Effect of regional myocardial ischaemia on left ventricular isovolumic contraction.

In anaesthetised, open-chest dogs, global isovolumic contractility indices were reduced by acute regional ischaemia involving 12 to 14% or more of left ventricular mass. These effects were not altered by controlled reduction of blood flow to the non-ischaemic region, but were exaggerated by isoprenaline during normal perfusion of the non-ischaemic region. The results were consistent with a contraction model characterised by simple reduction of the effective length of the contractile elements.