- Email: [email protected]
Does mitral valve prolapse cause nonspecific symptoms?
International Journal of Cardiology, Elsevier Biomedical Press
I (1982) 435-442
435
Does mitral valve prolapse cause nonspecific symptoms? Barry
F. Uretsky
Division of Cardiology, University of Pittsburgh School of Medicine, and Presbyterian-University Hospital, Pittsburgh, PA 15213, U.S.A. (Received
6 January
1982; revision received
Uretsky BF. Does mitral 1982; 1: 435-442.
valve prolapse
17 February
1982; accepted
cause nonspecific
19 February
symptoms?
1982)
Int J Cardiol
I studied the prevalence and symptoms of idiopathic mitral valve prolapse by auscuitation in 972 consecutive patients in an adult general medical population. Forty-five patients (4.6%) had idiopathic mitral valve prolapse defined by a nonejection click with or without a late systolic murmur. The prevalence was not significantly different in men and women. The mean age (49.9 yr) and age distribution of patients with prolapse were similar to those of patients without prolapse (47.7 yr). The prevalence of dizziness (4.1% vs. 1.5%), fatigue (4.4% vs. 2.6%), and palpitations (4.4% vs. 1.3%), was not significantly greater in patients with or without prolapse. Atypical chest pain (13% vs. 4.3%) and chronic anxiety (8.8% vs. 2.9%) were more frequent (-c 0.05) in the patients with prolapse than in those without prolapse. Of the patients with prolapse, 29 were healthy without clinically identifiable diseases while 16 had medical diseases. In the group without prolapse, l&l patients were healthy and 707 had other diseases. When patients with isolated prolapse without other associated diseases were compared to healthy patients without prolapse, the prevalence of atypical chest pain (17.4% vs. 17.2%) and chronic anxiety (7.1% vs. 10.3%) were not significantly different. When patients with prolapse and other diseases were compared to patients without prolapse and other diseases, the prevalence of atypical chest pain (6.2% vs. 1.1%) and chronic anxiety (6.2% vs. 1.7%) was again not significantly different. Thirty-two patients without prolapse were suspected but not confirmed of having disease and were not included in this analysis. The results would have been unaltered by their inclusion in the diseased group without prolapse.
Reprinr requesrs to: Barry F. Uretsky, Streets, Pittsburgh, PA 15213. U.S.A.
0167-5273/82/0000-0000/$02.75
M.D.,
3490 Presbyterian-University
0 1982 Elsevier Biomedical
Press
Hospital.
DeSoto
at O’Hara
436
Thus, the prevalence of commonly attributed nonspecific symptoms in patients with idiopathic mitral valve prolapse is not significantly different between healthy patients without or with prolapse without other diseases. These findings suggest a coincidence of a common syndrome with frequently occurring symptoms, rather than cause and effect.
Introduction Idiopathic mitral valve prolapse is a frequently encountered condition in the general medical population [l-4]. The entity has been associated with many symptoms, several of which are nonspecific [5]. This report describes the prevalence of nonspecific symptoms in patients with and without idiopathic mitral valve prolapse and the possible causal relationship between idiopathic mitral valve prolapse and these symptoms.
