The Parasternal Long Axis View in Isolation: Is it Good Enough?

Background: Focused cardiac ultrasound (FOCUS) is a vital tool to evaluate patients at the bedside, but its use can be limited by patient habitus, sonographer skill, and time to perform the examination.

Objective: Our primary goal was to determine the diagnostic accuracy of the parasternal long axis (PSLA) view in isolation for identifying pericardial effusion, left ventricular (LV) dysfunction, and right ventricular (RV) dilatation compared with a four-view FOCUS examination.

Methods: This was a retrospective study looking at FOCUS images. Examinations were blinded and randomized for review by point-of-care ultrasound faculty. The primary objective was measured by comparing ultrasound findings on PSLA view in isolation with findings on a full four-view FOCUS examination, which served as the criterion standard. Sensitivity and specificity were calculated.

Results: Of 100 FOCUS examinations; 36% were normal, 16% had a pericardial effusion, 41% had an LV ejection fraction < 50%, and 7% had RV dilatation. Sensitivity and specificity for identifying pericardial effusion, LV dysfunction, and RV dilatation were 81% (confidence interval [CI] 0.54-0.95) and 98% (95% CI 0.91-0.99), 100% (95% CI 0.88-1) and 91% (95% CI 0.80-0.97), and 71% (95% CI 0.30-0.94) and 99% (95% CI 0.93-1), respectively. All moderate to large effusions were identified correctly. Overall, there were only four clinically significant disagreements between PSLA alone and the four-view interpretations.

Conclusions: In isolation, the PSLA view was highly sensitive and specific for identifying LV ejection fraction and moderate to large pericardial effusions. It was highly specific for identifying RV dilatation, but had only moderate sensitivity.