## Abstract

Left ventricular (LV) O_{2} consumption (VO_{2}) per minute is measurable for both regular and arrhythmic beats. LV VO_{2} per beat can then be obtained as VO_{2} per minute divided by heart rate per minute for regular beats, but not for arrhythmic beats. We have established that VO_{2} of a regular stable beat is predictable by VO_{2} = a PVA + b E_{max} + 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 O_{2} cost of PVA, b is the O_{2} cost of E_{max}, and c is the basal metabolic VO_{2} per beat. We considered it theoretically reasonable to expect that the same formula could also predict LV VO_{2} of individual arrhythmic beats from their respective PVA and E_{max} with the same a, b, and c. We therefore applied this formula to the PVA - E_{max} data of individual arrhythmic beats under electrically induced atrial fibrillation (AF) in six canine in situ hearts. We found that the predicted VO_{2} of individual arrhythmic beats highly correlated linearly with either their VO _{2} (r = 0.96 ± 0.01) or E_{max} (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 VO_{2} of absolute arrhythmic beats from their E_{max} and PVA under AF.

Original language | English |
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Pages (from-to) | 135-142 |

Number of pages | 8 |

Journal | Japanese journal of physiology |

Volume | 55 |

Issue number | 2 |

DOIs | |

Publication status | Published - Apr 2005 |

## Keywords

- Arrhythmia
- Cardiac function
- Mechanoenergetics
- Oxygen consumption

## ASJC Scopus subject areas

- Physiology