Effect of Reverse Vessel Remodeling on Regression of Coronary Atherosclerosis in Patients Treated With Aggressive Lipid- and Blood Pressure-Lowering Therapy　- Insight From MILLION Study.

BACKGROUND: The MILLION study, a prospective randomized multicenter study, revealed that lipid and blood pressure (BP)-lowering therapy resulted in regression of coronary plaque as determined by intravascular ultrasound (IVUS). In the present study we performed additional analysis to investigate the associated factors with regression of coronary plaque.Methods and Results:We investigated serial 3D IVUS images from 68 patients in the MILLION study. Standard IVUS parameters were assessed at both baseline and follow-up (18-24 months). Volumetric data were standardized by length as normalized volume. In patients with plaque regression (n=52), plaque volumenormalizedsignificantly decreased from 64.8 to 55.8 mm3(P<0.0001) and vessel volumenormalizedsignificantly decreased from 135.0 to 127.5 mm3(P=0.0008). There was no difference in lumen volumenormalizedfrom 70.1 to 71.8 mm3(P=0.27). There were no correlations between % changes in vessel volume and cholesterol or BP. On the other hand, negative correlations between % change in vessel volume and vessel volumenormalizedat baseline (r=-0.352, P=0.009) or plaque volumenormalizedat baseline (r=-0.336, P=0.01) were observed. CONCLUSIONS: The current data demonstrated that in patients with plaque regression treated by aggressive lipid and BP-lowering therapy, the plaque regression was derived from reverse vessel remodeling determined by vessel volume and plaque burden at baseline irrespective of decreases in lipids and BP.

Overview of the 81st Annual Scientific Meeting of the Japanese Circulation Society　- Cardiovascular Medicine for the Next Generation.

The 81stAnnual Scientific Meeting of the Japanese Circulation Society was held in Kanazawa, Japan, on March 17-19, 2017 under a miraculously clear sky. The frontlines of healthcare and medicine are dramatically changing. Thus, "Cardiovascular Medicine for Next Generation" was chosen as the main theme of this meeting. The program was constructed around major identified issues, including renewal of our understanding of basic cardiovascular medicine, translational research, and preventive molecular medicine, all of which are anticipated to transcend the medical field over the next generation. Despite the provincial location, 15,672 participants, including more than 400 from overseas countries, attended the 3-day meeting, and there were in-depth discussions in the various sessions. In particular, to our great pleasure, Her Imperial Highness Princess Takamado kindly attended the opening ceremony and extended congratulations to us. The meeting successfully completed and we sincerely appreciate the great cooperation and support from all affiliates.

Impact of combined lipid lowering and blood pressure control on coronary plaque: myocardial ischemia treated by percutaneous coronary intervention and plaque regression by lipid lowering and blood pressure controlling assessed by intravascular ultrasonography (MILLION) study.

The aim of the study was to elucidate the aggressive reduction of both low-density lipoprotein cholesterol (LDL-C) and blood pressure (BP) reduced coronary atherosclerotic plaque volume compared with a standard treatment of LDL-C and BP in Japanese patients with coronary artery disease (CAD). This study is a prospective, randomized, and open-labelled with a blind-endpoint evaluation study. A total of 97 patients (81 men, mean age 62.0 ± 9.6) with CAD undergoing intravascular ultrasonography (IVUS)-guided percutaneous coronary intervention (PCI) were randomized, and 68 patients had IVUS examinations at baseline and at 18-24 months follow-up. Patients were randomly assigned to standard or aggressive strategies targeting LDL-C and a BP of 100 mg/dL and 140/90 mmHg vs. 70 mg/dL and 120/70 mmHg, respectively. The primary endpoint was the percent change in coronary plaque volume. Both standard and aggressive strategies succeeded to achieve target levels of LDL-C and BP; 74.9 ± 14.7 vs. 63.7 ± 11.9 mg/dL (NS) and 124.1 ± 9.4/75.8 ± 7.7 vs. 113.6 ± 9.6/65.8 ± 9.4 mmHg (systolic BP; NS, diastolic BP; p < 0.05), respectively. Both groups showed a significant reduction in the coronary plaque volume of -9.4 ± 10.7% and -8.7 ± 8.6% (NS) in standard and aggressive therapies, respectively. Both standard and aggressive intervention significantly regressed coronary plaque volume by the same degree, suggesting the importance of simultaneous reductions of LDL-C and BP for prevention of CAD.

