**2. Definition**

Primary mitral valve prolapsus (MVP) related to small (minor) cardiac abnormalities (MCA) is considered to be one of the most common heart valve anomalies. Mitral valve prolapsus (MVP) represents a range of valvular abnormalities that allow one or both mitral valve leaflets to extend above the plane that separates the atria and the ventricle.

MVP is such a pathology of the valve apparatus (some redundancy of it), in which one or both mitral valve flaps bend ("sag," prolapse) upward and posteriorly above the plane separating the atria and ventricles (above the valvular ring plane) during systole [10–12]. The valves can remain connected or can be separated, which leads to a different degree of regurgitation (**Figure 1**).

majority of patients with MVP have mitral regurgitation (MR), but most patients with MVP (approximately 75%) have mild, trace, or no MR [1]. Severe MR is uncommon, identified in 4% of patients with MVP. Unlike adults, mitral valvulopathy (MVP) with Marfan syndrome in newborns can be accompanied by severe regurgitation and functional disorders of the contractile activity of the heart leading to congestive heart failure [15]. Most often among all population groups (17–38%), MVP is noted in women of reproductive age [10, 16]. According to the REPLICA study (mitral valve prolapse prevalence among young people), MVP is detected

Mitral Valve Prolapse in Pregnancy: Modern Concept http://dx.doi.org/10.5772/intechopen.76692 81

Therapists working in obstetrics consider MVP the most common heart anomaly in pregnant women [18]. The proportion of MVP in the structure of small heart anomalies in pregnant women is 60.8% [19]. In the recent past, this pathology was considered to be so frequent, especially among young women, that a number of authors proposed to consider MVP as a variant of the normal structure of the mitral valve [20]. However, the standardization of echocardiographic criteria and a better understanding of the structure of the valvular apparatus led to a significant decrease in the frequency of the detection of true MVP, which is 0.5–3.0% in the population and 1% in women of all age groups with a maximum frequency—in reproductive age. A large

more often—in 4.3% of cases [17].

**Figure 1.** Mitral valve prolapse.

The more pronounced prolapse can be caused by myxomatous degeneration of mitral valve flaps. An anomaly of the mitral valve may be an isolated visceral manifestation of CTD, but it can also be a part of dysplastic syndromes. MVP (and sometimes the tricuspid valve prolapse) can be associated with other intracardiac anomalies, in particular, an interstitial septal defect [3, 5].

The average frequency of MVP in the population is 3–10% with a widespread frequency according to literature data, depending on population factors (gender, age, race) [6, 13, 14], as well as the diagnostic method and diagnostic criteria [10, 11].

Individuals with classic MVP (leaflet thickness of ≥5 mm; 1.3%) and non-classic MVP (leaflet thickness of <5 mm; 1.1%) had similar age and sex distributions. MVP prevalence was similar in three ethnic groups (2.7% in South Asian, 3.1% in European, and 2.2% in Chinese) [10]. MVP patients were leaner and had a greater degree of mitral regurgitation (MR) than the general population [6, 7]. MVP may be slightly more common in women than in men. The

**Figure 1.** Mitral valve prolapse.

tissue dysplasia [5–7]. The prolapse of the mitral valve is one of the most common and studied visceral manifestations of connective tissue dysplasia (CTD). Connective tissue dysplasia (DST) is the disorder of the connective tissue of polygenic multifactorial nature, combined into phenotypes on the basis of the commonness of external and/or visceral features [6]. CTD is characterized by defects in fibrous structures and the basic substance, leading to a disorder of homeostasis at the tissue, organ, and organism levels in the form of various morphofunctional

Interest in the study of MVP is due primarily to its relatively high frequency in the general population and among young women of reproductive age, as well as possible complications sudden death, arrhythmias and congestive disorders of the heart, infectious endocarditis, and thromboembolic disorders. However, previously reported MVP complications such as stroke, disautonomy (postural orthostatic tachycardia syndrome (POTS)), panic attacks, feelings of fear, and transient ischemic attacks [8] are not currently considered in connection with the MVP itself [9]. In the majority of women, no cardiovascular pathology has been detected in

Primary mitral valve prolapsus (MVP) related to small (minor) cardiac abnormalities (MCA) is considered to be one of the most common heart valve anomalies. Mitral valve prolapsus (MVP) represents a range of valvular abnormalities that allow one or both mitral valve leaflets

MVP is such a pathology of the valve apparatus (some redundancy of it), in which one or both mitral valve flaps bend ("sag," prolapse) upward and posteriorly above the plane separating the atria and ventricles (above the valvular ring plane) during systole [10–12]. The valves can remain connected or can be separated, which leads to a different degree of regurgitation

The more pronounced prolapse can be caused by myxomatous degeneration of mitral valve flaps. An anomaly of the mitral valve may be an isolated visceral manifestation of CTD, but it can also be a part of dysplastic syndromes. MVP (and sometimes the tricuspid valve prolapse) can be associated with other intracardiac anomalies, in particular, an interstitial septal

The average frequency of MVP in the population is 3–10% with a widespread frequency according to literature data, depending on population factors (gender, age, race) [6, 13, 14], as

Individuals with classic MVP (leaflet thickness of ≥5 mm; 1.3%) and non-classic MVP (leaflet thickness of <5 mm; 1.1%) had similar age and sex distributions. MVP prevalence was similar in three ethnic groups (2.7% in South Asian, 3.1% in European, and 2.2% in Chinese) [10]. MVP patients were leaner and had a greater degree of mitral regurgitation (MR) than the general population [6, 7]. MVP may be slightly more common in women than in men. The

to extend above the plane that separates the atria and the ventricle.

well as the diagnostic method and diagnostic criteria [10, 11].

disturbances of visceral and locomotor organs.