Methods and patient population Nine hundred seventy-two (972) patients were consecutively evaluated for mitral valve prolapse in a self-referred general medical practice. Each patient filled out a standardized questionnaire on symptoms and was then interviewed by a physician about each symptom. A complete physical examination was also performed. The following definitions were established. Ar_vpica/ chest pain: chest pain lacking one or more of the features of typical angina pectoris and not ascribable to another entity known to produce chest pain. Typical angina pectoris: chest discomfort precipitated by exertion and relieved by rest, lasting up to but no more than twenty minutes, and described as visceral in quality. Fatigue: the subjective sensation of tiredness which impaired the performance of daily activities. Dizziness: vertigo or lightheadedness. Palpitations: any abnormal sensation in the chest, which the patient attributed to a heart rhythm disturbance, e.g. ‘skipping’, ‘racing’. Chronic anxiety: considered present if the patient sought psychiatric or general medical care for free-floating fears or obsession not based on a life situation occurring at least once every two months during follow-up. Depressive states and psychoses were excluded. Mitral valve prolapse: The presence of the auscultatory finding of a nonejection click with or without a late systolic murmur. Patients with only a late systolic murmur were excluded from analysis. Echocardiography and phonocardiography were not routinely performed on all patients. Patients were examined in several positions, and most were examined on more than one occasion to decrease the possibility of an incorrect diagnosis. Mitral valve prolapse was considered idiopathic
431
if there were no diseases present such as Marfan’s syndrome, known to be associated with the auscultatory findings of prolapse. Coronary artery disease: a history of a well-documented myocardial infarction, typical angina pectoris, or angiographically documented coronary stenosis of 2 50% luminal diameter narrowing in at least one vessel. Patients were divided into ‘healthy’ and ‘diseased’ categories in order to determine the relationship between the state of health and the presence or absence of certain nonspecific symptoms. For the purpose of this analysis, ‘healthy’ and ‘diseased’ were defined in the following way: ‘Healthy’: no abnormality present with the exception of mitral valve prolapse. ‘Diseased’: any pathologic condition other than mitral valve prolapse. Statistical differences in disease and prevalence of symptoms were evaluated by the &i-square test for population differences. Patients with mitral valve prolapse and diseases known to be associated with mitral valve prolapse (four patients) were excluded from statistical analysis. Their inclusion would not, however, have significantly influenced the results. The Student t-test was used to compare the mean age of the two groups. In addition, 32 patients without prolapse with suspected but not confirmed disease were excluded from analysis in comparing ‘healthy’ and ‘diseased’ subgroups. Their inclusion in the ‘diseased’ subgroup would not have changed the results. Results Auscultatory findings compatible with mitral valve prolapse were present in 5.0% (49/972) of the population (Table l), thus making this entity the third most prevalent cardiovascular finding after hypertension (18%) and coronary artery disease (6.9%). Of the 49 patients with mitral valve prolapse, one developed a midsystolic click 6 months after an acute myocardial infarction and three patients demonstrated physical findings compatible with Marfan’s syndrome. Thus, 45 of 972 patients or 4.6% of the study population had idiopathic mitral valve prolapse. There was no significant sex difference in the prevalence of idiopathic mitral valve prolapse. Women showed a prevalence of 5.6% (29/517) and men 3.5% (16/45 1). Both the mean and median ages of the group with idiopathic mitral valve prolapse and that with non-idiopathic mitral valve prolapse were similar; the mean age of the group with idiopathic mitral valve prolapse was 44.1 years and without prolapse 46.7 years. The median age was 42.0 years in both groups. The prevalence of symptoms in the group with idiopathic mitral valve prolapse and that without prolapse is listed in Table 2. Atypical chest pain was more common (P < 0.05) in the group with idiopathic mitral valve prolapse (13%) than in patients without prolapse (4.3%). Chronic anxiety was also more prevalent (P -=z0.05) in the group with idiopathic mitral valve prolapse (8.8%) compared with the group without prolapse (2.9%). The prevalence of dizziness, fatigue, and palpitations was similar in the two groups. There was a higher prevalence (P < 0.01) of asymptomatic patients who presented for a checkup in the group with prolapse (60%, 27/45) vs. that without prolapse (158, 137/923).
438 TABLE
1
Cardiovascular
abnormalities
in population
(972 patients). Number
Hypertension Coronary artery disease Mitral valve prolapse Primary arrhythmia, including heart block Valvular heart disease, excluding prolapse Peripheral vascular and cerebrovascutar disease Other
of patients
177 67 49 23 20 16 9
% 18 6.9 5.0 2.4 2.1 1.6 0.9
TABLE 2 Prevalence
of symptoms. Prolapse (n=45)
Symptom
Percent of group
P
Nonprolapse (n =923)
(W) Atypical chest pain Chronic anxiety Dizziness Fatigue Palpitations
TABLE
6 4 2 2 2
13 8.8 4.4 4.4 4.4
Percent of group (%)
CO.05 CO.05 NS NS NS
40 25 14 24 12
4.3 2.9 1.5 2.6 1.3
3
Symptoms
in ‘healthy’
Symptom
patients. prolapse (n =29)
Percent of group
P
Nonprolapse (n=184)
(S)
(W) Atypical Chronic
chest pain anxiety
5 3
Percent of group
17.2 10.3
NS NS
32 13
17.4 7.1
Percent of group
P
Nonprolapse (n =707)
Percent of group
TABLE 4 Symptoms
in ‘diseased’
patients. Prolapse (n=16)
Symptom
(f%)
(%) Atypical Chronic
chest pain anxiety
1 1
6.2 6.2
NS NS
8 12
1.1 1.7
439
The symptoms of atypical chest pain and chronic anxiety were related to the presence (‘diseased’) or absence (‘healthy’) of other diseases. Of the group with prolapse, 64% (29/45) were considered ‘healthy’ vs. 21% (184/891) of the group without prolapse (P < 0.05). As a group, ‘healthy’ patients without prolapse had a higher prevalence of atypical chest pain and chronic anxiety than ‘diseased’ patients without prolapse (P < 0.05). Atypical chest pain was found in 17.4% (32/184) of the ‘healthy’ group and 1.1% (8/707) of the ‘diseased’ group (P < 0.05). Chronic anxiety was found in 7.1% (13/184) of the ‘healthy’ group and 1.7% (12/707) of the ‘diseased’ group (P < 0.05). However, ‘healthy’ groups with idiopathic mitral valve prolapse and without prolapse had a similar prevalence of atypical chest pain (Table3). In addition, ‘diseased’ groups with and without prolapse had a similar prevalence of chronic anxiety (Table 4).
