Clinical Mitral vake
A. James Liedtke, M.D. Joseph D. Babb, M.D. Robert L. DeJoseph, M.D. Hershey,
Echocardiography has proved of invaluable assistance in expanding our recognition of patients with the mid-systolic click, late-systolic murmur, or mitral valve prolapse syndrome. Recently a patient with this syndrome was studied at this institution and noted to have an additional echocardiographic finding in diastole which closely mimicked prolapsing left atria1 myxoma’ or flail posterior mitral valve leaflet.’ Neither of these conditions was present by other criteria. Such an unusual echocardiographic pattern is not commonly recognized in mitral valve prolapse and the authors were able to find only one prior reference to its presence in the literature.:’ Information concerning its prevalence and specificity are currently unavailable. We therefore undertook the present survey to describe this disorder and quantitate its occurrence in separate populations of patients with and without mitral valve prolapse. Data in support of a possible mechanism for the presence of this echocardiographic picture are also discussed. Patient
Echocardiograms done at this institution in the past three years were reviewed from a series of 100 patients with the presumptive diagnosis of mitral valve prolapse and from a group of 50 patients without this disorder. Twenty-three recordings were ultimately judged to be technically unsuited for definitive evaluation and were discarded from From the Division of Cardiology, Department of Medicine, The Milton S. Hershey Medical Center, The Pennsylvania State University College of‘ Medicine, Hershey, Pa. Received Accepted
A. James Liedtke, M.D., Division Center, Hershey, Pa. 17033.
analysis. Mitral valve prolapse was determined echocardiographically using the criteria developed by Kerber, Dillon, Popp, and DeMaria and co-workers-‘: buckling in midsystole, pansystolic bowing, or pansystolic collapse of the mitral echoes. Of the 83 patients with satisfactory recordings who met these criteria, 50 were female and 33 were male. Their average age was 35.1 years, with a range from 12 to 73 years. Of the control group of 44 patients without mitral valve prolapse, 21 were female and 23 were male with an average age of 40.8 years (range 14 to 63 years). Echocardiographic examinations were performed with an Ekoline 20A echograph coupled to a Honeywell model 1856 recorder. A 2.25 MHz Aerotech transducer with an outer diameter of 1.25 cm. focused at 7.5 cm. I.F. was used. Technics for performing the echocardiograms were reviewed independently by each investigator. Unanimous agreement as to the presence of the diastolic echocardiographic finding was required for inclusion in the study. Correlative clinical information was similarly obtained from all patients. Fifteen patients with mitral valve prolapse also underwent right and left heart catheterization. Methods of angiographic motion analysis were as previously described.” Group statistical comparisons were made by Chi-square and nonpaired Student’s t testing with significance defined as probability values less than five per cent. Results Three subgroups of patients were categorized for comparisons. The first group of 44 “control” patients without mitral valve prolapse diagnosed by echocardiogram had a variety of clinical diag-
noses. These included both cardiac (coronary artery disease, other chest pain syndromes, dysrhythmias, and various heart murmurs compatible in nature with either innocent flow murmurs, aortic stenosis, or atypical forms of mitral regurgitation) and non-cardiac diagnoses (renal failure, pulmonary emboli, acute pancreatitis, and fevers of unknown origin). None of these patients demonstrated the pattern of diastolic echoes under discussion. Contrasted with these was a population of 83 patients with the mitral valve prolapse syndrome, 71 of whom did not have the diastolic echocardiographic finding and 12 (14.5 per cent) of whom did (P < .Ol by Chi-square testing as compared to 2 x k contingency patients without mitral valve prolapse). Typical features of this finding are shown for two representative patients in Fig. 1. After first angling the transducer to locate the mitral valve apparatus,’ the ultrasonic beam was directed caudally to optimally transverse the structures of the anterior and posterior mitral valve leaflets. As shown, a series of roughly parallel echo signals were observed beneath the anterior mitral valve leaflet. These were very much akin to those previously reported in pedunculated and prolapsing left atria1 myxoma (but without an echoproducing tumor mass in the left atrium) or in flail mitral leaflet (such as occurs either in bacterial endocarditis or chordae rupture secondary to myxomatous degeneration). The latter diagnoses were all excluded by differential features in either the clinical course and/or specific laboratory testings. From the usual array of symptomatic complaints commonly reported by patients with this syndrome (atypical chest pain, dyspnea, fatigue, palpitations, syncope, and congestive heart failure), no one historical symptom predictably distinguished the group with diastolic echoes from those without. Similar results were obtained from a review of the physical findings (nonejection clicks, late systolic murmurs, gallop rhythms, rales, peripheral edema, and other chest wall and musculoskeletal abnormalities). The group with diastolic echoes did manifest a slight but significantly higher incidence of electrical events as recorded by routine electrocardiogram or 24-hour Holter monitoring. These included mild-to-moderate numbers of premature atria1 contractions (P < .Ol) and self-limiting runs of ventricular tachycardias (P < .005). There were
Fig. 1. Two patients (upper and lower sentativediastolic echo patterns beneath
reprethe anterior leaflets of the mitral valve (MV) as observed in their echocardiograms. These findings were typical of those noted in the 12 patients reviewed in this report.
