Determinants of reversible asynergy. The native coronary circulation.

To evaluate the influence of the native coronary circulation on the reversibility of asynergy, ventriculograms before and after sublingual nitroglycerin were performed in 51 patients with coronary artery disease and asynergy. The severity of stenotic lesions and caliber of the distal coronary vessels were determined by comparison with external catheter tip diameter corrected for magnification. Of 42 asynergic zones associated with larger than or equal to 90% proximal coronary occlusion, 27 (64%) were akinetic or dyskinetic while only 11 of 38 zones (29%) with less than 90% occlusion showed akinesis (P less than 0.005). Twenty-six of the 38 asynergic zones (69%) with less than 90% occlusion were reversible in contrast to 19 of the 42 zones (45%) with larger than or equal to 90% occlusion (P less than 0.05). Coronary collaterals were observed in 23 of 42 (55%) zones with larger than or equal to 90% occlusion in contrast to only 11 of 38 zones (29%) with less than 90% occlusion (P less than 0.05). Of the zones with both greater than or equal to 90% occlusion and collaterals, 74% were reversible, in contrast to only 11% without collaterals (P less than 0.001). Of the asynergic zones without collaterals, 63% with less than 90% occlusion were reversible in contrast to only 11% with larger than or equal to 90% occlusion (P less than 0.001). Pathologic Q waves were associated with 24 of 42 zones (57%) with larger than or equal to 90% occlusion compared to only nine of the 38 zones (24%) with less than 90% occlusion (P less than 0.01). The presence of Q waves was associated with a significant decrease in the incidence of reversibility regardless of the degree of coronary occlusion. Excluding the asynergic zones with either collaterals or Q waves, 79% with less than 90% occlusion were reversible in contrast to only 37% with larger than or equal to 90% coronary occlusion (P less than 0.05). In contrast, the caliber of the distal vessel could not be correlated with either the severity of asynergy or the presence of collaterals and was similar in both reversible and irreversible asynergic zones. In summary, larger than or equal to 90% proximal stenosis is associated with severe asynergy which is less likely to be reversible compared to asynergy associated with less than 90% coronary occlusion. In the presence of larger than or equal to 90% occlusion, coronary collaterals are associated with a significantly higher incidence of reversible asynergy and thus appear to serve a protective function. However, the caliber of the distal vessel per se does not effect the severity or reversibility of asynergy.