Discussion This study attempts to determine the prevalence of symptoms in patients with and without mitral valve prolapse in the general medical population. The group of patients in this analysis was preselected to a certain extent in that all sought medical care. As such, the results cannot be applied to the general population in the same way that might have been obtained from an epidemiologic survey such as the Framingham Study. However, the results probably reflect more closely the prevalence of symptoms of mitral valve prolapse in the general population than in studies of referred patients [ 11. Diagnosis
of mitral valve prolapse
There is no single diagnostic study which can be considered the ‘gold standard’ for mitral valve prolapse. We chose to use the midsystolic click as the diagnostic criterion because of its relative specificity and its uniform application in a large group of patients. It has previously been shown that a nonejection systolic click which varies in relation to maneuvers changing intravascular volume is relatively specific for mitral valve prolapse, although occasionally other entities can produce this finding [2]. Although an isolated late systolic murmur may be the only auscultatory finding in mitral valve prolapse, it is quite uncommon occurring only in 2% of the series reported by Jeresaty [3]. In addition, this finding is nonspecific and may be found in patients with other causes of mitral regurgitation such as papillary muscle dysfunction [3]. Thus, although an occasional patient with mitral valve prolapse was probably overlooked by our exclusion of the late systolic murmur, it also prevented including patients who had mitral regurgitation from other causes. The lack of phonocardiographic confirmation of the auscultatory finding represents a potential defect of this study. However, in order to avoid an additional bias, we felt that it would be necessary to perform phonocardiography on all patients. This would be a major logistic undertaking which was clearly not feasible in a screening study.
440
Other diagnostic modalities for the diagnosis of mitral valve prolapse also have their limitations. M-mode echocardiography in patients with a recordable and audible midsystolic click will demonstrate echocardiographic findings of mitral valve prolapse in approximately 80-90% of patients [4,5]. Thus, up to one-fifth of patients with an auscultatory finding relatively specific for mitral valve prolapse will have negative echocardiographic findings. Thus if we consider the auscultatory finding as evidence for the entity, then we must conclude that the echocardiogram is not 100% sensitive. Furthermore, in the referral series of Jeresaty [3], 16% of patients without auscultatory evidence of mitral valve prolapse had echocardiographic findings of the entity, so-called ‘silent mitral valve prolapse’. Thus, echocardiographic criteria of mitral valve prolapse would require echocardiographic screening of all 972 patients in our study to avoid missing the ‘silent prolapse’ subset. For logistic reasons, this procedure as well as two-dimensional echocardiography was not performed. Attempts to minimize diagnostic error included examining the patients in several positions many times and manipulating intraventricular volume by various maneuvers. Ultimately, however, the validity of the auscultatory finding rests upon the competency of the physician. Thus, it is comforting that the auscultatory results of the present study are similar to other screening studies [4,6]. Prevalence,
age and sex distribution
Our study demonstrates the relatively high prevalence (4.6%) of idiopathic mitral valve prolapse in a primary medical care population. This figure is in general agreement with screening studies which have noted evidence for mitral valve prolapse in 6- 17% of women [4,7] and in 2-9% of men [6.8]. Our study is the first to demonstrate a similar prevalence of this entity among men and women in a large heterogenous population. We were unable to verify, however, the clinical impression that mitral valve prolapse is more common in the younger groups [ 1,9]. Rather the entity reflected the mean and median age distribution of the medical population as a whole. The apparently higher prevalence of prolapse in young females [ 1,9,10] may reflect the fact that this patient group is often the most commonly encountered in the general medical practice [ 111. Women from 20 to 39 years accounted for 24.1% of our entire population, the largest 20 year group of patients in our series. Symptoms
and mitral valve prolapse
Along with others [ 1,9, lo]. we have found that a large fraction of patients with mitral valve prolapse complain of atypical chest pain (13.1%) and anxiety (8.8%). We have shown that compared to a control group, these proportions are significantly higher (P =C0.05). Thus, it may be concluded that atypical chest pain and anxiety neurosis truly are part of the mitral valve prolapse syndrome. There is, however, an alternative explanation which relates to the clustering of mitral valve prolapse patients in the ‘healthy’ group, that is, without any demonstrable disease other than the auscultatory findings of mitral valve prolapse.
