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Background: Automated border detection (ABD) allows semiautomated measurement of left ventricular (LV) areas. They can be combined with left ventricular pressure signals to generate pressure-area loops and pressure-dimension indices of contractility. This study compared conventional indices of ventricular performance (fractional area change [FAC] and circumferential fiber shortening [Vcfc]) with pressure-dimension indices of contractility. A secondary aim was to compare the effects of volatile anesthetics on the indices.

Methods: Using transesophageal echocardiography with automated border detection, FAC and Vcfc were obtained in 23 patients after cardiopulmonary bypass. Left ventricular pressures were obtained with a left ventricular catheter. Preload reduction by inferior vena caval occlusion was used to obtain end-systolic elastance (Ees), preload recruitable stroke force (PRSF), and dP/dtmax [middle dot] EDA-1 (EDA = end-diastolic area). In 11 patients, the measurements were repeated at 1 end-tidal minimum alveolar concentration of halothane or isoflurane. The results are expressed as mean /- SD.

Results: After cardiopulmonary bypass, FAC was 31.1 /- 7.9%, Vcfc was 0.6 /- 0.2 circ [middle dot] s-1, Ees was 25.8 /- 11.6 mmHg [middle dot] cm-2, PRSF was 60.8 /- 26.6 mmHg, and dP/dtmax [middle dot] -EDA-1 was 245 /- 123.4 mmHg [middle dot] s-1 [middle dot] cm-2. At 1 minimum alveolar concentration of a volatile anesthetic agent, FAC, Vcfc, and dP/dtmax [middle dot] EDA-1 remained unchanged. Significant decreases in Ees (19%) and PRSF (28%) were observed.

Conclusions: The association between pressure-dimension indices and Vcf (c) or FAC was weak or nonexistent. A reduction in myocardial contractility induced by the administration of volatile anesthetic agents was detected by Ees and PRSF, but not by FAC, Vcfc, or dP/dtmax [middle dot] EDA (-1). After myocardial revascularization, Ees and PRSF appear more sensitive than FAC or Vcfc for measuring changes in contractility.

(C) 1998 American Society of Anesthesiologists, Inc.