[Show abstract][Hide abstract] ABSTRACT: Background:
Brugada syndrome (BrS)-type electrocardiogram (ECG) is concealed by complete right bundle-branch block (CRBBB) in some cases of BrS. Clinical significance of BrS masked by CRBBB is not well known.Methods and Results:We reviewed an ECG database of 326 BrS patients who had type 1 ECG with or without pilsicainide. "BrS masked by CRBBB" was defined on ECG as <2-mm elevation of the J point at the time of CRBBB in the right precordial leads, and BrS-type J-point elevation ≥2 mm at the time of normalized QRS complex on relieved CRBBB. We identified 25 BrS patients (7.7%) with persistent (n=12) or intermittent CRBBB (n=13). Relief of CRBBB by pacing was performed in patients with persistent CRBBB. The prevalence of BrS masked by CRBBB was 3.1% (10/326 patients). Three patients had type 1 ECG, and 7 patients had type 2 or 3 ECG on relief of CRBBB. Two of these 10 patients had lethal arrhythmic events during the follow-up period (mean, 86.4±57.2 months). There was no prognostic difference between BrS masked by CRBBB and other BrS.
In a small BrS population, CRBBB can completely mask typical BrS-type ECG. BrS masked by CRBBB is associated with the same risk of fatal ventricular tachyarrhythmia as other BrS.
[Show abstract][Hide abstract] ABSTRACT: This book highlights recent advances in beta blockers research. Beta blockers have been used for the treatment of several clinical conditions and it is of paramount importance to understand their role and applications. Chapters of the book were written by experts in the fields of vascular disease, plastic surgery, cardiovascular medicine, pharmaceutical medicine and physiology from various countries such as the United States, the United Kingdom, Brazil, Japan and New Zealand.
Clinical topics on recent advances in â-blockers research covered in this book include the clinical effectiveness of â-blockers in patients with peripheral arterial disease, abdominal aortic aneurysm, heart failure, acute coronary syndrome, pulmonary hypertension, object memory recognition, portal hypertension and infantile hemangioma. These chapters were written by authors who are experts in their fields and by researchers who are most up-to-date in the recent literature on advances in â-blockers research.
This book would be of great value for researchers in the field of â-blockers and adds up-to-date knowledge on the use of this class of drugs in several diseases. It will certainly contribute additional, valuable knowledge to what is already known about this very important class of drugs. This book is also a valuable source of information for residents and medical students to help enable them to keep abreast with recent evidence concerning beta blockers.
1 edited by Yousef Shahin, 06/2015; Nova Science Publishers, New York, USA., ISBN: 978-1-63482-423-1
[Show abstract][Hide abstract] ABSTRACT: Ambulatory measurement of intrathoracic impedance (ITI) with an implanted device may detect increases in pulmonary fluid retention early, but the clinical utility of this method is not well established. The goal of this study was to test whether conventional ITI-derived parameters can diagnose fluid retention that may cause early stage heart failure (HF).Methods and Results:HF patients implanted with high-energy devices with OptiVol (Medtronic) monitoring were enrolled in this study. Patients were monitored remotely. At both baseline and OptiVol alert, patients were assessed on standard examinations, including analysis of serum brain natriuretic peptide (BNP). From April 2010 to August 2011, 195 patients from 12 institutes were enrolled. There were 154 primary OptiVol alert events. BNP level at the alerts was not significantly different from that at baseline. Given that ITI was inversely correlated with log BNP, we added a criterion specifying that the OptiVol alert is triggered only when ITI decreases by ≥4% from baseline. This change improved the diagnostic potential of increase in BNP at OptiVol alert (sensitivity, 75%; specificity, 88%).
BNP increase could not be identified based on OptiVol alert. Decrease in ITI ≥4% compared with baseline, in addition to the alert, however, may be a useful marker for the likelihood of HF (Clinical trial info: UMIN000003351).
[Show abstract][Hide abstract] ABSTRACT: Background:
Risk stratification in patients with Brugada syndrome for primary prevention of sudden cardiac death is still an unsettled issue. A recent consensus statement suggested the indication of implantable cardioverter defibrillator (ICD) depending on the clinical risk factors present (spontaneous type 1 Brugada electrocardiogram (ECG) [Sp1], history of syncope [syncope], and ventricular fibrillation during programmed electrical stimulation [PES+]). The indication of ICD for the majority of patients, however, remains unclear.