441
It should be emphasized that the symptoms of atypical chest pain and anxiety neurosis are more prevalent in the healthy than the diseased subgroups without prolapse. The reason for this finding must remain speculative as it was not the subject of this investigation. Perhaps atypical chest pain is one of a series of ‘functional’ complaints that directs an otherwise healthy patient to seek medical care. Another explanation could be that atypical pain is a clinical manifestation of one or more pathologic conditions which are at present poorly defined. Since chronic anxiety is not considered to have an organic basis, it is not unexpected that a sizeable number of patients with this symptom are otherwise healthy. If ‘healthy’ and ‘diseased’ groups are subdivided into categories with and without mitral valve prolapse, no differences in prevalence of atypical chest pain and chronic anxiety related to the presence or absence of prolapse are discerned. Atypical chest pain (17.2% vs. 17.4%) and anxiety (10.3% vs. 7.1%) in both the ‘healthy’ groups with and without prolapse were similar. Likewise, there was a similar prevalence of these symptoms in the ‘diseased’ subgroups with and without prolapse. The implication of these findings is that these two symptoms may not, in fact, be manifestations of idiopathic mitral valve prolapse. Rather, the association between the symptoms and mitral valve prolapse may represent nothing more than the convergence of two frequently observed phenomena in medical practice. Differences between the groups with and without prolapse and other symptoms commonly associated with the entity including dizziness or lightheadedness [6]. fatigue [6], and palpitations [6,7] were not discernable. Again, I suggest that the symptoms may only appear to be related to prolapse because this entity and the symptoms are frequently encountered in clinical practice. Their juxtaposition in the same patient may represent coincidence rather than cause and effect. The natural history of this entity is not addressed in this study. A prospective epidemiologic investigation would be required to accurately determine the incidence of complications and the sensitivity and specificity of other clinical findings truly associated with this syndrome. Our study does indicate that this syndrome is found frequently in a general medical population, that symptoms are generally uncommon and, of lower prevalence than has previously been reported and that these symptoms may in fact be only casually related to the entity. The relatively small number of patients with mitral valve prolapse in the present study suggests that any conclusion should be made cautiously. This study does question, however, the previously reported association between mitral valve prolapse and several nonspecific symptoms described in uncontrolled studies from referral centers, and suggest that this association in fact may not be causal.
Acknowledgement I gratefully the preparation
acknowledge the secretarial of this manuscript.
assistance
of Ms. Mary Yvonne
Wolf in
442
References 1 Jeresaty RM. Mitral valve prolapse-click syndrome. Prog Cardiovasc Dis 1973; 15: 623. 2 Barlow JB, Pocock WA. The problem of nonejection systolic clicks and associated mitral systolic murmurs: emphasis on the billowing mitral leaflet syndrome. Am Heart J 1975; 90: 636. 3 Jeresaty RM. Mitral valve prolapse. New York: Raven Press, 1979. 4 Procacci PM, Savran SV, Schreiter SL, Bryson AL. Prevalence of clinical mitral-valve prolapse in 1169 young women. N Engf J Med1976; 294: 1086. 5 DeMaria AN, Neumann A, Lee G, et al. Echocardiographic identification of the mitral valve prolapse syndrome. Am J Med 1975: 62: 819-829. 6 Darsee JR, Mikolich R, Nicoloff NB, Lesser LE. Prevalence of mitral valve prolapse in presumably healthy young men. Circulation 1979; 59: 619-622. 7 Markiewicz W, Stoner J, London E, Hunt SA, Popp RL. Mitral valve prolapse in one hundred presumably healthy females. Circulation 1976; 53: 464-473. 8 Sbarbaro JA, Mehhnan D, Wu L, Brooks HL. A prospective study of mitral valve prolapse in young men. Am J Cardiol 1978; 41: 433. 9 Hancock EW, Cohn K. The syndrome
associated
with midsystolic
click and late systolic murmur.