Impact of combined lipid lowering with blood pressure control on coronary plaque regression: rationale and design of MILLION study.

A line of epidemiological studies suggests that the accumulation of coronary risk factors promotes the progression of coronary atherosclerosis. Recent clinical studies showed that aggressive low-density lipoprotein (LDL) cholesterol-lowering therapy using statins could regress coronary atheroma and reduce major cardiovascular events. Additionally, therapy that controlled amlodipine-based blood pressure reduced major cardiovascular events in patients with hypertension compared with an atenolol-based regimen. An open-label randomized multicenter study is primarily planned to evaluate the changes in coronary atheroma volume using intravascular ultrasonography 18-24 months after intensive lowering of LDL-cholesterol and blood pressure compared with a standard therapy indicated by current guidelines in Japanese patients with coronary artery disease (CAD). The secondary endpoints include changes in serum lipid levels, inflammatory markers, glucose markers and blood pressure. In total, 100 subjects with CAD who are undergoing percutaneous coronary intervention will be tested. The MILLION study will provide new evidence and therapeutic standards for the prevention of CAD in Japanese patients by controlling both LDL-C levels and blood pressure.

Current perspectives in genetic cardiovascular disorders: from basic to clinical aspects.

We summarize recent advances in the clinical genetics of hypercholesterolemia, hypertrophic cardiomyopathy (HCM), and lethal arrhythmia, all of which are monogenic cardiovascular diseases being essential to understanding the heart and circulatory pathophysiology. Among the issues of hypercholesterolemia which play a pivotal role in development of vascular damages, familial hypercholesterolemia is the common genetic cardiovascular disease; in addition to identifying the gene mutation coding low-density lipoprotein receptor, lipid kinetics in autosomal recessive hypercholesterolemia as well as in proprotein convertase subtilisin/kexin 9 gene mutation were recently demonstrated. As for HCM, some gene mutations were identified to correlate with clinical manifestations. Additionally, a gene polymorphism of the renin-angiotensin system in development of heart failure was identified as a modifier gene. The lethal arrhythmias such as sudden death syndromes, QT prolongation, and Brugada syndrome were found to exhibit gene mutation coding potassium and/or sodium ion channels. Interestingly, functional analysis of these gene mutations helped to identify the role of each gene mutation in developing these cardiovascular disorders. We suggest considering the genetic mechanisms of cardiovascular diseases associated with hyperlipidemia, myocardial hypertrophy, or lethal arrhythmia in terms of not only clinical diagnosis but also understanding pathophysiology of each disease with therapeutic aspects.

Intravascular ultrasound appearance of scattered necrotic core as an index for deterioration of coronary flow during intervention in acute coronary syndrome.

In acute coronary syndrome (ACS) patients with deterioration of coronary flow during percutaneous coronary intervention (PCI), a scattered necrotic core pattern (SNC) is observed by intravascular ultrasound virtual histology (VH-IVUS). The purpose of this study was to evaluate the impact of SNC on deterioration of coronary flow during PCI in ACS. A total of 38 ACS patients were imaged using VH-IVUS before PCI. In addition to conventional definitions of thin-cap fibroatheroma by VH-IVUS (ID-TCFA), the SNC was defined as necrotic core foci with a maximum diameter of <14 pixels on a 400 × 400 VH-IVUS image in the presence of >50% plaque burden except in the ID-TCFA frame. Patients were divided into deterioration of coronary flow group (n = 15) and normal-reflow group (n = 23). The incidence of residual thrombus and plaque rupture, the external elastic membrane, plaque and fibrous volumes, the incidence of ID-TCFA and the average number of SNC per frame was significantly greater in deterioration of coronary flow group than in normal-reflow group (all parameters P < 0.05). Multivariate analysis revealed that the average number of SNC per frame was independently associated with deterioration of coronary flow in ACS patients (odds ratio 1.18, P < 0.05). In conclusion, an increased number of SNC is associated with deterioration of coronary flow during PCI in ACS patients.