Methods and results:
A total of 218 consecutive patients (211 male; aged 46 ± 13 years) with a type 1 Brugada ECG without a history of cardiac arrest who underwent evaluation for ICD including electrophysiological testing were examined retrospectively. During a mean follow-up period of 78 months, 26 patients (12%) developed arrhythmic events. On Kaplan-Meier analysis patients with each of Sp1, syncope, or PES+ suffered arrhythmic events more frequently (P=0.018, P<0.001, and P=0.003, respectively). On multivariate analysis Sp1 and syncope were independent predictors of arrhythmic events. When dividing patients according to the number of these 3 risk factors present, patients with 2 or 3 risk factors experienced arrhythmic events more frequently than those with 0 or 1 risk factor (23/93 vs. 3/125; P<0.001).
Syncope, Sp1, and PES+ are important risk factors and the combination of these risks well stratify the risk of later arrhythmic events.
[Show abstract][Hide abstract] ABSTRACT: Objectives
This study aimed to determine the usefulness of the combination of several electrocardiographic (ECG) markers on risk assessment of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS).
Detection of high/low-risk BrS patients using a noninvasive method is an important issue in the clinical setting. Several ECG markers related to depolarization and repolarization abnormalities have been reported, but the relationship and usefulness of these parameters in VF events are unclear.
Baseline characteristics of 246 consecutive patients (236 males; mean age, 47.6±13.6 years) with Brugada type ECG, including 13 patients with a history of VF and 40 patients with a history of syncopal episodes, were retrospectively analyzed. During the mean follow-up period of 45.1 months, VF in 23 patients and sudden cardiac death (SCD) in one patient were observed. Clinical/genetic and electrocardiographic parameters were compared with VF/SCD events.
By univariate analysis, history of VF, history of syncopal episodes, paroxysmal atrial fibrillation , spontaneous type 1 pattern in the precordial leads, ECG markers of depolarization abnormalities (PQ >200 ms, QRS duration ≥120 ms, and fragmented QRS [f-QRS]), and those of repolarization abnormalities (infero-lateral early repolarization [ER] pattern and QT prolongation) were associated with later cardiac events. By multivariable analysis, history of VF, history of syncopal episodes, infero-lateral ER pattern, f-QRS were independent predictors of documented VF and SCD (odds ratio, 19.61, 28.57, 2.87, and 5.21, respectively, P<0.05). Kaplan-Meier curves showed that the presence/absence of infero-lateral ER and f-QRS provided a worse/better prognosis (log-rank test, P<0.01).
The combination of depolarization and repolarization abnormalities in BrS is associated with later VF events. The combination of these abnormalities is useful for detecting high- and low-risk BrS patients.
Journal of the American College of Cardiology 05/2014; 63(20). DOI:10.1016/j.jacc.2014.01.072 · 16.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Patients with cardiac implantable electronic devices (CIEDs) have been followed with periodic clinic visits. The number of patients with CIEDs has been increasing and CIEDs have become more complex. The workload of both medical staff and patients for CIED follow-up has also been increasing. Remote monitoring (RM) technology has undergone many developments, and RM has been used since 2008 in Japan. The benefits of RM are evident, but there are also problems with the technology. Different systems and various skills are required for RM management compared to conventional follow-up methods.
Journal of Arrhythmia 05/2014; 30(6). DOI:10.1016/j.joa.2014.03.009
[Show abstract][Hide abstract] ABSTRACT: Multi-detector coronary CT angiography (CCTA) can detect coronary stenosis, but it has a limited ability to evaluate myocardial perfusion. We evaluated the usefulness of first-pass CT-myocardial perfusion imaging (MPI) in combination with CCTA for diagnosing coronary artery disease (CAD).
A total of 145 patients with suspected CAD were enrolled. We used 64-row multi-detector CT (Definition Flash, Siemens). The same coronary CCTA data were used for first-pass CT-MPI without drug loading. Images were reconstructed by examining the signal densities at diastole as colour maps. Diagnostic accuracy was assessed by comparison with invasive coronary angiography.
