Longitudinal epsilon and SR decrease with increasing LV dimensions in spite of an unaltered contractility. These results show and confirm that heart size influences epsilon and SR, which are highly load-dependent parameters.

No abstract

Standard machine settings with a FR of 50-60 Hz allow correct assessment of peak global longitudinal and circumferential strain. Correct definition of the region of interest within the myocardium as well as the reduction of noise and artefacts seem to be of highest importance for accurate 2D strain estimation.

The study compares the single dose histidine-tryptophan-ketoglutarate (HTK) cardioplegia to the repeatedly delivered St Thomas' Hospital Solution (STHS) with respect to preservation of left ventricular mechanoenergetics and leakage of troponin T in a porcine experimental model. Fourteen pigs were randomized to a single infusion of 30 ml/kg HTK cardioplegia (n=7) or 500 ml STHS (n=7) followed by 200 ml after 20 and 40 min. After 1 h of aortic cross-clamping on cardiopulmonary bypass (CPB), the pigs were weaned and the hearts reperfused for 4 h. Stroke work (SW) was determined by a conductance catheter in the left ventricle. Myocardial oxygen consumption (MvO(2)) was measured as a function of coronary blood flow and arterial-to-coronary sinus oxygen saturation difference. Troponin T was sampled from the coronary sinus. The slope of the SW-MvO(2) relationship increased by 1.09 (+/-0.53) in the HTK group compared with 0.33 (+/-0.70) in the STHS group following ischemia and 4 h of reperfusion (P=0.04). Troponin T was significantly higher in the HTK group compared with the STHS group (P=0.04). Repeatedly delivered STHS gives better preservation of postischemic mechanoenergetic function and lower troponin T release compared with single dose HTK cardioplegia, indicating improved cardioprotection with STHS.