Intraventricular pressure gradients throughout the cardiac cycle: effects of ischaemia and modulation by afterload

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Miguel Guerra (Author) Other; Mario Jorge Amorim (Author) Other; Carmen Bras Silva (Author) FMUP; Adelino F Leite Moreira (Author) FMUP

Journal

Title: Experimental Physiology

Vol. 98 No. 1

Pages: 149-160

ISSN: 0958-0670

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 16 Citations

ISI Web of Science

Scopus - 15 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

CORDIS: Health sciences

Other information

Authenticus ID: P-002-1PC

DOI: 10.1113/expphysiol.2012.066324

Abstract (EN): The aim of the present study was to characterize the intraventricular pressure gradients (IVPGs) througout the cardiac cycle, to correlate them with myocardial segmental asynchrony and to evaluate the effects of ischaemia and modulation by afterload. Open-chest anaesthetized rabbits (n = 6) were instrumented with pressure-tip micromanometers placed in the apex and outflow tract of the left ventricular (LV) cavity and with sonomicrometer crystals placed in the apex and base of the LV free wall to measure IVPGs and myocardial segment length changes during basal, afterloaded (aortic cross-clamping) and ischaemic conditions (left anterior descending coronary artery ligation). During early diastole (rapid filling), we recorded an IVPG (4.6 +/- 0.7 mmHg) from the cardiac base towards the apex followed by an apex-to-outflow pressure gradient (3.6 +/- 0.2 mmHg). During systole, we recorded an IVPG (0.6 +/- 0.1 mmHg) from apex to outflow during early rapid ejection, which inverted during late slow ejection. Interestingly, the maximal rate of LV pressure fall occurred earlier and relaxation rate was faster in the base than in the apex. While shortening of basal segments was complete at the end of ejection, apical segments always showed a significant amount of postsystolic shortening. The IVPGs were entirely lost during ischaemia and attenuated by afterload elevations. During ischaemia, systolic shortening of the apical segment decreased, while postsystolic shortening increased. The present study confirms the existence of diastolic and systolic IVPGs in the LV and demonstrates, for the first time, that this normal gradient pattern is related to physiological asynchrony between basal and apical myocardial segments. Moreover, we show that the IVPG, a marker of normal left ventricular function, can be attenuated, lost entirely or even reversed after regional acute ischaemia and afterload elevations.

Language: English

Type (Professor's evaluation): Scientific

Notes: <a href="http://www.scopus.com/record/display.url?eid=2-s2.0-84872173087&origin=resultslist&sort=plf-f&src=s&st1=Intraventricular+pressure+gradients+along+the+cardiac+cycle%3a+Effects+of+ischemia+and+modulation+by+afterload&sid=E139F028D1263B06742CA8B9CBB90290.I0QkgbIjGqqLQ4Nw7dqZ4A%3a20&sot=b&sdt=b&sl=123&s=TITLE-ABS-KEY%28Intraventricular+pressure+gradients+along+the+cardiac+cycle%3a+Effects+of+ischemia+and+modulation+by+afterload%29&relpos=0&relpos=0&citeCnt=3&searchTerm=TITLE-ABS-KEY%28Intraventricular+pressure+gradients+along+the+cardiac+cycle%3A+Effects+of+ischemia+and+modulation+by+afterload%29">Indexado na SCOPUS</a> <a href="http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord&KeyUT=:000313255900018">Indexado na ISI Web of Science</a>

No. of pages: 12