[Show abstract][Hide abstract] ABSTRACT: Background
The need for ways to minimize the number of implantable cardioverter-defibrillator (ICD) shocks is increasing owing to the risk of its adverse effects on life expectancy. Studies have shown that a longer detection time for ventricular tachyarrhythmia reduces the safety of therapies, in terms of syncope and mortality, but not substantially in terms of the success rate. We aimed to evaluate the effects of increased number of intervals to detect (NID) VF on the safety of ICD shock therapy and on the reduction of inappropriate shocks.
The present study was a prospective, multicenter, randomized, crossover study. Randomized VF induction testing with NID 18/24 or 30/40 was performed to compare the success rate of defibrillation with a 25-J shock and the time to detection. Inappropriate shock episodes were simulated retrospectively to evaluate a possibility of episodes avoidable at NID 24/32 and 30/40.
Thirty-one consecutive patients implanted with an ICD or cardiac resynchronization therapy-defibrillator (CRT-D) were enrolled in this study. The success rate of defibrillation was 100% in both NID groups at the first shock. The time from VF induction to detection showed a significant increase in the NID 30/40 group (6.16±1.29 s vs. 9.00±1.31 s, p<0.001). Among the 120 patients implanted with an ICD or CRT-D, 10 experienced 32 inappropriate shock episodes. The inappropriate shock reduction rate was 53.1% and 62.5% with NID 24/32 and 30/40, respectively.
The findings of this SANKS study suggest that VF NID 30/40 does not compromise the safety of ICD shock therapy, while decreasing the number of inappropriate shocks.
[Show abstract][Hide abstract] ABSTRACT: CaseA 64-year-old man with old anteroseptal myocardial infarction presented with electrical storm of ventricular tachycardia (VT). The QRS configuration during VT indicated right bundle branch (BB) block with a superior axis similar to that during sinus rhythm. The H-V interval during VT was 55 ms, which was shorter than that (70 ms) during sinus rhythm (Fig. 1). The pace map at the left posterior fascicular (LPF) area with BB potential matched clinical VT (Fig. 2). Entrainment pacing from the right ventricular apex indicated that BB reentrant VT was unlikely, and the diagnosis of inter-fascicular reentrant VT (IFRVT) was confirmed . During VT, radiofrequency ablation was applied to the left anterior fascicular area where BB potential was recorded during sinus rhythm to avoid complete atrioventricular block. VT was terminated in 1.5 s and was never observed afterwards. There are several reports on successful ablation of a retrograde limb of a IFRVT , but none in the setting of el
[Show abstract][Hide abstract] ABSTRACT: Macro-reentrant ventricular tachycardias (VT) utilizing the bundle branches and Purkinje fibers have been reported as verapamil sensitive VT (idiopathic left VT), bundle branch reentrant VT (BBRT) and inter-fascicular reentrant tachycardia (inter-fascicular VT). However, diagnostic confusion exists with these VTs due to the difficulty in differentiating between them with conventional electrophysiological (EP) studies. The aim of this study was to clarify the EP and anatomical entity of inter-fascicular VT, and provide successful methods for the radio frequency catheter ablation (RFCA) of inter-fascicular VT.
Journal of Interventional Cardiac Electrophysiology 06/2014; · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The patient was an 80-year-old man with low cardiac output syndrome associated with triple-vessel ischemic heart disease and severe aortic stenosis (AS). Deeming the patient unprepared for surgery because of his deteriorated general condition, we decided to perform revascularization with a percutaneous coronary intervention associated with intra-aortic balloon pump (IABP) and treat the severe AS with percutaneous balloon aortic valvuloplasty (BAV). Complete revascularization was successfully achieved and BAV was performed, improving the aortic valve area from 0.58 to 0.92 cm(2) and the pressure gradient from 41 to 26 mmHg. Postoperative hemodynamics improved, and the IABP was successfully removed.
