**4. Mixed genetic and non genetic cardiomyopathy**

#### **4.1. Dilated Cardiomyopathy (DCM)**

#### *4.1.1. Introduction*

The prevalence of idiopathic dilated cardiomyopathy is not well understood but an estimate in the USA is ∼40 per 100 000 persons [34]. DCM is the most common cardiomyopathy, accounting for 60% of all primary cardiomyopathies [35] and is a leading cause of heart failure and arrhythmia. Familial and sporadic forms of DCM are well described. Genetic factors are important, with 20% of cases having a familial basis with an autosomal dominant inheritance [36]. This has important implications for screening of first-degree relatives.

#### *4.1.2. Features of DCM on standard echocardiogram*

**Wall motion abnormalities**: Wall motion abnormality is global as opposed to regional abnormalities in ischemic cardiomyopathy. However, some regional variation in myocardial contractility may be encountered. Preservation of contractile function of basal inferolateral segment is not infrequent. Due to these overlapping features, ischemic cardiomyopathy should be conclusively excluded when appropriate.

**Cardiac Chamber Enlargement**: Left ventricular (LV) cavity enlargement and systolic dysfunction in the absence of valvular or ischemic heart disease are key diagnostic features of DCM. Dilatation of both left and right ventricles is encountered. Left ventricular cavity assumes a spherical shape in advanced cases (Figure-6). Chamber quantification is preferred over visual estimation for serial comparison. In addition to linear cavity dimension, which is increased in DCM, calculation of left ventricle volume and systolic function derived from modified biplane Simpson's method is recommended.

**Low Flow State**: Consequent to sluggish blood flow velocity, patients are at risk of developing LV mural thrombus. Low circulatory state can be appreciated by spontaneous echo contrast in left ventricle and by an increase in separation of mitral valve E point to ventricular septum and partial opening and early closure of aortic valve in systole. The latter is particularly important, as aortic stenosis may be overestimated on 2D echo (pseudo aortic stenosis) and underestimated by Doppler (low-gradient aortic stenosis) due to low flow state. Contractile augmentation with dobutamine is helpful in clarification in such situations [64].

The most frequently involved segments are apical, followed by the inferior and lateral midsegments. Severity and distribution of non compacted segment is better appreciated with use

Left ventricle contractile abnormality is present in patients with LVNC. The spectrum of myocardial function may range from normal to severe systolic dysfunction. Documentation of direct flow from ventricular cavity into inter-trabecular recesses either with color Doppler technique or following use of echo contrast is helpful in differentiating LVNC from other apical echocardiographic abnormalities such as apical hypertrophic cardiomyopathy and apical mural thrombus [31]. Information from 3DE is also helpful in identifying the extent of LVNC

The prevalence of idiopathic dilated cardiomyopathy is not well understood but an estimate in the USA is ∼40 per 100 000 persons [34]. DCM is the most common cardiomyopathy, accounting for 60% of all primary cardiomyopathies [35] and is a leading cause of heart failure and arrhythmia. Familial and sporadic forms of DCM are well described. Genetic factors are important, with 20% of cases having a familial basis with an autosomal dominant inheritance

**Wall motion abnormalities**: Wall motion abnormality is global as opposed to regional abnormalities in ischemic cardiomyopathy. However, some regional variation in myocardial contractility may be encountered. Preservation of contractile function of basal inferolateral segment is not infrequent. Due to these overlapping features, ischemic cardiomyopathy should

**Cardiac Chamber Enlargement**: Left ventricular (LV) cavity enlargement and systolic dysfunction in the absence of valvular or ischemic heart disease are key diagnostic features of DCM. Dilatation of both left and right ventricles is encountered. Left ventricular cavity assumes a spherical shape in advanced cases (Figure-6). Chamber quantification is preferred over visual estimation for serial comparison. In addition to linear cavity dimension, which is increased in DCM, calculation of left ventricle volume and systolic function derived from

**Low Flow State**: Consequent to sluggish blood flow velocity, patients are at risk of developing LV mural thrombus. Low circulatory state can be appreciated by spontaneous echo contrast in left ventricle and by an increase in separation of mitral valve E point to ventricular septum and partial opening and early closure of aortic valve in systole. The latter is particularly

[36]. This has important implications for screening of first-degree relatives.

of contrast echo.

12 Cardiomyopathies

*4.1.1. Introduction*

[33]. Screening of family members is advised.

*4.1.2. Features of DCM on standard echocardiogram*

be conclusively excluded when appropriate.

modified biplane Simpson's method is recommended.

**4.1. Dilated Cardiomyopathy (DCM)**

**4. Mixed genetic and non genetic cardiomyopathy**

**Secondary Mitral Regurgitation**: Altered mitral valve geometry from progressive LV cavity enlargement will lead to mitral regurgitation, which may be severe in advanced cases [37]. Presence of mitral regurgitation predicts poor outcome [38].

**Diastolic Dysfunction**: Presence of diastolic abnormality is established by Doppler interrog‐ ation of mitral inflow and mitral annular velocities. Severity of diastolic abnormality may be insightful and partly explanatory for the frequently observed discordance between degree of LV systolic dysfunction and severity of clinical symptoms. Patients with earlier stage of diastolic abnormality are less symptomatic when compared to those with more advanced diastolic dysfunction. Reduction in effective diastolic filling period is reflected by fusion of mitral diastolic E-wave and A-wave (Figure-6).

