Volatile anesthetics may impair late diastolic LV filling
MedWire News: Volatile anesthetics do not impair early diastolic relaxation in healthy people without cardiac disease, but do reduce global atrial function, say Swiss researchers.
“The findings of this study cannot be directly transferred to patients with pre-existing diastolic dysfunction,” caution D. Bolliger and team from University Hospital Basel.
“Therefore, further studies investigating the effects of volatile anesthetics in this patient population under controlled conditions are warranted.”
The effect of volatile anesthetics on diastolic function is not clear, in part, says the team, because of the wide range of pre-existing cardiac conditions in patients in previous studies.
Bolliger et al therefore studied 60 patients, aged 18 to 48 years, who were scheduled for minor procedures under general anesthesia and were free of heart disease. They believed that volatile anesthetics would not affect diastolic function in this group.
The patients were randomly assigned to receive sevoflurane, desflurane, or isoflurane, at 1 minimum alveolar concentration.
During spontaneous breathing, patients’ peak early (E’) diastolic velocities of the mitral annulus fell from 14.0 to 13.2 cm/sec with sevoflurane, rose from 14.5 to 17.1 cm/sec with desflurane, and rose nonsignificantly from 13.7 to 14.6 cm/sec with isoflurane.
During intermittent positive pressure ventilation (IPPV), E’ was not significantly different from baseline with desflurane or isoflurane, but was significantly decreased with sevoflurane, at 11.4 cm/sec.
Increases in E’ indicate improved function, whereas decreases indicate impairment. But the E’ values of patients given sevoflurane remained within the normal range during both stages, with the exception of one patient, the researchers note in the British Journal of Anaesthesia.
They therefore believe that the effect of sevoflurane on early diastolic relaxation may not be clinically relevant – at least in healthy patients.
Peak late (A’) diastolic velocities fell significantly during spontaneous breathing and to a similar extent with all three anesthetics. A’ fell from 8.3 to 6.3 cm/sec with sevoflurane, from 7.2 to 5.7 cm/sec with desflurane, and from 8.0 to 6.7 cm/sec with isoflurane. There were further falls on initiation of IPPV, but these were nonsignificant, showing that the effect was independent of IPPV.
A’ relates to active atrial contraction, so is a marker of global systolic atrial function. “Impairment of systolic atrial function potentially impairs late diastolic left ventricular (LV) function,” explain Bolliger et al.
They add: “This effect may become clinically relevant in patients with pre-existing diastolic dysfunction, for example, patients who depend on atrial contraction during LV filling.”
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By Eleanor McDermid