Cardiovascular Intervention and Therapeutics 06/2014;
[Show abstract][Hide abstract] ABSTRACT: A 74-year-old woman with takotsubo cardiomyopathy developed polymorphic ventricular tachycardia during the acute phase. She exhibited prominent J-wave and T-wave alternans preceding ventricular tachycardia. These abnormalities disappeared after recovery from myocardial stunning.
[Show abstract][Hide abstract] ABSTRACT: A 67-year-old man with non-obstructive hypertrophic cardiomyopathy had received an implantable cardioverter-defibrillator (ICD) for an unstable, sustained ventricular tachycardia (VT) induced by programmed stimulation during an electrophysiological study 5 years earlier. An intracardiac electrogram recorded by the ICD revealed repetitive, non-reentrant ventriculoatrial synchrony (RNRVAS) associated with hypotension. Electrophysiologic and hemodynamic studies indicated that RNRVAS was induced and reproducibly termed by a single ventricular extrastimulus from the right ventricular apex. Following attainment of the elective replacement indicator, we replaced the ICD with another having managed ventricular pacing, which automatically switched AAI and DDD, thereby avoiding unnecessary ventricular pacing. Thus far, the patient has not experienced further RNRVAS. Thus, we believe that automatic switching between AAI and DDD can prevent RNRVAS.
[Show abstract][Hide abstract] ABSTRACT: Background: The J wave and fragmented QRS (fQRS) on electrocardiography are suggested to be closely related to cardiac arrhythmogenesis. Takotsubo cardiomyopathy (TTC) occasionally causes fatal cardiac conditions including life-threatening ventricular arrhythmia. There has been, however, only 1 case report describing the J wave in TTC, and fQRS has not been reported thus far in relation to clinical courses and prognosis. Methods and Results: J wave and fQRS formation were investigated in 31 consecutive patients with TTC. Nine patients (29%) had J waves and/or fQRS (group A), whereas the remaining 22 did not (group B). The J wave (4 patients), fQRS (4 patients), or both (1 patient) appeared transiently during the hyperacute phase. Left ventricular ejection fraction was significantly lower in group A. Summed defect score of single-photon emission computed tomography using iodine 123 beta-methyl-p-iodophenyl-pentadecanoic acid, and creatine kinase MB isozyme (CKMB) were significantly higher in group A. On multivariate analysis CKMB was a significant indicator of J wave or fQRS. Moreover, the J wave was a significant indicator for cardiac death and/or ventricular tachyarrhythmia (odds ratio, 11.5; P=0.026). Conclusions: Patients with TTC frequently had J waves and/or fQRS during the hyperacute phase, and which were associated with myocardial damage. J wave was also an indicator for cardiac death and/or ventricular tachyarrhythmia. J waves and fQRS may be useful markers for myocardial damage.
[Show abstract][Hide abstract] ABSTRACT: THE PUBLISHER REGRETS THAT THIS ARTICLE HAS BEEN TEMPORARILY REMOVED. A REPLACEMENT WILL APPEAR AS SOON AS POSSIBLE IN WHICH THE REASON FOR THE REMOVAL OF THE ARTICLE WILL BE SPECIFIED, OR THE ARTICLE WILL BE REINSTATED.: The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
Heart rhythm: the official journal of the Heart Rhythm Society 01/2014; · 4.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Electrocardiogram (ECG) recorded at the upper intercostal lead positions is recommended as an additional diagnostic clue for Brugada syndrome (BrS), but similar recording conditions to unmask ECG signs have not been explored. Methods and Results: We evaluated the diagnostic usefulness for unmasking ECG signs of BrS using recordings at the upper intercostal lead position, on deep inspiration and on standing. In 34 patients (mean age, 49±14 years; 30 male) with diagnosed and suspected BrS, ECG type and ST-elevation in leads V1-V3 recorded at a higher position by 1 rib from the standard position (3ICS), and at standard lead positions (4ICS) on deep inspiration (DI test) and on standing (Stand test) were compared with the conventional lead positions (baseline). While type 1 ECG had been documented in 17 of 34 patients on at least 1 occasion in the past, only 4 had the sign at baseline during the study. Twenty patients had type 1 on 3ICS recording, 18 on DI test, and 6 on Stand test. Among 17 patients without previous documentation of spontaneous type 1, 7 had type 1 on 3ICS recording, 6 on DI test, and 1 on Stand test. Conclusions: ECG recording on deep inspiration is useful to unmask diagnostic signs of BrS and has similar accuracy to 3ICS recording.