A KCR1 variant implicated in susceptibility to the long QT syndrome.

The acquired long QT syndrome (aLQTS) is frequently associated with extrinsic and intrinsic risk factors including therapeutic agents that inadvertently inhibit the KCNH2 K(+) channel that underlies the repolarizing I(Kr) current in the heart. Previous reports demonstrated that K(+) channel regulator 1 (KCR1) diminishes KCNH2 drug sensitivity and may protect susceptible patients from developing aLQTS. Here, we describe a novel variant of KCR1 (E33D) isolated from a patient with ventricular fibrillation and significant QT prolongation. We recorded the KCNH2 current (I(KCNH2)) from CHO-K1 cells transfected with KCNH2 plus wild type (WT) or mutant KCR1 cDNA, using whole cell patch-clamp techniques and assessed the development of I(KCNH2) inhibition in response to well-characterized KCNH2 inhibitors. Unlike KCR1 WT, the E33D variant did not protect KCNH2 from the effects of class I antiarrhythmic drugs such as quinidine or class III antiarrhythmic drugs including dofetilide and sotalol. The remaining current of the KCNH2 WT+KCR1 E33D channel after 100 pulses in the presence of each drug was similar to that of KCNH2 alone. Simulated conditions of hypokalemia (1mM [K(+)](o)) produced no significant difference in the fraction of the current that was protected from dofetilide inhibition with KCR1 WT or E33D. The previously described α-glucosyltransferase activity of KCR1 was found to be compromised in KCR1 E33D in a yeast expression system. Our findings suggest that KCR1 genetic variations that diminish the ability of KCR1 to protect KCNH2 from inhibition by commonly used therapeutic agents constitute a risk factor for the aLQTS.

Impact of anti-apoptotic and anti-oxidative effects of bone marrow mesenchymal stem cells with transient overexpression of heme oxygenase-1 on myocardial ischemia.

Although mesenchymal stem cells (MSCs) have therapeutic potential for tissue injury, intolerance and poor cell viability limit their reparative capability. Therefore, we examined the impact of bone marrow-derived MSCs, in which heme oxygenase-1 (HO-1) was transiently overexpressed, on the repair of an ischemic myocardial injury. When MSCs and HO-1-overexpressed MSCs (MSC(HO-1)) were exposed to serum deprivation/hypoxia or H(2)O(2)-induced oxidative stress, MSC(HO-1) exhibited increased resistance to cell apoptosis compared with MSCs (17 +/- 1 vs. 30 +/- 2%, P < 0.05) and were markedly resistant to cell death (2 +/- 1 vs. 32 +/- 2%, P < 0.05). Under these conditions, vascular endothelial growth factor (VEGF) production was 2.1-fold greater in MSC(HO-1) than in MSCs. Pretreatment of MSCs and MSC(HO-1) with phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (Akt) pathway inhibitors such as LY-294002 (50 muM) or wortmannin (100 nM) significantly decreased VEGF production. In a rat infarction model with MSCs or MSC(HO-1) (5 x 10(6) +/- 0.1 x 10(6) cells/rat) transplantation, the number of TdT-mediated dUTP nick end-labeling-positive cells was significantly lower in the MSC(HO-1) group than in the MSC group (12.1 +/- 1.0 cells/field vs. 26.5 +/- 2.6, P < 0.05) on the 4th day after cell transplantation. On the 28th day, increased capillary density associated with decreased infarction size was observed in the MSC(HO-1) group (1,415 +/- 47/mm(2) with 21.6 +/- 2.3%) compared with those in the MSCs group (1,215 +/- 43/mm(2) with 28.2 +/- 2.3%, P < 0.05), although infarction size relative to area at risk was not different in each group at 24 h after transplantation. These results demonstrate that MSC(HO-1) exhibit markedly enhanced anti-apoptotic and anti-oxidative capabilities compared with MSCs, thus contributing to improved repair of ischemic myocardial injury through cell survival and VEGF production associated with the PI 3-kinase/Akt pathway.

