title: The onset of ventricular isovolumic contraction as reflected in the carotid artery distension waveform.
abstract: The blood pressure waveform carries information about the cardiac contraction and the impedance characteristics of the vascular bed. Here, we demonstrate that the start of isovolumic ventricular contraction is persistently reflected as an inflection point in the pressure wave as recorded in the aortic root (TP(IC)) as well as in the carotid artery distension waveform (TD(IC)) as it travels down the arterial tree. In a group of six patients with normal pressure gradients across the aortic valve after valve replacement, the TP(IC) had a small delay with respect to the onset of isovolumic ventricular contraction (<10 ms). In a group (n = 21) of young presumably healthy volunteers, the inflection point occurred persistently in the carotid distension waveform, as recorded by means of ultrasound, before the systolic foot (intersubject delay between inflection point and systolic foot: mean +/- SD = 40.0 +/- 9.4 ms, intrasubject SD 4.6 ms). Retrograde coronary blood flow during isovolumic ventricular contraction may be the origin of the persistent end-diastolic pressure and distension perturbation. This study shows that the duration of the isovolumic contraction can be reliably extracted from the carotid artery distension waveform.
authors.affiliation: Department of Biophysics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: van Houwelingen
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Barenbrug
authors.forename: M Christianne
authors.initials: MC
authors.lastname: Hoeberigs
authors.forename: Robert S
authors.initials: RS
authors.lastname: Reneman
authors.forename: Arnold P G
authors.initials: AP
authors.lastname: Hoeks
mesh_terms: D000328:Adult; D000368:Aged; D001011:Aorta / Q000502:physiology; D001021:Aortic Valve / Q000502:physiology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D004452:Echocardiography / Q000379:methods; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology; D014664:Vasodilation / Q000502:physiology; D016276:Ventricular Function; D016277:Ventricular Function, Left / Q000502:physiology