Fourier phase analysis of SPECT equilibrium radionuclide angiography in symptomatic patients with mitral valve prolapse without significant mitral regurgitation: Assessment of biventricular functional abnormalities suggesting a cardiomyopathy

Background. Ventricular premature beats are common in patients with mitral valve prolapse (MVP), The purpose of this study was to determine whether sy mptomatic patients with MVP had certain functional characteristics and if v entricular arrhythmia (VA) could be explained by functional extravalvular a bnormalities. Single photon emission computed tomography equilibrium radion uclide angiography with Fourier phase analysis was preferred to the planar radionuclide method. Only patients without significant mitral regurgitation were studied. Methods and Results, A total of 23 symptomatic patients with MVP (13 men, 1 0 women, mean age, 47 +/- 14 years) without mitral regurgitation underwent single photon emission computed tomography equilibrium radionuclide angiogr aphy, Symptoms were present in 20 patients, and VA was present in 14 patien ts. Ejection fraction, regional wall motion, and Fourier phase analysis wer e examined in both ventricles and compared with results for normal subjects . Ventricular abnormalities were observed in 20 (87%) patients: decreased l eft ventricular and; right ventricular ejection fractions, increased standa rd deviations of the mean phase and focal wall motion, and/or delayed phase abnormalities. Abnormalities were less frequent but more marked in the rig ht ventricular free wall, the infundibulum, or the septum compared with lef t ventricular delayed abnormalities, which were more frequent but limited. In 12 of 14 patients with VA, phase-delayed areas were observed in the vent ricle where the origin of ventricular premature beats was suspected on the basis of their electrocardiographic morphologic features. A relation was fo und between late potentials and delayed-phase areas (right ventricle or sep tum) and left bundle branch block morphologic features of VA. Conclusions. Symptomatic patients with MVP frequently have ventricular dysf unction in 1 or both ventricles, sometimes limited but more marked in the p resence of severe VA even without significant mitral regurgitation, suggest ing structural modification. The use of a sensitive, accurate, and 3-dimens ional method such as single photon emission computed tomography equilibrium radionuclide angiography may be of interest for a noninvasive investigatio n, especially in young symptomatic patients with MVP and VA.