An enhanced device for transluminal retrieval of vascular stents without surgical procedures: experimental studies.

BACKGROUND: Although efforts have been focused on developing endovascular procedures by which intravascular devices such as stents could be effectively deployed, few data exist regarding devices for the nonsurgical retrieval of deployed stents. Therefore, we designed to enable retrieval of deployed stents without a surgical procedure. METHODS: The device consisted of four components: ultra-low profile forceps with 2.0 mm in diameter, conducting shaft with 1.8 mm in diameter, control handle by which the forceps is opened or closed, and a covering sheath. This device was designed to advance into the vessel lumen along a 0.014-inch guidewire by over the wire fashion. RESULTS: The forceps could firmly catch nonexpanded as well as expanded tubular-type stents with open cells in an in vitro model that was 4.0 mm in diameter. Then, we used this device in porcine renal arteries with 2.5-5.0 mm in diameter. At first, a fragmented 0.014-inch guidewire could be safely removed without vessel damage that was confirmed by intravascular ultrasound. This device could successfully remove four of five inappropriately and 11 of 14 appropriately deployed stents. Under these conditions, intravascular ultrasound demonstrated minor vessel wall dissection in two-third of cases. CONCLUSIONS: These results demonstrate that the present device can be used for transluminal removal of foreign bodies such as nonexpanded as well as expanded stents in acute phase. Further miniaturization may enable using this type of device in the renal as well as coronary arteries.

Impact of renin-angiotensin system polymorphisms on development of systolic dysfunction in hypertrophic cardiomyopathy. Evidence from a study of genotyped patients.

BACKGROUND: Although the renin-angiotensin system (RAS) can affect the development of left ventricular (LV) hypertrophy, few data exist regarding the relationships between RAS polymorphisms and alteration of LV function. The effect of RAS polymorphisms on LV function in genotyped hypertrophic cardiomyopathy (HCM) was examined in the present study. METHODS AND RESULTS: The study group comprised 126 carriers with sarcomere gene mutations from 49 HCM families (64 males, mean age 51±21 years). LV morphology and function were evaluated by echocardiography. In angiotensin-converting enzyme (ACE) insertion/deletion (I/D), the D allele (n=81) exhibited significantly larger LV end-systolic dimension (LVDs) (32±11mm) and lower ejection fraction (56±15%) than those with the II genotype (28±7mm and 62±12%, respectively, P<0.05; n=45). Although angiotensin II type 1 receptor (AT(1)-R) A/C(1166) polymorphism did not affect echocardiographic parameters, the presence of the ACE D allele with the AT(1)-R C(1166) allele (n=9) was associated with larger LVDs (37±17mm) and lower ejection fraction (48±20%) compared with other genotypes (30±9mm and 58±14%, respectively, P<0.05; n=117). Under these conditions, severe LV hypertrophy was frequently associated with LV wall thinning. CONCLUSIONS: The presence of both the ACE D and AT(1)-R C(1166) allele is associated with LV dilation with systolic dysfunction in genotyped HCM. In addition to the severity of LV hypertrophy, screening for these RAS polymorphisms could contribute to further risk stratification of patients with HCM, although other genetic polymorphisms should be further examined.

Hokuriku-plus familial hypercholesterolaemia registry study: rationale and study design.

