Left and Right Ventricular Systolic Function

Cardiac Cycle

Systole is defined as the segment of the cardiac cycle from mitral valve closure to aortic valve closure ( Fig. 6.1 ). The onset of systole is identified on the electrocardiogram as ventricular depolarization (onset of the QRS complex), with the end of systole occurring after repolarization (end of T wave). In terms of ventricular pressure curves over time, systole begins when LV pressure exceeds left atrial (LA) pressure, resulting in closure of the mitral valve. Mitral valve closure is followed by isovolumic contraction, during which the cardiac muscle depolarizes, calcium influx and myosin-actin shortening occur, and ventricular pressure rises rapidly at a constant ventricular volume (although shape changes do occur). When ventricular pressure exceeds aortic pressure, the aortic valve opens. During ejection (aortic valve opening to closing), LV volume falls rapidly as blood flows from the LV to the aorta. LV pressure exceeds aortic pressure for approximately the first half of systole, corresponding to a rapid acceleration of blood flow and a small pressure difference from the ventricle to the aorta. In the normal heart, pressure crossover occurs in mid-systole, so during the second half of systole, aortic pressure exceeds LV pressure, thus resulting in continued forward blood flow but at progressively slower velocities (deceleration). Aortic valve closure occurs at the dicrotic notch of the aortic pressure tracing, immediately following end-ejection. In sum, systole includes isovolumic contraction and ventricular ejection (acceleration and deceleration phases). Ventricular volume ranges from a maximum at end-diastole (or onset of systole) to a minimum at end-systole.

Physiology of Systolic Function

During systole, ventricular myocardial fibers contract circumferentially and longitudinally, resulting in myocardial wall thickening and inward motion of the endocardium. The simultaneous decrease in ventricular size and increase in pressure result in ejection of a volume of blood (stroke volume) from the ventricle. Stroke volume reflects the pump performance of the heart. The decrease in chamber volume relative to end-diastolic volume, or ejection fraction, reflects overall ventricular function . Ventricular function and pump performance depend on:

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  Contractility (the basic ability of the myocardium to contract)

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  Preload (initial ventricular volume or pressure)

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  Afterload (aortic resistance or end-systolic wall stress)

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  Ventricular geometry

Contractility is the intrinsic ability of the myocardium to contract, independent of loading conditions or geometry. Evaluation of contractility itself thus requires measurement of ventricular ejection performance under different loading conditions. Experimentally, contractility often is described by the slope of the end-systolic pressure-volume relationship ( E _max ). To derive this value, LV pressure is graphed on the vertical axis, with volume (not time) on the horizontal axis ( Fig. 6.2 ). This pressure-volume “loop” then represents a single cardiac cycle, with different pressure-volume loops for the same ventricle representing different loading conditions (e.g., increasing or decreasing ventricular end-diastolic volume or changing afterload). E _max is the slope of the line that intersects the end-systolic pressure-volume point for each curve. A decrease in contractility results in a decrease in stroke volume and larger LV volumes ( Fig. 6.3 ). Contractility itself can be affected by several physiologic parameters including heart rate, coupling interval, and metabolic factors, in addition to disease processes and pharmacologic agents.

The effect of preload on ventricular ejection performance is summarized by the Frank-Starling curve showing ventricular end-diastolic volume (or pressure) on the horizontal axis and stroke volume on the vertical axis ( Fig. 6.4 ). For a given degree of contractility, a curvilinear relationship exists between these variables such that increasing end-diastolic volume results in a greater stroke volume. An increase in contractility results in a greater increase in stroke volume for a given increase in preload; a decrease in contractility has the opposite effect.

Afterload , defined by resistance or impedance, has an inverse relationship with myocardial fiber shortening such that increasing vascular resistance results in a decreased stroke volume (see Fig. 6.4 ). An increase in contractility allows maintenance of a normal stroke volume with a higher afterload. With a decrease in contractility, even slight increases in afterload further decrease myocardial fiber shortening and stroke volume.

