Asumi Takei

Determinant of microvolt-level T-wave alternans in patients with dilated cardiomyopathy

OBJECTIVESnThe aim of this study was to clarify the clinical significance and the determinant of microvolt-level T-wave alternans (TWA) in patients with dilated cardiomyopathy (DCM).nnnBACKGROUNDnThe prevention of sudden death in patients with DCM remains the therapeutic target. T-wave alternans has been proposed as a powerful tool for identification of patients at high risk for ventricular arrhythmias and sudden death in coronary artery disease.nnnMETHODSnIn 58 DCM patients, TWA was measured during bicycle exercise testing using a CH 2000 system (Cambridge Heart, Bedford, Massachusetts). The New York Heart Association class, signal-averaged electrocardiogram, QT dispersion, left ventricular end-diastolic diameter (LVDd) and percent fractional shortening detected by echocardiogram and the grade of the ventricular arrhythmia were obtained in all patients.nnnRESULTSnT-wave alternans was positive in 23 patients (TWA+ group), negative in 25 (TWA- group) and indeterminate in 10. Univariate analysis showed that the percentage of patients with ventricular tachycardia (VT) and the LVDd in the TWA+ group was significantly higher than those in the TWA- group (61% vs. 8%, p < 0.001 and 65 +/- 11 mm vs. 58 +/- 8 mm, p < 0.05, respectively). The sensitivity, specificity and predictive accuracy of TWA for VT were 88%, 72% and 77%, respectively. Multivariate analysis showed that the presence of VT was a major independent determinant of TWA in patients with DCM (p = 0.003).nnnCONCLUSIONSnT-wave alternans was closely related to VT in patients with DCM. T-wave alternans is a useful noninvasive test for identifying high risk patients with DCM who have VT.

Dabigatran in the peri-procedural period for radiofrequency ablation of atrial fibrillation: efficacy, safety, and impact on duration of hospital stay.

PurposeDabigatran is effective for both the prevention of stroke and bleeding in patients with atrial fibrillation (AF). However, the safety and efficacy of the use of dabigatran in the peri-procedural period for radiofrequency catheter ablation (RFCA) of AF is unknown. Therefore, the purpose of this study was to evaluate the safety and efficacy of dabigatran in the peri-procedural period for RFCA of AF and the duration of hospital stay.MethodsConsecutive patients (nu2009=u2009227) who underwent RFCA for AF were prospectively analyzed. Peri-procedural anticoagulant therapy with dabigatran (nu2009=u2009101, D group) was compared with warfarin and heparin bridging (nu2009=u2009126, W group). Dabigatran was discontinued 12–24xa0h before and restarted 3xa0h after the procedure. Warfarin was stopped 3xa0days before the procedure and unfractionated heparin was administered.ResultsIschemic stroke occurred in one patient of the D group (0.8xa0%). There was no significant difference between the two groups in the incidence of major bleeding (three cases of cardiac tamponade in each group and one case of intracranial bleeding in the W group, pu2009=u20090.93) or minor bleeding (five cases in the D group vs. five in the W group, pu2009=u20090.54). The duration of hospital stay was significantly shorter in the D group than in the W group (7.2 vs. 10.3xa0days, pu2009=u20090.0001).ConclusionsPeri-procedural anticoagulation therapy with dabigatran for RFCA of AF was equally safe and effective compared with warfarin and heparin bridging. The use of dabigatran for RFCA of AF shortened the duration of hospital stay.

Circulating intermediate CD14++CD16+monocytes are increased in patients with atrial fibrillation and reflect the functional remodelling of the left atrium

Aims A recent large clinical study demonstrated the association between intermediate CD14++CD16+monocytes and cardiovascular events. However, whether that monocyte subset contributes to the pathogenesis of atrial fibrillation (AF) has not been clarified. We compared the circulating monocyte subsets in AF patients and healthy people, and investigated the possible role of intermediate CD14++CD16+monocytes in the pathophysiology of AF. Methods and results This case–control study included 44 consecutive AF patients without systemic diseases referred for catheter ablation at our hospital, and 40 healthy controls. Patients with systemic diseases, including structural heart disease, hepatic or renal dysfunction, collagen disease, malignancy, and inflammation were excluded. Monocyte subset analyses were performed (three distinct human monocyte subsets: classical CD14++CD16−, intermediate CD14++CD16+, and non-classical CD14+CD16++monocytes). We compared the monocyte subsets and evaluated the correlation with other clinical findings. A total of 60 participants (30 AF patients and 30 controls as an age-matched group) were included after excluding 14 AF patients due to inflammation. Atrial fibrillation patients had a higher proportion of circulating intermediate CD14++CD16+monocytes than the controls (17.0 ± 9.6 vs. 7.5 ± 4.1%, P < 0.001). A multivariable logistic regression analysis demonstrated that only the proportion of intermediate CD14++CD16+monocytes (odds ratio: 1.316; 95% confidence interval: 1.095–1.582, P = 0.003) was independently associated with the presence of AF. Intermediate CD14++CD16+monocytes were negatively correlated with the left atrial appendage flow during sinus rhythm (r= −0.679, P = 0.003) and positively with the brain natriuretic peptide (r = 0.439, P = 0.015). Conclusion Intermediate CD14++CD16+monocytes might be closely related to the pathogenesis of AF and reflect functional remodelling of the left atrium.