INTRODUCTION: Familial hypercholesterolaemia (FH) is an autosomal-dominant inherited genetic disease. It carries an extremely high cardiovascular risk associated with significantly elevated low-density lipoprotein (LDL) cholesterol. The diagnostic rate of this disease in some European nations is quite high, due to the presence of multiple prospective registries. On the other hand, few data-and in particular multicentre data-exist regarding this issue among Japanese subjects. Therefore, this study intends to assemble a multicentre registry that aims to comprehensively assess cardiovascular risk among Japanese FH patients while taking into account their genetic backgrounds. METHODS AND ANALYSIS: The Hokuriku-plus FH registry is a prospective, observational, multicentre cohort study, enrolling consecutive FH patients who fulfil the clinical criteria of FH in Japan from 37 participating hospitals mostly in Hokuriku region of Japan from April 2020 to March 2024. A total of 1000 patients will be enrolled into the study, and we plan to follow-up participants over 5 years. We will collect clinical parameters, including lipids, physical findings, genetic backgrounds and clinical events covering atherosclerotic and other important events, such as malignancies. The primary endpoint of this study is new atherosclerotic cardiovascular disease (ASCVD) events. The secondary endpoints are as follows: LDL cholesterol, secondary ASCVD events and the occurrence of other diseases including hypertension, diabetes and malignancies. ETHICS AND DISSEMINATION: This study is being conducted in compliance with the Declaration of Helsinki, the Ethical Guidelines for Medical and Health Research Involving Human Subjects, and all other applicable laws and guidelines in Japan. This study protocol has been approved by the Institutional Review Board at Kanazawa University. We will disseminate the final results at international conferences and in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: UMIN000038210.

Long QT syndrome and associated gene mutation carriers in Japanese children: results from ECG screening examinations.

LQTS (long QT syndrome) is caused by mutations in cardiac ion channel genes; however, the prevalence of LQTS in the general population is not well known. In the present study, we prospectively estimated the prevalence of LQTS and analysed the associated mutation carriers in Japanese children. ECGs were recorded from 7961 Japanese school children (4044 males; mean age, 9.9+/-3.0 years). ECGs were examined again for children who had prolonged QTc (corrected QT) intervals in the initial ECGs, and their QT intervals were measured manually. An LQTS score was determined according to Schwartz's criteria, and ion channel genes were analysed. In vitro characterization of the identified mutants was performed by heterologous expression experiments. Three subjects were assigned to a high probability of LQTS (3.5< or = LQTS score), and eight subjects to an intermediate probability (1.0< LQTS score < or =3.0). Genetic analysis of these II subjects identified three KCNH2 mutations (M124T, 547-553 del GGCGGCG and 2311-2332 del/ins TC). In contrast, no mutations were identified in the 15 subjects with a low probability of LQTS. Electrophysiological studies showed that both the M124T and the 547-553 del GGCGGCG KCNH2 did not suppress the wild-type KCNH2 channel in a dominant-negative manner. These results demonstrate that, in a random sample of healthy Japanese children, the prevalence of a high probability of LQTS is 0.038% (three in 7961), and that LQTS mutation carriers can be identified in at least 0.038% (one in 2653). Furthermore, large-scale genetic studies will be needed to clarify the real prevalence of LQTS by gene-carrier status, as it may have been underestimated in the present study.

Impact of QT variables on clinical outcome of genotyped hypertrophic cardiomyopathy.

