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Background: The comparative outcomes of subcutaneous implantable cardioverter-defibrillator (S-ICD) and transvenous ICD (T-ICD) have not been well studied. The aim of this study was to evaluate the safety and efficacy of currently available S-ICD and T-ICD. Methods: The study included 86 patients who received an S-ICD and 1:1 matched to those who received single-chamber T-ICD by gender, age, diagnosis, left ventricular ejection fraction (LVEF), and implant year. The clinical outcomes and implant complications were compared between the two groups. Results: The mean age of the 172 patients was 45 years, and 129 (75%) were male. The most common cardiac condition was hypertrophic cardiomyopathy (HCM, 37.8%). The mean LVEF was 50%. At a mean follow-up of 23 months, the appropriate and inappropriate ICD therapy rate were 1.2% vs. 4.7% (χ2 = 1.854, P = 0.368) and 9.3% vs. 3.5% (χ2 = 2.428, P = 0.211) in S-ICD and T-ICD groups respectively. There were no significant differences in device-related major and minor complications between the two groups (7.0% vs. 3.5%, χ2 = 1.055, P= 0.496). The S-ICD group had higher T-wave oversensing than T-ICD group (9.3% vs. 0%, χ2= 8.390, P= 0.007). Sixty-five patients had HCM (32 in S-ICD and 33 in T-ICD). The incidence of major complications was not significantly different between the two groups. Conclusions: The efficacy of an S-ICD is comparable to that of T-ICD, especially in a dominantly HCM patient population. The S-ICD is associated with fewer major complications demanding reoperation. Key words: Hypertrophic cardiomyopathy; Implantable cardioverter-defibrillator; Outcome; Subcutaneous implantable cardioverter-defibrillator

Background— The prognosis of patients with saddleback or noncoved type (non–type 1) ST-elevation in Brugada syndrome is unknown. The purpose of this study was to clarify the long-term prognosis of probands with non–type 1 ECG and those with coved (type 1) Brugada-pattern ECG. Methods and Results— A total of 330 (123 symptomatic, 207 asymptomatic) probands with a coved or saddleback ST-elevation ≥1 mm in leads V 1 –V 3 were divided into 2 ECG groups—type 1 (245 probands) and non–type 1 (85 probands)—and were prospectively followed for 48.7�15.0 months. The absence of type 1 ECG was confirmed by drug provocation test and multiple recordings. The ratio of individuals with a family history of sudden cardiac death (14%) was lower than previous studies. Clinical profiles and outcomes were not notably different between the 2 groups (annual arrhythmic event rate of probands with ventricular fibrillation; type 1: 10.2%, non–type 1: 10.6%, probands with syncope; type 1: 0.6%, non–type 1: 1.2%, and asymptomatic probands; type 1: 0.5%, non–type 1: 0%). Family history of sudden cardiac death at age P =0.005; hazard ratio, 2.66; 95% confidence interval, 1.06 to 6.71; P =0.03, respectively, by multivariate analysis), although spontaneous type 1 ECG and ventricular fibrillation inducibility by electrophysiological study were not reliable parameters. Conclusions— The long-term prognosis of probands in non–type 1 group was similar to that of type 1 group. Family history of sudden cardiac death and the presence of early repolarization were predictors of poor outcome in this study, which included only probands with Brugada-pattern ST-elevation.

Introduction: Most of the early repolarization patterns (ERP) in electrocardiography (ECG) are benign but some of them are associated with ventricular fibrillation (VF). We evaluated whether or not a high spatio-temporal resolution magnetocardiography (MCG) could non-invasively detect malignant types of ERP. Methods: Sixty four-channel MCG, standard 12-lead ECG, and signal averaged ECG (SAECG) were recorded in 120 patients with inferolateral ERP in ECG without any major structural heart diseases; 13 of them had a history of VF (VF(+)-group) and the remaining 107 had no VF (VF(-)-group). We evaluated the following novel MCG indexes: MCG-QRS (msec), root mean square of terminal 40 msec magnetic field (MCG-RMS) (msec), and the duration under 10% of maximal amplitude (MCG-LAS) (msec) of the highest amplitude channel. Results: The amplitude and distribution of the J-wave, ST-T morphology in ECG, parameters of SAECG were not significantly different, whereas MCG-QRS and MCG-LAS were significantly longer and MCG-RMS was smaller in ERP-VF(+) compared with ERP-VF(-) group (107(SD=24) vs 84(13) msec, P Conclusions: MCG-QRS >100 msec was a simple and effective criterion for prediction of high risk ERP subjects, thus MCG analysis is an useful screening tool to detect malignant ERP out of the numerous benign ones.

