Knowledge of ventricular function is the basic step in the evaluation of all patients with cardiovascular abnormalities. The general status of LV function may be evident from the history and physical examination; however, quantification of LV function is important to explain a patient’s symptoms, to select the optimal therapeutic option, to select the optimal time for surgical treatment, and to monitor the efficacy of therapy. It should be emphasized that the evaluation of ventricular function includes the parameters of diastolic function as well as those of systolic function. Coronary artery disease is the most common reason for referral for echocardiography, and the basic information required for evaluation of ventricular function is usually sufficient for responding to the referral unless stress echocardiography is requested. A referral for the diagnosis of coronary artery disease requires complete evaluation of the following:

These parameters should be as quantitative as possible (e.g., the Simpson method for LV volume and LVEF, area-length or Simpson method for LA volume, and proximal isovelocity surface area method for mitral regurgitation). If the definition of the endocardium is poor, the administration of contrast may be necessary. If a patient’s symptoms are related predominantly to exertion, then filling pressures, pulmonary artery systolic pressure, and mitral regurgitation as well as LV global and regional function should be evaluated during exercise (1,2,3).

After coronary artery disease, the evaluation of dyspnea and heart failure is the most common reason for referral for echocardiography. Echocardiography is the most useful diagnostic test for evaluating patients who have symptoms of heart failure. Dyspnea is a clinical manifestation of various cardiac and noncardiac disorders. A referral for this diagnosis requires complete evaluation of the following:

It is critical that diastolic function be evaluated in patients who have a normal LVEF and clinical evidence of heart failure (4). The use of myocardial tissue Doppler or tissue Doppler imaging has facilitated the ability of echocardiographers to diagnose diastolic heart failure and pericardial disease that may otherwise be missed (5,6). The estimation of filling pressure and grading of diastolic function are also useful for the management and prognosis of patients with systolic dysfunction (7,8). Stress echocardiography for the assessment of wall motion or filling pressure (or both) should be considered if dyspnea is thought to be an angina equivalent or is exertional in nature (1). The measurement of valvular hemodynamics, the diastolic filling pattern, and pulmonary pressure needs to be repeated with exercise if data obtained from the patient at rest do not explain the exertional dyspnea. An assessment of mechanical dyssynchrony should be a routine part of the echocardiography examination of patients with systolic dysfunction and ventricular conduction delay (see Chapter 5).

A diagnostic algorithm for a comprehensive evaluation of patients who present with symptoms of heart failure is presented in Figure 23-1. To establish that the patient’s symptoms are truly heart failure, the structural or functional abnormality that compromises the ability of the ventricles to fill with or eject blood needs to be demonstrated. The echocardiography evaluation begins with two-dimensional
(2D) transthoracic echocardiography (TTE) or, under certain clinical circumstances, transesophageal echocardiography (TEE). If a structural or systolic functional abnormality is the underlying cause of heart failure, the initial evaluation should be able to identify the lesion by detecting, for example, reduced systolic contraction, a dilated ventricle, a valvular abnormality, or congenital heart disease. Subsequent Doppler and color flow imaging confirms the diagnosis and quantifies the hemodynamic severity of the underlying problem. However, in about half of the patients who have heart failure, the initial 2D echocardiography study may not show any obvious abnormality in systolic function or cardiac structure because the heart failure is related to diastolic dysfunction or to an abnormality in diastolic filling at rest or with exertion (or both). Therefore, a comprehensive evaluation of diastolic function or filling is essential for all patients with suspected heart failure, as described in Chapter 8. Even in patients who have systolic heart failure, diastolic evaluation provides important prognostic and filling pressure information. The initial Doppler evaluation of diastolic filling is usually the recording of mitral inflow and pulmonary vein velocities. For most patients, diastolic filling can be categorized as restrictive (i.e., increased filling pressure and/or decreased compliance) or nonrestrictive (i.e., normal filling pressure with or without abnormal relaxation) on the basis of the mitral inflow and pulmonary vein velocities. If diastolic filling is restrictive, it is necessary to determine whether the restrictive filling is due to myocardial disease or pericardial constriction (see Chapter 17). The echocardiographic findings in these two conditions have several major differences. One of the most helpful differences is the early diastolic velocity of the mitral anulus recorded with tissue Doppler imaging. Constrictive pericarditis should be considered in all patients who have symptoms of heart failure and a normal LVEF if the early diastolic anulus velocity (E′) is 8 cm/s or greater. If the baseline diastolic filling pattern is nonrestrictive, exercise-induced cardiac dysfunction and noncardiac disorders or purely right-heart dysfunction should be considered. If the patient has an underlying abnormality of myocardial relaxation, which is usually obvious on a mitral inflow recording, the diastolic filling pattern or pressure needs to be measured with exercise, as described in Chapter 8.

