Limitations of pulmonary wedge V waves in diagnosing mitral regurgitation.

To study the usefulness of large V waves in pulmonary capillary wedge tracings in establishing the diagnosis of mitral regurgitation, data on 1,021 consecutive cardiac catheterizations were reviewed. Wedge tracings were obtained by Swan-Ganz catheterization in 208 patients, usually because of suspected valve disease. One hundred two patients had no trace of mitral regurgitation angiographically, 69 had mild to moderate and 37 had severe regurgitation. V waves were graded as trivial (less than 5), intermediate (5 to 10) or large (10 or more mm Hg above mean wedge pressure). Of 50 patients with large V waves, 18 (36 percent) had no or trace mitral regurgitation; these included 5 with mitral stenosis, 3 with a mitral valve prosthesis, 4 with coronary disease and congestive failure, 2 with aortic valve disease and congestive failure and 2 with a ventricular septal defect. Of 37 patients with severe mitral regurgitation, 16 (43 percent) had large and 12 (32 percent) had trivial V waves. Thus, mitral regurgitation is the most common cause of large V waves; however, large V waves are neither highly sensitive nor specific for severe regurgitation. Increased left atrial compliance may be associated with trivial V waves in the presence of severe regurgitation. Mitral obstruction, congestive heart failure and ventricular septal defect may all be associated with large V waves in the absence of significant mitral regurgitation.