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Mode of frequency distribution of external work efficiency of arrhythmic beats during atrial fibrillation remains normal in canine heart
- Source :
- The Journal of Physiological Sciences. 59:75-80
- Publication Year :
- 2008
- Publisher :
- Springer Science and Business Media LLC, 2008.
-
Abstract
- The external work (EW) efficiency of individual arrhythmic beats of the left ventricle (LV) cannot directly be obtained since LV O(2) consumption (VO(2)) of each beat cannot directly be measured under beat-to-beat varying contractile and loading conditions. We, however, have recently reported that VO(2) of each arrhythmic beat can reasonably be estimated by VO(2) = aPVA + bE(max) + c even under varying PVA and E(max). Here, PVA is the LV pressure-volume (P-V) area as a measure of the LV total mechanical energy, E(max) is the LV end-systolic elastance as an index of the LV contractility, a is a constant O(2) cost of PVA, b is a constant O(2) cost of E(max), and c is the basal metabolic VO(2) of the beat, all on a per-beat basis. Using the above formula in this study, we calculated VO(2) of the individual arrhythmic beats from their measured PVA and E(max) during electrically induced atrial fibrillation (AF) in normal canine hearts. We then calculated their LV EW efficiency by dividing their measured EW with the estimated VO(2). We found that the thus calculated EW efficiency of the arrhythmic beats had a rightward skewed distribution with a mode of 15% and a maximum of 18% around a mean of 13% on average in six hearts. This mode remained comparable to the efficiency (15%) at regular tachycardia though 22% lower than mean arrhythmic tachycardia.
- Subjects :
- Tachycardia
Pacemaker, Artificial
medicine.medical_specialty
Physiology
Work efficiency
Canine heart
Contractility
Dogs
Oxygen Consumption
Internal medicine
Atrial Fibrillation
Ventricular Pressure
medicine
Animals
O2 consumption
business.industry
Myocardium
Heart
Atrial fibrillation
medicine.disease
Myocardial Contraction
medicine.anatomical_structure
Ventricle
cardiovascular system
Cardiology
medicine.symptom
Energy Metabolism
business
Beat (music)
Subjects
Details
- ISSN :
- 18806562 and 18806546
- Volume :
- 59
- Database :
- OpenAIRE
- Journal :
- The Journal of Physiological Sciences
- Accession number :
- edsair.doi.dedup.....aead3b0fe4c1e0e0c04f564ed9acf327