Introduction: Previous studies showed that ventricular pacing (VP) increased the cardiac event of patients with pacemaker (PM). However, these studies consisted of patients under 75 years old and the influence of VP for elderly patients (over 75 years old) is still unclear. We sought to evaluate long-term effect of VP for elderly patients. Methods: A total of 782 patients (mean 57.2 years old) underwent PM implantation for brady-arrhythmia were enrolled from 1978 to 2005. The elderly patients (199 patients, over 75 years old, mean 80.7 years old) and all patients were divided into VP and non-VP group, and evaluated adverse events (death or readmission for heart failure). Results: The mean follow-up period was 10.1 years and 84 elderly patients (42%) developed adverse events. Kaplan-Meier analysis revealed that (1) VP increased the adverse event in all patients. (2) There was no significant difference in the adverse events of elderly patients between VP and non-VP group (Fig). Conclusion: VP may be tolerated for elderly patients with PM, whereas VP has no effect for the prognosis.

Background: Fragmented QRS (fQRS) in 12-lead ECG, ascribed to myocardial scar, has been shown to predict future cardiac events in patients with both ischemic and non-ischemic dilated cardiomyopathy (NIDCM). Various definitions and low specificity of fQRS, however, limited its use. We hypothesized that the advantage of 64-channel magnetocardiography (MCG), i.e., high spatio-temporal resolution, enables more accurate detection of fragmented LV conduction (fLV), that would lead to accurate prediction of future events. Methods: In 51 patients with NIDCM and narrow QRS (LVEF, 22±7%; QRS duration, 99±11 ms), we recorded MCG. We defined, in MCG superimposed vector magnitude waveforms, fLV as distinct abnormal components (>20% of maximal amplitude). In current arrow map, fLV corresponded to heterogeneous QRS currents (Figure). We predicted major adverse cardiac events (MACE), including sudden cardiac death (SCD), sustained ventricular tachyarrhythmias (VF/VT), appropriate defibrillator discharge (Def) and left ventricular assist device implantation (LVAD). Results: fLV was present in 27 (Group-F) and not in 24 (Group-N). Age, gender, ECG and echocardiographic findings, laboratory data and medications were similar irrespective of fLV. During a mean follow-up of 2.2 years, MACE occurred in 19 (4 SCD, 9 VF/VT, 2 Def, and 4 LVAD). MACE more frequently occurred with fLV (63%, 17/27) than without (8%, 2/24, Kaplan-Meier analysis, p Conclusion: MCG analysis is a promising noninvasive tool to accurately detect fragmentation and predict MACE in patients with NIDCM and normal QRS.

Background: Left bundle branch block (LBBB) is known to be a risk factor in patients with heart failure or structural heart diseases. We have already reported that the fragmented QRS (fQRS) activity on QRS vector magnitude waveform (VMW) derived from high-resolution multi-channel magnetocardiography (MCG) represents heterogeneous left ventricular (LV) activation sequences due to myocardial scar and can predict adverse outcomes in patients with dilated and hypertrophic cardiomyopathy. Therefore, we investigated whether MCG also can predict the outcome of patients with LBBB noninvasively using fQRS. Methods: 64-ch MCG was recorded in 58 patients with LV dysfunction (LVEF Results: The fQRS was identified on MCG in 29 patients (Group-A), but not in the rest of 29 patients (Group-B). Age, Sex, presence of structural heart disease, QRS or QTc interval, fQRS (≥8 spikes in leads I, aVL, V5 and V6) on 12-lead ECG, history of arrhythmias, LVEF, and medications were not different between 2 groups. During the follow-up of 30 ± 23 months, cardiac events (sudden cardiac death, heart failure, hospitalization, and life-threatening arrhythmia) occurred more frequently in the Group-A (17/29, 58.6%) than in the Group-B (3/29, 10.3%; p < 0.0002), although patients with fQRS on ECG showed the similar event rate to those without. Multivariate analysis revealed that the presence of fQRS on MCG was only an independent predictor of poor outcome (p=0.0137). Conclusions: The prognosis of LBBB patients with fQRS on MCG was poor. The fQRS on MCG, which indicates the presence of inhomogeneous LV conduction, can be a reliable marker for predicting adverse outcomes in patients not only with cardiomyopathy but also with LBBB.

