Junichi Yamasaki

Diagnostic accuracy of 123I-meta-iodobenzylguanidine myocardial scintigraphy in dementia with Lewy bodies: a multicenter study.

Background and Purpose Dementia with Lewy bodies (DLB) needs to be distinguished from Alzheimer’s disease (AD) because of important differences in patient management and outcome. Severe cardiac sympathetic degeneration occurs in DLB, but not in AD, offering a potential system for a biological diagnostic marker. The primary aim of this study was to investigate the diagnostic accuracy, in the ante-mortem differentiation of probable DLB from probable AD, of cardiac imaging with the ligand 123I-meta-iodobenzylguanidine (MIBG) which binds to the noradrenaline reuptake site, in the first multicenter study. Methods We performed a multicenter study in which we used 123I-MIBG scans to assess 133 patients with clinical diagnoses of probable (n = 61) or possible (n = 26) DLB or probable AD (n = 46) established by a consensus panel. Three readers, unaware of the clinical diagnosis, classified the images as either normal or abnormal by visual inspection. The heart-to-mediastinum ratios of 123I-MIBG uptake were also calculated using an automated region-of-interest based system. Results Using the heart-to-mediastinum ratio calculated with the automated system, the sensitivity was 68.9% and the specificity was 89.1% to differentiate probable DLB from probable AD in both early and delayed images. By visual assessment, the sensitivity and specificity were 68.9% and 87.0%, respectively. In a subpopulation of patients with mild dementia (MMSE ≥ 22, n = 47), the sensitivity and specificity were 77.4% and 93.8%, respectively, with the delayed heart-to-mediastinum ratio. Conclusions Our first multicenter study confirmed the high correlation between abnormal cardiac sympathetic activity evaluated with 123I-MIBG myocardial scintigraphy and a clinical diagnosis of probable DLB. The diagnostic accuracy is sufficiently high for this technique to be clinically useful in distinguishing DLB from AD, especially in patients with mild dementia.

Successful Radiofrequency Catheter Ablation of Nonreentrant Supraventricular Tachycardia Due to Simultaneous Conduction Through Dual Atrioventricular Nodal Pathways

Objectives We evaluated whether pacing algorithms (PA) triggered by onset mechanism (OM) of atrial fibrillation (AF) were actually effective. Methods Ten patients (5males, mean age 67.5+/−7.3years) who received Vitatrons Selection pacemaker with >1 AF during 3months after implantation were included. PA were turned off (phase OFF), selectively turned on based on OM of AF (phase ON), and turned on based on all 4 PA (phase ALL-ON) for 3months by crossover method. We compared atrial pacing dependency (%pacing), number of AF, cumulative AF duration, and number of PAC between each setting. The effect of %pacing on AF was evaluated. Result %pacing was greater during phases ON and ALL-ON (phases OFF: 55.6+/−34.7%, ON: 84.2+/−19.7%, ALL-ON: 90.1+/−14.7%, p=0.0004). Number of AF (229.6+/−381.1, 152.8+/−226.5, 318.3+/−577.7, NS), cumulative AF duration (8240+/−12308min, 4013.1+/−8290.5min, 8656.4+/−18071.2min, NS) and number of PAC (88705.6+/−150316.5, 41525.4+/−48130, 139285.1+/−215336.9, NS) were minimized during phase ON. Number of AF negatively correlated with %pacing (r=−0.457, p=0.01). Conclusions PA decreased AF when those were selectively turned on. Higher %pacing was effective to decrease AF regardless of PA. Carefully chosen PA maximizing %pacing will be effective for AF suppression.

3-D mapping of Left Atrial Conduction Pattern

The purpose of this study is to examine a normal conduction pathway of the left atrium. During pulmonary vein isolation using a three‐dimensional mapping system, we observed the characteristics of the conduction pattern. Subjects consisted of 15 patients with paroxysmal atrial fibrillation (mean age, 62.8 ± 8.4 years). Left atrial activation conduction begins in the interatrial septum, and moves toward the peak of the ridge between the left atrial appendage and left pulmonary vein. In coronary sinus or appendage pacing, conduction was in the opposite direction at the same location. The mean conduction velocity in this area was 2.03 ± 0.43 m/s. Features of decrement conduction were not present. Anatomical position of the appendage differed greatly between patients. A detailed observation using the inner‐cavity view of a three‐dimensional mapping system also showed that the peak of the ridge reached the center of the roof.

