Yusuke Hayashi

Risk stratification of ventricular fibrillation in Brugada syndrome using noninvasive scoring methods

BACKGROUND Risk stratification for ventricular fibrillation (VF) in patients with Brugada syndrome (BrS) remains controversial. OBJECTIVE The purpose of this study was to construct a novel prediction model for VF risk in BrS patients using noninvasive parameters. METHODS A total of 143 Japanese BrS patients with VF (n = 35) and without VF (n = 108) were retrospectively enrolled. We built a logistic regression model predicting VF occurrence and evaluated it by cross-validation. RESULTS Frequencies of history of syncope and spontaneous type 1 ECG, r-J interval in V1, QRS duration in V6, and LAS40, Tpeak-Tend dispersion, and max T-wave alternans were significantly associated with VF occurrence in univariate analyses. The history of syncope, r-J interval in V1, QRS duration in V6, and Tpeak-Tend dispersion were identified as independent predictors by multivariate logistic regression analysis. The predictive model was constructed using all these parameters with good discrimination of VF occurrence (area under the curve 0.869 with 97.1% sensitivity and 65.7% specificity). The area under the curve based on leave-one-out cross-validation was 0.845, with 97.1% sensitivity and 63.0% specificity suggesting good performance of the model. Retrospective survival analysis revealed that the cumulative VF event rate was significantly higher in patients at high risk than in those with low risk using the log rank test (P = 2.97 × 10(-8)). Notably, no BrS patient below the cutoff value developed a subsequent VF event. CONCLUSION This novel prediction method may effectively assesses VF risk in BrS patients, especially when determining implantable cardioverter-defibrillator placement for asymptomatic BrS patients.

Parathyroid hormone and systolic blood pressure accelerate the progression of aortic valve stenosis in chronic hemodialysis patients

BACKGROUND Aortic valve stenosis (AS) is a frequent complication contributing to poor prognosis in chronic hemodialysis (CHD) patients. However, little is known regarding the risk factors affecting AS progression. The purpose of this study was to define risk factors affecting AS progression in CHD patients. METHODS We retrospectively investigated 34 consecutive CHD patients with asymptomatic AS (mild in 9, moderate in 20, severe in 5; aortic valve area (AVA), 1.31±0.31cm(2); mean age, 69±8years) who underwent followed-up paired transthoracic echocardiography with period of at least six months apart (22±9months). AS progression was evaluated using the absolute reduction in AVA per year. RESULTS CHD patients were divided into 20 patients with rapid progression (AVA reduction, >0.1cm(2) per year) and 14 with slow progression (AVA reduction, ≤ 0.1cm(2) per year). Serum parathyroid hormone (PTH) level was significantly higher in patients with rapid progression than in those with slow progression [343±489pg/ml vs. 76±80pg/ml, P<0.05]. In univariate analysis, AS progression by absolute AVA reduction per year was associated with age, PTH level, initial AVA, systolic blood pressure (SBP), diastolic blood pressure, total cholesterol, and left ventricular diameter at end-diastole and end-systole. Multiple regression analysis indicated that serum PTH level and SBP remained independently associated with AS progression. CONCLUSIONS AS progression was accelerated in the presence of high PTH and SBP. Careful monitoring and intensive treatment of these parameters may have a beneficial effect on secondary prevention in CHD patients.

Long RP' Tachycardia With Unusual Entrainment Responses: What Is the Mechanism?

A 71-year-old man with palpitation was referred for electrophysiological study and radiofrequency ablation. Baseline findings of 12-lead electrocardiogram during sinus rhythm and echocardiography were normal. Atrio-His (AH) and His-ventricular (HV) intervals were measured as 113 and 40 milliseconds, respectively. Dual atrioventricular (AV) nodal physiology was observed during programmed atrial stimulation. The earliest atrial activation during ventricular constant pacing was recorded at His bundle region, and para-Hisian pacing showed an AV nodal pattern. Short RP’ tachycardia (SVT 1) accompanied by a jump-up in the AH interval was induced by atrial extrastimulation or atrial constant pacing (Fig. 1). During SVT 1, the AH and HV intervals were measured as 453 and 40 milliseconds, respectively, and the earliest atrial activation was recorded at the His bundle region. Ventricular extrastimuli delivered during SVT 1 when the His bundle is refractory did not reset the atrial cycle. Figure 2A shows a transition from SVT 1 to long RP’ tachycardia (SVT 2) with a true atrial–atrial-ventricular (AAV) response after cessation of ventricular entrainment pacing (VEP) during SVT 1. During SVT 2, the AH and HV intervals were measured as 125 and 42 milliseconds, respectively, and the earliest atrial activation was recorded at the coronary sinus (CS) ostium. Ventricular extrastimuli delivered during SVT 2 did not reset the atrial cycle, and VEP during SVT2 was performed (Fig. 2B). What is the mechanism underlying the 2 entrainment responses?

Radiofrequency catheter ablation for treatment of premature ventricular contractions triggering ventricular fibrillation from the right ventricular outflow tract in a patient with early repolarization syndrome

Introduction Ventricular fibrillation (VF) triggered by premature ventricular contraction (PVC) most frequently originates from the His-Purkinje system and right ventricular outflow tract (RVOT) in patients with idiopathic VF. Radiofrequency catheter ablation (RFCA) of triggering PVCs is reportedly useful for the successful elimination of VF. The diagnosis of early repolarization (ER) syndrome is made on the basis of the presence of J-point elevation Z1 mm in Z2 contiguous inferior and/or lateral leads of a standard 12-lead electrocardiogram (ECG) in patients resuscitated from otherwise unexperienced VF or polymorphic ventricular tachycardia (VT). However, the efficacy of RFCA of triggering PVCs in ER syndrome has not been fully evaluated. We report a case in which successful RFCA of triggering PVCs eliminated a VF episode in a patient with ER syndrome.