J Med 1966; 41: 183-196. 10 Barlow JB, Bosman CK, Pocock WA, Marchand P. Late systolic murmurs and non-ejection systolic clicks: An analysis of 90 patients. Br Heart J 1978; 30: 203-218.
Am
(Mid-Late’)
I (1982) 435-442
435
Does mitral valve prolapse cause nonspecific symptoms? Barry
F. Uretsky
Division of Cardiology, University of Pittsburgh School of Medicine, and Presbyterian-University Hospital, Pittsburgh, PA 15213, U.S.A. (Received
6 January
1982; revision received
Uretsky BF. Does mitral 1982; 1: 435-442.
valve prolapse
17 February
1982; accepted
cause nonspecific
19 February
symptoms?
1982)
Int J Cardiol
I studied the prevalence and symptoms of idiopathic mitral valve prolapse by auscuitation in 972 consecutive patients in an adult general medical population. Forty-five patients (4.6%) had idiopathic mitral valve prolapse defined by a nonejection click with or without a late systolic murmur. The prevalence was not significantly different in men and women. The mean age (49.9 yr) and age distribution of patients with prolapse were similar to those of patients without prolapse (47.7 yr). The prevalence of dizziness (4.1% vs. 1.5%), fatigue (4.4% vs. 2.6%), and palpitations (4.4% vs. 1.3%), was not significantly greater in patients with or without prolapse. Atypical chest pain (13% vs. 4.3%) and chronic anxiety (8.8% vs. 2.9%) were more frequent (-c 0.05) in the patients with prolapse than in those without prolapse. Of the patients with prolapse, 29 were healthy without clinically identifiable diseases while 16 had medical diseases. In the group without prolapse, l&l patients were healthy and 707 had other diseases. When patients with isolated prolapse without other associated diseases were compared to healthy patients without prolapse, the prevalence of atypical chest pain (17.4% vs. 17.2%) and chronic anxiety (7.1% vs. 10.3%) were not significantly different. When patients with prolapse and other diseases were compared to patients without prolapse and other diseases, the prevalence of atypical chest pain (6.2% vs. 1.1%) and chronic anxiety (6.2% vs. 1.7%) was again not significantly different. Thirty-two patients without prolapse were suspected but not confirmed of having disease and were not included in this analysis. The results would have been unaltered by their inclusion in the diseased group without prolapse.
Reprinr requesrs to: Barry F. Uretsky, Streets, Pittsburgh, PA 15213. U.S.A.
0167-5273/82/0000-0000/$02.75
M.D.,
3490 Presbyterian-University
0 1982 Elsevier Biomedical
Press
Hospital.
DeSoto
at O’Hara
436
Thus, the prevalence of commonly attributed nonspecific symptoms in patients with idiopathic mitral valve prolapse is not significantly different between healthy patients without or with prolapse without other diseases. These findings suggest a coincidence of a common syndrome with frequently occurring symptoms, rather than cause and effect.
Introduction Idiopathic mitral valve prolapse is a frequently encountered condition in the general medical population [l-4]. The entity has been associated with many symptoms, several of which are nonspecific [5]. This report describes the prevalence of nonspecific symptoms in patients with and without idiopathic mitral valve prolapse and the possible causal relationship between idiopathic mitral valve prolapse and these symptoms.