**Figure 6.** Apical four chamber view shows a dilated LV cavity with a spherical appearance. RV cavity is normal in this example. Pulse-wave Doppler at mitral leaflet tip shows fusion of diastolic E and A waves. Latter is a reflection of re‐ duced diastolic filling period.

**Right Ventricular (RV) Function**: RV enlargement to a similar degree as the LV is associated with poor outcome [39]. RV systolic function can be measured by fractional area change or by tricuspid annular plane systolic excursion (TAPSE) [40]. TAPSE < 14 mm is associated with adverse prognosis [41]. In another study, 3DE derived measurement of RV volume and function was superior to conventional method [42].

#### *4.1.3. Novel echo techniques*

Routine use of Doppler-derived strain and 2D strain may have limited application in clinically manifest disease. Application of these techniques in preclinical state and in asymptomatic family members with inherited type of DCM may identify at risk subset of patients. Observa‐ tion of intersegmental discordance in the timing of strain measures, particularly those of opposing segments identify a subset of DCM patients with LV dyssynchrony, who may benefit from cardiac resynchronization therapy.

#### **4.2. Restrictive cardiomyopathy (non-hypertrophied and non-dilated)**

#### *4.2.1. Introduction*

Primary restrictive cardiomyopathy (RCM) predominantly affects the elderly, with a slight female predominance [43]. Clinical presentation is with signs and symptoms of systemic and pulmonary venous congestion from diastolic heart failure and pulmonary HTN [43]. As opposed to other types of primary cardiomyopathies which have distinctive morphologic abnormalities, the diagnosis of RCM is largely dependent on an altered physiology of blood flow through the heart consequent to a non compliant ventricle. The condition has no distinc‐ tive histologic features [44]. RCM should be distinguished from infiltrative disorders of the heart where, in addition to restrictive physiology which may be indistinguishable from RCM, distinctive morphologic and histopathologic changes are present. Amyloid heart disease and endomyocardial fibrosis are typical examples of the latter.

**Figure 7.** Morphologic and functional abnormality in restrictive cardiomyopathy is represented in this example. There is biatrial enlargement on apical four chamber view (panel A). Restrictive diastolic filling abnormality (E: A ratio of > 2

Echocardiography Findings in Common Primary and Secondary Cardiomyopathies

http://dx.doi.org/10.5772/55036

15

For the purpose of this review, discussion will be limited to key features of commonly

Inflammatory cardiomyopathy is defined by myocarditis in association with cardiac dysfunc‐ tion [11]. Idiopathic, autoimmune, and infectious forms of inflammatory cardiomyopathy are recognized [11]. Echo findings are of non-specific LV cavity dilatation associated with global LV dysfunction similar to that seen in idiopathic dilated cardiomyopathy. Regional variation

A transient and reversible cardiomyopathy first reported in Japan by Dote, et al., in 1991 [49]. Clinical presentation may be indistinguishable from acute coronary syndrome, invariably necessitating coronary angiography for exclusion of obstructive coronary artery disease. Prevalence is about 1-2% of patients undergoing coronary angiography for acute coronary syndrome. A precipitating emotional or physical stressor is typical. Complimentary imaging

with rapid deceleration of early mitral inflow velocity) by Doppler is noted (panel B).

**5. Acquired primary and secondary cardiomyopathy**

encountered acquired cardiomyopathy.

in LV contractility is not infrequently encountered.

**5.2. Takotsubo cardiomyopathy (stress cardiomyopathy)**

**5.1. Inflammatory myocarditis**

#### *4.2.2. Features of RCM on standard echocardiogram*

Left ventricle (LV) appearance and contractility is usually normal. LV cavity size may be small. Biatrial enlargement in the absence of significant regurgitation of mitral and tricuspid valves or atrial fibrillation and with normal LV kinetics in patients with signs and symptoms of heart failure should prompt consideration of RCM (Figure-7). Impaired diastolic relaxation of the LV is encountered but a key diagnostic feature is the presence of restrictive physiology on Doppler as evidenced by an increase in E:A ratio >2 with rapid deceleration of early mitral inflow (E) velocity, usually to < 150 msec (Figure-7) [45]. This, in conjunction with reduced early mitral annular velocity (E') and elevated E/E' ratio, is confirmatory of elevated left ventricular end diastolic pressure (LVEDP). Reduced E' velocity, reflecting underlying myocardial disease, is useful in distinguishing RCM from constrictive pericarditis where mitral annular velocities are preserved [46-47]. Deformation of the LV on 2D speckle strain is constrained in the circumferential direction in constrictive pericarditis and in the longitudinal direction in RCM [48]. Flow propagation velocity on color M-mode of mitral inflow can provide additional insight into diastolic dysfunction of RCM.

**Figure 7.** Morphologic and functional abnormality in restrictive cardiomyopathy is represented in this example. There is biatrial enlargement on apical four chamber view (panel A). Restrictive diastolic filling abnormality (E: A ratio of > 2 with rapid deceleration of early mitral inflow velocity) by Doppler is noted (panel B).
