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Introduction We previously reported that LP positive patients after percutaneous coronary intervention (PCI) had higher rate of re-hospitalization in the small-scale study (135 patients). In this study, we evaluated correlation between LP and later cardiac events leading to re-hospitalization more extensively in greater population. Methods and results A 24-h high-resolution (HR) ambulatory electrocardiogram (ECG) was performed in 421 patients that received PCI for the treatment of acute coronary syndrome (ACS) within 30 days. Various baseline characteristics and post-PCI ECG parameters including LP were examined for correlation with later re-hospitalization. LP was evaluated based on 3 different conditions, i.e., the worst, mean and best values, from 24-h signal-averaged QRS wave data. During the post-PCI follow-up period (611 ± 489.0 days), 90 patients were re-hospitalized due to cardiac events. Multivariate analysis identified only positive LP based on the worst value as an independent predictor for re-hospitalization with OR 2.26. Most of re-hospitalization cases (>75%) were predominantly attributed to ischemic events. LP positive population had significantly higher incidences of ischemic events as well as overall re-hospitalization compared to LP negative population. The predictive power of LP was decreased when it was combined with other variables. The receiver operating characteristic analysis determined the LP cut-off values consistent with the LP positive criteria previously reported and standardized. Conclusion The presence of LP in the 24-h HR ambulatory ECG post-PCI was an independent predictor for a risk of re-hospitalization due to ischemic cardiac events in ACS patients.

Several studies have reported that the left ventricular (LV) lead implant success rate ranges between 88.0% and 92.4%. Coronary venous anatomy differs among patients thus, necessitating multiple types of leads. To date, the implant success rate among Japanese patients utilizing a pre-specified family LV leads (including bipolar and quadripolar) is not well known. The Attain Success Japan Study enrolled patients indicated for a de novo or an upgrade cardiac resynchronization therapy implant. Patients were followed for 3 months, and the implant success rates with Medtronic Attain family LV leads as well as the incidence of complications related to the LV lead were evaluated.Three hundred 53 patients were enrolled from 29 sites in Japan; 346 patients had LV lead implant attempts. The LV lead was successfully implanted in 336 patients (97.1%). Bipolar and quadripolar LV lead implants were successful in 97.2% and 99.2% of patients, respectively (P = 0.43). Four complications (1.2%) related to the LV leads were reported; all of which occurred in patients receiving bipolar LV leads. The quadripolar LV leads were more frequently implanted in the apical segment compared with bipolar leads (21.6% versus 3.8%, P < 0.01). This study demonstrated a high implant success rate and a low LV lead-related complication rate, regardless of bipolar, or quadripolar in a Japanese cohort of patients.

Background Iodine-123 metaiodobenzylguanidine (123 I-MIBG) is useful for detecting sympathetic innervation in the heart, and has been closely associated with fatal arrhythmias. However, such imaging is typically calibrated to the area of highest uptake and thus is unable to identify areas of hyperinnervation. We hypothesized that normal 123 I-MIBG uptake regions in the denervated heart would demonstrate nerve sprouting and correlate with the potential for arrhythmogenesis. Methods Twenty New Zealand white rabbits treated with phenol or sham were prepared under anesthesia. Sympathetic innervation was quantified using autoradiography and immunostaining 4 weeks after phenol application, and electrophysiological study was performed. Results 123 I-MIBG revealed maximal local differences in isotope uptake in the border zone between areas with attenuated and abundant MIBG compared with that seen between adjacent regions within the lowest uptake areas. On immunostaining, heterogeneous and decreased expressions of growth-associated protein 43 signal were observed in the MIBG-attenuated areas; however, abundant signals were recognized in the MIBG-abundant areas. Upregulation of the tyrosine hydroxylase signal was observed at the part of the MIBG-abundant area. In electrophysiological study, the dispersion of activation recovery interval (ARI) was increased in the phenol-applied areas by norepinephrine infusion. Stellate stimulation exacerbated the ARI dispersion in both the phenol-applied and nonapplied areas, and was associated with increased inducibility of ventricular tachycardia and ventricular fibrillation. Conclusions The presence of hyperinnervation in the nondenervated regions of denervated rabbit hearts suggests that heterogeneous neural remodeling occurs in regions with seemingly normal 123 I-MIBG uptake and contributes to electrical instability.

