Myocardial work analysis in left ventricular non-compaction, and its association with cardiovascular outcomes

Abstract

Abstract Introduction Left ventricular (LV) non-compaction (LVNC) is a rare cardiomyopathy characterised by a two-layered LV myocardium with prominent trabeculae separated by deep recesses perfused from the LV cavity. Myocardial work analysis (MWA) is a novel echocardiographic method that calculates pressure-strain loops from longitudinal strain and bedside blood pressure measurement. Our study investigates the MWA features of LVNC patients and their association with outcomes. Methods We compared 40 LVNC with preserved LVEF (≥50%) (pEF-LVNC) and 40 LVNC patients with reduced LVEF (<50%) (rEF-LVNC) to 40 healthy matched controls. GE EchoPAC® (Version 203) was used for echocardiographic analysis. A combined endpoint was defined as heart failure progression, sustained ventricular tachycardia, thromboembolic accidents, and atrial fibrillation. Results Clinical characteristics, conventional echocardiography, and strain analysis results are detailed in Table 1 and Figure 1. Myocardial work index was significantly reduced in rEF-LVNC (1088 [138–1211 mm.Hg%]) and pEF-LVNC (1394 [1138–1501 mm.Hg%]) in comparison to control (1827 [1758–1981 mm.Hg%]), but there was no difference between the two LVNC groups. Global constructive work (GCW) was significantly lower in rEF-LVNC (1094 [947–1281 mm.Hg%]) than in pEF-LVNC (1730 [1368–1691 mm.Hg%]) (p=0.001), while both LVNC groups were lower than control (2201 [1965–2406 mm.Hg%]) (pEF-LVNC p=0.001, rEF-LVNC p<0.0001). Global wasted work (GWW) was significantly lower in rEF-LVNC (204 [181–231 mm.Hg%]) than in pEF-LVNC (154 [115–171 mm.Hg%], p<0.0001) and control (61 [45–98 mm.Hg%], p<0.0001). Global work efficiency (GWE) was significantly lower in rEF-LVNC (18.3 [15.4–19.6%], p=0.001 than in pEF-LVNC and control. In both pEF-LVNC and rEF-LVNC, impaired GWE and GCS were the parameters most significantly associated with increased risk of cardiovascular events as detailed in Figure 2. Conclusion MWA is a promising parameter for risk assessment of LVNC patients especially because it is less load-dependent and, unlike LVEF, incorporates left ventricular haemodynamics. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): 2018 research grant from the Swiss Heart Foundation