Left ventricular diastolic function and dysfunction: Central role of echocardiography

Abstract

Comprehensive and precise assessment of left ventricular (LV) systolic and diastolic function is necessary to establish, or exclude, heart failure as a cause or component of dyspnea. Echocardiography with Doppler readily assesses LV diastolic function; advantages include that echocardiography is non-invasive, does not require radiation, is portable, rapid, readily available, and in competent hands, can provide an accurate and comprehensive assessment of LV systolic and diastolic function. Correct assessment of LV diastolic function is relevant in patients with both depressed and preserved LV ejection fraction (EF ≥ 50%, and < 50%, respectively). Tissue Doppler (TD) imaging has been useful in demonstrating impaired LV relaxation in the setting of preserved LVEF, which, in the setting of increased cardiac volume, can result in elevated LV filling pressures, and dyspnea due to diastolic heart failure. TD imaging is not always critical in patients with depressed LVEF, since such patients by definition have impaired LV relaxation, and thus significant increases in volume will result in increases in LV filling pressure due to impaired LV compliance. Thus, in depressed LVEF, transmitral flow velocities (E and A, and E/A) and deceleration time, pulmonary venous Doppler, left atrial volume, and pulmonary artery (PA) pressures suffice for the accurate assessment of LV filling pressures. Overall, diastolic assessment by echo-Doppler can be readily achieved in by using a comprehensive diastolic assessment-incorporating many 2-dimensional, conventional and tissue Doppler variables-as opposed to relying on any single, diastolic parameter, which can lead to errors.

Figure 1.

Comprehensive diastolic assessment with echocardiography in a patient with diastolic heart failure: Chronic hypertension is a common scenario for the development of diastolic dysfunction, and the hypertrophied left ventricle (LV) develops impaired relaxation, and in the right loading conditions, can result in elevated left atrial (LA) pressure. This patient with chronic hypertension presented with dyspnea. Echocardiography revealed concentric LV hypertrophy (LV mass index was 119 g/m², Panel A) with preserved LV ejection fraction of 62%. The patient also has severely dilated left atrium (LA) from chronic elevation in LA pressures in the setting of left ventricular hypertrophy from chronic hypertension (Panel B). This patient had severe LA enlargement, with an unindexed LA volume of 137 ml and an indexed volume of 72 ml/m². Panel C shows restrictive diastolic filling pattern in the transmitral spectral Doppler with E/A = 2.46 and deceleration time = 121 ms, reflective of significantly elevated LV filling pressures. Panel D shows tissue Doppler at the lateral LV mitral annulus with a depressed e′ velocity of 5.7 cm/s, indicating impaired LV relaxation; when e′ is divided into the transmitral E velocity of 177 cm/s, this results in an elevated E/e′ of 31, confirming significantly elevated LV filling pressures.

Figure 2.

Diastolic function grades: Left ventricular (LV) diastolic function ranges from normal (Grade 0) to impaired relaxation (Grade I), to pseudonormal (Grade II), to restrictive (Grade III), and irreversibly restrictive (Grade IV). LV relaxation and left atrial pressures (LAp) increase from Grades 0 to IV, as does LA volume. Mitral valve inflow (MVI), tissue Doppler imaging, Valsalva manoeuver, flow propagation velocity (Vp) and pulmonary venous flow are all helpful in distinguishing Grades of LV diastolic function, and should be used together for an integrated approach to the assessment of diastolic function as recommended in current guidelines (Figure adapted from Reference [31]).

Figure 3.

Diastolic assessment: Transmitral flow propagation velocity (Vp): Placing the color Doppler sample volume from the mitral annular level to the left ventricular (LV) apex, the more rapid the LV relaxation, the faster blood travels from the mitral annular level to the LV apex, and hence the more vertical the color Doppler mitral inflow m-mode and the more rapid the Vp slope (left panel). On the other hand, the more impaired the LV relaxation, the slower it take for blood to go from the mitral annular to the LV apex, hence a “flatter” Vp slope (right panel).

Figure 4.

Tricuspid regurgitation velocity for pulmonary artery systolic pressure estimation in diastolic dysfunction: In patients with significant left ventricular (LV) diastolic dysfunction with chronically elevated LV filling pressures, back-pressure through the left atrium (LA), into the pulmonary veins, and across the pulmonary venous-capillary bed into the pulmonary arterioles and pulmonary arteries (PA), results in elevation of PA pressure. Thus, PA systolic pressure elevation, in the absence of significant intrinsic lung disease and resultant elevated pulmonary vascular resistance (PVR), is a reasonable correlate of elevated LA pressures. PA systolic pressure can be estimated by Doppler using the tricuspid regurgitation peak systolic velocity and adding to it an estimate of right atrial (RA) pressure. This image shows a TR velocity of 3.64 m/s, equivalent to a TR systolic pressure of 53 mmHg, which indicates at least moderate PA hypertension in patient with chronically elevated LA pressure due to ischemic cardiomyopathy and diastolic dysfunction. RV = right ventricular.

Figure 5.

An integrated approach to the assessment of left ventricular diastolic function: Normal LV ejection fraction: As recommended in current guidelines, use of multiple echo-Doppler parameters results in a more accurate assessment of left ventricular (LV) diastolic function than using any single echo-Doppler parameter in isolation. In the patient with normal LV ejection fraction (EF), it is reasonable to start with early transmitral diastolic velocity/tissue Doppler early diastolic velocity (E/e′), as it can be difficult to discern whether a patient with preserved LVEF has impaired or normal LV relaxation. Following E/e′, other echo-Doppler variables are added to result in an accurate assessment of LV diastolic function (From Reference [5]).

Figure 6.

An integrated approach to the assessment of left ventricular diastolic function: Depressed ejection fraction: As recommended in current guidelines, use of multiple echo-Doppler parameters results in a more accurate assessment of left ventricular (LV) diastolic function than using any single echo-Doppler parameter in isolation. In the patient with depressed LV ejection fraction (EF), it is reasonable to start with early and late transmitral diastolic inflow velocities and deceleration time (E, A and DT, respectively), as it can assumed that patients with depressed LVEF ( < 50%) have, by definition, impaired LV relaxation. Following transmitral diastolic flow, other echo-Doppler variables are added to result in an accurate assessment of LV diastolic function (From Reference [5]).