Myocardial work indices in bileaflet mitral valve prolapse patients

Abstract

Aims: Mechanisms underlying left ventricular dysfunction and arrhythmogenesis in bileaflet mitral valve prolapse (BMVP) patients are not well defined. Myocardial work index (MWI) is a non-invasive assessment that correlates with myocardial oxygen consumption. We aimed to compare global and regional MWI in BMVP patients with normal controls.

Methods and results: In this retrospective study, we calculated MWI in BMVP patients and controls using GE EchoPAC (GE Healthcare, Chicago, IL, USA) software. Of 147 BMVP patients (59% women, mean age 54 ± 15 years), 16 had a flail mitral leaflet. There was regional heterogeneity in MWIs, with increased posterolateral trident myocardial work (2099 ± 271 vs. 1895 ± 321 mm Hg%, P = 0.039), constructive work (2831 ± 366 vs. 2257 ± 338 mm Hg%, P < 0.001), wasted work [87 (52-194) vs. 71 (42-103) mm Hg%, P = 0.015], peak systolic strain (-23.0 ± 2.4 vs. -19 ± 3%, P < 0.001), and reduction in myocardial work efficiency [95.00 (93.50-97.75) vs. 96.75 (95.00-97.75) %, P = 0.020] in 100 BMVP patients compared with age- and sex-matched controls. BMVP patients' basal septal wall MWIs were lower than those of controls. The higher work indices in patients with BMVP were reduced in those who developed flail leaflets. No significant differences in work indices were seen between ventricular arrhythmia and non-arrhythmia BMVP patients.

Conclusion: Regional differences in MWIs were noted in the BMVP patients compared with controls, with overall reduced myocardial efficiency in the posterolateral trident and basal septal regions. In cross-sectional analysis, MWIs were not different in patients with ventricular tachyarrhythmias. Impact of MWI on long-term prognosis needs to be determined.

Keywords: bileaflet mitral valve prolapse; constructive work; myocardial work indices; pressure–strain loop; wasted work.