Impact of right ventricular systolic function in patients with significant tricuspid regurgitation. A cardiac magnetic resonance study.

BACKGROUND: Right ventricle (RV) dilatation and dysfunction are established criteria for intervention in severe tricuspid regurgitation (TR); however thresholds to support intervention are lacking. New measures of RV function such as RV shortening (RVS) and effective RV ejection fraction (eRVEF) may be earlier markers of RV dysfunction. PURPOSE: to compare the prognostic impact of different parameters of RV function and to describe cut-off values of RV size/function and TR severity of poor prognosis. METHODS: Consecutive patients evaluated in the Heart Valve Clinic with significant TR (severe, massive or torrential TR) undergoing a CMR study were included. In addition to parameters of biventricular volume and function, RVS and eRVEF were assessed. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined. RESULTS: 75 patients were included (age 75 ± 8 years, female 75%). During a median follow-up of 3 years (IQR: 1.4-3.9 years), 39% experienced the endpoint. Cut-off values of worse prognosis were: RVS ≥ -14%, eRVEF ≤34%, RVEF ≤58%, RV-EDV ≥100 ml/m2, TR regurgitant fraction (TRF) ≥40% and TR volume ≥ 42 ml. RVS and eRVEF identified higher rates of RV dysfunction than RVEF. After adjustment for age and LVEF, both eRVEF ≤34% (HR: 5.29 [2.25-12.4]) and RVS ≥ -14% (HR: 3.46 [1.13-9.17]) were significantly associated with outcomes. Among all parameters of RV function, eRVEF was the strongest predictor of outcomes, incremental to RVEF (ΔC-statistic 0.139 [0.040-0.237], p = 0.005). Patients with eRVEF ≤34% and RV-EDV ≥100 ml/m2 or eRVEF ≤34% and TRF ≥40% had the worst prognosis (p < 0.01 for both). CONCLUSION: RVS and eRVEF identify higher rates of RV dysfunction beyond RVEF. Among all measures, eRVEF held the strongest association with outcomes, incremental to RVEF.

Prognostic implications of global myocardial mechanics in hypertrophic cardiomyopathy by cardiovascular magnetic resonance feature tracking. Relations to left ventricular hypertrophy and fibrosis.

BACKGROUND: Interstitial fibrosis, myocardial fiber disarray and non-uniform shortening are common histological features of hypertrophic cardiomyopathy (HCM). The degree of LV hypertrophy and fibrosis are postulated to contribute to the impairment of myocardial shortening. Cardiovascular magnetic resonance myocardial (CMR) feature tracking (CMR-FT) has emerged as a robust method that provides quantitative measurements of myocardial deformation. Our aim was first to evaluate LV strain parameters in HCM by CMR-FT and their dependence on both functional parameters and late gadolinium enhancement (LGE); and secondly we sought to determine their association with major cardiovascular outcomes. METHODS AND RESULTS: 74 patients with HCM and 75 controls subjects underwent a CMR study including LGE imaging. Global peak longitudinal, circumferential and radial systolic strain values (GLS, GCS, GRS) were measured by CMR-FT. A primary endpoint of all-cause mortality and secondary combined endpoint of hospital admission related to heart failure, lethal ventricular arrhythmias or cardiovascular death were defined. Patients with HCM showed attenuation of all LV strain values (p<0.001). Multivariate analysis showed that both LV hypertrophy and %of LGE were independent predictors of attenuated LV strains. All systolic LV strain parameters were impaired in patients with primary and secondary endpoints (follow up time: 25.6±9.9months, p<0.05 and p<0.01 respectively). Abnormal GLS, GCS and GRS were significantly associated with primary and secondary endpoints. CONCLUSION: Both LV hypertrophy and fibrosis contribute to the impairment of LV myocardial mechanics in HCM. In this population, reduced LV strain is associated with poor cardiac outcomes, particularly cardiovascular mortality and HF.