Topographic variability of the left atrium and pulmonary veins assessed by 3D-CT predicts the recurrence of atrial fibrillation after catheter ablation☆

Catheter ablation (CA) is an established therapy for atrial fibrillation (AF). However, the assessment of anatomical information and predictors of AF recurrence remain unclear. We investigated the relationship between anatomical information on the left atrium (LA) and pulmonary veins (PVs) from three‐dimensional computed tomography images and the recurrence of AF after CA.

Discrepancy between electrical and mechanical dyssynchrony in patients with heart failure and an electrical disturbance.

Cardiac resynchronization therapy (CRT) improves the survival rates of patients with heart failure, but 30–40% of them do not respond to CRT, partially because of the position of the left ventricular (LV) lead. The relationship between the electrical and mechanical activation of the left ventricle is unknown. The aim of this study was to compare the electrical and mechanical dyssynchrony.

Recognition of inferiorly dislocated fast pathways guided by three-dimensional electro-anatomical mapping

PurposeSlow pathway (SP) ablation of atrioventricular (AV) nodal reentrant tachycardia (AVNRT) can be complicated by unexpected AV block even at sites >10xa0mm inferior to the bundle of His (HB), and one cause is thought to be the inferior dislocation of an antegrade fast pathway (A-FP). We assessed locations of FPs guided by CARTO.MethodsSites of FPs were mapped guided by CARTO before SP ablation in 18 patients with slow–fast AVNRT. The A-FP was defined as the site with the minimum interval between the stimulus and HB potential when pace mapping in the right atrial septum.ResultsThe A-FP was 7.9u2009±u20097.5xa0mm inferior and 2.9u2009±u20095.0xa0mm posterior to the HB. In 6 of 18 patients (33%), the A-FP was inferiorly dislocated >10xa0mm to the HB. SP ablation was successfully performed in all patients at sites >10xa0mm from both the HB and the A-FP without AV block. In the inferiorly dislocated A-FP group, A-FPs seemed to be positioned much more on atrial sites and sufficiently posterior to SP ablation sites.ConclusionsThe A-FP inferiorly dislocated >10xa0mm to the HB in one third of patients with AVNRT and seemed to be positioned deep on atrial sites. It is again emphasized that SP ablation within the triangle of Koch should be performed at a very ventricular annulus site, particularly in the inferiorly dislocated A-FP group.

Prophylactic catheter ablation of ventricular tachycardia before cardioverter-defibrillator implantation in patients with non-ischemic cardiomyopathy: Clinical outcomes after a single endocardial ablation

Outcomes related to prophylactic catheter ablation (PCA) for ventricular tachycardia (VT) before implantable cardioverter‐defibrillator (ICD) implantation in non‐ischemic cardiomyopathy (NICM) are not well characterized. We assessed the efficacy of single endocardial PCA in NICM patients.

Electrical storm after cardiac resynchronization therapy suppressed by triple-site biventricular pacing and atrioventricular nodal ablation

Introduction Cardiac resynchronization therapy (CRT) has emerged as an effective treatment strategy for patients with advanced drugrefractory heart failure (HF), left ventricular systolic dysfunction, and ventricular dyssynchrony. However, stimuation of the left ventricle (LV) induces monomorphic entricular tachycardia (VT) in some patients. We presnt the case of a patient with ischemic cardiomyopathy who xperienced VT storm after biventricular pacing (BiVp), hich was controlled by triple-site biventricular pacing TriVp) and atrioventricular nodal (AVN) ablation.

Reduction in coronary microvascular resistance through cardiac resynchronization and its impact on chronic reverse remodelling of left ventricle in patients with non-ischaemic cardiomyopathy

AIMSnLeft bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function.nnnMETHODS AND RESULTSnTwenty-two patients with non-ischaemic cardiomyopathy (New York Heart Association class, III or IV; LV ejection fraction, ≤35%; QRS duration, ≥130 ms) were enrolled. One week after implantation of the CRT device, coronary flow velocity and pressure in the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCx) were measured invasively, before and after inducing hyperemia by adenosine triphosphate administration, with two programming modes: sequential atrial and biventricular pacing (BiV) and atrial pacing in patients with LBBB or sequential atrial and right ventricular pacing in patients with complete atrioventricular block (Control). We assessed hyperemic microvascular resistance (HMR, mean distal pressure divided by hyperemic average peak velocity) and the relationship between the change in HMR and mid-term LV reverse remodelling. Hyperemic microvascular resistance was lower during BiV than during Control (LAD: 1.76 ± 0.47 vs. 1.54 ± 0.45, P < 0.001; LCx: 1.92 ± 0.42 vs. 1.73 ± 0.31, P = 0.003). The CRT-induced change in HMR of the LCx correlated with the percentage change in LV ejection fraction (R = -0.598, P = 0.011) and LV end-systolic volume (R = 0.609, P = 0.010) before and 6 months after CRT.nnnCONCLUSIONnCardiac resynchronization therapy improves coronary flow circulation by reducing microvascular resistance, which might be associated with LV reverse remodelling.

Visualization of the Antegrade Fast and Slow Pathway Inputs in Patients with Slow-Fast Atrioventricular Nodal Reentrant Tachycardia

Mapping of the antegrade fast pathway (A‐FP) exact sites and antegrade slow pathway (A‐SP) input locations has not been well described.