Heart and vessels
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Spinal cord ischemia may develop into paraplegia in some cases during operation of the thoracoabdominal aorta. This is attributable to the vulnerability of spinal motor neurons to ischemia. In this study, iloprost was used as an agent to decrease the severity of ischemia and reperfusion injury to the spinal cord motor neurons. ⋯ The number of viable cells was higher, whereas the number of nonviable cells was lower in iloprost group, when compared with the control group (P<0.05). Higher numbers of viable motor neurons were consistent with the neurological findings. As a result of this study we concluded that iloprost infused during clamping of the aorta mitigates the spinal cord injury due to ischemia and reperfusion, and has a significant protective effect.
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Inotropic support after cardiac surgery is sometimes employed for a long period without any definite criteria to wean patients from it. There are few reports describing factors influencing the inotropic support period. This study was undertaken to clarify the proper inotropic support period, especially to judge which patients can be weaned from it within 24 h. ⋯ Multivariate analysis indicated that intra-aortic balloon pumping, blood transfusion, and cardiopulmonary bypass time significantly influenced the inotropic support period. Intra-aortic balloon pumping, blood transfusion, and cardiopulmonary bypass time might determine the inotropic support period. Appropriate surgical procedure and methods both reducing cardiopulmonary bypass time (<75 min) and minimizing blood loss are the keys to weaning patients from inotropic support within 24 h.
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Delayed afterdepolarization (DAD)-induced triggered activity has been considered to be one of the generation mechanisms of ventricular arrhythmias in the presence of intracellular Ca2+ overload. In this study, we analyzed the antiarrhythmic effects of class I antiarrhythmic drugs, namely, disopyramide, procainamide, mexiletine, and flecainide, on a recently developed DAD-induced triggered arrhythmia model, which consists of a canine ventricular septum preparation cross-circulated with a blood-donor dog. ⋯ Similar doses have been demonstrated to suppress intraventricular conduction in the same experimental model. These results suggest that the Na+ channel inhibition by class I drugs is an effective pharmacological intervention for suppressing Ca2+ overload, which may provide a rationale for the short-term use of class I drugs against the triggered arrhythmias in clinical practice.
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Comparative Study
Tachycardia exacerbates abnormal left ventricular-arterial coupling in heart failure.
The purpose of this study was to assess the effect of heart rate on left ventricular (LV)-arterial coupling and LV mechanical efficiency before and after heart failure (CHF). The production of LV stroke work (SW) and mechanical efficiency depends on the coupling of the LV and arterial system. The response of LV-arterial coupling to tachycardia may be altered in heart failure. ⋯ After CHF, an increase in HR to 180 min(-1) increased E(A) but not E(ES), thus E(ES)/ E(A) fell to 0.44 +/- 0.06 ( P < 0.05) and SW/PVA fell to 0.41 +/- 0.05 ( P < 0.05). Under normal conditions, LV-arterial coupling remains optimal during increases in HR. After CHF, tachycardia exacerbates the suboptimal baseline LV-arterial coupling, reducing the efficiency of producing SW.
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Case Reports
Acute myocardial infarction and congestive heart failure following a blunt chest trauma.
A 42-year-old man experienced chest discomfort after being struck by a low-speed flying object. Two weeks after the accident, the patient complained of severe shortness of breath accompanied by ankle edema. Chest X-ray indicated acute pulmonary edema and left ventricular enlargement. ⋯ Subsequent medical therapy with diuretics and enalapril led to significant improvement in ventricular function and the patient's symptoms. We conclude that a mild blunt chest trauma can cause myocardial infarction and severe congestive heart failure. Careful investigations into myocardial ischemia or infarction and a close follow-up should be conducted in all patients presenting with a blunt chest trauma.