80 Structural Insufficiency Anomalies in Cardiac Valves

10 years after the diagnosis of MVP [3].

**2. Definition**

(**Figure 1**).

defect [3, 5].

majority of patients with MVP have mitral regurgitation (MR), but most patients with MVP (approximately 75%) have mild, trace, or no MR [1]. Severe MR is uncommon, identified in 4% of patients with MVP. Unlike adults, mitral valvulopathy (MVP) with Marfan syndrome in newborns can be accompanied by severe regurgitation and functional disorders of the contractile activity of the heart leading to congestive heart failure [15]. Most often among all population groups (17–38%), MVP is noted in women of reproductive age [10, 16]. According to the REPLICA study (mitral valve prolapse prevalence among young people), MVP is detected more often—in 4.3% of cases [17].

Therapists working in obstetrics consider MVP the most common heart anomaly in pregnant women [18]. The proportion of MVP in the structure of small heart anomalies in pregnant women is 60.8% [19]. In the recent past, this pathology was considered to be so frequent, especially among young women, that a number of authors proposed to consider MVP as a variant of the normal structure of the mitral valve [20]. However, the standardization of echocardiographic criteria and a better understanding of the structure of the valvular apparatus led to a significant decrease in the frequency of the detection of true MVP, which is 0.5–3.0% in the population and 1% in women of all age groups with a maximum frequency—in reproductive age. A large retrospective study, during which 16,185 echocardiograms were analyzed, performed according to clinical indications in the Consultative-Diagnostic Center of National Medical Research Center of V.A. Almazov (St. Petersburg, Russia) from 2008 to 2011, also showed a low prevalence of MVP and in the Russian population—1.3% [21].

dilatation and signs of connective tissue dysplasia of seven or more points gives reason to consider it as associated with the Marfan syndrome. However, it should be emphasized that only 1–2% of patients with MVP have one of the monogenic undifferentiated disor-

Mitral Valve Prolapse in Pregnancy: Modern Concept http://dx.doi.org/10.5772/intechopen.76692 83

**2.** independent clinically and prognostically significant syndrome: primary familial mitral valve prolapse (MIM 157700), primary myxomatous mitral valve prolapse (MIM 607829 or 610,840). In the absence of signs of one of the monogenic NNST, in the case of detection of MVP with hemodynamically significant mitral regurgitation and/or myxomatous degeneration of the valves in persons with a young age, it is possible to speak with a high probability of the presence of a clinically significant primary MVP. To diagnose genetically determined primary MVP, it is not possible to restrict only echocardiography to a study, but it is necessary to take into account the results of a family survey, the phenotypic data, and the clinical picture of the disease. For evaluation of MVP, its combination with the signs of dysplasia of the connective tissue or the absence thereof is also important. The combination of MVP with clinical symptomatics allows talking about the syndrome of MVP. It is characterized by vegetative dysfunction, arterial hypotension and orthostatic failure, cardiac rhythm disturbances, and repolarization disorders on

**3.** the minor heart anomaly, often accompanying other classified and unclassified dysplastic

With the exclusion of MVP syndrome, prolapse of the valves without their thickening and significant mitral regurgitation can be regarded as one of the variants of a small heart anomaly, the number of which, as is well known, closely correlates with the number of external signs of

To explain the causes of primary prolapse of the mitral valve, several theories have been proposed. Proponents of the "myocardial" theory in the histological study of the myocardium found interstitial fibrosis and hypertrophy of myofibrils in patients with mitral valve prolapse and in electron microscopy—degenerative changes in mitochondria, endocardium

The revealed changes allowed to make an assumption about the similarity of morphological changes with mitral valve prolapse and dilated cardiomyopathy. However, after conducting a complex echocardiographic, radionuclide, and angiographic study, the hypothesis of the cardiomyopathic etiology of the primary prolapse of the mitral valve has not been confirm [6, 26]. The theory of the "rheumatic" nature of the prolapse of the mitral valve was also common. This point of view is confirmed by information about a greater frequency of prolapse in patients with rheumatism. Supporters of this theory explained the mechanism of prolapse of the valves with partial chord separation as a result of inflammatory changes in the endocardium [5, 27]. There are also data indicating the possible involvement of a viral infection in the

ders of the connective tissue [6];

the ECG [6];

syndromes.

dysembryogenesis detected [24].

**4. Etiopathogenesis**

thickening [25, 26].