BACKGROUND: Although QT variables such as its interval and/or dispersion can be clinical markers of ventricular tachyarrhythmia, few data exist regarding the role of QT variables in genotyped hypertrophic cardiomyopathy (HCM). Therefore, we analyzed QT variables in genotyped subjects with or without left ventricular hypertrophy (LVH). METHODS: QT variables were analyzed in 111 mutation and 43 non-mutation carriers who were divided into three groups: A, those without ECG abnormalities and echocardiographically determined LVH (wall thickness > or =13 mm); B, those with ECG abnormalities but LVH; and C, those with ECG abnormalities and LVH. We also examined clinical outcome of enrolled patients. RESULTS: Maximal LV wall thickness in group C (19.0 +/- 4.3 mm, mean +/-SD) was significantly greater than that in group A (9.2 +/- 1.8) and group B (10.4 +/- 1.8). Under these conditions, maximum QTc interval and QT dispersion were significantly longer in group C than those in group A (438 +/- 38 ms vs 406 +/- 30 and 64 +/- 31 vs 44 +/- 18, respectively; P < 0.05). QTc interval and QT dispersion in group B (436 +/- 50 and 64 +/- 22 ms) were also significantly greater than those in group A. During follow-up periods, four sudden cardiac deaths and one ventricular fibrillation were observed in group C, and two nonlethal ventricular tachyarrhythmias were observed in group B. CONCLUSIONS: Patients with HCM-related gene mutation accompanying any ECG abnormalities frequently exhibited impaired QT variables even without LVH. We suggest that careful observation should be considered for those genotyped subjects.

Low Baseline High-Sensitive C-Reactive Protein is Associated with Coronary Atherosclerosis Regression: Insights from the MILLION Study.

AIM: The prospective, randomized, multicenter Myocardial Ischemia Treated with Percutaneous Coronary Intervention and Plaque Regression by Lipid Lowering & Blood Pressure Controlling assessed by Intravascular Ultrasonography (MILLION) study demonstrated that combined treatment with atorvastatin and amlodipine enhanced coronary artery plaque regression. Although the baseline high-sensitive C-reactive protein (hs-CRP) reportedly plays an important role in atherogenesis, few data exist regarding the relationship between hs-CRP and plaque regression in patients receiving a combined atorvastatin and amlodipine therapy. METHODS: A total of 68 patients (male, 55; mean age, 64.2 years) with baseline and follow-up 3-dimensional intravascular ultrasound examinations in the MILLION study were stratified by baseline hs-CRP level quartiles. The serial measurements of lipid, blood pressure, and percentage changes in the plaque volume were compared between the groups, and the factors associated with the percentage change in the plaque volume were assessed. RESULTS: There were no significant between-group differences in the extent of change in low-density lipoprotein cholesterol (LDL-C) or systolic and diastolic blood pressure after 18-24 months of treatment. The percentage change in the plaque volume showed a linear association with the baseline hs-CRP (p for trend ＜0.05); however, there was no correlation with changes in LDL-C or systolic and diastolic blood pressure. In the multiple regression analysis, the baseline hs-CRP level was independently associated with the percentage change in the plaque volume (ß=0.29, p=0.022). CONCLUSIONS: Coronary plaque regression was associated with the baseline hs-CRP level in patients treated with a combined lipid- and blood pressure-lowering therapy.

Expression and function of ephrin-B1 and its cognate receptor EphB2 in human atherosclerosis: from an aspect of chemotaxis.

Although several cytokines and chemokines have been demonstrated to play pivotal roles in the pathophysiological conditions of atherosclerosis, few findings exist regarding the expression and function of cytokine-modulating molecules such as ephrin-Bs and their cognate receptors, EphBs, in human atherosclerosis. Therefore, in the present study, we screened novel genes modulating atherogenesis by cDNA array and quantitatively determined them by real-time RT (reverse transcription)-PCR in human carotid atherosclerotic plaques. Ephrin-B1 and EphB2, key regulators of embryogenesis, were significantly up-regulated in plaques compared with those in adjacent control tissues [ephrin-B1, 0.638+/-0.106 compared with 0.831+/-0.152, or 130% (P<0.05); EphB2, 1.296+/-0.281 compared with 2.233+/-0.506, or 172% (P<0.05)]. Immunohistological analysis demonstrated that both ephrin-B1 and EphB2 were expressed in macrophages and T-lymphocytes in plaques as well as in monocytes, T-lymphocytes and arterial endothelial cells isolated from healthy adults. Interestingly, the extracellular domains of ephrin-B1 and EphB2, the expression of which were both enhanced in stimulated THP-1 cells, significantly inhibited spontaneous (22.5 and 27.6% respectively; P<0.01) and MCP-1 (monocyte chemoattractant protein-1)-dependent (29.7 and 22.6% respectively; P<0.01) migration of monocytes. In conclusion, these results demonstrate that ephrin-B1 and EphB2 are overexpressed in atherosclerotic tissue and might locally regulate cell migration, possibly through modulating cytokine-related chemotaxic activity; however, the functional role of these molecules in atherogenesis should be investigated further.