First-pass CT-MPI in combination with CCTA significantly improved diagnostic performance compared with CCTA alone. With per-vessel analysis, the sensitivity, specificity, positive predictive value and negative predictive value increased from 81% to 85%, 87% to 94%, 63% to 79% and 95% to 96%, respectively. The area under the receiver operating characteristic curve for detecting CAD also increased from 0.84 to 0.89 (p=0.02). First-pass CT-MPI was particularly useful for assessing segments that could not be directly evaluated due to severe calcification and motion artefacts.
First-pass CT-MPI has an additional diagnostic value for detecting coronary stenosis, in particular in patients with severe calcification.
[Show abstract][Hide abstract] ABSTRACT: In several cases with idiopathic ventricular fibrillation (VF), VF was initiated by premature ventricular contractions (PVCs) from the Purkinje system. However, the precise characteristics of the Purkinje activity in patients with idiopathic VF remain unclear. We performed an electrophysiological study in a patient with idiopathic VF and examined the correlation between the Purkinje potential and the incidence of PVCs/polymorphic ventricular tachycardia (PMVT). In this case of idiopathic VF, the Purkinje activity caused multiform PVCs and PMVT. The The Purkinje activity and slow conduction of Purkinje fibers are associated with the occurrence of multiform PVCs and PMVT.
Internal Medicine 04/2014; 53(7):725-8. DOI:10.2169/internalmedicine.53.1147 · 0.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: A major cause of heart failure (HF) related hospitalizations is fluid accumulation. Recent studies have suggested that intrathoracic impedance (ITI) may be a useful parameter to track daily changes in pulmonary fluid status. OptiVol alert (OA), which is a fluid status algorithm calculated from ITI, can detect impending fluid accumulation at an early stage. However, the sensitivity and specificity of OA for deteriorated HF have not been sufficient for it to be a clinically useful parameter. Therefore, we sought to examine the difference of various parameters between OA and baseline.
Objectives: The purpose of study 1 was to examine how various parameters changed in OA compared to baseline. And the purpose of study 2 was to evaluate what parameters could predict increased log BNP.
Methods: This study was a prospective multicenter study. Patients who suffered from structural heart disease and who had been implanted with a high energy device with an OptiVol feature were included in this study. The patients underwent various examinations at enrolment and following an OA. In study 1, primary endpoint was to examine how log BNP changed between OA and baseline. Secondary endpoint was to examine how other parameters changed between OA and baseline. We defined low ITI as equal or less than 96% of ITI at baseline.
Results: From 2010 to 2011, 200 patients in 12 institutes were enrolled in the present study. Mean age was 65.3 years, mean ejection fraction was 44.2% and mean log BNP was 2.2 ng/ml. We had 376 OA events and 289 periodical follow-up events. In primary endpoint of study 1, there was no significant difference in log BNP between OA and baseline. However, the change rate of ITI was negatively correlated with the change rate of log BNP (r = -0.35, p < 0.01). In 115 OA events with low ITI, log BNP was significantly higher than that at baseline (2.33 vs 2.19, p < 0.01). In secondary endpoint of study 1, there was no significant difference in body weight, cardio-thoracic ratio in chest X ray, end diastolic volume, end systolic volume and tricuspid regurgitation pressure gradient between OA and baseline. In study 2, we searched what parameters could predict increased log BNP by 0.4 compared to that at baseline. To predict increased log BNP by 0.4, the area under ROC curve for OA events with low ITI was significantly larger than that for only OA events (0.78 vs 0.62, p < 0.01).
Conclusions: There was no significant difference in log BNP between OA and baseline. However, OA events with low ITI can predict increased BNP, but only OA events.
[Show abstract][Hide abstract] ABSTRACT: PurposeThe purpose of this study was to clarify the prognosis of cardiac resynchronization therapy with defibrillators (CRT-Ds) in Japan.Methods
We selected 384 patients implanted with a CRT-D device from the observation database (n=1482) of the Japanese Cardiac Device Therapy Registry. We investigated the CRT criteria, including the presence of New York Heart Association (NYHA) class III/IV symptoms, left ventricular ejection fraction (LVEF) ≤35%, and QRS duration ≥120 ms. The patients were divided into 2 groups: the group fulfilling all of the 3 criteria (Group A, n=229) and the group not fulfilling the criteria (Group B, n=155). We compared mortality and appropriate shock rates between the 2 groups.ResultsThere was no significant difference in mortality (17.9% vs. 13.5%) or appropriate shock rates (32.5% vs. 31.6%) during the observation period of 29.0±15.7 months between the 2 groups. A logistic multivariate analysis showed that appropriate shocks (hazard ratio [HR]=1.85) and class III antiarrhythmic agents (HR=2.33) were independently associated with all-cause death, and that age ≥70 years (HR=0.55), male gender (HR=2.07), and presence of a single-chamber device (HR=1.78) were associated with appropriate shocks. The prognosis of Group A was better than that of the COMPANION trial.Conclusions
Japanese patients with CRT-D devices had a better prognosis than did those in the COMPANION trial, but no significant differences were observed between patients fulfilling and those not fulfilling the above mentioned criteria.
