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Echocardiography in Heart Failure
Heart failure (HF) is a clinical syndrome characterized by fatigue, breathlessness, and edema caused by an abnormality of heart function. While the etiologies of HF differ, and HF can occur with reduced or preserved ejection fraction, or with low or high cardiac output, all forms of HF share a basic pathophysiology: the inability to provide adequate cardiac perfusion to the body at rest or with exertion or to only do so at the expense of elevated cardiac filling pressures. Clinically HF is characterized by a specific constellation of signs and symptoms ( Box 21.1 ), and several of which must be present for the diagnosis. The Framingham HF criteria have further categorized signs and symptoms of HF into major and minor criteria and require that one major and two minor criteria be fulfilled to make the diagnosis ( Box 21.2 ).
BOX 21.1
Signs and Symptoms of Heart Failure
| Symptoms | Signs |
|---|---|
| Shortness of breath | Elevated jugular venous pressure |
| Fatigue | Third heart sound (gallop) |
| Reduced exercise tolerance | Rales on auscultation |
| Orthopnea | Radiographic cardiomegaly |
| Paroxysmal nocturnal dyspnea | Hepatojugular reflex |
| Edema | Hepatomegaly |
| Weight loss > 4.5 lbs in response to treatment | Pleural effusion |
| Tachycardia |
BOX 21.2
Framingham Criteria for the Diagnosis of Heart Failure
| Major Criteria | Minor Criteria |
|---|---|
| Acute pulmonary edema | Ankle edema |
| Cardiomegaly | Dyspnea on exertion |
| Hepatojugular reflex | Hepatomegaly |
| Neck vein distention | Nocturnal cough |
| Paroxysmal nocturnal dyspnea or orthopnea | Pleural effusion |
| Pulmonary rales | Tachycardia (heart rate >120 beats per minute) |
| Third heart sound (S3 gallop rhythm) |
Echocardiography plays a central role in the diagnosis and management of patients with HF ( Fig. 21.1 ). It is the primary method for assessment of left ventricular ejection fraction (LVEF), which is used to distinguish HF with reduced ejection fraction (HFrEF) from HF with preserved ejection fraction (HFpEF), a crucial determination because evidenced-based therapies only exist for the former. Echocardiography can also help to distinguish among the different types and the potential etiologies of HF and can be useful to identify specific causes of HD, such as sarcoidosis, amyloidosis, hypertrophic cardiomyopathy, or primary valvular abnormalities, some of which might be amenable to specific targeted therapies. Moreover, dilatation of the heart itself results in functional mitral regurgitation, which is both a marker of HF severity and may itself be amenable to therapeutic intervention. In addition, right ventricular function and left atrial (LA) size have incremental prognostic value in HF, and assessing these chambers has become crucial to the assessment of the HF patient.
Role of echocardiography in heart failure. EF , Ejection fraction; HFpEF , heart failure with preserved ejection fraction; HFrEF , heart failure with reduced ejection fraction; LA , left atrial; LBBB , left bundle branch block; RV right atrial.
Assessment of Cardiac Structure and Function
Assessment of Ejection Fraction
Assessment of cardiac structure and function is an essential step in the evaluation of patients with HF. Determination of ejection fraction (see Chapter 14 ) is essential to categorizing the patient as having HFrEF, or HFpEF. An LVEF of 40% or less is generally considered evidence of “reduced” ejection fraction. The definition of what constitutes “preserved” ejection fraction has been debated; some have proposed that “preserved” be used generically for any ejection fraction over 40%, while others believe true HFpEF only begins with LVEF > 45% or even 50%. The 2016 European Society of Cardiology (ESC) Heart Failure Guidelines recently suggested that HF with LVEF in the range from 40% to 49% be termed “Heart Failure with Mid-Range Ejection Fraction” (HFmrEF) ( Table 21.1 ). This categorization has not been adopted by other guidelines. The crucial reason to assess ejection fraction in patients with HF is that evidenced-based therapies exist for patients with HF and rEF, including angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), angiotensin receptor neprilysin inhibitors (ARNIs), beta-blockers, and mineralocorticoid receptor antagonists. These therapies are not indicated in patients with LVEF > 40%, for which no specific treatment other than relief of symptoms is currently approved. Several methods used to assess LVEF are outlined in Chapter 14 .
TABLE 21.1
2016 ESC Categorization of Heart Failure
From Ponikowski P, Voors AA, Anker SD, et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: the task force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). Developed with the special contribution of the Heart Failure Association (HFA) of the ESC. Eur Heart J. 2016; 37(27):2129–2200.
| Type of HF | HFrEF | HFmrEF | HFpEF | |
|---|---|---|---|---|
| CRITERIA | 1 | Symptoms ± Signs a | Symptoms ± Signs a | Symptoms ± Signs a |
| 2 | LVEF <40% | LVEF 40%–40% | LVEF ≥50% | |
| 3 | — |
|
|
|
BNP, B-type natriuretic peptide; HF, heart failure; HFmrEF, heart failure with mid-range ejection fraction; HFpEF, heart failure with preserved ejection fraction; HFrEF, heart failure with reduced ejection fraction; LAE, left atrial enlargement; LVEF, left ventricular ejection fraction; LVH, left ventricular hypertrophy; NT-proBNP, N-terminal pro-B type natriuretic peptide.
a Signs may not be present in the early stages of HF (especially in HFpEF) and in patients treated with diuretics.
