title: Measurements of human coronary vascular impedance.
abstract: The aim of this study was to develop a method of measuring human coronary circulation impedance in a clinical setting. The authors measured coronary flow reserve (CFR) in 27 patients with chest pain and normal coronary arteries. A Judkins-style, 8F Doppler-tipped angiographic catheter was positioned in the left coronary ostium. Resting coronary flow velocity (RFV) and response to a hyperemic 12 mg intracoronary dose of papaverine (PFV) were measured. The signals were recorded by a recorder connected to a microprocessor with analogue-to-digital converter and a maths coprocessor. Using this the authors could obtain values for impedance at RFV (IR) and at PFV (IP). The CFR was defined as the ratio: PFV/RFV. An impedance index (II) was obtained as the ratio of coronary vascular impedance at peak hyperemia to the impedance at rest. The CFR was 3.2 +/- 1.2 and the II was 0.33 +/- 0.11. There was a strong inverse correlation between the CFR and the II (r = -0.9). The authors conclude that this new approach may allow a further insight into the coronary pathophysiology and may become useful in clinical cardiology, eg, in the assessment of heart transplant and Syndrome X patients.
authors.affiliation: Cardiac Unit, Papworth Hospital, Cambridge, England.
authors.forename: A
authors.initials: A
authors.lastname: Chauhan
authors.forename: C D
authors.initials: CD
authors.lastname: Potter
authors.forename: P A
authors.initials: PA
authors.lastname: Mullins
authors.forename: D R
authors.initials: DR
authors.lastname: Wheeldon
authors.forename: M C
authors.initials: MC
authors.lastname: Petch
authors.forename: P M
authors.initials: PM
authors.lastname: Schofield
mesh_terms: D000328:Adult; D000787:Angina Pectoris / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D004452:Echocardiography; D017097:Electric Impedance; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012016:Reference Values; D014655:Vascular Resistance / Q000502:physiology*