123I-MIBG myocardial scintigraphy for the diagnosis of DLB: a multicentre 3-year follow-up study

Background and purpose We previously reported the usefulness of iodine-123 metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy for differentiation of dementia with Lewy bodies (DLB) from Alzheimer’s disease (AD) in a cross-sectional multicentre study. The aim of this study was, by using reassessed diagnosis after 3-year follow-up, to evaluate the diagnostic accuracy of 123I-MIBG scintigraphy in differentiation of probable DLB from probable AD. Methods We undertook 3-year follow-up of 133 patients with probable or possible DLB or probable AD who had undergone 123I-MIBG myocardial scintigraphy at baseline. An independent consensus panel made final diagnosis at 3-year follow-up. Based on the final diagnosis, we re-evaluated the diagnostic accuracy of 123I-MIBG scintigraphy performed at baseline. Results Sixty-five patients completed 3-year follow-up assessment. The final diagnoses were probable DLB (n=30), possible DLB (n=3) and probably AD (n=31), and depression (n=1). With a receiver operating characteristic curve analysis of heart-to-mediastinum (H/M) ratios for differentiating probable DLB from probable AD, the sensitivity/specificity were 0.77/0.94 for early images using 2.51 as the threshold of early H/M ratio, and 0.77/0.97 for delayed images using 2.20 as the threshold of delayed H/M ratio. Five of six patients who were diagnosed with possible DLB at baseline and with probable DLB at follow-up had low H/M ratio at baseline. Conclusions Our follow-up study confirmed high correlation between abnormal cardiac sympathetic activity evaluated with 123I-MIBG myocardial scintigraphy at baseline and the clinical diagnosis of probable DLB at 3-year follow-up. Its diagnostic usefulness in early stage of DLB was suggested. Trial registration number UMIN00003419.

P.1. Supraventricular Arrhythmias

Objectives We evaluated whether pacing algorithms (PA) triggered by onset mechanism (OM) of atrial fibrillation (AF) were actually effective. Methods Ten patients (5males, mean age 67.5+/−7.3years) who received Vitatrons Selection pacemaker with >1 AF during 3months after implantation were included. PA were turned off (phase OFF), selectively turned on based on OM of AF (phase ON), and turned on based on all 4 PA (phase ALL-ON) for 3months by crossover method. We compared atrial pacing dependency (%pacing), number of AF, cumulative AF duration, and number of PAC between each setting. The effect of %pacing on AF was evaluated. Result %pacing was greater during phases ON and ALL-ON (phases OFF: 55.6+/−34.7%, ON: 84.2+/−19.7%, ALL-ON: 90.1+/−14.7%, p=0.0004). Number of AF (229.6+/−381.1, 152.8+/−226.5, 318.3+/−577.7, NS), cumulative AF duration (8240+/−12308min, 4013.1+/−8290.5min, 8656.4+/−18071.2min, NS) and number of PAC (88705.6+/−150316.5, 41525.4+/−48130, 139285.1+/−215336.9, NS) were minimized during phase ON. Number of AF negatively correlated with %pacing (r=−0.457, p=0.01). Conclusions PA decreased AF when those were selectively turned on. Higher %pacing was effective to decrease AF regardless of PA. Carefully chosen PA maximizing %pacing will be effective for AF suppression.

P.1. Supraventricular ArrhythmiasP.1.2 Successful Radiofrequency Catheter Ablation of Nonreentrant Supraventricular Tachycardia Due to Simultaneous Conduction Through Dual Atrioventricular Nodal Pathways

Objectives We evaluated whether pacing algorithms (PA) triggered by onset mechanism (OM) of atrial fibrillation (AF) were actually effective. Methods Ten patients (5males, mean age 67.5+/−7.3years) who received Vitatrons Selection pacemaker with >1 AF during 3months after implantation were included. PA were turned off (phase OFF), selectively turned on based on OM of AF (phase ON), and turned on based on all 4 PA (phase ALL-ON) for 3months by crossover method. We compared atrial pacing dependency (%pacing), number of AF, cumulative AF duration, and number of PAC between each setting. The effect of %pacing on AF was evaluated. Result %pacing was greater during phases ON and ALL-ON (phases OFF: 55.6+/−34.7%, ON: 84.2+/−19.7%, ALL-ON: 90.1+/−14.7%, p=0.0004). Number of AF (229.6+/−381.1, 152.8+/−226.5, 318.3+/−577.7, NS), cumulative AF duration (8240+/−12308min, 4013.1+/−8290.5min, 8656.4+/−18071.2min, NS) and number of PAC (88705.6+/−150316.5, 41525.4+/−48130, 139285.1+/−215336.9, NS) were minimized during phase ON. Number of AF negatively correlated with %pacing (r=−0.457, p=0.01). Conclusions PA decreased AF when those were selectively turned on. Higher %pacing was effective to decrease AF regardless of PA. Carefully chosen PA maximizing %pacing will be effective for AF suppression.