Large V waves in the pulmonary wedge pressure tracing in the absence of mitral regurgitation

The accurate diagnosis of mitral regurgitation has important therapeutic implications. We have observed that large V waves in the pulmonary wedge pressure (PW) may be misleading In the diagnosis of mitral regurgitation. Of 237 consecutive patients with high quality hemodynamic, angiographic, and echocardiographic data, 27 had large V waves (peak V 10 mm Hg greater than pulmonary wedge mean pressure). Ventriculograms were analyzed in blind fashion by 3 expert angiographers for any angiographic evidence of mitral regurgitation; 17 patients had mitral regurgitation (group I), and 10 did not (group II). The control group (group III) of 22 patients had normal V waves and no mitral regurgitation. Twenty-two hemodynamic and echocardiographic variables were compared among groups. The only significant difference between groups I and II was in the slope of the ascent of the V wave (74.3 versus 141.9 mm/s, p = 0.021), also expressed as the mitral regurgitation index (6.01 versus 9.45, p = 0.005). A slope of 100 mm/s or slower had a sensitivity of 80% to confirm mitral regurgitation and a specificity of 70% to rule it out. The size of the V wave and the V PW mean ratio were similar in groups I and II (38.5 ± 11 versus 37.5 ± 11 mm Hg, and 1.67 ± 0.3 versus 1.69 ± 0.4, respectively, mp = NS) and were not helpful in predicting the presence or absence of mitral regurgitation. Among patients without mitral regurgitation (groups II and III), those with large V waves had a higher pulmonary wedge mean pressure (23.5 versus 15.6 mm Hg, p = 0.01), a higher A wave (25.3 versus 16.4 mm Hg, p = 0.032), a more elevated mitral regurgitation index (9.45 versus 3.99, p = 0.001), a larger left atrial size (24.5 versus 21.6 cc, p = 0.05), a greater V wave to pulmonary wedge mean pressure ratio (1.69 versus 1.10, p = 0.001), and a faster slope of ascent of the V wave (141.9 versus 53.05 mm/s, p = 0.005). We conclude that large V waves in the pulmonary wedge pressure tracing can be seen in the absence of mitral regurgitation. The size of the V wave is related to factors that determine left atrial compliance. Caution is called for in the diagnosis of mitral regurgitation by pulmonary wedge pressure alone.