Measurement of LV systolic function independent of loading conditions is difficult using echocardiographic or other clinical approaches. It rarely is possible to construct pressure-volume loops under different loading conditions because of the problem of measuring instantaneous LV volumes and the potential risk of altering loading conditions in ill patients. Thus clinical evaluation of ventricular function has focused on measurements of cardiac output, ejection fraction, and end-systolic dimension or volume, even though the load dependence of these measures is a clearly acknowledged limitation. Strain and strain rate measurements offer another approach to evaluation of ventricular function and are becoming more widely used.

Ventricular Volumes and Geometry

The normal shape of the LV is symmetric, with two relatively equal short axes and with the long axis running from the base (mitral annulus) to the apex. In long-axis views, the apex is slightly rounded, so the apical half of the ventricle resembles a hemiellipse. The basal half of the ventricle is more cylindrical, so the ventricle appears circular in short-axis views. Various assumptions about LV shape have been used to derive formulas for calculating ventricular volumes from linear dimensions (M-mode) and cross-sectional areas (two-dimensional [2D] echo). Formulas using linear or cross-sectional measurements are simplifications to greater or lesser degrees, and variability exists among patients in the shape of the ventricle. Calculation of LV size from three-dimensional (3D) images avoids inaccuracy related to geometric assumptions.

Cardiac Output

The basic function of the heart is as a pump, so measurements of cardiac output are useful in routine day-to-day patient management. Cardiac output is the volume of blood pumped by the heart per minute, with stroke volume being the amount pumped on a single beat. Although cardiac output can be derived from ventricular volumes, as described earlier, various other approaches to measurement are available, including right heart catheterization with indicator dilation methods (Fick, thermodilution); inert gas rebreathing approaches; angiographic, radionuclide, or cardiac magnetic resonance) ventricular volumes; and cardiac magnetic resonance or Doppler flow-velocity methods.

Response to Exercise

Ventricular systolic function and cardiac output are dynamic, responding rapidly to the metabolic demands of the individual. Cardiac output increases from a mean of 6 L/min at rest to 18 L/min with exercise in young, healthy adults. Most of this increase in cardiac output is mediated by an increase in heart rate. With supine exercise, only a minimal increase in stroke volume (about 10%) occurs, whereas with upright exercise, the increase in stroke volume is approximately 20% to 35%. With exercise, end-diastolic volume is unchanged or slightly decreased, but ejection fraction increases and end-systolic volume decreases. With imaging techniques, endocardial motion and myocardial wall thickening are augmented, with an appearance of “hypercontractility” during and immediately following exercise.

Qualitative Evaluation of Systolic Function

Both global and regional ventricular function can be evaluated with 2D echocardiography on a semiquantitative scale by an experienced observer. On transthoracic (TTE) imaging, overall LV systolic function is evaluated best from multiple tomographic planes, typically:

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  Parasternal long-axis view

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  Parasternal short-axis view

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  Apical four-chamber view

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  Apical two-chamber view

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  Apical long-axis view

On transesophageal (TEE) imaging, equivalent views from a high TEE and transgastric position are used. Attention to image acquisition is needed to obtain adequate endocardial definition. 3D image acquisition from the TTE or TEE approach allows simultaneous display of two or more tomographic planes and likely will be more widely used as 3D image quality and endocardial definition are improved.

The echocardiographer then integrates the degree of endocardial motion and wall thickening from these views to classify overall systolic function as normal, mildly reduced, moderately reduced, or severely reduced. Some experienced observers can estimate ejection fraction visually from 2D images with a reasonable correlation with ejection fractions measured quantitatively by echocardiography or other techniques. Typically, ejection fraction is estimated in intervals of 5% to 10% (i.e., 20%, 30%, 40%, and so on), or an estimated ejection fraction range is reported (e.g., 20% to 30%).

Several other imaging parameters provide a qualitative measure of LV systolic function. M-mode signs include:

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  The separation between the maximum anterior motion of the anterior mitral leaflet and maximum posterior motion of the ventricular septum (E-point septal separation)

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  The degree of anteroposterior motion of the aortic root

With normal systolic function, the anterior mitral leaflet opens to nearly fill the ventricular chamber, thus resulting in little (0 to 5 mm) E-point septal separation. With systolic dysfunction, this distance is increased because of a combination of LV dilation and reduced motion of the mitral valve as a result of low transmitral volume flow. Similarly, LV systolic dysfunction results in reduced LA filling and emptying (low cardiac output), seen on M-mode as reduced anteroposterior motion of the aortic root (see Fig. 9.5 ).

