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Satomi K.,National Cerebral and Cardiovascular Center
Circulation Journal | Year: 2010

Pulmonary vein (PV) isolation is a cornerstone of atrial fibrillation (AF) ablation. This technique is now widely spread all over the world. Numerous studies have demonstrated that complete PV isolation with circular lesions has a better outcome in patients with paroxysmal and persistent AF. In contrast, it may lead to iatrogenic left atrial tachycardia (AT) as an adverse effect of the ablation. Three mechanisms of AT can develop after AF ablation, including macro-reentrant AT, focal AT and PV tachycardia. AT after AF ablation is predominantly related to the arrhythmogenicity of the PVs, lesions created by the ablation procedure and damaged atrial tissue from the persistent tachyarrhythmias. The 3-dimensional maps play an important role in clarifying the mechanism of the tachycardia and the optimal ablation site for ATs. Source

Anzai T.,National Cerebral and Cardiovascular Center
Circulation Journal | Year: 2013

After myocardial infarction (MI), inflammatory cells such as neutrophils, followed by monocytes and macrophages, infiltrate and phagocytose the necrotic tissues, as well as secreting a variety of inflammatory cytokines. The vulnerable myocardium, which consists of necrotic tissue and inflammatory cells, is susceptible to wall stress, resulting in infarct expansion. Subacute cardiac rupture is an extreme form of infarct expansion, whereas ventricular aneurysm is its chronic form and a trigger for subsequent left ventricular (LV) remodeling. Although post-infarction inflammation is essential for the healing process, excessive inflammation could play an important role in the development of LV remodeling. Increase in the C-reactive protein level, which reflects myocardial inflammation, is reported to be a useful predictive marker for cardiac rupture, ventricular aneurysm and LV remodeling. In addition, an increase in peripheral monocyte count is associated with a poor outcome after MI, and an animal study has demonstrated that granulocyte/macrophage-colony stimulating factor induction causes excessive macrophage infiltration in the infarcted area and worsening of LV remodeling. Recently, it was also found that dendritic cells play an important role in controlling excessive inflammation caused by monocytes/macrophages. Thus, inflammation that develops after MI is a doubleedged sword, and how to control inflammation to suppress pathological remodeling is an important issue to be considered in developing new treatment for heart failure. Source

Goto Y.,National Cerebral and Cardiovascular Center
Progress in Cardiovascular Diseases | Year: 2014

In Japan, metabolic risk factors have been increasing due to the westernization and urbanization of lifestyle. This justifiably raises a concern that the incidence of coronary heart disease (CHD) in Japan will increase over time, and indeed, recent epidemiological studies in Japan suggest the incidence of acute myocardial infarction (AMI) is increasing. Cardiac rehabilitation (CR) in Japan has been traditionally performed in the inpatient setting. To obtain reimbursement, a CR facility must fulfill certain criteria including being a medical institution with a cardiology/cardiac surgery section which has at least a cardiologist/cardiac surgeon and an experienced CR physician as full-time employees. These criteria create challenges to the availability of outpatient CR after hospital discharge. A recent analysis found outpatient CR participation rate was estimated to be between 3.8 and 7.6% in Japan. This review describes recent trends in the incidence of AMI and the current status of the use of CR in Japan. © 2014 Elsevier Inc. Source

Cardiac resynchronization therapy (CRT) improves heart failure symptoms, cardiac function and long-term prognosis. As a result, it has been established as a treatment for refractory heart failure by using a specialized pacemaker to restore coordinated ventricular contractions with pacing. Despite being an invasive treatment, however, the above effects are not observed in 30-45% of patients selected based on the standard criteria that includes New York Heart Association class III or IV heart failure, left ventricular ejection fraction ≤35%, and QRS duration ≥120 or 130 ms. From the fact that quantifiable resynchronization was associated with hemodynamic and clinical improvements, it should follow that mechanical dyssynchrony is a critical substrate for the benefits from CRT. The PROSPECT study unexpectedly demonstrated limitations of echocardiographic parameters using M-mode, pulsed-wave Doppler, and tissue Doppler imaging for accurately and reproducibly predicting response to CRT. However, advances in speckle tracking strain and real-time 3-D echocardiography have furthered the development of more sophisticated indices of dyssynchrony. Stress echocardiography might be useful for the detection of latent mechanical dyssynchrony in failing hearts. Because the substrate for CRT efficacy is multifactorial, a discriminant score that includes various clinical parameters and echocardiographic indices of mechanical dyssynchrony is needed to improve patient selection for CRT. Source

As a result of the advent and advances of multidetector row computed tomography (MDCT), coronary computed tomography (CT) has become popular and is performed at many institutions. Coronary CT is useful for diagnosing cases of moderate risk of coronary artery disease. On the other hand, it has been shown that most cardiac infarctions (=70%) occur from mild to moderate stenoses (ie, ≤50%). Thus, conventional cardiac angiographic findings alone cannot predict developing cardiac infarction. The mechanism by which ruptured plaque and subsequent thrombus leads to developing cardiac infarction has been shown, so determining which plaque tended to rupture, the so-called "vulnerable plaque", and treatment of it are in the spotlight. Coronary CT can visualize and evaluate non-invasively not only the lumen but also the arterial wall. The findings that are suspicious for vulnerable plaque on coronary CT are low-density plaque, positive remodeling, and spotty calcification. However, CT is restricted in its resolution (temporal, spatial and contrast resolution). The diagnosis of vulnerable plaque by CT is still challenging. This report demonstrates the present conditions and problems for the characterization of the plaque using coronary CT. Source

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