Journal of Arrhythmia 06/2013; 29(3):168–174. DOI:10.1016/j.joa.2013.04.006
[Show abstract][Hide abstract] ABSTRACT: Background:
We investigated the acute effects of implantable cardioverter-defibrillator shock on myocardium, cardiac function, and hemodynamics in relation to left ventricular systolic function.
Methods and results:
We studied 50 patients who underwent implantable cardioverter-defibrillator implantation and defibrillation threshold (DFT) testing: 25 patients with left ventricular ejection fraction (LVEF) ≥ 45% and 25 patients with LVEF <45%. We measured cardiac biomarkers (creatine kinase, creatine kinase-MB, myoglobin, cardiac troponin T and I, and N-terminal probrain natriuretic peptide). Left ventricular relaxation was assessed by global longitudinal strain rate during the isovolumetric relaxation period using speckle-tracking echocardiography. Blood sampling and echocardiography were performed before, immediately after, and 5 minutes and 4 hours after DFT testing. Mean arterial pressure was measured directly during DFT testing. Cardiac biomarkers showed no significant changes in either group. LVEF was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in the group with reduced LVEF (P<0.001), whereas LVEF reduction was not observed in the group with preserved LVEF (P=0.637). Global isovolumetric relaxation period was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in both groups (preserved LVEF: 0.39 ± 0.14 versus 0.23 ± 0.13* versus 0.23 ± 0.13* versus 0.40 ± 0.13 s(-1), *P<0.001 versus baseline; reduced LVEF: 0.15 ± 0.05 versus 0.08 ± 0.04† versus 0.09 ± 0.04† versus 0.15 ± 0.05 s(-1), †P<0.001 versus baseline, repeated-measures ANOVA). Time to recovery of mean arterial pressure to the baseline was prolonged in the group with reduced LVEF (P<0.001).
Implantable cardioverter-defibrillator shock transiently impairs cardiac function and hemodynamics especially in patients with systolic dysfunction, although significant tissue injury is not observed.
[Show abstract][Hide abstract] ABSTRACT: Oxidative stress has been implicated in the pathogenesis of heart failure. Reactive oxygen species (ROS) are produced in the failing myocardium, and ROS cause hypertrophy, apoptosis/cell death and intracellular Ca2+ overload in cardiac myocytes. ROS also cause damage to lipid cell membranes in the process of lipid peroxidation. In this process, several aldehydes, including 4-hydroxy-2-nonenal (HNE), are generated and the amount of HNE is increased in the human failing myocardium. HNE exacerbates the formation of ROS, especially H2O2 and ·OH, in cardiomyocytes and subsequently ROS cause intracellular Ca2+ overload. Treatment with beta-blockers such as metoprolol, carvedilol and bisoprolol reduces the levels of oxidative stress, together with amelioration of heart failure. This reduction could be caused by several possible mechanisms. First, the beta-blocking effect is important, because catecholamines such as isoproterenol and norepinephrine induce oxidative stress in the myocardium. Second, anti-ischemic effects and negative chronotropic effects are also important. Furthermore, direct antioxidative effects of carvedilol contribute to the reduction of oxidative stress. Carvedilol inhibited HNE-induced intracellular Ca2+ overload. Beta-blocker therapy is a useful antioxidative therapy in patients with heart failure.
[Show abstract][Hide abstract] ABSTRACT: Syncope in patients with Brugada syndrome is usually associated with ventricular tachyarrhythmia, but some episodes of syncope can be related to autonomic disorders.
The purpose of this study was to investigate the characteristics of syncope to differentiate high-risk syncope episodes from low-risk events in patients with Brugada syndrome.
