Cardiac myocyte function and left ventricular strains after brief ischemia and reperfusion in rabbits.

• DOI: 10.1161/01.cir.90.4.1942
• Publication Date: 2012-06-12T00:34:42Z
• Authors: W Y Lew; Y Nishikawa; H Su
• Keywords: Cardiac myocyte; Lagomorpha

BACKGROUND After a brief episode of ischemia, myocardial function may be depressed for prolonged periods despite reperfusion. The mechanisms postischemic dysfunction differ depending on the experimental model. Regional ischemia and reperfusion in intact animal provide clinically relevant model, but variables are difficult to control. Experimental conditions can well controlled isolated cardiac muscle myocyte preparations, these models limited by assumptions used mimic This study combines unique advantages both preparations. We characterized vivo alterations regional two-dimensional finite strains with produced animal, then myocytes from region characterize vitro myocytes. METHODS AND RESULTS In seven anesthetized rabbits, three piezoelectric crystals were inserted triangular array measure around large coronary artery left ventricular anterior free wall. 15 minutes reperfusion, at stable level approximately 30% 40% below control values between 1 6 hours after direction maximal shortening deformations was midway circumferential longitudinal directions during did not shift second group five 45 compared 48 normal rabbits. Each rabbit (postischemic control) contributed 9 +/- (SD) study. All studied within hour isolation (approximately 3 5 myocytes). Myocytes stimulated 0.5 Hz perfused 2 mmol/L [Ca2+] Tyrode's solution unloaded cell shortening. There significantly less (12.4 2.1%) than (16.2 1.2%). Maximal length (Lmax) longer (134 7 microns) (122 microns), as minimum (Lmin) (118 8 versus 103 microns, respectively). duration (time stimulation Lmin) shorter (279 56 milliseconds) (405 44 milliseconds). Peak rates (-dL/dt) lengthening (+dL/dt) differ. CONCLUSIONS depression reduced without direction. Cardiac myocardium display functional impairments similar those measured vivo, an 25% reduction decreased contraction duration. indicates that induce intrinsic contractility independently external loading conditions. model useful examining cellular dysfunction.