Evidence of a dominant backward-propagating suction wave responsible for diastolic coronary filling in humans, attenuated in left ventricular hypertrophy

Background-Coronary blood flow peaks in diastole when aortic blood pressure has fallen. Current models fail to completely explain this phenomenon. We present a new approach-using wave intensity analysis-to explain this phenomenon in normal subjects and to evaluate the effects of left ventricular hypertrophy (LVH). Method and Results-We measured simultaneous pressure and Doppler velocity with intracoronary wires in the left main stem, left anterior descending, and circumflex arteries of 20 subjects after a normal coronary arteriogram. Wave intensity analysis was used to identify and quantify individual pressure and velocity waves within the coronary artery circulation. A consistent pattern of 6 predominating waves was identified. Ninety-four percent of wave energy, accelerating blood forward along the coronary artery, came from 2 waves: first a pushing wave caused by left ventricular ejection-the dominant forward-traveling pushing wave; and later a suction wave caused by relief of myocardial microcirculatory compression-the dominant backward-traveling suction wave. The dominant backward-traveling suction wave (18.2 +/- 13.7x10(3) W m(-2) s(-1), 30%) was larger than the dominant forward-traveling pushing wave (14.3 +/- 17.6x10(3) W m(-2) s(-1), 22.3%, P=0.001) and was associated with a substantially larger increment in coronary blood flow velocity (0.51 versus 0.14 m/s, P<0.001). In LVH, the dominant backward-traveling suction wave percentage was significantly decreased (33.1% versus 26.9%, P=0.01) and inversely correlated with left ventricular septal wall thickness (r=-0.52, P<0.02). Conclusions-Six waves predominantly drive human coronary blood flow. Coronary flow peaks in diastole because of the dominance of a suction wave generated by myocardial microcirculatory decompression. This is significantly reduced in LVH.