Left ventricular (LV) O2 consumption (VO2) per minute is measurable for both regular and arrhythmic beats. LV VO2 per beat can then be obtained as VO2 per minute divided by heart rate per minute for regular beats, but not for arrhythmic beats. We have established that VO2 of a regular stable beat is predictable by VO2 = a PVA + b Emax + c, where PVA is the systolic pressure-volume area as a measure of the total mechanical energy of an individual contraction and E max is the end-systolic maximum elastance as an index of ventricular contractility of the contraction. Furthermore, a is the O2 cost of PVA, b is the O2 cost of Emax, and c is the basal metabolic VO2 per beat. We considered it theoretically reasonable to expect that the same formula could also predict LV VO2 of individual arrhythmic beats from their respective PVA and Emax with the same a, b, and c. We therefore applied this formula to the PVA - Emax data of individual arrhythmic beats under electrically induced atrial fibrillation (AF) in six canine in situ hearts. We found that the predicted VO2 of individual arrhythmic beats highly correlated linearly with either their VO 2 (r = 0.96 ± 0.01) or Emax (0.97 ± 0.03) while both also highly correlated linearly with each other (0.88 ± 0.04). This suggests that the above formula may be used to predict LV VO2 of absolute arrhythmic beats from their Emax and PVA under AF.
|Number of pages||8|
|Journal||Japanese journal of physiology|
|Publication status||Published - Apr 2005|
- Cardiac function
- Oxygen consumption
ASJC Scopus subject areas