60/60 sign in acute pulmonary embolism is a pattern detected by Doppler echocardiography indicating a disturbed right ventricular ejection pattern.
The sign has two components:
Tricuspid regurgitation (TR) jet gradient of less than 60 millimeters of mercury (TR velocity less than 3.9 meters per second)
Pulmonary flow acceleration time of less than 60 milliseconds [1,2].
It may be noted that TR gradient should be above 30 mm Hg to indicate pulmonary hypertension due to pulmonary embolism. High TR gradients may indicate chronic thromboembolic pulmonary hypertension, especially in presence of right ventricular free wall hypertrophy suggesting long standing pulmonary hypertension.
False positive results have been noted in pulmonary fibrosis and acute respiratory distress following lung resection . 60/60 has been noted to have a sensitivity of 25% and specificity of 94% in one study , compared to 19% sensitivity and 100% for McConnell sign. But other studies have shown false positivity for McConnell sign as right ventricular free wall hypokinesia/akinesia can occur in right ventricular myocardial infarction as well (McConnell sign is hypokinesia of right ventricular free wall with relative sparing of the contraction of right ventricular apex).
Kurzyna M, Torbicki A, Pruszczyk P, Burakowska B, Fijałkowska A, Kober J, Oniszh K, Kuca P, Tomkowski W, Burakowski J, Wawrzyńska L. Disturbed right ventricular ejection pattern as a new Doppler echocardiographic sign of acute pulmonary embolism. Am J Cardiol. 2002 Sep 1;90(5):507-11.