who could make effective use of CARELINK® system and those who could not. Subjects and Method: Sixty patients who had registered until December 2009 at our institution were analyzed. These patients were divided into two groups: those who were able to use the device effectively (group G, n = 49) and those who were not (group F = 11). Patient background, automatic or manual telemetries, new or existing implant patient, presence of adverse events, and the use or non-use of a checklist at the time of introduction were compared between the two groups. Results: In group G, more patients used a checklist at the time of introduction than that in group F (use of checklist/total, 31/49 in group G vs. 3/11 in group F; P, 0.029). No significant difference was observed in other factors between the two groups. Conclusion: We consider that the method used to explain the system are important to make the patients understand handling methods of CARELINK® system. The number of patients introduced to remote monitoring of implantable devices will continue to increase in the future; therefore, we must continue to develop innovative approaches for their effective us.

We experienced 2 cases in which oversensing of a particular noise after the implantation of an implantable cardiac device was observed in the acute phase. These were unusual cases in which the noise exhibited a low frequency pattern and appeared several hours after the implantation, but disappeared within 1 week. Here we present these cases and the details of an experiment investigating the origin of the noise and the methods for its prevention. The noise in these cases led to pacing inhibition and could have induced an inappropriate shock due to oversensing, but its morphology and electromagnetic interference were atypical for a lead failure or myopotentials. The noise spontaneously disappeared from the analysis of the data stored in the device. In an experiment based on the Irnich model, in which it was assumed that blood invaded a damaged grommet, low frequency noise occurred which was similar to the noise in the two cases. We concluded that care must be exercised when handling grommets.

We successfully performed radiofrequency catheter ablation (RFCA) in 2 cases involving patients with idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) originating from the pulmonary artery (PA). The QRS morphology of the VTs and PVCs in the two cases exhibited a left bundle-branch block (LBBB) morphology with an inferior axis. Activation and pace mappings were performed in the right ventricular outflow tract (RVOT) and above the pulmonary valve to determine the origin of the VTs and PVCs. In both cases, the earliest ventricular activation was recorded in the PA above the pulmonary valve. Applications of radiofrequency current at those sites in the PA resulted in the elimination and noninducibility of the VT and PVC. During the follow-up, the VT or PVC did not recur without any antiarrhythmic drug administration.

Background: There have been numerous reports about coronary sinus (CS) anomalies related to posteroseptal accessory pathways (APs). The purpose of this study was to explore the diameter and morphology of CS in patients with posteroseptal APs. Methods: We performed direct CS angiography in 105 patients with 22 posteroseptal APs and 83 APs in other regions, and 25 control subjects. We compared the diameter of the CS ostium in all subjects, and assessed the correlation of the local activation time in the patients with posteroseptal APs. Results: The proximal size (diameter) of the CS in the patients with posteroseptal APs (13:6 ± 1:1 mm) was larger than that in the patients with other types of APs (10:2 ± 1:8 mm [p < 0:001]) and that in the control subjects (9:6 ± 1:5 mm [p < 0:001]). Dilatation of the CS in the patients with posteroseptal APs extended up to 20 mm inside the CS. In 15 (68%) of the patients with posteroseptal APs, the proximal site of the CS demonstrated a windsock appearance. Conclusions: We concluded that the larger size and the wind cone appearance of proximal CS were unique structural characteristics in most patients with posteroseptal APs.

A 49-year-old male was referred to the hospital because of syncope caused by ventricular tachycardia (VT) with a pulse of 240 bpm and QRS morphology with a LBBB configuration and superior axis. The patient had been on a long-term regimen of steroids to treat his scleroderma. Satisfying 2 major criteria (QRS widening and an epsilon wave in the right chest leads) and 3 minor criteria (a slight enlargement and akinesis of the right ventricle, positive late potential in the signal averaged electrocardiogram and left bundle branch block-type VT) he was diagnosed with arrhythmogenic right ventricular cardiomyopathy. A voltage map of his right ventricle (RV) during sinus rhythm was obtained using an electroanatomical mapping system (CARTO, Biosense-Webster, Diamond, CA, USA). Two islet-like low voltage areas were found and linear double potentials were recognized between areas in the lateral wall of the right ventricle (RV) very close to the tricuspid annulus. The earliest activation of the double potential line during VT was 70 msec prior to the QRS onset. We applied radiofrequency energy at that point during the VT and it successfully slowed and terminated the VT. Thereafter the VT could not be induced by any stimulation from multiple RV sites.