Validation of Global Longitudinal Strain and Strain Rate as Reliable Markers of Right Ventricular Dysfunction: Comparison with Cardiac Magnetic Resonance and Outcome

ABSTRACT

BACKGROUND: Right ventricular (RV) dysfunction in ischemic cardiomyopathy (ICM) is associated with poor prognosis, but RV assessment by conventional echocardiography remains difficult. We sought to validate RV global longitudinal strain (RVGLS) and global longitudinal strain rate (RVGLSR) against cardiac magnetic resonance (CMR) and outcome in ICM. METHODS: In 57 patients (43 men, 64 +/- 12 years) with ICM who underwent conventional and strain echocardiography and CMR, RVGLS and RVGLSR were measured off-line. RV dysfunction was determined by CMR [RV ejection fraction (RVEF) < 50%]. Patients were followed over 15 +/- 9 months for a composite of death and hospitalization for worsening heart failure. RESULTS: RVGLS showed significant correlations with CMR RVEF (r = -0.797, p < 0.01), RV fractional area change (RVFAC, r = -0.530, p < 0.01), and tricuspid annular plane systolic excursion (TAPSE, r = -0.547, p < 0.01). RVGLSR showed significant correlations between CMR RVEF (r = -0.668, p < 0.01), RVFAC (r = -0.394, p < 0.01), and TAPSE (r = -0.435, p < 0.01). RVGLS and RVGLSR showed significant correlations with pulmonary vascular resistance (r = 0.527 and r = 0.500, p < 0.01, respectively). The best cutoff value of RVGLS for detection of RV dysfunction was -15.4% [areas under the curve (AUC) = 0.955, p < 0.01] with a sensitivity of 81% and specificity 95%. The best cutoff value for RVGLSR was -0.94 s-1 (AUC = 0.871, p < 0.01), sensitivity 72%, specificity 86%. During follow-up, there were 12 adverse events. In Cox-proportional hazard regression analysis, impaired RVGLS [hazard ratio (HR) = 5.46, p = 0.030] and impaired RVGLSR (HR = 3.95, p = 0.044) were associated with adverse clinical outcome. CONCLUSION: Compared with conventional echocardiographic parameters, RVGLS and RVGLSR correlate better with CMR RVEF and outcome.