On 2D echocardiography, the mitral annulus moves toward the ventricular apex in systole, with the magnitude of this motion proportional to the extent of shortening in ventricular length—a useful measure of overall LV systolic function. Normal subjects have motion of the mitral annulus toward the apex ≥8 mm, with a mean value of 12 ± 2 mm in both four- and two-chamber views. The sensitivity of mitral annulus motion <8 mm is 98%, with a specificity of 82% for identification of an ejection fraction <50%.

Qualitative evaluation of overall systolic function is a simple and highly predictive index that is of great clinical utility. Conversely, several factors can limit the usefulness of this evaluation. First, the accuracy of the estimated ejection fraction is dependent on the experience of each observer. Second, inadequate endocardial definition can result in incorrect estimates of systolic function. Third, integration of data from multiple tomographic images can be difficult when the pattern of contraction is asynchronous (with conduction defects, pacers, postoperative septal motion) or when the pattern of contraction is asymmetric (with prior myocardial infarction or with ischemia), especially when dyskinesis is present. To some extent, these limitations are minimized by an experienced observer, optimal endocardial definition, use of contrast to enhance border recognition, and integration of data from multiple views. However, when possible, it is preferable to avoid the limitations of estimates of systolic function by performing quantitative measurements.

Regional ventricular function also can be evaluated by imaging in multiple tomographic planes on TTE or TEE imaging. Regional function is evaluated qualitatively by dividing the ventricle into segments corresponding to the coronary artery anatomy and then grading wall motion on a 1 to 4+ scale as normal (score = 1), hypokinetic (score = 2), akinetic (score = 3), or dyskinetic (score = 4). In some cases, hyperkinesis (i.e., a compensatory increase in wall motion in regions remote from an acute myocardial infarction or the normal increase seen with exercise) also is scored. Evaluation of segmental wall motion is discussed in detail in Chapter 8 .

Quantitative Evaluation of Systolic Function

Linear Dimensions

LV internal dimensions and wall thickness are routinely measured using 2D echocardiography. Measurements of LV size are most accurate when the ultrasound beam is perpendicular to the blood-endocardium interface because of the precision of axial, compared with lateral, resolution. In some specific situations, such as serial evaluation of the patient with chronic aortic or mitral regurgitation, 2D guided M-mode measurements are recommended, particularly when identification of the endocardium is suboptimal on the 2D images ( Table 6.1 ).

TABLE 6.1

Left Ventricular Dimension Measurements

	TTE-2D	TTE-2D Guided M-Mode	TEE
Transducer position	Parasternal	Parasternal	Transgastric
Image plane	Long-axis	Long-axis	Two-chamber view (rotation angle 60°–90°)
Measurement position in LV chamber	Perpendicular to LV long axis in the center of the LV	Perpendicular to LV long axis in the center of the LV	Perpendicular to LV long axis in the center of the LV
	Biplane imaging or rotation between long- and short-axis views helps ensure a centered measurement.	Correct M-line orientation often requires moving the transducer up an interspace.	Ensuring a centered measurement is more difficult on TEE.
Measurement site along LV length	Just apical to the mitral leaflet tips (chordal level)	Just apical to the mitral leaflet tips (chordal level)	At the junction of the basal third and apical two thirds of the LV
Measurement technique	White-black interface	Leading edge-to-leading edge	White-black interface
Timing in cardiac cycle
End-diastole	Onset of QRS frame just before MV closure, or maximum LV volume	Onset of QRS frame just before MV closure, or maximum LV volume	Onset of QRS frame just before MV closure, or maximum LV volume
End-systole	Minimum LV volume or frame just before aortic valve closure	Minimum LV volume or frame just before aortic valve closure	Minimum LV volume or frame just before aortic valve closure
Advantages	It is feasible in most patients. Measurements can be made perpendicular to LV long axis.	High sampling rate facilitates identification of endocardium. Reproducible	It allows intraoperative monitoring preload. Ultrasound beam is perpendicular to endocardium from TG view, improving border recognition.
Disadvantages	Endocardial and epicardial borders may be difficult to identify accurately. It has a slow frame rate compared with M-mode.	M-line measurements should be made only if a perpendicular LV measurement is possible. This requires more attention to transducer and M-line position.	Image plane may be oblique. Wall thickness is measured in a transgastric short-axis view.

