[Two cases with the heart murmur originated from aortocoronary bypass: the diagnostic use of dipyridamole (author's transl)].

Two cases with the heart murmurs considered to be caused by aortocoronary (A-C) bypass surgery were reported. Case 1: A systolic and an early and late diastolic murmurs were noted following A-C bypass surgery. The murmurs were located at the second left intercostal space. After methoxamine, the systolic and early diastolic murmurs increases slightly in intensity, while the late diastolic murmur did not change. Amyl nitrite inhalation slightly increased the intensity of the systolic murmur, but did not that of the diastolic murmur. Dipyridamole injection at a rate of 0.142 mg/kg/min resulted in the increase of both systolic and diastolic murmurs. Case 2: A diastolic murmur was noted following the bypass surgery, which was situated over the fourth left intercostal space, 4 cm outside from the left sternal border. Methoxamine injection intensified the murmur. The murmur was not affected by amyl nitrite. After dipyridamole injection, the murmur was slightly intensified. Dipyridamole is known to dilate coronary vessels without affecting appreciably the systemic circulation. In these two cases, the murmur noted following A-C bypass surgery was increased with dipyridamole, suggesting clinical applicability of this drug in ascertaining the bypass flow murmur.