A novel beta-myosin heavy chain gene mutation, p.Met531Arg, identified in isolated left ventricular non-compaction in humans, results in left ventricular hypertrophy that progresses to dilation in a mouse model.

Mutations in the betaMHC (beta-myosin heavy chain), a sarcomeric protein are responsible for hypertrophic and dilated cardiomyopathy. However, the mechanisms whereby distinct mutations in the betaMHC gene cause two kinds of cardiomyopathy are still unclear. In the present study we report a novel betaMHC mutation found in a patient with isolated LVNC [LV (left ventricular) non-compaction] and the phenotype of a mouse mutant model carrying the same mutation. To find the mutation responsible, we searched for genomic mutations in 99 unrelated probands with dilated cardiomyopathy and five probands with isolated LVNC, and identified a p.Met531Arg mutation in betaMHC in a 13-year-old girl with isolated LVNC. Next, we generated six lines of transgenic mice carrying a p.Met532Arg mutant alphaMHC gene, which was identical with the p.Met531Arg mutation in the human betaMHC. Among these, two lines with strong expression of the mutant alphaMHC gene were chosen for further studies. Although they did not exhibit the features characteristic of LVNC, approx. 50% and 70% of transgenic mice in each line displayed LVH (LV hypertrophy) by 2-3 months of age. Furthermore, LVD (LV dilation) developed in approx. 25% of transgenic mice by 18 months of age, demonstrating biphasic changes in LV wall thickness. The present study supports the idea that common mechanisms may be involved in LVH and LVD. The novel mouse model generated can provide important information for the understanding of the pathological processes and aetiology of cardiac dilation in humans.

Assessment of QT intervals and prevalence of short QT syndrome in Japan.

BACKGROUND: Long QT syndrome causes ventricular tachyarrhythmias and sudden death. Recently, a short QT interval has also been shown to be associated with an increased risk of tachyarrhythmia and sudden death. However, the prevalence of short QT syndrome is not well-known. HYPOTHESIS: The aim of this study was to assess the distribution of corrected QT intervals (QTc) and prevalence of short QT syndrome. METHODS: This study comprised 12,149 consecutive subjects who received a consultation at Kanazawa University Hospital, Kanazawa, Japan, and had an electrocardiogram (ECG) between February 2003 and May 2004. Of these subjects, 1,165 subjects were excluded because of inappropriate ECGs, while the remaining 10,984 subjects had their last-recorded ECGs analyzed. RESULTS: The QTc values showed a nearly normal distribution (408 +/- 25 msec(1/2)), and were significantly longer in females (412 +/- 24 msec(1/2)) than in males (404 +/- 25 msec(1/2)) (p < 0.05). Among 5,511 males, 69 subjects (1.25%) exhibited QTc < 354 msec(1/2) (2 standard deviations [SDs] below the mean in males), and among 5,473 females, 89 subjects (1.63%) exhibited QTc < 364 msec(1/2) (2 SDs below the mean in females). Only 3 subjects (0.03% in all subjects and 0.05% in males) exhibited QTc < 300 msec(1/2), however, none had clinical symptoms of short QT syndrome. CONCLUSIONS: Short QT syndrome may be very rare.

Limited effects of long-term enzyme replacement therapy on the cardiac conduction system in Fabry disease.

