Contrast echocardiography for assessing left ventricular vortex strength in heart failure: a prospective cohort study

This study investigated the incremental role of echocardiographic-contrast particle image velocimetry (Echo-PIV) in patients with heart failure (HF) for measuring changes in left ventricular (LV) vortex strength (VS) during phases of a cardiac cycle. Echo-PIV was performed in 42 patients, including 23 HF patients and 19 controls. VS was measured as a fluid-dynamic parameter that integrates blood flow rotation over a given area and correlated with non-invasively derived indices of LV mechanical performance. In comparison with early and late diastole, the VS was higher during isovolumic contraction (IC) for control and HF patients with the preserved ejection fraction (P = 0.002 and P = 0.01, respectively), but not for HF patients with the reduced ejection fraction (P = 0.41). On multivariable regression analysis, the VS during IC (VSIC) was independently related to late-diastolic VS and LV longitudinal strain (R(2)= 0.63, P < 0.001 and P = 0.003, respectively). Patients in whom diastolic VS was augmented during IC showed a higher LV stroke volume (P = 0.01), stroke work (P = 0.02), and mechanical efficiency (P = 0.008). Over a median follow-up period of 2.9 years, eight (34%) HF patients were hospitalized for decompensated HF. In comparison with the rest, these eight patients showed markedly reduced longitudinal strain (P = 0.002), and lower change in VS (P = 0.004). Our preliminary data suggest that the persistence of vortex from late diastole into IC is a haemodynamic measure of coupling between diastole and systole. The change in VS is correlated with LV mechanical performance and shows association with adverse clinical outcomes seen in HF patients.