A 62-year-old man presenting with congestive heart failure due to a fistula between an aortic pseudoaneurysm and the right pulmonary artery is described. The shunt occurred 4 years after aortic valve ...and supracoronary graft replacement and was diagnosed by transesophageal contrast echocardiography. After redo surgery the patient made an uneventful recovery.
Highlights • Recurrent events are common in patients with heart failure, though hardly analyzed • Recurrent events may reveal effects not seen by time-to-first event analysis • Gap-time method may be ...helpful to analyses recurrent events
Abstract We present a 44-year-old man with invasive aortic and tricuspid valve endocarditis complicated by electrical storm, which was immediately diagnosed and successfully treated due to the ...patient's telemetry electrocardiogram (ECG). This case highlights a rare but potentially fatal complication in patients with invasive endocarditis and the need for very careful clinical evaluation and monitoring of these patients.
Myocardial and Systemic Iron Depletion in Heart Failure Maeder, Micha T., MD; Khammy, Ouda, BSci; dos Remedios, Cris, PhD ...
Journal of the American College of Cardiology,
07/2011, Letnik:
58, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Objectives This study sought to determine the potential pathophysiological link between anemia and disease severity, and adverse outcome in heart failure (HF). Background Anemia frequently ...accompanies advanced HF; however, the pathophysiological mechanism responsible for the association between anemia and more severe HF remains uncertain. We hypothesized that a depletion of myocardial iron content may provide the biological link. Methods Complementary clinical and basic studies were performed. Hemodynamic, biochemical, and echocardiographic investigations were performed in 9 healthy controls and 25 patients with advanced HF (left ventricular ejection fraction: 23 ± 10%). Tissue iron content and type 1 transferrin receptor (Tfr1) expression were assessed in human myocardial tissue, and the regulation of Tfr1 expression was studied in isolated cardiomyocytes. Results HF patients displayed evidence of iron deficiency as measured by lower serum iron (p < 0.05) and transferrin saturation (TFS) (p < 0.05). When subclassified according to the presence of anemia, TFS was lower in anemic compared with nonanemic HF patients, whereas TFS in nonanemic HF patients was intermediate. In association, myocardial iron content was reduced in HF versus non-HF samples (0.49 ± 0.07 μg/g vs. 0.58 ± 0.09 μg/g, p < 0.05), and there was a significant reduction (p < 0.05) in the myocardial mRNA expression of Tfr1, which plays a key role in cellular iron transport. In the context of HF, catecholamines and aldosterone both down-regulated Tfr1 expression in isolated cardiomyocytes. Conclusions This study suggests the presence of iron depletion in the failing human heart, providing a potential link for the association between anemia and adverse prognosis in HF.
Invasive coronary angiography and computed tomography (CT) coronary angiography directly visualise coronary anatomy but do not provide information about the presence of inducible myocardial ...ischaemia. Due to its excellent negative predictive value CT coronary angiography is a suitable test to exclude significant coronary artery disease. However, given its high rate of false positive results particularly in the presence of significant coronary calcification CT coronary angiography only rarely is a real alternative to invasive coronary angiography in clinical practice. The coronary artery calcium score (CACS) is a surrogate for the extent of coronary atherosclerosis and a possible marker of biological age but does not provide any anatomical or pathophysiological information. In asymptomatic patients a CACS of zero is associated with a very low likelihood of a significant coronary stenosis and a good prognosis. However, this is not the case in symptomatic patients, and thus, CACS does not play a significant role in the diagnostic work-up in symptomatic patients in daily routine.
Tests for the diagnosis of coronary artery disease (CAD) rely on two main diagnostic principles, that is direct visualisation of coronary anatomy or detection of stress-induced myocardial ischaemia. ...Whether a given test is useful for the patient's management critically depends on the clinical context, that is pre-test probability for significant CAD. Not every test is suitable for every patient. Non-invasive tests have the highest diagnostic yield in patients with chest pain and intermediate pre-test probability. In these patients, tests typically confirm the presence of CAD or make it highly unlikely. In patients with low or high pre-test probability, non-invasive tests provide hardly any added diagnostic information. However, in patients with high pre-test probability of CAD, non-invasive tests are helpful for risk stratification. In asymptomatic patients, there is no established indication for any tests apart from calculation of a global cardiovascular risk based on traditional risk factors and initiation of primary preventive measures if appropriate.