MV, Mitral valve; TG, transgastric.

On a standard examination, ventricular size is measured in the parasternal long-axis view, at the level of the mitral leaflet tips (mitral chordal level), perpendicular to the long axis of the ventricle ( Fig. 6.5 ). Biplane imaging or scanning between the long- and short-axis views is also helpful to ensure that the measurements are centered in the short-axis plane. TEE measurements of LV internal dimensions are made in a transgastric two-chamber view at the junction between the basal third and apical portion of the ventricle. Wall thickness is measured in the transgastric short-axis view. On 2D images, LV internal dimensions are measured at end-diastole and end-systole from the tissue-blood interface (white-black transition). End-diastole is defined as the onset of the QRS complex, the first frame after mitral valve closure or maximum ventricular volume. End-systole is defined as the smallest ventricular volume or the frame just after aortic valve closure.

When 2D guided M-mode measurements are used, the transducer often needs to be moved cephalad to obtain a perpendicular angle between the M-line and the long axis of the ventricle. If only an oblique orientation is possible, correctly aligned measurements should be made from the 2D image instead. The major advantage of M-mode echocardiography is high time resolution, which facilitates recognition of endocardial motion and thus a more accurate measurement of ventricular internal dimensions. On M-mode, the LV posterior wall endocardium is the most continuous line with the steepest systolic motion ( Fig. 6.6 ). The posterior wall epicardium is identified as the echo reflection immediately anterior to the pericardium. The septal endocardium also shows the steepest slope in systole with a continuous reflection through the cycle. On the right ventricular (RV) side of the septum, it is important to exclude any reflections that are caused by RV trabeculations. Conversely, a dark “mid-septal” stripe often is noted and should not be confused with the endocardial borders. LV wall thickness and dimensions are measured from the leading edge to leading edge of each interface of interest for optimal measurement accuracy. For example, ventricular internal dimensions are measured from the leading edge of the septal endocardium to the leading edge of the posterior wall endocardium. Normal values for linear ventricular dimensions depend on age and sex ( Fig. 6.7 ).

In addition to LV wall thickness and internal dimensions (LVID) at end-diastole (d) and end-systole (s), endocardial fractional shortening (FS) can be calculated as:

$\text{FS}\left(\%\right)=({\text{LVID}}_d-{\text{LVID}}_s)/{\text{LVID}}_d\times 100\%$

Fractional shortening is a rough measurement of LV systolic function, with the normal range being about 25% to 45% (95% confidence limits). Instead of endocardial fractional shortening, as shown in Eq. 6.3 , mid-wall fractional shortening is a better reflector of contractility because it reflects both the inward motion of the endocardium and the degree of wall thickening. However, mid-wall shortening calculations are rarely used in clinical practice because 2D measures of ventricular systolic function are more robust.

2D and 3D Ventricular Volumes

The 2D echocardiographic calculation of ventricular volumes is based on endocardial border tracing at end-diastole and end-systole in one or more tomographic planes on TTE or TEE images ( Table 6.2 and Appendix A , Table A.1 ). Prerequisites for quantitative evaluation by 2D echocardiography are:

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  Nonoblique standard image planes or image planes of known orientation relative to the long and short axis of the LV

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  Inclusion of the apex of the ventricle

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  Adequate endocardial definition

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  Accurate identification of the endocardial borders

