3D echo in everyday life: Could it reset our threshold for interventions?

Abstract

Background Left ventricular ejection fraction (LVEF), the single most important metric in cardiology, is the cornerstone on which prognosis is estimated and costly decisions such as whether to implant an ICD are based. LVEF is most often assessed by 2D echocardiography (2DE), although 3D echocardiography (3DE) has been shown repeatedly to be more accurate. Aim of the study. We set out to assess whether using 3DE would reclassify the severity of LV impairment in patients with LVEF < 35% by 2DE. Setting. Tertiary cardiac centre serving a population of one million, and performing approximately 100 ICD implants/year. Methods. Successive patients in sinus rhythm, with good endocardial border definition and LVEF<35% by 2D Simpson’s method, had scans according to the BSE protocol. 3D loops were acquired from the apical 4-chamber view and were analysed off-line using for regional wall motion abnormalities (RWMAs) and LVEF. The patients were classified in subgroups according to EF value: less than 20%, 20-25%, 25-30%, 35% and more than 35%. Moderate LV systolic was defined as LVEF between 35% and 45% and severe as LVEF ≤35%. Results. We studied 100 patients (78 M, mean age (SD) 69.94 (13.54) years). 2DE had been requested for decision-making regarding ICD implantation in 86 patients (86%) and for LVEF measurement after acute coronary syndromes in 14 patients (14%). Regional wall motion abnormalities (RWMAs) were present in half of patients (55%, 51 pts – 56% in LAD territory, 31% in RCA/CX territory and 12% multiple territories). 3D LVEF regrouped 67% of patients: 10% to a lower EF and 57% to a higher EF subgroup. Twenty nine patients (29%) were reclassified from severe LV systolic dysfunction by to 2DE to moderate LV systolic dysfunction by 3DE. Patients with RWMAs were more often reclassified than patients without RWMAs (p=0.006). The LV dimensions were lower for the reclassified patients. The image quality had no effect on reclassification. Conclusion Measuring LVEF by 3DE reclassifies the severity of LV systolic impairment in a substantial proportion of patients with 2D LVEF<35% and RWMAs, which may have important clinical and financial implications by resetting thresholds for costly interventions such as ICD implants. Keywords: biological attack, biological warfare, biological agents, international legislation, medical protection.