POSTEXTRASYSTOLIC POTENTIATION AND DOBUTAMINE ECHOCARDIOGRAPHY IN PREDICTING RECOVERY OF MYOCARDIAL-FUNCTION AFTER CORONARY-BYPASS REVASCULARIZATION

Background Identification of viable but hibernating myocardium remains a relevant issue in the current era of myocardial revascularization. Echocardiography can be helpful in detecting reversible contractile dy sfunction and optimizing the selection of patients for coronary bypass surgery. Methods and Results Eighty-four consecutive candidates for b ypass surgery with chronic multivessel coronary artery disease were sc reened, and 60 were included in this prospective study. Preoperative e valuation of a reversible contractile dysfunction in asynergic myocard ial regions was performed by dobutamine infusion at 5 (low dose) and 1 0 (intermediate dose) mu g.kg(-1).min(-1) with each stage lasting at l east 5 minutes; postextrasystolic potentiation (PESP), with a coupling interval ranging from 500 to 300 ms with a progressive 10-ms decrease ; or a combination of both dobutamine infusion and PESP. Sensitivity ( 92% versus 86%) and predictive accuracy (89% versus 84%) were higher w ith PESP than dobutamine (P=.009 and P=.001, respectively), but the co mbination did not improve sensitivity or accuracy. Dobutamine induced ischemic dysfunction in 15% of patients at the intermediate dose; howe ver, the low dose resulted in loss of sensitivity. Conclusions PESP ec hocardiography is a useful and cost-effective method to identify viabl e myocardium in patients with multivessel coronary disease undergoing revascularization and is more sensitive and accurate than dobutamine i nfusion.