[Show abstract][Hide abstract] ABSTRACT: Over half of all admitted acute decompensated heart failure (ADHF) patients have renal failure. Although diuretics represent the mainstay of treatment strategy even in this population, there are unmet needs for safer and more effective treatment. Tolvaptan is a vasopressin-2 receptor antagonist, and we hypothesized that adding tolvaptan to standard diuretic therapy would be more effective in ADHF patients with renal function impairment.
The Answering question on tolvaptan's efficacy for patients with acute decompensated heart failure and renal failure (AQUAMARINE) is a multicenter, randomized controlled clinical trial, which will enroll 220 patients from 17 hospitals in Japan. ADHF patients whose estimated glomerular filtration rate is above 15 and below 60 mL/min/1.72 m(2) will be randomly assigned within 6 h after admission to usual care with furosemide or tolvaptan add-on therapy. Primary endpoint is achieved urine output within 48 h. Secondary endpoints include dyspnea relief measured by 7-points Likert scale, incidence of worsening renal function, dose of furosemide used within 48 h, and changes of brain natriuretic peptide.
This study is the first multicenter study in Japan to evaluate clinical effectiveness of tolvaptan add-on therapy in ADHF patients with renal failure. The results of this study address the treatment strategy of this high-risk population (UMIN Clinical Trial Registry Number: UMIN000007109).
Cardiovascular Drugs and Therapy 09/2013; 28(1). · 2.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Fragmented QRS (fQRS) can predict cardiac events, and inducible ventricular tachycardia/fibrillation (VT/VF) is a known high-risk factor for arrhythmic death. However, whether fQRS is a predictor of cardiac events in patients with inducible VT/VF is unknown. We aimed to evaluate whether fQRS is a predictor of cardiac events in patients with structural heart disease and inducible VT/VF. Methods and Results: We retrospectively investigated 98 patients with structural heart disease who had a defibrillator device implanted. All patients underwent electrophysiological testing prior to or after device implantation and VT/VF was induced. fQRS was present in 30 patients. Appropriate defibrillator therapies were similar between the fQRS and non-fQRS groups (47% vs. 47%). In total, 25 patients (26%) died during a mean follow-up period of 87±43 months. All-cause mortality (12 [40%] vs. 13 [19%]) and cardiovascular deaths (9 [30%] vs. 4 [6%]) were significantly higher in the fQRS group than non-fQRS group, respectively; Kaplan-Meier analysis revealed significantly lower event-free survival for all-cause mortality (P=0.012) and cardiovascular deaths (P=0.001) for fQRS patients. A multivariable Cox regression model revealed that fQRS was an independent predictor of cardiovascular death (hazard ratio, 4.58; 95% confidence interval, 1.34-15.64; P=0.015). Conclusions: fQRS is a predictor of cardiovascular death in patients with structural heart disease and inducible VT/VF.
[Show abstract][Hide abstract] ABSTRACT: A 47-year-old man underwent slow pathway ablation for slow-fast atrioventricular nodal reentrant tachycardia. Following the procedure, he felt palpitations while swallowing, and swallowing-induced atrial tachycardia was diagnosed. Swallowing-induced atrial tachycardia arose from the right atrium-superior vena cava junction and was cured by catheter ablation. After the procedure, the patient's heart rate variability changed significantly, indicating suppression of parasympathetic nerve activity. In this case, swallowing-induced atrial tachycardia was related to the vagal nerve reflex. Analysis of heart rate variability may be helpful in elucidating the mechanism of swallowing-induced atrial tachycardia.
