Title

Influence of Isoflurane on Left Atrial Function in Dogs With Pacing-Induced Cardiomyopathy: Evaluation With Pressure-Volume Relationships

Document Type

Article

Language

eng

Format of Original

6 p.

Publication Date

12-2003

Publisher

Elsevier

Source Publication

Journal of Cardiothoraic and Vascular Anesthesia

Source ISSN

1053-0770

Original Item ID

doi: 10.1053/j.jvca.2003.09.006

Abstract

Objective

The actions of volatile anesthetics on left ventricular (LV) function in normal and failing hearts have been previously evaluated, but the effects of these agents on left atrial (LA) function in the presence of LV dysfunction are unknown. The hypothesis was tested that isoflurane alters LA mechanics evaluated with pressure-volume relations.

Design

Prospective.

Setting

Laboratory.

Participants

Barbiturate-anesthetized dogs (n = 8) were instrumented for measurement of aortic, LA, and LV pressures (micromanometers), and LA volume (epicardial orthogonal sonomicrometers) after 3 weeks of rapid ventricular pacing (220 beats/min).

Interventions

LA myocardial contractility (Ees) was assessed with end-systolic pressure-volume relations. LA stroke work and reservoir function were assessed by A and V loop area, respectively, from the steady-state pressure-volume diagram. LA-LV coupling was determined by the ratio of Ees to LV elastance (ELV). Dogs received 0.6, 0.9, and 1.2 minimum alveolar concentration isoflurane in a random manner, and LA function was determined after a 20-minute equilibration at each dose.

Measurements and main results

Isoflurane significantly (p < 0.05) decreased heart rate, mean arterial pressure, LV end-systolic pressure, and LV +dP/dtmax. Isoflurane produced dose-related reductions in Ees and Ees/ELV. Declines in LA stroke work, emptying fraction, reservoir volume, V loop area, and the active LA contribution to LV filling also occurred.

Conclusions

The results indicate that isoflurane depresses LA myocardial contractility, impairs LA-LV coupling, and reduces active LA contribution to LV filling in dogs with pacing-induced cardiomyopathy. The impact of isoflurane on LA function in the presence of LV dysfunction has profound effects on cardiac performance.

Comments

Journal of Cardiothoraic and Vascular Anesthesia, Vol. 17, No. 6 (December 2003): 709-714. DOI.