BACKGROUND Sleep-disordered breathing (SDB) is highly associated with arterial hypertension (HT). Sympathetic hypertonia increases the risk of sudden cardiac death in patients with sleep apnea. This study aims to noninvasively investigate the electrophysiological features in SDB patients with and without arterial HT. METHODS Fifty-three patients with SDB were classified into two groups: SDB group and SDB + HT group. Twenty subjects with arterial HT were enrolled as controls (HT group). To assess arrhythmogenic vulnerability, high-resolution 24-hour ambulatory electrocardiograms were obtained for analyzing continuous late potential (LP), T-wave amplitude variability (TAV), and heart rate variability (HRV). RESULTS A higher incidence of positive LP was observed in the SDB + HT (85%) group than that observed in the SDB (50%) and HT (20%) groups (P < 0.01). TAV was highest in the SDB + HT group (78 μV) compared with the SDB (61 μV) and HT groups (42 μV; P < 0.01). Positive LP and TAV values were observed at night in the SDB + HT and SDB groups. The low-frequency/high-frequency of the HRV analysis was highest in the SDB + HT (4.7) group compared with that in the SDB (2.9) and HT (2.9) groups (P = 0.01). CONCLUSION Nocturnal LP, TAV, and HRV examinations were useful to investigate arrhythmogenesis. SDB patients with arterial HT showed a high prevalence of depolarization and repolarization abnormalities and relative sympathetic hyperactivity. This suggests that an electrophysiological instability is more prevalent in SDB patients with arterial HT.

Background High-risk patients with Brugada syndrome (BrS) have inherent late potential (LP) fluctuations that might be explained by autonomic activity, electrolyte abnormality, and body temperature changes. However, the correlation between postural changes and LP determinates remains unknown. Methods Forty patients with BrS (38 men, 43.9 ± 13.5 years) and 15 controls (15 men, 42.4 ± 11.2 years) were enrolled. LP variations were investigated at five body positions using high-resolution ambulatory monitoring electrocardiography (HR-ambulatory ECG). The HR-ambulatory ECG was recorded for 3 hours and LP parameters (fQRSd, LAS40, and RMS40) were obtained for at least 15 minutes in each at the supine, left and right lateral decubitus, and prone and sitting positions. Results Determinate LP in the BrS group was significantly abnormal in all positions. Among the five body positions, positive LP were much more frequent in the supine and left and right lateral decubitus positions than in the prone and sitting positions and normalized in the last two positions in patients with BrS. RMS40 variance by postural change was significantly larger in the coved group than in the saddle back group. Determinate LP improved in the sitting position compared to the supine position in the coved group. Conclusions Positive LP findings normalized in the sitting position in patients in the coved BrS group with a resuscitation history, suggesting that depolarization instability might be related to the risk of fatal ventricular arrhythmia. Posture-induced LP variance should be examined using HR-ambulatory ECG analysis in patients with BrS.

Background Because nifekalant hydrochloride (NIF) displayed a superior defibrillating effect on ventricular tachycardia/fibrillation (VT/VF) in cardiopulmonary arrest (CPA) patients, despite some QT prolongation, its effect on transmural dispersion of repolarization (TDR) in the left ventricle (LV) in an animal model of CPA was investigated. Methods and Results Eight beagle dogs were created with a myocardial infarction under anesthesia, and then VT/VF induction by continuous stimulation and cardiopulmonary resuscitation (CPR) were repeated. NIF (0.3 mg/kg) was administered under acidotic conditions (pH 7.26). The QTc interval measured by Y-lead ECG showed no significant prolongation before and after NIF. The activation recovery interval (ARI) measured by 64-lead LV surface mapping showed minimum ARI prolongation (40%) by NIF without maximum ARI prolongation, and as a result the ARI dispersion decreased by 67%. The repolarization time (RPT) with the plunge electrode showed 13-19% prolongation in the subendocardium and subepicardium with CPR, but NIF prolonged the RPT in the middle layer alone (17%), and as a result Plunge-TDR decreased by 82% (n=8, p

Risk stratification is important in the management of Brugada syndrome (BrS). Late potentials (LPs) and T-wave amplitude variability (TAV) in high-resolution ambulatory electrocardiography (ECG) were retrospectively investigated.One hundred and twenty-seven patients diagnosed with BrS on 12-lead ECG were classified into 3 groups: documented ventricular fibrillation (VF)/asystole (n=19), episodes of syncope alone (n=30), and asymptomatic (n=78). Healthy volunteers were enrolled as controls (n=25). In the BrS patients, LPs showed appreciable circadian periodicity; filtered QRS duration (fQRS) and duration of the terminal low-amplitude signal40 μV (LAS40) increased, whereas root mean square voltage of the terminal 40 ms of the fQRS (RMS40) decreased at night compared with the day. TAV did not have such a circadian periodicity. LP-positive incidence (night-time) and peak TAV were as follows: VF/asystolesyncope/asymptomaticcontrol (P0.001). VF/asystole was discriminated from control at a ratio of 81-84% by night-time LPs (fQRS116 ms, LAS4035 ms, RMS4025 μV) or peak TAV (54 μV); VF/asystole was discriminated from syncope/asymptomatic at a ratio of 60-69%, by night-time LPs (fQRS122 ms, LAS4042 ms, RMS4018μV) or peak TAV (58 μV). Combined analysis of LPs and peak TAV increased the discriminant ratio up to 93% and 77%, respectively.Analysis of both LPs and TAV (taking circadian periodicity into account) is useful in identification of high-risk BrS patients.