[Show abstract][Hide abstract] ABSTRACT: Chronic obstructive pulmonary disease (COPD) is one of the important underlying diseases of atrial fibrillation (AF). However, the prevalence and electrophysiological characteristics of typical atrial flutter (AFL) in patients with AF and COPD remain unknown. The purpose of the present study was to investigate those characteristics.METHODS AND RESULTS: We investigated 181 consecutive patients who underwent catheter ablation of AF. Twenty-eight patients were diagnosed with COPD according to the Global Initiatives for Chronic Obstructive Lung Disease (GOLD) criteria. Forty patients with no lung disease served as a control group. We analysed the electrophysiological characteristics in these groups. Typical AFL was more common in the COPD group (19/28, 68%) than in the non-COPD group (13/40, 33%; P = 0.006). The prevalence of AFL increased with the severity of COPD: 4 (50%) of 8 patients with GOLD1, 13 (72%) of 18 patients with GOLD2, and 2 (100%) of 2 patients with GOLD3. Atrial flutter cycle length and conduction time from the coronary sinus (CS) ostium to the low lateral right atrium (RA) during CS ostium pacing before and after the cavotricuspid isthmus ablation were significantly longer in the COPD group than in the non-COPD group (285 vs. 236, 71 vs. 53, 164 vs. 134 ms; P = 0.009, 0.03, 0.002, respectively).CONCLUSION: In COPD patients with AF, conduction time of RA was prolonged and typical AFL was commonly observed.
[Show abstract][Hide abstract] ABSTRACT: AIMS: Prophylactic catheter ablation (CA) has been established to reduce the incidence of appropriate implantable cardioverter-defibrillator (ICD) therapy (anti-tachycardia pacing or shock) in secondary prevention patients. The aim of this study was to determine whether prophylactic CA for induced ventricular tachycardia (VT) reduces the incidence of appropriate ICD therapy in primary prevention patients.METHODS AND RESULTS: We retrospectively investigated 66 consecutive patients with structural heart disease who had undergone ICD implantation as primary prevention and electrophysiological study. Patients with hypertrophic cardiomyopathy or no inducible monomorphic VT had been excluded, and the remaining 38 patients were divided into two groups; those who had undergone prophylactic CA for induced monomorphic VT (the CA group, n = 18), and those who had not undergone CA (the non-CA group, n = 20). During a mean follow-up of 50 ± 38 months, 1 patient (5%) received appropriate ICD therapy in the CA group and 13 (65%) in the non-CA group. Kaplan-Meier survival analysis revealed a significantly higher event-free survival rates for appropriate ICD therapy in the CA group compared with the non-CA group (P = 0.003). Among the patients, one patient (5%) in the CA group and nine patients (45%) in the non-CA group suffered appropriate shock (P = 0.018).CONCLUSIONS: Prophylactic CA for induced monomorphic VT reduces the incidence of appropriate ICD therapy including shock in primary prevention patients. These results indicate that prophylactic CA may be considered for structural heart disease patients who are candidates for ICD implantation as primary prevention.
[Show abstract][Hide abstract] ABSTRACT: Type 1 ST-segment elevation is diagnostic of Brugada syndrome and its presence may be associated with a high risk of arrhythmic events. However, similar changes on electrocardiogram (ECG) are observed in various normal and abnormal conditions. A type 1 ECG can also be unmasked by administration of sodium channel blockers in equivocal or suspected cases of Brugada syndrome, and this drug challenge test is frequently used in the diagnosis of symptomatic patients showing non-type 1 ECG patterns. The presence of a transient spontaneous type 1 ECG rather than a drug-induced type I ECG is an important sign for risk prediction of arrhythmia events, even in asymptomatic patients. In asymptomatic individuals, multiple and repeated ECG recordings rather than drug testing are recommended for detecting the transient appearance of a spontaneous type 1 ECG, which may indicate the future development of arrhythmic events. There is little doubt that ECG interpretation, including diagnostic criteria and differential diagnosis, constitutes the hallmark of Brugada syndrome.