Background: Effects of location of mutation on clinical phenotype in a large scale of patients with LQT3 syndrome are unclear. Methods and Results: Forty-nine patients (male=30, proband=25) with an SCN5A mutation were retrospectively studied from a Japanese multicenter registry and divided into patients with mutations located in the transmembrane (TM) portion and the non-transmembrane (non-TM) portion. Although there was no significant difference in the QTc interval between the two groups (478±78 vs. 508±37ms; p=0.079), both cumulative cardiac event rates and lethal cardiac event (VF and/or aborted cardiac arrest) rates were significantly higher in the TM group (Figure , p=0.006, p=0.007, respectively). By performing the multivariate analysis, longer QTc interval and the TM group was an independent risk factor for cardiac events (QTc≥500ms vs. QTc Conclusion: In this multicenter study, Japanese LQT3 patients with mutations located in the transmembrane portion were at higher risk for cardiac events.

Background : It has been reported that ST-segment elevation was augmented at early recovery phase or at peak exercise during exercise testing in some patients with Brugada syndrome (BrS), but its diagnostic and prognostic value has not fully been clarified. Methods : Treadmill exercise testing (TMT) was conducted in 93 patients (pts) with BrS (22 documented VF, 31 syncope alone, and 40 asymptomatic; 91 males, 46±14 years) and 22 healthy control subjects (20 males, 48±14 years, 11 with incomplete right bundle branch block (RBBB) and 4 with complete RBBB). Results : The augmentation of ST-segment elevation ≥0.05mV in V1-V3 leads compared with that before exercise was observed at early recovery phase (1– 4 minutes at recovery phase) in 32 BrS pts (34%, Group1), at peak exercise in 8 BrS pts (9%, Group 2), but not in either the remaining 53 BrS pts (57%, Group 3) or 22 control subjects. There were no significant differences among the 3 BrS groups in the baseline clinical (age, gender, family history of sudden death, SCN5A mutation), electrocardiographic (PR, QRS duration, QTc interval and ST amplitude), and electrophysiologic (AH, HV interval, and VF induction) variables except for the positive ratio of signal averaged ECG (87%, 48%, 63%; P= 0.001). No significant difference was observed in the proportion of previous cardiac events (VF/syncope/asymptomatic; 6/12/14, 0/3/5, 16/16/21, respectively for Group 1, 2, and 3). During 76.0, 74.8, and 52.0 months follow-up, VF occurred in 12/32 (38%) pts of Group1, 0/8 (0 %) pts of Group2, and 10/53 (19%) pts of Group3. Augmentation of ST-segment elevation at early recovery phase was a significant and an independent predictor for subsequent VF occurrence (12/32 (38%) in Group1 vs. 10/61 (16%) in Group2 and 3; hazard ratio [HR]= 1.68; P=0.014), especially in 31 pts with a history of syncope alone (6/12 (50%) in Group1 vs. 1/19 (5%) in Group2 and 3; HR=3.44; P=0.004). Conclusions : Our data suggest that augmentation of ST-segment elevation at early recovery phase during exercise testing can be a predictor of poor prognosis in patients with Brugada syndrome, especially in those with a history of syncope alone.

A 42-year-old man was admitted to our hospital with shortness of breath on light effort. An ECG revealed advanced AV block (Figure 1A), and a chest CT scan showed markedly increased thickness (12 mm) of the right ventricular wall (Figure 2A). The endomyocardial biopsy showed a noncaseous epithelioid …