Evaluation of myocardial contractility determination with tissue tracking echocardiography after levosimendan infusion in patients with poor left ventricular function and hemodynamics

The efficacy and safety of prophylactic use of levosimendan on patients undergoing coronary artery bypass graft: a systematic review and meta-analysis

Prophylactic use of levosimendan in cardiac surgery remains controversial and no meta-analysis has been done exclusively about that in patients undergoing coronary artery bypass graft (CABG) surgery. We conducted this systematic review and meta-analysis of levosimendan in CABG using PubMed, Embase, Scopus, and Cochrane Library (till April 20, 2018). Two-hundred and forty manuscripts were identified and 21 randomized trials (1727 patients in total) investigating the effect of levosimendan on the patients undergoing CABG surgery were finally included in this analysis. We found that levosimendan was an effective, well-tolerated inotropic agent in CABG, which was associated with a significantly reduced mortality rate [odds ratio (OR) 0.43, 95% confidence interval (CI) (0.26, 0.71), p = 0.001, I² = 0%] and postoperative atrial fibrillation [OR 0.50, 95% CI (0.26, 0.97), p = 0.04, I² = 76%], but a higher incidence of hypotension [OR 2.26, 95% CI (1.05, 4.85), p = 0.04, I² = 79%]. Subgroup analyses revealed that such a benefit was mainly observed in the isolated CABG, the preoperative administration, with-bolus and on-pump subgroups. More high-quality and well-designed prospective studies are needed to confirm or disprove our findings in future.

Myocardial contractility assessed by dynamic electrical impedance measurements during dobutamine stress

In this study, the electrical impedance of myocardial tissue is measured dynamically during the cardial cycle. The multisine-based approach used to perform electrical impedance spectroscopy (EIS) measurements allows acquiring complete spectral impedance information of the tissue dynamics during contraction. Measurements are performed in situ in the left ventricule of swines during contractility stress tests induced by dobutamine infusion. Additionally, the ECG and the left ventricular (LV) pressure are also acquired synchronously to the impedance signals. The calculated impedance magnitude exhibits a periodic behavior during tissue contraction. The amplitude (peak-to-peak) of this signal is quantified and the compared to the maximum first derivative of the LV pressure (dP/dtmax) that is used as an indicator of contractility variations. The results show a linear correlation between impedance amplitude and dP/dtmax during dobutamine-increased contractility. The present work demonstrates how fast EIS measurements during heart contraction can represent a feasible method to assess changes in myocardial contractility.