no significant differences in estimates of internal size or geometry for the left atrium, left ventricle, and aortic root as measured by echocardiogram. Fifteen patients with the echocardiographic diagnosis of mitral valve prolapse underwent cardiac catheterization. Four of these patients had the diastolic echo finding under discussion; 11 did not. Prolapse of the posterior leaflet of the
Fig. 2. A schematic illustration (lateral projection) of one possible mechanism to explain the diastolic echoes noted in 12 patients with mitral valve prolapse discussed in this study. Either through patulous transformation of the leaflet, elongation of the chordae, or loss of support of the inferior papillary muscle, the posterior leaflet during diastole may be drawn forward (indicated by single arrow), possibly from a venturilike effect of rapid ventricular filling, and “curl” (indicated by double arrows) beneath the anterior leaflet, thus giving rise to the characteristic diastolic echoes.
mitral valve was angiographically confirmed in all cases. There was nothing by hemodynamic status or by contrast angiography to suggest that those patients with the diastolic echoes had more longstanding or severe forms of mitral leaflet prolapse or mitral regurgitation. The group with the diastolic echoes did have postero-inferior hypokinesis beneath the mitral valve as determined by segmental motion analysis of the ventriculogram which has been previously reported.” Discussion
A major breakthrough in the diagnosis of mitral valve prolapse has occurred with the advent of echocardiography.” With proper regard to technique and transducer positioning,“. lo this method has provided easily recognizable and highly distinguishing features, the most frequent of which include: a smooth pansystolic posterior hammock-like bowing of the mitral valve leaflets (perhaps the most common), a mid-to-late systolic posterior motion of the leaflets extending at least two mm. posterior from the line of normal coaptation, and/or a marked posterior motion of the anterior mitral leaflet echo back toward the left atria1 wall visible for more than 50 per cent of systole.7, l1 Little has previously been written of any comparable motion abnormalities in diastole. Felner and Schlant” did report a finding, presumably identical to that described here, which closely mimicked prolapsing left atria1 myxoma or valvular vegetations on a flail posterior mitral
valve leaflet.‘-” They attributed this peculiarity to echoes resulting from hyperdynamic motion of the left atria1 wall. Proof of this was not elucidated nor were statistics provided to describe the prevalence and specificity of this pattern in mitral valve prolapse. Our data, retrospectively reviewed from 83 patients with the click-murmur syndrome and from 44 patients without this dysfunction, established that the diastolic echoes were unique to those with mitral valve prolapse (P < .Ol). The finding was not common in prolapse patients but did occur with a frequency of 14.5 per cent. None of the many presenting features of the history or physical examination appeared helpful in predicting those patients ultimately found to have the abnormality. Similarly there was no evidence to indicate by angiography or echocardiography that the hemodynamic status or mitral regurgitation was worse in those patients with the diastolic echoes. The frequency of dysrhythmias (increased prevalence of premature atria1 contractions and self-limiting runs of ventricular tachycardia in the subgroup with diastolic echoes) was interesting but too nonspecific for the purpose of identifying subgroups. The differential diagnosis for this finding was confined to alternate considerations of left atria1 myxoma and flail mitral leaflet. Myxoma may be easily excluded by additional echocardiographic criteria (no echo-producing mass in the left atrium or echo-free space between the anterior mitral valve leaflet and the diastolic echoes in early diastole) and other clinically distinguishing features. Flail mitral leaflet secondary to chordae rupture may prove more difficult due to the obvious overlap in semantic classifications and clinical spectrums of the two diseases. Chordal dysplasia in the mitral valve prolapse syndrome may lead to spontaneous rupture of one or several chordae, resulting in either no symptoms or variable symptoms. However, the classical echocardiographic descriptions of the flail posterior leaflet, with or without valvular vegetations’. :I (which could be confused with the present finding) have previously been associated with important destruction of the mitral valve apparatus and consequent hemodynamic collapse. A recent review of the echocardiographic criteria for determining flail mitral leaflet has been made by Humphries and associates,‘” who proposed four additional findings. In that catego-
