The Annals of Thoracic Surgery, Vol 31, 176-181, Copyright © 1981 by The Society of Thoracic Surgeons
Coronary flow and regional function before and after supraarterial myotomy for myocardial bridging
RC Hill, WR Chitwood Jr, TM Bashore, JD Sink, JL Cox and AS Wechsler
Myocardial bridges have been associated with clinical and metabolic
evidence of ischemia, although the mechanism for this is unclear. We
measured coronary blood flow and segmental function at different heart
rates prior to and after release of a myocardial bridge involving the left
anterior descending coronary artery in a patient with angina. Before lysis
of the bridge, atrial pacing was associated with a decreased systolic
flow/total flow, increased duration of systole, a lag in diastolic flow,
and functional deterioration. After release of the bridge, pacing was
associated with increased systolic flow/total flow and systolic interval,
no diastolic flow lag, and no functional deterioration. These data imply
that before bridge division, systolic flow and the initiation of diastolic
flow were impeded. Functional abnormalities resulting from the flow
discrepancies at heart rates of 120 to 150 beats per minute may have
accounted for this patient's symptoms.