Cardiology
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To assess the short-term reliability of temporary epicardial pacing wires in patients after open heart surgery and to determine the influence of preoperative factors on the performance of these wires. ⋯ Although both atrial and ventricular temporary epicardial leads are reliable for short-term use, their function deteriorates on a daily basis. Perioperative factors are generally not helpful in predicting the performance of temporary epicardial pacing wires.
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Currently, several modalities are available to predict viability, however, studies comparing various modalities validated by functional recovery after revascularization are scarce. This study analyzed the relative merits of low-dose dobutamine echocardiography, F-18 deoxyglucose (FDG) positron emission tomography (PET) and (99m)Tc sestamibi single-photon emission computed tomography to predict functional recovery after revascularization in patients with chronic myocardial infarction. ⋯ Recovery of chronically dysfunctional myocardium can be predicted with high accuracy by stimulation of contractile reserve or by concordant match of preserved glucose metabolism and residual perfusion.
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It is unknown whether surgical revascularization of viable and chronic reversibly dysfunctional myocardium in patients with heart failure is associated with a favorable effect on the autonomic control of heart rate. We studied 38 coronary artery bypass surgery (CABG) patients with an ejection fraction of 36 +/- 7%. ⋯ In spite of viable myocardium and recovery of left ventricular function following CABG, HRV indices were reduced 6 months postoperatively. A potential prognostic benefit gained by revascularizing patients with viability may occur in spite of deteriorated autonomic control of heart rate.
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Octogenarians are the fastest growing segment of the population and little is known about the results of cardiopulmonary resuscitation (CPR) after in-hospital cardiac arrest in this population. ⋯ In comparison with other life-saving strategies, CPR in octogenarians is effective. The favorable cost-effectiveness ratio is highly dependent on the patients' preference for quality rather than quantity of life, as expressed by the utility assumptions.
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Cellular mechanisms of adenosine include a direct effect on the activation of the adenosine-sensitive potassium current (I(K,Ado)) and an indirect effect on antagonism of catecholamine-stimulated adenylate cyclase activity. However, previous studies evaluating the influence of catecholamine activity on the electrophysiologic effects of adenosine have yielded conflicting results. We tested the hypotheses that if adenosine exerts its atrioventricular (AV) nodal blocking effects directly by activating the I(K,Ado) potassium current, rather than indirectly by reversing the catecholamine effects, then pretreatment with beta-adrenergic blockade would not potentiate the effects of adenosine in terminating AV nodal-dependent supraventricular tachycardia (SVT). ⋯ Intravenous esmolol infusion (up to 100 mg total dose) usually fails to terminate AV nodal-dependent SVT. In the esmolol-resistant tachycardia, esmolol pretreatment does not produce a positive synergistic effect on the efficacy of adenosine-induced termination of SVT. Therefore, in this tachycardia adenosine may exert its effects on AV nodal conduction directly by activation of the I(K,Ado) potassium current, rather than by antagonizing the beta-adrenergic system.