Impact of harmonic imaging on transthoracic echocardiographic identification of infective endocarditis and its complications

Objective: To evaluate the comparative diagnostic value of harmonic imaging ( HI) in the assessment of patients with suspected infective endocarditis ( IE). Setting: Tertiary referral centre. Design: 139 consecutive patients were evaluated with three imaging modalities: transthoracic echocardiography with fundamental imaging ( FI); HI; and transoesophageal echocardiography ( TOE). Image quality was assessed for each modality by semiquantitative scoring ( 0, poor, to 3, excellent). Presence, dimension, and characteristics of vegetations were assessed separately for each imaging modality, as well as presence of abscesses. Results: 35 patients had definite IE. TOE was positive in 33 patients, HI in 28, and FI in 12 ( p< 0.001 for FI v HI and v TOE). Mean image quality was 1.4 ( 0.7) for FI, 2.1 ( 0.6) for HI ( p< 0.01 v FI), and 2.6 ( 0.4) for TOE ( p< 0.001 v HI). The association between FI and TOE findings was Phi = 0.35 (chi(2) = 17.57, p = 0.0014) and between HI and TOE it was Phi = 0.95 (chi(2) = 125.72, p< 0.0001; p< 0.0001 v FI). The global echo score of vegetations was 7.1 ( 3.3) with FI, 8.5 ( 3.4) with HI, and 11.3 ( 3.9) with TOE ( p, 0.001 v HI). Compared with TOE, FI identified only one of seven abscesses ( sensitivity 14%) and HI identified two of seven abscesses ( sensitivity 28%). Conclusions: HI provides an accurate assessment of suspected IE. TOE achieves superior definition of IE related abnormalities.