Ventricular filling mechanisms: study of regional pressure gradients and myocardial segmental lengths along the cardiac cycle.

• Type: Summary of Presentation in an International Conference
• Date: 2006

Authors

Guerra MS (Author) FMUP; Amorim MJ (Author) Other; Brás-Silva C (Author) FMUP; Leite-Moreira AF (Author) FMUP

Conference proceedings International

Title: European Journal of Heart Failure

Initial page: 74

ESC Annual Congress 2006

Helsínquia, Finlândia, 17 a 20 de Junho de 2006

Scientific classification

FOS: Medical and Health sciences > Other medical sciences

Other information

Resumo (PT): Experimental and clinical studies have shown significant diastolic intraventricular pressure gradients (IVPG) in early as well as late diastole and their sensibility to changes in preload and ischemia. However, data about systolic IVPG and their modulation by ischemia is lacking, as well as, a correlation between regional intraventricular pressures and myocardial segmental lengths. Simultaneous apical and outflow tract left ventricular (LV) pressures were recorded in 5 anesthetized open-chest rabbits by 2 high-fidelity micromanometers. Two pairs of ultrasonic crystals were implanted in the epicardium of the LV to measure the basal and apical segments. IVPG and segments were analysed in control and after LAD coronary artery occlusion, along the cardiac cycle, at baseline and isovolumetric cycles. During early diastole we recorded an IVPG (4.64-0.7mmHg) from apexto- outflow and a similar although smaller IVPG (0.5-t-0.1mmHg) during atrial contraction. While basal segments re-extend (8.4-t-l.0mm) during all the diastole, apical segments shorten (-4.7-t-1.7mm) firstly and lengthen (14.44-0.4mm) in the late phase of diastole. During systole we recorded an IVPG (0.64-0.1mmHg) from apex to outflow-tract during rapid ejection phase which inverts (-0.8-1,0. lmmHg) during slow ejection phase. This pressure gradient pattern during ejection parallels the aorticventricular pressure gradients, which might favour ventricular emptying. In fact, when ventricular emptying is opposed by a£tedoad elevations or after ischemia, the early systolic IVPG is reversed (-0.9-1,0. l mmHg and - 0.64-0.4mmHg, respectively), indicating ventricular ejection impairment. Furthermore, earlier and faster shortening of basal (1764-18msec) than apical (202-t-14msec) segments observed during systole might favour mitraJ-apica3 flow during diastole. This physiological profile is lost after ischemia. The present study confirms the existence of diastolic and systolic IVPG 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 showed that IVPG, a marker of normal left ventricular function can be attenuated, lost entirely, or even reversed in the presence of ischemia.

Language: English

Type (Professor's evaluation): Scientific

Notes: ESC Annual Congress 2006, published in journal, European Journal of Heart Failure. 2006; Vol.5(Suppl.1):74-74.