Katsunori Okajima

Onset heart rate of microvolt-level T-wave alternans provides clinical and prognostic value in nonischemic dilated cardiomyopathy.

OBJECTIVES This study was designed to determine the prognostic value of onset heart rate (OHR) in T-wave alternans (TWA) in patients with nonischemic dilated cardiomyopathy (DCM). BACKGROUND One of the current major issues in DCM is to prevent sudden cardiac death (SCD). However, the value of the OHR of TWA as a prognostic indicator in DCM remains to be elucidated. METHODS We prospectively investigated 104 patients with DCM undergoing TWA testing. The end point of this study was defined as SCD, documented sustained ventricular tachycardia/ventricular fibrillation. Relations between clinical parameters and subsequent outcome were evaluated. RESULTS Forty-six patients presenting with TWA were assigned to one of the following two subgroups according to OHR for TWA of < or = 100 beats/min: group A (n = 24) with OHR < or = 100 beats/min and group B (n = 22) with 100 < OHR < or = 110 beats/min. T-wave alternans was negative in 37 patients (group C) and indeterminate in 21 patients. The follow-up result comprised 83 patients with determined TWA. During a follow-up duration of 21 +/- 14 months, there was a total of 12 arrhythmic events, nine of which included three SCDs in group A, two in group B and one in group C. The forward stepwise multivariate Cox hazard analysis revealed that TWA with an OHR < or = 100 beats/min and left ventricular ejection fraction were independent predictors of these arrhythmic events (p = 0.0001 and p = 0.0152, respectively). CONCLUSIONS The OHR of TWA is of additional prognostic value in DCM.

Relation Between Left Ventricular Morphology and Reduction in Functional Mitral Regurgitation by Cardiac Resynchronization Therapy in Patients With Idiopathic Dilated Cardiomyopathy

The presence of functional mitral regurgitation (MR) is considered a significant risk factor for poor clinical prognosis in patients with idiopathic dilated cardiomyopathy (IDC). The objectives of this study were to test the hypothesis that not only global but also local left ventricular (LV) remodeling, including the position of the papillary muscles, may contribute to the development of MR in patients with IDC and wide QRS durations and can be reversed with cardiac resynchronization therapy (CRT). Eighty-four subjects were studied, 44 patients with IDC who underwent CRT and 40 age- and gender-matched controls. The position of the posteromedial papillary muscle was similar in the 2 groups, whereas the position of the anterolateral papillary muscle in patients with IDC was displaced more posteriorly than in controls. Multivariate analysis revealed that reduction in coaptation height (β = 0.44, p <0.001) and LV dyssynchrony by speckle-tracking radial strain (β = 0.303, p <0.01) were independent determinants of reduction in MR 5 ± 2 days after CRT; in contrast, restoration of the position of the posteriorly displaced anterolateral papillary muscle (β = 0.50, p <0.001) and the increase in sphericity index (β = 0.440, p <0.001) were identified as independent determinants of reduction in MR 6 ± 1 months after CRT. In conclusion, asymmetric local LV remodeling was observed at baseline, and asymmetric local LV reverse remodeling was observed at long-term follow-up after CRT in patients with IDC. Furthermore, different parameters contribute to the reduction in MR observed at short- and long-term follow-up after CRT.

Impact of esophageal temperature monitoring guided atrial fibrillation ablation on preventing asymptomatic excessive transmural injury

Even with the use of a reduced energy setting (20–25 W), excessive transmural injury (ETI) following catheter ablation of atrial fibrillation (AF) is reported to develop in 10% of patients. However, the incidence of ETI depends on the pulmonary vein isolation (PVI) method and its esophageal temperature monitor setting. Data comparing the incidence of ETI following AF ablation with and without esophageal temperature monitoring (ETM) are still lacking.

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.

Reverse remodelling induces progressive ventricular resynchronization after cardiac resynchronization therapy ‘from vicious to virtuous cycle’

AIMS Cardiac resynchronization therapy (CRT) can stop the vicious cycle resulting from dyssynchrony and generates left ventricular (LV) reverse remodelling. Our objective was to assess the time course and the relationship between improvement in LV dyssynchrony and reverse remodelling after CRT. METHODS AND RESULTS Sixty-four consecutive patients were evaluated before, immediately after, and 3- and 6 months after CRT. We measured LV volumes, ejection fraction (EF), and sphericity index, and dyssynchrony was assessed using speckle-tracking radial strain. Response was defined as a >15% decrease in end-systolic volume (ESV) 6 months after CRT, and event-free survival was followed for 24 months. Responders and non-responders had similar baseline LV volumes and EF. During the first and the following 3 months after CRT, LV volumes gradually decreased (end-diastolic volume: 195±73 to 164±60* to 129±51 mL†, ESV: 141±70 to 110±47* to 82±40 mL†), and sphericity index and EF progressively increased (sphericity index: 1.52±0.20 to 1.75±0.31* to 1.94±0.34†, EF: 28±7 to 34±7* to 38±8%†, *†P<0.001) in responders. No such changes were observed in non-responders. Furthermore, dyssynchrony diminished progressively during the first and the following 3 months after CRT and patients with progressive resynchronization experienced fewer major cardiovascular events than those without (P<0.001). CONCLUSION CRT can stop the vicious cycle of remodelling and dyssynchrony, and actually, turn it into the virtuous cycle of reverse remodelling and further resynchronization.