TABLE 6.2

2D and 3D Echocardiographic Measurement of LV Volumes and Ejection Fraction

	2D	3D
Window	Apical Patient in steep left lateral position Apical cutout in exam stretcher Avoid apical foreshortening.	Apical Patient in steep left lateral position Apical cutout in exam stretcher Adjust transducer position to ensure inclusion of entire LV.
Image acquisition	Four-chamber and two-chamber views Adjust depth to mitral annulus level. Adjust gain, time-gain compensation, harmonic imaging, and other instrument parameters to optimize endocardial definition. Left-sided contrast enhances endocardial border identification when image quality is suboptimal.	Apical volumetric acquisition Full-volume gated acquisition Use 2D images for initial positioning and adjusting gain. Use split screen display of orthogonal views to optimize acquisition. Breath hold during acquisition to minimize stitch artifacts. Left-sided contrast enhances endocardial border identification when image quality is suboptimal.
Endocardial borders	Manual tracing at ED and ES ED defined as onset of QRS ES defined as minimal LV volume Trace borders at time of image acquisition and adjust, if needed, on final review.	Semiautomated endocardial border detection Exclude papillary muscles and trabeculations from LV chamber. Review and adjust borders after acquisition.
Volume calculations	Apical biplane formula	Surface-rendered LV volumes

ED, End-diastole; ES, end-systole.

When image quality is suboptimal, use of left-sided echo contrast improves endocardial definition. Currently, 2D or contrast-enhanced endocardial borders must be traced manually by an experienced physician or sonographer for accurate quantitation of LV systolic function. Because 2D echocardiography is a tomographic technique, LV volume calculations are based on geometric assumptions about the shape of the LV. By convention, the papillary muscles are included in the ventricular chamber, with endocardial borders extrapolated along the base of the papillary muscle, following the expected curvature of the ventricular wall. Obviously, accuracy in individual patients will be highest with methods that have the fewest geometric assumptions and that use data from multiple tomographic images (see Appendix B , Table B.1 ).

Several approaches for the calculation of LV volumes from tomographic data, based on different geometric assumptions, have been proposed, ranging from a simple ellipsoid shape to complex hemicylindrical or hemiellipsoid shapes ( Fig. 6.8 ). The most robust and practical method for clinical use is Simpson's rule or method of disks, which calculates ventricular volume as the sum of a series of parallel “slices” from apex to base.

$\text{LV volume}=\sum _{i=1}^n{A}_{i}T$

Where A is the area and T is the thickness of each of n slices. For example, if 20 disks are summated, LV volume is:

$\text{LV volume}=\sum _{n=20}\left[A_i\times L/20\right]$

This approach is recommended in consensus guidelines because it is accurate even when ventricular geometry is distorted ( Table 6.3 ). The apical biplane approach requires tracing of endocardial borders at end-diastole and end-systole in both four-chamber and two-chamber views, from either TTE or TEE images ( Fig. 6.9 ). These borders are then used to calculate cross-sectional areas of a series of elliptical disks. End-diastolic volume is calculated from end-diastolic images, and end-systolic volume is calculated from end-systolic images. Normal LV volumes are smaller in women compared with men and decrease with age in both sexes ( Fig. 6.10 ). Stroke volume is the difference between end-diastolic volume (EDV) and end-systolic volume (ESV) ( Eq. 6.2 ), whereas ejection fraction (EF) is calculated with Eq. 6.1 .

TABLE 6.3

American Society of Echocardiography and European Association of Cardiovascular Imaging Recommendations for Left Ventricular Chamber Quantification