The diagnostic principle of stress echocardiography and cardiac magnetic resonance imaging (CMR) for the diagnosis of coronary artery disease is based on the visualisation of ischaemia-induced wall ...motion abnormalities. From a logistic point of view, stress echocardiography is the easiest test given that it can be performed at bedside. Both stress echocardiography and stress CMR also permit direct visualisation of myocardial perfusion at rest and during pharmacological stress (typically adenosine) using contrast administration (microbubbles for stress echocardiography, gadolinium for stress CMR). These novel methods for the visualisation of myocardial perfusion seem to provide information similar to that obtained using myocardial perfusion imaging but these techniques (particularly myocardial perfusion echocardiography) are not broadly established in daily practice yet. Similar to other non-invasive tests stress echocardiography and stress CMR have the highest diagnostic yield in patients with intermediate probability of significant coronary artery disease.
The principle of exercise stress test and myocardial perfusions scintigraphy (MPS) is based on the detection of exercise-induced myocardial ischaemia by ECG and non-invasive assessment of myocardial ...perfusion respectively, MPS being the more sensitive method. The exercise stress test is the method of choice in patients with a normal resting ECG and good exercise tolerance, whereas MPS is a suitable test for patients with abnormal resting ECG and/or exercise intolerance. Stressors for MPS included exercise, pharmacological stress, or a combination. Both exercise stress test and MPS are suitable for the evaluation of patients with chest pain and intermediate pre-test probability of significant coronary artery disease. For patients with high pre-test probability, both tests are helpful for risk stratification. Neither test makes sense for the evaluation of patients with chest pain and low pre-test probability of significant coronary artery disease or unselected asymptomatic patients.
Lead Free Piezoelectric Materials Maeder, MDemartin; Damjanovic, D; Setter, N
Journal of electroceramics,
07/2004, Letnik:
13, Številka:
1-3
Journal Article
Recenzirano
Lead oxide based ferroelectrics, represented by lead zirconate titanate (Pb(Zr, Ti)O sub(3)) or PZT) are the most widely used materials for piezoelectric actuators, sensors and transducers due to ...their excellent piezoelectric properties. Considering lead toxicity, there is interest in developing piezoelectric materials that are biocompatible and environmentally friendlier. The low density of non-lead based materials can also be an advantage in transducers for underwater and medical imaging due to expected lower acoustical impedance. Another impetus for seeking alternative to lead based compositions is the need for piezoelectric materials for operation at high temperatures. Several classes of materials are now being reconsidered as potentially attractive alternatives to PZT for special applications. The potassium niobate family, KNbO sub(3), exhibits low dielectric constants, large thickness coupling coefficient along certain non-polar directions, and low density, all of which have advantages for high frequency transducer applications. Several compositions belonging to bismuth titanate family, Bi sub(4)Ti sub(3)O sub(12), such as SrTi sub(4)Bi sub(4)O sub(15), are promising candidates for high temperature applications. Lead free materials alone (eg. (Na sub(0.5)Bi sub(0.5))TiO sub(3)) or in solution with PT (BiScO sub(3) - PbTiO sub(3)) are also potentially interesting as they combine high piezoelectric activity and, in some cases, relatively high T sub(c). For these families of piezoelectric materials, the processing and piezoelectric response under different conditions of pressure, frequency, and temperature are presently much less understood than for the classical lead containing systems. In this presentation we review and discuss piezoelectric properties of selected lead free compositions (principally for members of the potassium niobate family and bismuth titanate layered compounds) in relation to structural and microstructural features as well as extrinsic contributions (domain walls displacement, conductivity) to their electromechanical properties. It is shown that it is possible to obtain remarkably stable piezoelectric response in some compositions, while others exhibit strong dependence of piezoelectric properties on driving field and frequency. Origins of these different behaviours are discussed.
PDF