Hypertension is a common condition that contributes significantly to cardiovascular morbidity and mortality. Patients who are referred for echocardiography frequently have hypertension. Hypertrophy of the LV is a characteristic response to systemic hypertension, and LV mass is an independent prognostic indicator (9). Two-dimensional and M-mode echocardiography can measure LV wall thickness and estimate LV mass, both of which are indices of LV hypertrophy (see Chapter 7). The use of three-dimensional echocardiography should improve the accuracy of the measurements of LV mass. When measuring LV mass, it is important to consider the age, body surface area, and sex of the patient. The values for upper-normal LV mass index are listed in the Appendix.

Not uncommonly, global systolic LV function in hypertensive patients is hyperdynamic because of the hyperadrenergic state and intravascular volume contraction resulting from diuretic therapy. Hypercontractile systolic function in the context of LV hypertrophy may result in dynamic LVOT obstruction, which produces a characteristic systolic late-peaking, dagger-shaped, continuous wave Doppler signal (see Chapter 15). This has been termed hypertensive hypertrophic cardiomyopathy (10). Vasodilator or diuretic therapy aggravates LVOT obstruction.

Infrequent, but important, causes of hypertension are coarctation of the aorta and pheochromocytoma. The descending thoracic aorta should be interrogated from the suprasternal notch with continuous wave Doppler echocardiography. Pulsed wave Doppler recording of the abdominal aorta shows a characteristic velocity wave form (see Chapter 20).

Diastolic function is another important variable that should be evaluated with 2D, Doppler, and tissue Doppler echocardiography in patients with systemic hypertension because hypertension is the most common cause of diastolic heart failure. The earliest diastolic abnormality in hypertension is a relaxation abnormality, and Doppler imaging shows a prolonged LV isovolumic relaxation time, reduced mitral inflow early filling velocity (E), increased mitral inflow late filling velocity (A), reduced E/A ratio, prolonged mitral inflow deceleration time (DT), and reduced E′ and flow propagation velocity. The diastolic
filling pattern becomes more restrictive as congestive heart failure develops at a later stage or with a hypertensive crisis and increased filling pressure (11). A triphasic mitral inflow velocity pattern may be seen with markedly delayed relaxation and decreased compliance (12) (see Chapter 8).

In patients with hypertension and chronic renal failure, myocardial texture may become abnormal, simulating the appearance of cardiac amyloidosis, but it usually is accompanied by a marked increase in QRS voltage on the electrocardiogram (ECG), in contrast to the low voltage in cardiac amyloidosis. Therefore, in addition to the parameters listed for an evaluation of cardiac function, the following information needs to be assessed and evaluated in patients with systemic hypertension:

Although various bedside maneuvers are helpful in determining the cause of murmur with auscultation, it is often necessary to confirm the clinical suspicion or to characterize the morphologic and hemodynamic abnormalities responsible for the murmur. Another frequent reason for referral for echocardiography is mitral valve prolapse. It is still the most common cause of severe mitral regurgitation and mitral valve repair (or replacement), but most patients with mitral valve prolapse are free of symptoms. Because of the medical, financial, and psychologic impact of the diagnosis of mitral valve prolapse, strict diagnostic criteria should be used (see Chapter 12): 1) thickened or myxomatous mitral leaflets, 2) systolic displacement of the mitral leaflet into the LA at least 3 mm or more beyond the mitral anulus in the parasternal or apical long-axis view, and 3) mitral regurgitation.