ry, which could possibly be confused with those of the present study(i.e., flail posterior leaflet), the echocardiograms were not nearly as filled with echo reflecting material as were our cases. Further, the clinical presentations again suggested advanced left ventricular failure requiring mitral valve replacement in the majority of patients. Such was not the case in the present study and perhaps serves as the best clue to proper categorization and differentiation. However, a mild overlap of patients with myxomatous degeneration of the mitral valve apparatus giving rise to either mitral valve prolapse or asymptomatic chordal rupture still remains. The mechanism for this diastolic echo pattern is not established. Certain observations in this study suggest that it arises from the posterior mitral leaflet per se. Gilbert and co-workers,‘:’ employing two-dimensional echocardiography, detected in certain patients with angiographically-proven evidence of mitral valve prolapse an unusual and exaggerated excursion of the mitral leaflets during diastolic opening. These motions were observed in a setting of reverse superior displacement of one or both leaflets above the level of the mitral valve ring during systole and were characterized as a rapid and abrupt whiplike opening of the leaflets in diastole. Recent work of DeMaria and colleagues,‘” also using cross-sectional echocardiography, showed clearcut morphological abnormalities of the mitral apparatus in the prolapse syndrome including increases in posterior mitral valve leaflet size, width, and length. The angiographic data in one of our patients with the diastolic echoes suggested a unique juxtapositioning of the posterior mitral leaflet with respect to the anterior leaflet during diastolic filling. Taken together, these observations provide the basis for detailing one possible mechanism. Either through patulous transformation of the leaflet, elongation of the chordae, or loss of support of the inferior papillary muscle, the posterior leaflet during diastole may be drawn forward and anteriorly, possibly from a venturilike effect of rapid ventricular filling, and “curl” beneath the anterior leaflet, thus giving rise to the characteristic diastolic echoes. This is illustrated in Fig. 2. Summary
(MVP) syndrome. An unusual echocardiographic finding reported in this study was observed in 12 of 83 patients (14.5 per cent) with MVP syndrome. The finding consisted of a pattern of multiple, high-intensity parallel echoes behind the anterior mitral leaflet noted throughout diastole which in character were closely akin to those previously observed in left atria1 myxoma or hemodynamically significant flail mitral valve leaflet. These latter diagnoses were excluded by other criteria. The prevalence of this finding in patients with MVP was significantly increased (P < .Ol by Chi-square contingency testing) when contrasted with 44 patients without MVP. There was no identifying feature in the clinical history or physical examination which could be used to predict those in whom the diastolic echoes were observed. However, a significant increase in dysrhythmias as recorded by routine electrocardiogram or 24-hour Holter monitoring was noted. Angiographic information obtained in selected patients suggested that the posterior leaflet per se caused these diastolic echoes. Because of patulous transformation of the valve, elongation of the chordae, or loss of support of the papillary muscle from the posterior free wall, the posterior leaflet appeared drawn forward toward the anterior leaflet, perhaps from a venturi-like effect caused by the rapid ingress of blood during diastolic filling. This malpositioning of the posterior leaflet was not associated with significant mitral regurgitation and appears to represent but another facet in the spectrum of mitral valve prolapse. REFERENCES
Echocardiology is an important ing patients with the mitral
tool in diagnosvalve prolapse
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1979, Vol. 97, MO. 3