We studied 84 patients with type 1 electrocardiogram and syncope. Patients were divided into 2 groups: patients with prodrome (prodromal group; n = 41) and patients without prodrome (nonprodromal group; n = 43).
Ventricular fibrillation (VF) was documented at index event in 19 patients: 4 patients (21%) with documented VF experienced a prodrome prior to the onset of VF, whereas 15 patients (79%) did not have symptoms prior to documented VF (P <.01). Twenty-seven patients in the prodromal group and 7 patients in the nonprodromal group were considered to have syncope related to autonomic dysfunction. Syncope in other patients was defined as unexplained syncope. During the follow-up period (48 ± 48 months), recurrent syncope due to VF occurred in 13 patients among patients with only unexplained syncope and was more frequent in the nonprodromal group (n = 10) than in the prodromal group (n = 3; P = .044). In multivariate analysis, blurred vision (hazard ratio [HR] 0.20) and abnormal respiration (HR 2.18) and fragmented QRS (HR 2.39) were independently associated with the occurrence of VF.
Syncope with prodrome, especially blurred vision, suggests a benign etiology of syncope in patients with Brugada syndrome.
Heart rhythm: the official journal of the Heart Rhythm Society 11/2011; 9(5):752-9. DOI:10.1016/j.hrthm.2011.11.045 · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Intermittent arm ischemia before percutaneous coronary intervention induces remote ischemic preconditioning (RIPC) and attenuates myocardial injury in patients with myocardial infarction. Several studies have shown that intermittent arm ischemia increases coronary flow and is related to autonomic nerve system. The aim of this study was to determine whether intermittent arm ischemia induces vasodilatation of other arteries and to assess changes in the autonomic nerve system during intermittent arm ischemia in humans. We measured change in the right brachial artery diameter during intermittent left arm ischemia through three cycles of 5-min inflation (200 mmHg) and 5-min deflation of a blood-pressure cuff using a 10-MHz linear array transducer probe in 20 healthy volunteers. We simultaneously performed power spectral analysis of heart rate. Ischemia-reperfusion of the left arm significantly dilated the right brachial artery time-dependently, resulting in a 3.2 ± 0.4% increase after the 3rd cycle. In the power spectral analysis of heart rate, the high-frequency domain (HF), which is a marker of parasympathetic activity, was significantly higher after the 3rd cycle of ischemia-reperfusion than baseline HF (P = 0.02). Intermittent arm ischemia was accompanied by vasodilatation of another artery and enhancement of parasympathetic activity. Those effects may play an important role in the mechanism of RIPC.
The Journal of Physiological Sciences 09/2011; 61(6):507-13. DOI:10.1007/s12576-011-0172-9 · 1.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It is estimated that approximately half of the deaths in patients with HF are sudden and that the most likely causes of sudden death are lethal ventricular tachyarrhythmias such as ventricular tachycardia (VT) or fibrillation (VF). However, the precise mechanism of ventricular tachyarrhythmias remains unknown. The KCNH2 channel conducting the delayed rectifier K(+) current (I(Kr)) is recognized as the most susceptible channel in acquired long QT syndrome. Recent findings have revealed that not only suppression but also enhancement of I(Kr) increase vulnerability to major arrhythmic events, as seen in short QT syndrome. Therefore, we investigated the existence of a circulating KCNH2 current-modifying factor in patients with HF.
We examined the effects of serum of HF patients on recombinant I(Kr) recorded from HEK 293 cells stably expressing KCNH2 by using the whole-cell patch-clamp technique. Study subjects were 14 patients with non-ischemic HF and 6 normal controls. Seven patients had a history of documented ventricular tachyarrhythmias (VT: 7 and VF: 1). Overnight treatment with 2% serum obtained from HF patients with ventricular arrhythmia resulted in a significant enhancement in the peaks of I(Kr) tail currents compared to the serum from normal controls and HF patients without ventricular arrhythmia.
Here we provide the first evidence for the presence of a circulating KCNH2 channel activator in patients with HF and ventricular tachyarrhythmias. This factor may be responsible for arhythmogenesis in patients with HF.
PLoS ONE 05/2011; 6(5):e19897. DOI:10.1371/journal.pone.0019897 · 3.23 Impact Factor