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Background: Short-term success does not always correlate well with long-term outcome in cases of catheter ablation (CA) for atrial fibrillation (AF). The aim of this study is to examine about the predictor which can differentiate between short- and long-term recurrence of AF after CA of AF. Methods and Results: Total of 52 patients (48; ±9 years, male; 33) were involved. The patients were divided into two groups; Group A: AF recurred earlier than 3 months after CA for AF (35 cases), Group B: AF recurred later than 1 year after CA for AF (17 cases). With multivariate analysis, following parameters were analyzed between Group A and B; diameter of left atrium (LAD) (38.7; ±5.6 vs 40.3; ±9.3 mm, NS), left ventricular ejection fraction (LVEF) (66.0; ±11.9 vs 59.8; ±9.2%, NS), the maximum diameter of pulmonary veins (MDPV) (23.1; ±3.4 vs 25.0; ±2.9 mm, NS), score of CHADS2 (SCHADS) (1.35; ±0.14 vs 1.31; ±0.21, NS), cardiothoracic ration on chest X-ray (CTR) (49.3; ±3.9 vs 51.2; ±4.3, NS) and total number of radiofrequency energy application (RFAP) (62.4; ±11.8 vs 83.9; ±13.8, P

Introduction: We report 2 cases of ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) which required radiofrequency energy (RF) application in the great cardiac vein (GCV) and/or the epicardium for treating VAs. Case 1: Sixty-five year-old female with idiopathic VAs underwent RF-catheter ablation (CA). The earliest activation site of VAs was observed in GCV, to which left descending coronary artery (LAD) run close. Sufficient RF delivery could not be performed due to the concerns about the injury to LAD, and the procedure resulted in a transient therapeutic effect. Case 2: Fifty-one year-old male suffering from VAs associated with non-ischemic cardiomyopathy underwent RF-CA. In 1st session, the earliest activation site of VAs was recognized in GCV, however, RF-CA application in GCV failed to abolish VAs. In 2nd session with the subxiphoidal pericardial approach, the earliest site was located at LVS extremely close to LAD. Despite the multiple RF applications in the vicinity sites of that portion, we were unable to abolish VAs. Conclusion: In sporadic cases, epicardial approach is required to eliminate VAs. However, the discretion and attention have to be paid in order to avoid the serious complications for treating VAs originating from LVS.

Recently, T-wave variability (TWV) has been notified by Dr. Zareba et al., as attractive marker of repolarization abnormalities. Differing from T-wave alternans which merely observes alternative beat-to beat changes of the amplitude of T-waves, TWV reflects morphological changes of the entire component aspect of ST-T waves by dividing ST-T segment into 40 ms duration for each beat. This method was useful for identifying the high risk patients in myocardial ischemia or dilated cardiomyopathy, however until now there are still few reports about the utility. TWV was measured by the ambulatory monitoring, and therefore a clinical significance might be a great role to capture the repolarization changes during sleep at night. We investigated the longitudinal fluctuations of TWV in the two kinds of disease to stratify risks for fatal arrhythmia. One is Brugada syndrome and the other is sleep apnia syndrome. We used high-resolution ambulatory ECG (2.5 µV, 1000 Hz) manufactured by the Ela Medical company for 24-hours continuously. The data of TWV were analyzed and other electrocardiographic parameters including late potentials (LP), heart rate variability (HRV), heart rate turbulence (HRT), and QT/RR slope were also analyzed using same data. In this symposium, we will report the results of these analyses.