Methods and patient population Nine hundred seventy-two (972) patients were consecutively evaluated for mitral valve prolapse in a self-referred general medical practice. Each patient filled out a standardized questionnaire on symptoms and was then interviewed by a physician about each symptom. A complete physical examination was also performed. The following definitions were established. Ar_vpica/ chest pain: chest pain lacking one or more of the features of typical angina pectoris and not ascribable to another entity known to produce chest pain. Typical angina pectoris: chest discomfort precipitated by exertion and relieved by rest, lasting up to but no more than twenty minutes, and described as visceral in quality. Fatigue: the subjective sensation of tiredness which impaired the performance of daily activities. Dizziness: vertigo or lightheadedness. Palpitations: any abnormal sensation in the chest, which the patient attributed to a heart rhythm disturbance, e.g. ‘skipping’, ‘racing’. Chronic anxiety: considered present if the patient sought psychiatric or general medical care for free-floating fears or obsession not based on a life situation occurring at least once every two months during follow-up. Depressive states and psychoses were excluded. Mitral valve prolapse: The presence of the auscultatory finding of a nonejection click with or without a late systolic murmur. Patients with only a late systolic murmur were excluded from analysis. Echocardiography and phonocardiography were not routinely performed on all patients. Patients were examined in several positions, and most were examined on more than one occasion to decrease the possibility of an incorrect diagnosis. Mitral valve prolapse was considered idiopathic
431
if there were no diseases present such as Marfan’s syndrome, known to be associated with the auscultatory findings of prolapse. Coronary artery disease: a history of a well-documented myocardial infarction, typical angina pectoris, or angiographically documented coronary stenosis of 2 50% luminal diameter narrowing in at least one vessel. Patients were divided into ‘healthy’ and ‘diseased’ categories in order to determine the relationship between the state of health and the presence or absence of certain nonspecific symptoms. For the purpose of this analysis, ‘healthy’ and ‘diseased’ were defined in the following way: ‘Healthy’: no abnormality present with the exception of mitral valve prolapse. ‘Diseased’: any pathologic condition other than mitral valve prolapse. Statistical differences in disease and prevalence of symptoms were evaluated by the &i-square test for population differences. Patients with mitral valve prolapse and diseases known to be associated with mitral valve prolapse (four patients) were excluded from statistical analysis. Their inclusion would not, however, have significantly influenced the results. The Student t-test was used to compare the mean age of the two groups. In addition, 32 patients without prolapse with suspected but not confirmed disease were excluded from analysis in comparing ‘healthy’ and ‘diseased’ subgroups. Their inclusion in the ‘diseased’ subgroup would not have changed the results. Results Auscultatory findings compatible with mitral valve prolapse were present in 5.0% (49/972) of the population (Table l), thus making this entity the third most prevalent cardiovascular finding after hypertension (18%) and coronary artery disease (6.9%). Of the 49 patients with mitral valve prolapse, one developed a midsystolic click 6 months after an acute myocardial infarction and three patients demonstrated physical findings compatible with Marfan’s syndrome. Thus, 45 of 972 patients or 4.6% of the study population had idiopathic mitral valve prolapse. There was no significant sex difference in the prevalence of idiopathic mitral valve prolapse. Women showed a prevalence of 5.6% (29/517) and men 3.5% (16/45 1). Both the mean and median ages of the group with idiopathic mitral valve prolapse and that with non-idiopathic mitral valve prolapse were similar; the mean age of the group with idiopathic mitral valve prolapse was 44.1 years and without prolapse 46.7 years. The median age was 42.0 years in both groups. The prevalence of symptoms in the group with idiopathic mitral valve prolapse and that without prolapse is listed in Table 2. Atypical chest pain was more common (P < 0.05) in the group with idiopathic mitral valve prolapse (13%) than in patients without prolapse (4.3%). Chronic anxiety was also more prevalent (P -=z0.05) in the group with idiopathic mitral valve prolapse (8.8%) compared with the group without prolapse (2.9%). The prevalence of dizziness, fatigue, and palpitations was similar in the two groups. There was a higher prevalence (P < 0.01) of asymptomatic patients who presented for a checkup in the group with prolapse (60%, 27/45) vs. that without prolapse (158, 137/923).
