Herz
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The bidirectional cavopulmonary anastomosis is a surgical procedure suitable for patients with cyanotic congenital heart disease and univentricular physiology. This operation is able to increase the effective pulmonary blood flow without any additional load on the cardiac work and without any further distortion on the pulmonary artery branches. The cavopulmonary anastomosis can represent the first stage for patients destined for Fontan repair or a definitive palliative operation in high risk Fontan candidates. ⋯ Despite these data and a normal ambulatory ECG, spirometry and echocardiographic analysis, the stress test showed discouraging results. In fact, mean work time and peak heart rate were significantly different from normal values showing an impaired functional capacity of these children. In conclusion we think that bidirectional cavopulmonary anastomosis can not be considered an adequate definitive palliation but it represents a very good stage to preserve the pulmonary arteries and to prepare the systemic ventricle towards the Fontan repair.
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It has been previously demonstrated that radiofrequency (RF) energy can be safely applied to successfully eliminate accessory pathways in patients with the Wolff-Parkinson-White syndrome. This technique may also be used to successfully eliminate atrioventricular (AV) nodal reentrant tachycardia by elimination of either the fast or slow AV nodal pathways. However, RF energy has achieved only limited success in eliminating ventricular tachycardia (VT) in patients with structural heart disease, such as coronary artery disease and dilated cardiomyopathy. ⋯ It also resulted in no detectable change in cardiac function by Doppler echocardiography. Based on these findings, we conclude that RF catheter ablation of VT in patients without structural heart disease was highly effective and safe. It may therefore be considered as early therapy in these patients.
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Stroke is caused by intracerebral or subarachnoid hemorrhage in about 15% of clinical presentations and the remaining 85% result from ischemia. About 15% of ischemic strokes are caused by emboli arising from the heart. In younger patients (18 to 50 years) with ischemic strokes or transient ischemic attacks (TIA), the incidence of cardiac embolism is increased to 23 to 36%. ⋯ In the case of cardiac embolism, the computer tomography (CT) usually shows infarction in or near the cortex in the region of the middle or posterior cerebral artery. About 10 to 20% of strokes due to cardiac embolism show secondary hemorrhage after the event, more frequently in association with large infarcts and in patients on anticoagulant treatment. Angiography can provide indirect evidence of embolic origin by showing occlusion of an intracerebral artery in the absence of arteriosclerotic changes. Traditional echocardiography may detect a possible source of embolism in 10% of all patients with ischemic stroke, only in 1.5%, however, in patients with no clinical signs of heart disease. Transesophageal echocardiography has a higher sensitivity for detection of sources of cardiac embolism. The use of magnetic resonance tomography and ultrafast CT will assume greater importance in the future. Holter monitoring of the ECG in patients with acute ischemic stroke or TIAs detects arrhythmias possibly responsible for emboli in about 2%. High-risk patients: The most common cause of cardiac embolism is atrial fibrillation (45%), followed by ischemic heart disease (15%) and in 10% each, aneurysm, rheumatic heart disease, prosthetic valve replacement and other cardiac diseases.(ABSTRACT TRUNCATED AT 400 WORDS)
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Vasodilators have been shown to improve hemodynamics of the failing heart as a short-term effect and to decrease mortality as a long-term result. We therefore studied the effect of different vasodilators on myocardial mechanics and energetics in patients with idiopathic dilated cardiomyopathy (IDC) NYHA II to III. In these patients undergoing routine heart catheterization myocardial oxygen consumption was measured using the argon method, and left ventricular pressure and geometry were obtained from left ventricular angiography using a Millar tip microcatheter. ⋯ In conclusion, vasodilators decrease left ventricular pressure and chamber size and thereby proportionally reduce MVO2/beat. The reduction of energy needed for myocardial contraction may partially explain the long-term effects of the ACE-inhibitors and combinations of vasodilators. Pure positive inotropic substances, especially beta 1-agonists, increase myocardial oxygen consumption with minor changes of systolic stress-time integral.(ABSTRACT TRUNCATED AT 250 WORDS)
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Impaired diastolic function of the hypertrophied and stiffened left ventricle is a characteristic feature of hypertrophic cardiomyopathy (Figure 1). Altered left ventricular filling dynamics and reduced left ventricular distensibility or increased left ventricular diastolic chamber stiffness are associated with reduced left ventricular stroke volume, increased left ventricular filling pressures and compressive effects on the coronary microcirculation. These factors contribute importantly to the clinical presentation of many patients, including symptoms of fatigue, dyspnea and angina pectoris. ⋯ Other factors are nonuniform and asynchronous regional ventricular function due to differing increases in thickness of the ventricular walls and ischemia (Figure 4). Calcium channel blockers exert a favorable influence on left ventricular relaxation and filling (Figure 5); verapamil and diltiazem are preferable to nifedipine. Verapamil increases left ventricular stroke volume without an increase in the end-diastolic pressure (Figure 6), reduces regional asynchrony if present, and leads to a more homogeneous regional diastolic filling (Figure 4).(ABSTRACT TRUNCATED AT 250 WORDS)