The long-term effects of enzyme replacement therapy (ERT) on cardiac function and the conduction system in Fabry disease are not clearly understood. We report a case of a 48-year-old man with non-classical Fabry disease treated with ERT for 11 years. He was diagnosed with Fabry disease at age 27 years based on the presence of decreased alpha-galactosidase A activity in the peripheral leukocytes and of the causal alpha-galactosidase A mutation (Val339Gln). Subsequently, peritoneal dialysis was initiated for renal failure at age 35 years. ERT was initiated at age 39 years to halt the progression of cardiac dysfunction. Electrical conduction disturbances progressed gradually to complete atrioventricular block with atrial standstill during 9 years of ERT despite the lack of progression of ventricular hypertrophy. Although he underwent permanent pacemaker implantation to prevent sudden cardiac death, the atrioventricular junctional rhythm remained, thereby lowering the ventricular pacing rate. Based on this case, we recognize that the effects of ERT are limited for inhibiting the progression of Fabry disease and especially for inhibiting arrhythmia and conduction disturbances. Early diagnosis of Fabry disease and early initiation of ERT might be the key to further improvements in this disease and its associated conditions. .

Differences in the diagnostic value of various criteria of negative T waves for hypertrophic cardiomyopathy based on a molecular genetic diagnosis.

Differences in the diagnostic value of a variety of definitions of negative T waves for HCM (hypertrophic cardiomyopathy) have not yet been clarified, resulting in a number of definitions being applied in previous studies. The aim of the present study was to determine the most accurate diagnostic definition of negative T waves for HCM in genotyped populations. Electrocardiographic and echocardiographic findings were analysed in 161 genotyped subjects (97 carriers and 64 non-carriers). We applied three different criteria that have been used in previous studies: Criterion 1, negative T wave >10 mm in depth in any leads; Criterion 2, negative T wave >3 mm in depth in at least two leads; and Criterion 3, negative T wave >1 mm in depth in at least two leads. Of the three criteria, Criterion 3 had the highest sensitivity (43% compared with 5 and 26% in Criterion 1 and Criterion 2 respectively; P<0.0001) and retained a specificity of 95%, resulting in the highest accuracy. In comparison with abnormal Q waves, negative T waves for Criterion 3 had a lower sensitivity in detecting carriers without LVH (left ventricular hypertrophy) (12.9% for negative T waves compared with 22.6% for abnormal Q waves). On the other hand, in detecting carriers with LVH, the sensitivity of negative T waves increased in a stepwise direction with the increasing extent of LVH (P<0.001), whereas there was less association between the sensitivity of abnormal Q waves and the extent of LVH. In conclusion, Criterion 3 for negative T waves may be the most accurate definition of HCM based on genetic diagnoses. Negative T waves may show different diagnostic value according to the different criteria and phenotypes in genotyped populations with HCM.

Acute necrotizing eosinophilic myocarditis complicated by complete atrioventricular block promptly responded to glucocorticoid therapy.

Acute myocarditis is frequently accompanied with conduction disturbances. Complete atrioventricular (AV) block may occur in acute myocarditis, but rarely in eosinophilic myocarditis. Acute necrotizing eosinophilic myocarditis, the most severe form of eosinophilic myocarditis, is generally fatal, and rarely complicated by complete AV block. We report a case of a 66-year-old woman with acute necrotizing eosinophilic myocarditis who presented with general malaise and nausea. She suddenly fell into cardiogenic shock because of complete AV block and worsened heart failure. Ultrasound cardiography revealed pericardial effusion, edematous myocardium, and reduced contractility of the left ventricle. The biopsied specimens showed marked interstitial infiltration with predominant eosinophils accompanied with myocardial necrosis. Oral administration of glucocorticoid in moderate dose promptly resolved the complete AV block, her clinical symptoms, and cardiac function. We recognized that acute necrotizing eosinophilic myocarditis can be complicated by complete AV block. Steroid therapy could be effective in the treatment of conduction disturbance as well as myocardial inflammation. .