Longitudinal strain combined with delayed-enhancement magnetic resonance improves risk stratification in patients with dilated cardiomyopathy

Objective Late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging has been reported to be associated with unfavourable outcomes; however, few studies have addressed the prognostic value of left ventricular (LV) deformation parameter indicated by global longitudinal strain (GLS) in two-dimensional speckle-tracking (2DST) echocardiography in patients with non-ischaemic dilated cardiomyopathy (DCM). This study aims to investigate whether the combination of GLS and LGE is useful in stratifying the risk in patients with DCM. Methods We studied 179 consecutive symptomatic patients with DCM (age, 61±15 years; 121 males; left ventricular ejection fraction (LVEF) 33%±9%; New York Heart Association (NYHA) class II: n=71, III: n=107, IV: n=1) who underwent CMR and echocardiography with conventional assessment and 2DST analysis. Results There were 40 rehospitalisations for heart failure, including 7 cardiac deaths and 2 implantations of LV assist device during follow-up (3.8±2.5 years). Univariable Cox proportional hazard regression analysis showed that NYHA class, blood pressure, B-type natriuretic peptide, LV end-diastolic and end-systolic volumes, LVEF, left atrium volume, GLS and LGE were significantly associated with long-term outcome. Multivariable analysis revealed that GLS and LGE were independently associated with long-term outcome (p<0.05, both). In additional analyses, we found independent associations between GLS and LV reverse remodelling after the optimal medical therapy, and between LGE and life-threatening arrhythmias (p<0.05, both). Conclusion Combining GLS and LGE could be useful for risk stratification and prognostic assessment in patients with DCM.

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.

Incidence of esophageal injury after pulmonary vein isolation in patients with a low body mass index and esophageal temperature monitoring at a 39 °C setting

Esophageal injury following catheter ablation of atrial fibrillation (AF) is reported to occur in 35% of patients. Even with a low energy setting (20–25 W), lesions develop in 10% of patients. Body mass index (BMI) has been reported to be a predictor of esophageal injury, indicating that patients with a low BMI (<24.9 kg/m2) are at a higher risk. We hypothesized that catheter ablation with a lower energy setting of 20 W controlled by esophageal temperature monitoring (ETM) at 39 °C could prevent esophageal injury even in patients with a BMI <24.9 kg/m2.

Visualizing radiofrequency lesions using delayed-enhancement magnetic resonance imaging in patients with atrial fibrillation: A modification of the method used by the University of Utah group

Atrial tissue fibrosis has previously been identified using delayed‐enhancement MRI (DE‐MRI) in patients with atrial fibrillation (AF). Although the clinical importance of DE‐MRI is well recognized, the visualization of atrial fibrosis and radiofrequency (RF) lesions has still not been achieved in Japan, primarily because of the differences in contrast agents, volume‐rendering tools, and technical experience. The objective of this study was to visualize RF lesions by using commercially available tools.

Improvement in the quality of the cardiac vein images by optimizing the scan protocol of multidetector-row computed tomography

The present study aimed at optimizing the scan protocol for multidetector-row computed tomography (MDCT) to adequately visualize coronary veins. Circulation time (Cir.T) was defined as the time period from the injection of contrast media into the coronary artery to the pervasion of the contrast media into the coronary sinus as observed by coronary angiography. We investigated the relation between the Cir.T and echocardiographic parameters in 64 patients. The left ventricular end-diastolic diameter (LVDd) and left ventricular end-systolic diameter (LVDs) were correlated with the Cir.T (r = 0.58, P < 0.0001, and r = 0.60, P < 0.0001 respectively). In addition, the left ventricular ejection fraction (LVEF) was negatively correlated with the Cir.T (r = 0.48, P < 0.0001). The average Cir. T was longer in patients with LVEF < 35% (8.0 s vs 6.7 s; P < 0.05) or LVDd > 55 mm (7.9 s vs 6.2 s; P < 0.05) than in the other patients. The quality of the MDCT images of the coronary veins obtained at different scan timings (coronary artery phase and 10 s or 15 s after the coronary artery phase) were graded and classified into four categories (0 = worst, 3 = best) in 25 patients with LVEF < 35%. The delays of 10 and 15 s after the coronary artery phase significantly improved the mean image quality (P < 0.05). The Cir.T was prolonged in patients with low LVEF and LV dilation. An appropriate delay improved the quality of the MDCT images of the coronary veins in patients with LV dysfunction.