Introduction: The benefit of additional ablation of complex fractionated electrograms (CFE) has been reported in treating patients with persistent atrial fibrillation (per-AF). However, the ideal target patients group for this strategy remains unclear. We report a series of cases with per-AF in which addition of CFE ablation to PVI resulted in successful outcome in freedom from AF. Method and Results: Three patients with symptomatic per-AF (2 with lone AF and 1 with tachycardia-induced cardiomyopathy, AF duration 4–16 months, age 56±6 yrs, 3 male, LA diameter of 43, 46 and 49 mm) under went a single ablation with PVI plus CFE ablation using NavX. The amounts of CFE region were variable (12–34 cm2). However, the distribution was similar among patients (in both the LA roof toward the appendage and LA septum anterior to the right superior PV). All CFE regions were located along area with voltage of 0.5–1.0 mV. Although termination of AF was not achieved, the mean cycle length in the LA significantly prolonged by CFE ablation. Following a single procedure, all three patients remained in sinus rhythm at >4-months follow-up. Conclusion: The details of the clinical and electrophysiological characteristics underlying these three cases will be discussed.

Background Intravenous amiodarone is considered to be the first-line drug for the treatment of ventricular tachycardia or fibrillation. However, in Japan, nifekalant had been used before the introduction of amiodarone; therefore, most clinical studies on amiodarone use have been small-scale studies. The aim of the present study was to review the literature concerning the actual use of amiodarone and nifekalant in order to evaluate the effects of both drugs and the most appropriate mode of administration. Methods The Japan Medical Abstracts Society, PubMed, and Scopus databases were used to identify the reports. The resulting data were used for a systematic review focusing on the effectiveness of amiodarone in comparison with that of nifekalant and the dose differential effect of amiodarone. Results The search returned 9 studies, including 310 patients, that compared the effectiveness of amiodarone and nifekalant, as well as 3 studies, including 108 patients, that analyzed the effectiveness of treatment according to amiodarone dose. Of 418 patients, 187 in whom amiodarone was used for cardiopulmonary resuscitation (CPR) were included in a review that compared the doses recommended by Japanese guidelines 2009 (125 mg intravenous [i.v.] over 10 min) and the American Heart Association guidelines (300 mg bolus i.v.). Amiodarone and nifekalant were equally effective in preventing electrical storm (67% vs. 67%). The defibrillation effect for CPR was also equal in the 2 groups (60% vs. 54%). Hypotension and bradycardia were recorded as adverse effects in the amiodarone group (9.5% and 5.3%), whereas torsades de pointes was observed in the nifekalant group (1.4%). In the analysis of the dose-differential effect of amiodarone, the rates of successful return of spontaneous circulation and discharge survival were higher in the 125-mg slow i.v. group than in the 300-mg bolus i.v. group (76% vs. 53% and 54% vs. 26%, respectively). Conclusions Amiodarone and nifekalant were equivalent in their prophylactic and defibrillation efficacy. Concerning the initial amiodarone dose, the 125 mg intravenous [i.v.] over 10 min seemed to be more appropriate for the Japanese population.

SummaryBackgroundIschemic “pre”-conditioning has been shown to have antiarrhythmic effects. The aim of this study was to investigate whether ischemic “post”-conditioning (post-CON) also has antiarrhythmic effects in ST-segment elevation myocardial infarction (STEMI) patients undergoing coronary angioplasty (PCI) as a clinical model of post-CON.Methods and resultsA total of 61 patients suffering from an acute myocardial infarction (AMI) were included. The QT dispersion (QTd) was measured before each balloon inflation (BI) and after deflation (BD) during PCI. The hemodynamic parameters and electrocardiogram were also assessed during PCI. All data were analyzed using a logistic regression analysis. A total of 36 of 61 STEMI patients could be analyzed according to the protocol. The QTd shortened significantly as the BI and BD were repeated (p

Intravenous amiodarone (AMD) induces multiple antiarrhythmic effects via blocking of Na(+), Ca(2+), and IKr channels, and beta receptors. A patient on chronic dialysis was administered AMD for nonsustained ventricular tachycardia after successful cardiopulmonary resuscitation. QT prolongation occurred 5 h after AMD administration. AMD was withdrawn at 24 h because of prolonged QTc interval (716 ms), which persisted for a further 48 h (661 ms). Ventricular premature contraction (VPC) was significantly decreased at 7h; however, VPC increased again after discontinuing AMD. Depolarization changes induced by the Na(+)-channel blocking action of AMD were analyzed. There was increasing filtered QRS-duration and duration of low-amplitude signals at voltage40 µV, and decreasing root-mean-square voltage of signals in the last 40 ms of ventricular late potentials (LPs) within 7 h. However after stopping AMD, LPs were reversed. The blood concentration of AMD reached the effective level within 10 min but decreased immediately to an ineffective level. Onset and disappearance of the VPC-inhibiting effect corresponded to the depressive effect on depolarization but not with the increase in the prolonged repolarization effect and blood concentration. Even if the QT interval is sufficiently prolonged, the Na(+)-channel blocking action is required for AMD to induce the antiarrhythmic effect.