Echocardiographic measures of cardiac structure and function have been shown to have prognostic value in HF. Although LVEF has been the most studied and is a potent predictor of outcome in HF, it is certainly not the only predictor ( Fig. 21.2 ), and measures of both systolic and diastolic function have been related to outcomes in heart failure. Measures of left ventricular size, such as end-diastolic and end-systolic volumes also relate to outcomes.
Determination of Heart Failure Etiology
HF can be caused by numerous diseases that impair or influence cardiac function, which, while distinct, can lead to similar signs and symptoms ( Table 21.2 ). While evidenced-based therapies in HFrEF are typically utilized irrespective of etiology, understanding the etiologic factors contributing to HF can be extremely useful on an individual patient basis, and echocardiography can be helpful in the determination of etiology. Patients whose HF is due to a prior myocardial infarction (see Chapter 20 ) will typically have evidence of regional wall motion abnormalities in a coronary artery distribution. Previously infarcted regions can be thin, severely hypokinetic, akinetic, or even aneurysmal. Occasionally, patients with profound ongoing ischemia can have global left ventricular dysfunction (hibernating myocardium). Hibernating myocardium may be distinguishable from irreversible left ventricular dysfunction with dobutamine echocardiography in which augmented function may be apparent at low doses of dobutamine, and dysfunction may be apparent at higher doses due to ischemia (see Chapter 27 ).
TABLE 21.2
Etiologies of Heart Failure
From Ponikowski P, Voors AA, Anker SD, et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: The task force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). Developed with the special contribution of the Heart Failure Association (HFA) of the ESC. Eur Heart J. 2016;37(27):2129-2200.
| Diseased Myocardium | ||
| Ischemic heart disease | Myocardial scar | |
| Myocardial stunning/hibernation | ||
| Epicardial coronary artery disease | ||
| Abnormal coronary microcirculation | ||
| Endothelial dysfunction | ||
| Toxic damage | Recreational substance abuse | Alcohol, cocaine, amphetamine, anabolic steroids |
| Heavy metals | Copper, iron, lead, cobalt | |
| Medications | Cytostatic drugs (e.g., anthracyclines), immunomodulating drugs (e.g., interferons monoclonal antibodies such as trastuzumab, cetuximab), antidepressant drugs, antiarrhythmics, nonsteroidal antiinflammatory drugs, anesthetics. | |
| Radiation | ||
| Immune-mediated and inflammatory damage | Related to infection | Bacteria, spirochetes, fungi, protozoa, parasites (Chagas disease), rickettsiae, viruses (HIV/AIDS) |
| Not related to infection | Lymphocytic/giant cell myocarditis, autoimmune diseases (e.g., Graves disease, rheumatoid arthritis, connective tissue disorders, mainly systemic lupus erythematosus), hypersensitivity and eosinophilic myocarditis (Churg-Strauss). | |
| Infiltration | Related to malignancy | Direct infiltrations and metastases |
| Not related to malignancy | Amyloidosis, sarcoidosis, hemochromatosis (iron), glycogen storage diseases (e.g., Pompe disease), lysosomal storage diseases (e.g., Fabry disease) | |
| Metabolic derangements | Hormonal | Thyroid diseases, parathyroid diseases, acromegaly, GH deficiency, hypercortisolemia, Conn disease, Addison disease, diabetes, metabolic syndrome, pheochromocytoma, pathologies related to pregnancy and peripartum |
| Nutritional | Deficiencies in thiamine, L-carnitine, selenium, iron, phosphates, calcium, complex malnutrition (e.g., malignancy, AIDS, anorexia nervosa), obesity | |
| Genetic abnormalities | Diverse forms | HCM, DCM, LV noncompaction, ARVC, restrictive cardiomyopathy (for details see respective expert documents), muscular dystrophies and laminopathies |
| Abnormal Loading Conditions | ||
| Hypertension | ||
| Valve and myocardium structural defects | Acquired | Mitral, aortic, tricuspid and pulmonary valve diseases |
| Congenital | Atrial and ventricular septum defects and others (for details see a respective expert document) | |
| Pericardial and endomyocardial pathologies | Pericardial | Constrictive pericarditis Pericardial effusion |
| Endomyocardial | HES, EMF, endocardial fibroelastosis | |
| High output states | Severe anemia, sepsis, thyrotoxicosis, Paget disease, arteriovenous fistula, pregnancy | |
| Volume overload | Renal failure, iatrogenic fluid overload | |
| Arrhythmias | ||
| Tachyarrhythmias | Atrial, ventricular arrhythmias | |
| Bradyarrhythmias | Sinus node dysfunctions, conduction disorders | |
ARVC, Arrhythmogenic right ventricular cardiomyopathy; DCM, dilated cardiomyopathy; EMF, endomyocardial fibrosis; GH, growth hormone; HCM, hypertrophic cardiomyopathy; HES, hypereosinophilic syndrome; HIV/AIDS, human immunodeficiency virus/acquired immune deficiency syndrome; LV, left ventricular.
