Dock’s murmur in LAD stenosis

Dock’s murmur in LAD stenosis

Dock’s murmur is an early diastolic murmur heard in coronary artery stenosis. Initial documentation was in a man with heart failure due to hypertension and left ventricular aneurysm. The diastolic murmur was recorded in a sharply localized area, only when he was in the erect posture. This high pitched murmur was thought to be from a stenotic left anterior descending coronary artery which was suspected to have a recanalized thrombus [1].

Sangster JF et al reported 3 cases with coronary stenosis and diastolic murmur. The murmur was heard in the third left intercostal space, in a small area, about four centimeters from the midsternal line [2]. Phonocardiogram documented a crescendo-decrescendo early diastolic murmur. In their first case, a diastolic thrill was felt over the left anterior descending (LAD) coronary artery during bypass graft surgery. The murmur disappeared when the artery was fully occluded in another case. Angiography had demonstrated the absence of aortic regurgitation in these cases.

Similar murmur with echocardiographic demonstration of LAD stenosis has been reported [3]. Echocardiography was also useful in ruling out aortic regurgitation as a cause of the murmur. In another interesting case, a diastolic murmur of coronary artery stenosis disappeared immediately after aortocoronary bypass surgery [4]. Two months later the murmur reappeared when she had acute anteroseptal myocardial infarction presumed to be due to occlusion of the bypass graft. Coronary angiography done 10 months after the surgery showed occlusion of the bypass graft, but the murmur was no longer heard.

In yet another report two patients had diastolic murmur caused by coronary artery stenosis. Both cases were associated with severe localized narrowing of proximal LAD demonstrated by angiography [5]. The murmur disappeared after acute myocardial infarction involving the area supplied by the stenosed artery. Intermittent diastolic murmur caused by coronary artery stenosis has also been reported [6].

References

1. Dock W, Zoneraich S. A diastolic murmur arising in a stenosed coronary artery. Am J Med. I967;42:6I7-619.
2. Sangster JF, Oakley CM. Diastolic murmur of coronary artery stenosis. Br Heart J. 1973;35:840-4.
3. Stankovic I, Kafedzic S, Putnikovic B, Neskovic AN. An Echocardiographic Illustration of the Dock’s Murmur in a Patient With Wellens Syndrome. Can J Cardiol. 2016 Dec;32(12):1578.e3-1578.e5.
4. Burg JR, Weaver KA, Russell T 2nd, Kassebaum DG. Disappearance of coronary artery stenosis murmur after aortocoronary bypass. Chest. 1973 Mar;63(3):440-2.
5. Cheng TO. Diastolic murmur caused by coronary artery stenosis. Ann Intern Med. 1970 Apr;72(4):543-6.
6. Aintablian A, Etess H, Hamby RI. Intermittent diastolic murmur. Caused by coronary artery stenosis. N Y State J Med. 1975 Aug;75(9):1536-7.