Introduction: Diastolic dysfunction is common in left ventricles (LV) with concentric hypertrophy (CH). Isoflurane has been shown to be negatively lusitropic in a dose-dependent way. The clinical effect of isoflurane on LV with CH and impaired relaxation (IR) has not been studied so far.
Method: 15 patients scheduled for coronary-artery-bypass-graft-surgery were enrolled. All had LV-CH (septal wall thickness > 1.3cm) with IR (E/A < 1, deceleration time (DT) > 240 ms, S/D > 1) determined by transoesophageal echocardiography (TOE). They were anaesthetized with midazolam, sufentanil and pancuronium. Haemodynamics were monitored by ECG, invasive pressures and thermodilution cardiac output (CO). The systemic vascular resistance (SVR) was calculated. Before and after isoflurane (0.8-1.2% end-tidal) LV-End Diastolic-Area (LVEDA) and Fractional-Area-Change (FAC) were determined by 2D-TOE, E/A-ratio, DT and S/D-ratio by transmitral and pulmonary venous PW-Doppler, and Em/Am-ratio and isovolumetric relaxation time (IVRT) by tissue-Doppler. Filling pressures were kept constant during the study. Parameters before and after isoflurane were compared by paired t-test (P < 0.05 was considered significant).
Results: 1 female and 14 males (age: 63 ± 9 years, BSA: 2 ± 0.2 m2, EF: 61 ± 12%) were studied. None had wall motion or mitral valve abnormalities during the study. The mean septal thickness was 1.44 ± 0.1 cm.
Discussion: Isoflurane did not cause further diastolic impairement. In contrast, there was slight improvement in relaxation indicated by larger E/Aratio, faster DT and shorter IVRT. With isoflurane LVEDA increased while filling pressures were constant, implying larger LV-compliance. Since SVR reduction alone does not show the same effects, improved handling of intracellular calcium may be considered as an underlying mechanism. We conclude that clinical relevant concentrations of isoflurane have beneficial effects on diastolic function in LV-CH with IR.
1 Pagel PS, Grossman W, Haering JM, et al. Left ventricular diastolic function in the normal and diseased heart. Anesthesiology
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