438 TABLE
1
Cardiovascular
abnormalities
in population
(972 patients). Number
Hypertension Coronary artery disease Mitral valve prolapse Primary arrhythmia, including heart block Valvular heart disease, excluding prolapse Peripheral vascular and cerebrovascutar disease Other
of patients
177 67 49 23 20 16 9
% 18 6.9 5.0 2.4 2.1 1.6 0.9
TABLE 2 Prevalence
of symptoms. Prolapse (n=45)
Symptom
Percent of group
P
Nonprolapse (n =923)
(W) Atypical chest pain Chronic anxiety Dizziness Fatigue Palpitations
TABLE
6 4 2 2 2
13 8.8 4.4 4.4 4.4
Percent of group (%)
CO.05 CO.05 NS NS NS
40 25 14 24 12
4.3 2.9 1.5 2.6 1.3
3
Symptoms
in ‘healthy’
Symptom
patients. prolapse (n =29)
Percent of group
P
Nonprolapse (n=184)
(S)
(W) Atypical Chronic
chest pain anxiety
5 3
Percent of group
17.2 10.3
NS NS
32 13
17.4 7.1
Percent of group
P
Nonprolapse (n =707)
Percent of group
TABLE 4 Symptoms
in ‘diseased’
patients. Prolapse (n=16)
Symptom
(f%)
(%) Atypical Chronic
chest pain anxiety
1 1
6.2 6.2
NS NS
8 12
1.1 1.7
439
The symptoms of atypical chest pain and chronic anxiety were related to the presence (‘diseased’) or absence (‘healthy’) of other diseases. Of the group with prolapse, 64% (29/45) were considered ‘healthy’ vs. 21% (184/891) of the group without prolapse (P < 0.05). As a group, ‘healthy’ patients without prolapse had a higher prevalence of atypical chest pain and chronic anxiety than ‘diseased’ patients without prolapse (P < 0.05). Atypical chest pain was found in 17.4% (32/184) of the ‘healthy’ group and 1.1% (8/707) of the ‘diseased’ group (P < 0.05). Chronic anxiety was found in 7.1% (13/184) of the ‘healthy’ group and 1.7% (12/707) of the ‘diseased’ group (P < 0.05). However, ‘healthy’ groups with idiopathic mitral valve prolapse and without prolapse had a similar prevalence of atypical chest pain (Table3). In addition, ‘diseased’ groups with and without prolapse had a similar prevalence of chronic anxiety (Table 4).
Discussion This study attempts to determine the prevalence of symptoms in patients with and without mitral valve prolapse in the general medical population. The group of patients in this analysis was preselected to a certain extent in that all sought medical care. As such, the results cannot be applied to the general population in the same way that might have been obtained from an epidemiologic survey such as the Framingham Study. However, the results probably reflect more closely the prevalence of symptoms of mitral valve prolapse in the general population than in studies of referred patients [ 11. Diagnosis
of mitral valve prolapse
There is no single diagnostic study which can be considered the ‘gold standard’ for mitral valve prolapse. We chose to use the midsystolic click as the diagnostic criterion because of its relative specificity and its uniform application in a large group of patients. It has previously been shown that a nonejection systolic click which varies in relation to maneuvers changing intravascular volume is relatively specific for mitral valve prolapse, although occasionally other entities can produce this finding [2]. Although an isolated late systolic murmur may be the only auscultatory finding in mitral valve prolapse, it is quite uncommon occurring only in 2% of the series reported by Jeresaty [3]. In addition, this finding is nonspecific and may be found in patients with other causes of mitral regurgitation such as papillary muscle dysfunction [3]. Thus, although an occasional patient with mitral valve prolapse was probably overlooked by our exclusion of the late systolic murmur, it also prevented including patients who had mitral regurgitation from other causes. The lack of phonocardiographic confirmation of the auscultatory finding represents a potential defect of this study. However, in order to avoid an additional bias, we felt that it would be necessary to perform phonocardiography on all patients. This would be a major logistic undertaking which was clearly not feasible in a screening study.
