Imaging characteristics of papillary muscle site of origin of ventricular arrhythmias in patients with mitral valve prolapse.

BACKGROUND: Mitral valve prolapse has been associated with increased risk of ventricular arrhythmias. We aimed to examine whether certain cardiac imaging characteristics are associated with papillary muscle origin of ventricular arrhythmias in these patients. METHODS AND RESULTS: We screened electronic medical records of all patients documented to have mitral valve prolapse on either transthoracic echocardiogram (TTE) or cardiac magnetic resonance imaging (CMR) in our center, who also underwent an electrophysiologic study (EPS) between 2007 and 2016. Anterior and posterior mitral leaflet thickness and prolapsed distance were measured on TTE and late gadolinium enhancement (LGE) was assessed on CMR. Patients were categorized as papillary muscle positive (pap (+)) or negative (pap (-)) using EPS. Eighteen patients were included in this study. Of the 15 patients who underwent TTE, a significantly higher proportion of patients in the pap (+) group had an anterior to posterior leaflet prolapse ratio of >0.45 indicating more symmetric leaflet prolapse. There were no differences in anterior or posterior leaflet thickness or prolapse distance between the groups. Patients in the pap (+) group were more likely to be women. Of the 7 patients who underwent CMR, those who were pap (+) were more likely to have LGE in the region of the papillary muscles than those who were pap (-). CONCLUSION: Female gender, more symmetric bileaflet prolapse on TTE, and the presence of papillary muscle LGE on CMR may be associated with papillary muscle origin of ventricular arrhythmias in patients with mitral valve prolapse.

[Symptomatic mitral valve prolapse. Left ventricular dysfunction and beneficial effect of digitalis]. / Prolapso sintomático da válvula mitral. Disfunção ventricular esquerda e efeito benéfico do digitálico.

PURPOSE: To study the left ventricular function by M-mode echocardiography in symptomatic patients with primary mitral valve prolapse (MVP), without significant mitral regurgitation, during the phenylephrine test, before and after digitalization. METHODS: Thirty one patients with MVP and 10 normal subjects as a control group were studied by M mode echocardiography: Percentage of systolic shortening (DD), ejection fraction (EF) and mean velocity of circumferential fibers shortening (Vcf) were measured. The echocardiographic recordings were obtained at rest and during the continuous infusion of phenylephrine (40-60 micrograms/min) in order to allow an increase of 20-30 mmHg in systolic pressure. RESULTS: At rest, cardiac size and function were normal in both groups. During phenylephrine infusion in 27 patients a decrease in DD (from 37.7 +/- 4.6 to 31.0 +/- 4.0, p < 0.001); in EF (from 0.76 +/- 0.05 to 0.66 +/- 0.6, p < 0.001); in Vcf (from 1.05 +/- 0.77 to 0.76 +/- 0.13, p < 0.001) were observed. From this group 20 patients received digoxin. After the digitalization the phenylephrine test did not cause changes in DD (from 38.3 +/- 5.0 to 39.2 +/- 3.8, NS); in EF (from 0.77 +/- 0.06 to 0.77 +/- 0.04, NS); in Vcf (from 1.05 +/- 0.19 to 0.94 +/- 0.13, NS). These patients during the submaximal exercise test, showed significant increases at the total work load (from 617 +/- 248 to 982 +/- 244 watts, p < 0.001) and cardiac efficiency (from 25.0 +/- 11.5 to 37.2 +/- 10.4, p < 0.001). On the other hand the phenylephrine infusion in the control group did not result in changes in DD, EF and Vcf. CONCLUSION: Symptomatic patients with primary MVP showed total recovering of left ventricular dysfunction with digitalization during the phenylephrine test, with improvement of cardiac efficiency.

[Clinical survey of 126 cases with mitral valve prolapse detected at the annual health check-up].

Clinical and echocardiographic survey of mitral valve prolapse (MVP) was performed in 616 cases, which were selected from about 6,000 health check-up. An echocardiographic study revealed MVP in 126 cases. The prevalence of MVP was about 2% (health check-up survey) and 20.5% (echo study). The male and female ratio was 102/24. Frequent premature contractions, isolated atrial fibrillation and an apical systolic murmur were more frequently associated with MVP. Among 13 cases of isolated atrial fibrillation, seven with MVP were permanent, while other six without MVP were transient. Most cases (77%) were asymptomatic. Mild mitral regurgitation proved by auscultation and phonocardiography was observed in only two cases (1.6%), and most of the cases (81%) had no mitral regurgitant signals by a Doppler study.