Cardiac power output is a central haemodynamic measure which describes pumping capability and performance of the heart. This is a unique measure as it accounts for both, flow- and pressure-generating capacities of the heart. Cardiac power output (CPO) is calculated from mean arterial pressure and cardiac output. Popular noninvasive methods for cardiac output measurement today include rebreathing methods. From the practical and clinical perspective it is important to know which of the commonly measured cardio-respiratory variables, obtained from a cardiopulmonary exercise test, are good predictors of peak CPO in healthy but also in heart failure populations. Until now there has been no measurement of cardiac power output in patients implanted with a left ventricular assist device (LVAD) and those explanted (recovered) patients. In a comparison study design it has been shown that peak cardiac power output differentiates well during cardiac restoration using LVADs and emphasizes the benefits of this therapy. It seems that CPO has the potential to be a key physiological marker of heart failure severity and can guide the management of LVAD patients. Furthermore as a consequence of acute reduction of LVAD support, there is a decrease in cardiac pumping capability and exercise performance. A decrease at rest and at peak exercise, expressed in percentages, was higher in central haemodynamics, particularly in CPO, than in the conventionally measured peak oxygen consumption. This suggests that CPO is more sensitive to acute reduction of LVAD support than oxygen consumption. In patients with severe heart failure and those implanted with an LVAD, the relationship between peak CPO and peak oxygen consumption is only modest. In healthy adults and LVAD explanted patients this relationship was high. No strong relationship was found between peak CPO and anaerobic threshold, circulatory power, oxygen pulse or ventilatory efficiency in LVAD implanted and patients with severe heart failure. Finally, regarding di fferent modalities of exercise training, in contrast with resistance training, aerobic exercise training may increase both maximal flow-generating capacity of the heart and peak oxygen consumption and also delays anaerobic metabolism in patients with stable chronic heart failure. Improved peak oxygen consumption, following aerobic exercise training, is closely associated with an exercise-induce increase in cardiac output.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:497313 |
| Date | January 2009 |
| Creators | Jakovljevic, Djordje |
| Publisher | Bucks New University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://bucks.collections.crest.ac.uk/9797/ |
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