Zeitschrift für Kardiologie
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This paper explains the physiological and biochemical basis of the anaerobic threshold (AT), achieved during physical exercise. The lactate concentration is approximately the same at rest in relatively fit adults, in normal sedentary subjects in adult patients with heart disease. But during exercise, the increase of lactate is inversely related to the physical fitness of the individual. ⋯ The anaerobic threshold can be determined during the ramp program using the following four parameters: 1) steeper increase of VCO2 as compared to VO2 (V-slope-method); 2) respiratory exchange ratio = 0.95; 3) PETO2 increase; 4) VE/VO2 increase. The V-slope-method can be successfully applied, not only in healthy volunteers, but also in patients suffering from cardiac and/or pulmonary (breathing abnormalities) diseases. The so far published data show that the anaerobic threshold in healthy people and patients is a highly reproducible, accurately measurable, securely achievable parameter for the non-invasive evaluation of the individual cardiopulmonary exercise capacity.
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Comparative Study
[Neurohumoral and hemodynamic effects in combination therapy of enoximone and dopamine].
Twelve patients with severe heart failure (NYHA class III-IV) were investigated by intraindividual comparison for the hemodynamic and neurohumoral effects of dopamine (3 and 6 micrograms/kg/min), enoximone (8 micrograms/kg/min), and the combination of both medications (dopamine 3 micrograms/kg/min+enoximone 8 micrograms/kg/min) using right heart catheterization. The duration of active treatment was 8 h for each substance with a subsequent washout time of 16 h. Dopamine led to a dose-dependent increase in cardiac index of 10-13% and 18-37% under 3 and 6 micrograms/kg/min, respectively (p < 0.001). ⋯ An additive effect on heart rate was not observed. The respective monotherapies with low-dose dopamine and enoximone had no remarkable effect on plasma catecholamines, while dopamine at a dose of 6 micrograms/kg/min and combination therapy led to a significant increase in noradrenaline levels. There was a highly significant decrease in the plasma concentration of the atrial natriuretic factor under enoximone and combination therapy (p < 0.001) as well as a significant decrease in aldosterone (0 < 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
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A refractory low-cardiac-output syndrome is, in pediatric patients, most often due to impaired myocardial function after corrective surgery in congenital heart disease. Therapy has to focus on postoperative adaptation, which usually takes place within a few days. We report on three therapeutic strategies to "bridge" this phase of postoperative adaptation. ⋯ In low-cardiac-output syndrome refractory to all therapeutic measures mechanical circulatory support is the final method to keep the patient alive. In 11 children with refractory low-cardiac-output syndrome mechanical circulatory support was performed. In three of these, extracorporal membrane oxygenation (ECMO) was used, in eight children a ventricular assist device (Berlin Heart) was used.(ABSTRACT TRUNCATED AT 400 WORDS)
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Patients with coronary artery disease undergoing coronary artery bypass grafting can develop perioperative low cardiac output failure requiring positive inotropic support. Commonly, the sympathetic amines, dopamine, dobutamine or adrenaline are used in low-output state. However, patients on long-term cardioselective beta-blocking therapy may experience problems with such a treatment. ⋯ Following intubation anesthesia was continued with 0.025 mg/kg/h fentanyl. In anesthesia steady state the patients of both groups were treated with 2 micrograms/kg/min dopexamine over a period of 15 min and then with 4 micrograms/kg/min dopexamine over a further period of 15 min. Measurements of cardiovascular dynamics included heart rate (HR), cardiac index (CI), stroke volume index (SVI), mean arterial blood pressure (MAP), coronary perfusion pressure (CPP), systemic vascular resistance (SVR), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), right atrium pressure (RAP), pressure work index (PWI) and arterial-mixed venous oxygen content difference (AVDO2), which were monitored or calculated by standard formulas.(ABSTRACT TRUNCATED AT 250 WORDS)
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Postoperative junctional ectopic tachycardia is associated with a poor prognosis in patients after open-heart surgery. This dysrhythmia has been shown to be resistant to medical treatment as well as to epicardial pacing and external cardioversion. ⋯ Hypothermia (rectal temperature 32-34 degrees C) was effective in decreasing the ventricular rate of the dysrhythmia (< 170 bpm). After spontaneous cessation of the tachycardia, sinus rhythm resumed, resulting in stable hemodynamics.