Regional wall motion abnormalities can also be present in other forms of cardiomyopathy leading to HF, including sarcoidosis or Chagas’ disease and abnormalities of mechanical conduction, such as bundle branch blocks. Sarcoidosis should be considered when regional wall motion abnormalities are apparent but are not present in a coronary distribution, as specific treatments exist for cardiac sarcoidosis. Patients with wall motion abnormalities due to bundle branch block, specifically left bundle branch block, especially when there is no specific evidence or history of infarction, can have further deterioration of systolic function and ventricular dilatation due to inefficient contraction. Cardiac resynchronization therapy (CRT) has been shown to be beneficial when dilatation or dysfunction is severe in patients with left bundle branch block.
Evaluation of cardiac chamber wall thickness can also point to specific etiologies and diagnoses. Increased wall thickness on echocardiography can be suggestive of hypertrophic cardiomyopathy ( Chapter 23 ), infiltrative heart disease such as amyloidosis or glycogen storage diseases ( Chapter 24 ), chronic kidney disease ( 
; see also Chapter 41 ), or hypertensive heart disease. Distinguishing among these causes can be critical, as targeted therapies are available for some of these specific HF etiologies.
Assessment of Valvular Function in Heart Failure
Heart failure can be caused by primary abnormalities of cardiac valves. Aortic stenosis can lead to pressure-overload hypertrophy and, in the end stage, failure of the left ventricle (see Chapter 29 ). Aortic regurgitation can lead to severe dilatation of the left ventricle (see Chapter 29 ) secondary to the massive volume load imposed by an incompetent aortic valve. Mitral regurgitation, from any etiology, can similarly lead to HF by volume overload of the left ventricle, resulting in progressive dilatation and dysfunction, as well as contributing to elevation in LA pressures (see Chapter 28 ). While mitral stenosis typically will not result in left ventricular dilatation or dysfunction, the elevated LA pressure that results from mitral stenosis leads to elevated pulmonary venous pressures with resulting symptoms similar to HF secondary to left ventricular dysfunction and ultimately right HF. Right-sided valvular abnormalities, including both disorders of the pulmonary and tricuspid valves (see Chapter 30 ), can lead to right ventricular failure (see Chapter 16 ), with symptoms that typically include edema or anasarca, and ultimately renal and hepatic dysfunction secondary to high venous pressures.
Mitral Regurgitation in Heart Failure
Mitral regurgitation can be caused by either primary processes (such as prolapse, flail, or valve degeneration due to endocarditis), or can be functional, that is, secondary to ventricular dilatation and apical displacement of the papillary muscles that occur as the ventricle remodels (see Chapter 20, Chapter 28 ). Primary mitral regurgitation, when severe, will lead to volume overload and left ventricular dysfunction over a long period of time. There is considerable debate over timing of cardiac surgery in such patients. When signs and symptoms of HF have developed, the ventricular dysfunction is generally considered irreversible, although correction of the valvular abnormality, either with surgery or some of the newer percutaneous approaches, can retard or prevent further deterioration. Patients with primary mitral regurgitation should be followed with periodic assessment of ventricular size, function, and a quantitative measure of mitral regurgitation severity (see Chapter 28 ). Functional mitral regurgitation occurs when the ventricle dilates for any number of reasons, including myocardial infarction, and is usually a result of both annular dilatation and apical displacement of the papillary muscles. This results in tethering of the chordal structures and mitral leaflets. In functional mitral regurgitation, the regurgitant jet is central in origin ( , ), although leaflet tethering can eventually lead to an eccentric downstream direction ( ). Functional mitral regurgitation can further contribute to dilatation and dysfunction of the ventricle, and this can be amenable to surgical repair (using annuloplasty rings or replacements). Percutaneous approaches are already approved for treating primary (organic) mitral regurgitation and are being tested in clinical trial for functional mitral regurgitation, using devices that either bring the leaflets together or reduce mitral annular size. Functional mitral regurgitation is an independent risk factor for adverse outcomes in HF ( Fig. 21.3 ).
Patients with HF and mitral regurgitation should have full quantitative assessment of mitral regurgitant severity, including assessment of effective orifice area and regurgitant fraction by proximal isovelocity surface area (PISA) techniques (see Chapter 28 ). Moreover, the pulmonary veins should be assessed for potential flow reversal. In patients with moderate mitral regurgitation, serial assessment can determine when a patient is worsening and may encourage earlier consideration for intervention.
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