Biomedical subjects
Publications and source records attributed to A Boccanelli.
A case of double aortic arch with severe congenital mitral incompetence and mild pulmonary arteries stenosis is described. A possible embriogenetic explanation of the anomaly is discussed in the light of preferential foetal blood flows.
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Nine patients with aortic root dilatation without dissection and four patients with a dissecting aneurysm of the ascending aorta were studied with single-plane echocardiography. Previously reported echocardiographic findings, which have been shown to be similar in these two groups of patients, are confirmed. In addition to (a) aortic root dilatation, (b) thickening of the anterior and/or the posterior aortic wall, and (c) the multiple parallel echoes within the widened aortic walls, which are all considered to be not specific signs of dissection, the authors outline the presence of some specific echocardiographic patterns in patients with a dissecting hematoma of the ascending aorta. These include: 1) the loss of contiguity between the inner borders of the anterior aortic wall and the interventricular septum when the dissection is confined to the anterior wall of the aorta; 2) the loss of contiguity between the inner and/or outer borders of the posterior aortic wall and the mitral anulus if the hematoma extends to the posterior wall of the aorta.
An unexpected clinical presentation of an unusual pacing failure has been observed in two patients who had had recent implantation of a pacemaker model whose electrodes were made of an nonnoble metal alloy. An intermittent current leakage from the output capacitor and possibly from the output transistor accounted for electrolytic corrosion at the anode, premature depletion of the battery, heart muscle damage and for massive gas generation around electrodes, leading to right ventricular perforation, pneumopericardium and subcutaneous thoracic emphysema. The occurrence of this syndrome shows that, if nonnoble metals are used for electrodes, more attention should be addressed to those conditions which add to polarization problems, as is current leakage from the output circuit components.
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Cardiac remodeling is a physiologic or pathologic condition that occurs after myocardial infarction, pressure overload, myocardial inflammatory diseases, idiopathic dilated cardiomyopathy or volume overload. In spite of different etiologies, molecular, biochemical and mechanical processes are the same. The change in left ventricular function brings about a complex neuro-hormonal disorder, and disease progression is due to the combined action of several biological factors with toxic effects on the heart and vessels. The renin-angiotensin-aldosterone system (RAAS) is very important in this process, through the effects on hydro-saline balance or through direct processes on myocardium. A direct effect of aldosterone in myocardial fibrosis after the detection of heart tissue aldosterone production has been demonstrated. In the past, the attention of physicians and researchers was focused on angiotensin II inhibition; and therefore, on angiotensin-converting enzyme (ACE) inhibitors, considering them sufficient to antagonize the effects of aldosterone. Nevertheless, this theory has been confuted in recent studies, with the evidence of elevated plasmatic aldosterone levels in patients treated with ACE-inhibitors and angiotensin receptor blockers. This phenomenon probably is due to the activation of secondary ACTH mediated pathways of trial aldosterone production. It has been demonstrated that aldosterone receptor inhibition is effective in reducing cardiac remodeling and mortality. AREA-IN CHF is the first multicentric, double blind, randomized, placebo control study to compare canrenone, an aldosterone receptor blocker, with placebo. The primary end point is the echocardiographic evaluation of left ventricular remodeling. Secondary end points are left ventricular end-systolic volume, ejection fraction, diastolic filling patterns, NYHA functional class, and mortality and hospitalizations of cardiac origin. In addition, bio-humoral effects of aldosterone receptor blocker therapy will be investigated. The study results will be available at the end of 2006.