440
Other diagnostic modalities for the diagnosis of mitral valve prolapse also have their limitations. M-mode echocardiography in patients with a recordable and audible midsystolic click will demonstrate echocardiographic findings of mitral valve prolapse in approximately 80-90% of patients [4,5]. Thus, up to one-fifth of patients with an auscultatory finding relatively specific for mitral valve prolapse will have negative echocardiographic findings. Thus if we consider the auscultatory finding as evidence for the entity, then we must conclude that the echocardiogram is not 100% sensitive. Furthermore, in the referral series of Jeresaty [3], 16% of patients without auscultatory evidence of mitral valve prolapse had echocardiographic findings of the entity, so-called ‘silent mitral valve prolapse’. Thus, echocardiographic criteria of mitral valve prolapse would require echocardiographic screening of all 972 patients in our study to avoid missing the ‘silent prolapse’ subset. For logistic reasons, this procedure as well as two-dimensional echocardiography was not performed. Attempts to minimize diagnostic error included examining the patients in several positions many times and manipulating intraventricular volume by various maneuvers. Ultimately, however, the validity of the auscultatory finding rests upon the competency of the physician. Thus, it is comforting that the auscultatory results of the present study are similar to other screening studies [4,6]. Prevalence,
age and sex distribution
Our study demonstrates the relatively high prevalence (4.6%) of idiopathic mitral valve prolapse in a primary medical care population. This figure is in general agreement with screening studies which have noted evidence for mitral valve prolapse in 6- 17% of women [4,7] and in 2-9% of men [6.8]. Our study is the first to demonstrate a similar prevalence of this entity among men and women in a large heterogenous population. We were unable to verify, however, the clinical impression that mitral valve prolapse is more common in the younger groups [ 1,9]. Rather the entity reflected the mean and median age distribution of the medical population as a whole. The apparently higher prevalence of prolapse in young females [ 1,9,10] may reflect the fact that this patient group is often the most commonly encountered in the general medical practice [ 111. Women from 20 to 39 years accounted for 24.1% of our entire population, the largest 20 year group of patients in our series. Symptoms
and mitral valve prolapse
Along with others [ 1,9, lo]. we have found that a large fraction of patients with mitral valve prolapse complain of atypical chest pain (13.1%) and anxiety (8.8%). We have shown that compared to a control group, these proportions are significantly higher (P =C0.05). Thus, it may be concluded that atypical chest pain and anxiety neurosis truly are part of the mitral valve prolapse syndrome. There is, however, an alternative explanation which relates to the clustering of mitral valve prolapse patients in the ‘healthy’ group, that is, without any demonstrable disease other than the auscultatory findings of mitral valve prolapse.
441
It should be emphasized that the symptoms of atypical chest pain and anxiety neurosis are more prevalent in the healthy than the diseased subgroups without prolapse. The reason for this finding must remain speculative as it was not the subject of this investigation. Perhaps atypical chest pain is one of a series of ‘functional’ complaints that directs an otherwise healthy patient to seek medical care. Another explanation could be that atypical pain is a clinical manifestation of one or more pathologic conditions which are at present poorly defined. Since chronic anxiety is not considered to have an organic basis, it is not unexpected that a sizeable number of patients with this symptom are otherwise healthy. If ‘healthy’ and ‘diseased’ groups are subdivided into categories with and without mitral valve prolapse, no differences in prevalence of atypical chest pain and chronic anxiety related to the presence or absence of prolapse are discerned. Atypical chest pain (17.2% vs. 17.4%) and anxiety (10.3% vs. 7.1%) in both the ‘healthy’ groups with and without prolapse were similar. Likewise, there was a similar prevalence of these symptoms in the ‘diseased’ subgroups with and without prolapse. The implication of these findings is that these two symptoms may not, in fact, be manifestations of idiopathic mitral valve prolapse. Rather, the association between the symptoms and mitral valve prolapse may represent nothing more than the convergence of two frequently observed phenomena in medical practice. Differences between the groups with and without prolapse and other symptoms commonly associated with the entity including dizziness or lightheadedness [6]. fatigue [6], and palpitations [6,7] were not discernable. Again, I suggest that the symptoms may only appear to be related to prolapse because this entity and the symptoms are frequently encountered in clinical practice. Their juxtaposition in the same patient may represent coincidence rather than cause and effect. The natural history of this entity is not addressed in this study. A prospective epidemiologic investigation would be required to accurately determine the incidence of complications and the sensitivity and specificity of other clinical findings truly associated with this syndrome. Our study does indicate that this syndrome is found frequently in a general medical population, that symptoms are generally uncommon and, of lower prevalence than has previously been reported and that these symptoms may in fact be only casually related to the entity. The relatively small number of patients with mitral valve prolapse in the present study suggests that any conclusion should be made cautiously. This study does question, however, the previously reported association between mitral valve prolapse and several nonspecific symptoms described in uncontrolled studies from referral centers, and suggest that this association in fact may not be causal.
Acknowledgement I gratefully the preparation
acknowledge the secretarial of this manuscript.
assistance
of Ms. Mary Yvonne
Wolf in
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