Gallopamil activity on asynergic viable myocardium in acute myocardial infarction: Insights on stunned and hibernating myocardium

The influence of the calcium antagonist gallopamil on the contractility of asynergic viable myocardium after acute myocardial infarction treated with thrombolysis was investigated by two-dimensional echocardiography. Sixteen patients with greater than or equal to 1 viable segment(s), identified duri ng the low-dose phase (up to 10 mu g/kg/min) of a dobutamine echocardiograp hic test (up to 40 mu g/kg/min) performed 4-5 days after a first acute myoc ardial infarction, were given a gallopamil intravenous bolus (50 mu g/kg) 1 2-24 hours later. Two-dimensional echocardiography was done before and 15 m inutes after the bolus. A score index of 1 (normokinesis) to 4 (dyskinesis) and a 16-segment model were used. A segment was considered viable when a r esting asynergy (score greater than or equal to 2) improvement of greater t han or equal to 1 grade was seen during low-dose dobutamine. Follow-up echo cardiograms were done 3-5 months later. A total of 30 viable segments were found; of these, 10 showed sustained improvement in contractility (group A) during high-dose dobutamine, while 20 exhibited a biphasic response return ing to their basal contractile state (group B). After the gallopamil bolus, 9 of 10 group A segments improved their contractility, in comparison with 0 of 20 group B segments (P < .001). Infarct-related vessel significant (gr eater than or equal to 75%) coronary stenosis was present in the tributary vessel of 0 of 10 group A and of 20 of 20 group B segments (P < .001). At f ollow-up, 9 of 10 group A segments showed a spontaneous contractile improve ment; of the 20 group B segments, 8 of 10 that underwent revascularization (7 angioplasty, 3 bypass graft) showed contractile improvement, in comparis on with 0 of 10 segments not revascularized (P = .001). We conclude that ga llopamil may reverse the contractile dysfunction of postischemic stunned my ocardium in patients with acute myocardial infarction, whereas no effects a re apparent on ischemic/hibernating myocardium.