Parameter	Recommended Measurements	Comments
LV size	2D LV volumes (biplane method, indexed to BSA)	Should be routinely assessed on all diagnostic echo studies.	Upper limits of normal EDV
			Men	74 mL/m 2
			Women	61 mL/m 2
			LV ESV
			Men	31 mL/m 2
			Women	24 mL/m 2
	3D LV volumes (indexed to BSA)	Recommended when feasible depending on image quality.
	LV linear dimensions	Useful when accurate volumes are not available.
LV global systolic function	2D ejection fraction (biplane method of disks)	Should be routinely assessed on all diagnostic echo studies.	Lower limit of normal
			Men	<52%
			Women	<54%
	3D ejection fraction	Recommended when feasible depending on image quality.
	GLS (2D speckle tracking)	GLS is most often calculated using midwall deformation. Serial GLS measurements in patients should use same equipment and software for each study.	Normal About negative 20% but depends on equipment and software.
LV regional function	16-segment model with visual grading of wall motion as normal, hypokinetic, akinetic, or dyskinetic	See Chapter 8 for details. For perfusion studies, a 17-segment model is recommended.
	Regional longitudinal strain (speckle tracking)	Not routine due to lack of standardization.
LV mass	M-mode or 2D calculated mass indexed to BSA	Important research tool but not routine on clinical studies. 3D methods are promising, but reference values are not yet established.	Upper limits of normal LV mass by linear measurement
			Men	115 g/m 2
			Women	95 g/m 2
			LV mass from 2D imaging
			Men	102 g/m 2
			Women	88 g/m 2

BSA, Body surface area; EDV, end-diastolic volume; ESV, end-systolic volume; GLS, global longitudinal strain.

Summarized from the American Society of Echocardiography and European Association of Cardiovascular Imaging Recommendations published in 2015 in Lang RM, Badano LP, Mor-Avi V, et al: Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging, J Am Soc Echocardiogr 28(1):1–39.e14, 2015.

When only a four-chamber view is available, a single-plane ejection fraction can be calculated that summates a series of disks with a circular cross-sectional area. Another alternative is the area-length method, which assumes that the base of the ventricle is approximated by a cylinder and the apex by an ellipsoid, sometimes called the “bullet” formula; this formula uses a long-axis length L and the cross-sectional area A _m of an orthogonal short-axis view at the mid-papillary level:

$\text{LV volume}=5/6\times A_{m}L$

In the presence of a distorted ventricular shape or regional wall motion abnormalities, these alternate methods are less accurate because, if the region of abnormal wall motion is included in the dimension or area measurements, volumes will be overestimated and vice versa.

3D echocardiography provides more accurate measurements of LV volumes and ejection fraction that are independent of geometric assumptions ( Appendix B , Table B.2 ). Current instrumentation allows semiautomated border detection from the 3D volumetric data set with calculation of end-diastolic and end-systolic volumes and ejection fraction. From an apical window, the key steps in 3D data acquisition for evaluation of the LV are as follows:

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  Start with 2D apical views to optimize gain settings, typically higher than for 2D imaging.

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  Guide the 3D acquisition by use of a split screen display of orthogonal views of the LV.

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  Acquire the 3D volume data set during a breath hold to minimize stitch artifacts.

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  Consider use of contrast to opacify the LV to improve endocardial border identification.

Data are displayed as a cine loop 3D-rendered LV volume, a graph of LV volume over the cardiac cycle, and images showing regional wall motion or regional ejection fraction, depending on the specific ultrasound system ( Fig. 6.11 ). In clinical practice, limitations of 3D evaluation of the LV include lower temporal and spatial resolution compared with 2D imaging and difficulty including the entire LV chamber within the 3D volume data set. However, 3D volumes and ejection fraction are more accurate than 2D measurements, so quantitative evaluation of LV systolic function 3D echocardiography is recommended, whenever possible.

Left Ventricular Speckle Tracking Strain Imaging

Speckle tracking strain is less load dependent compared with other echocardiographic parameters and allows detection of early LV systolic dysfunction before overt evidence of a fall in ejection fraction, as detailed in Chapter 4 ( Fig. 6.12 ). Most often global longitudinal strain (GLS) is measured with images acquired in apical four-chamber, two-chamber, and long-axis views. Longitudinal strain is a negative number with the normal value varying among different ultrasound systems, but typically it is about 20%. Global longitudinal strain includes data from all three apical views, with results presented in a target-type color-coded chart, a graph of strain over the cardiac cycle for each myocardial wall, and a single number representing global longitudinal systolic LV function.

Left Ventricular Geometry and Mass

LV mass is the total weight of the myocardium, derived by multiplying the volume of myocardium by the specific density of cardiac muscle. LV mass can be estimated from M-mode dimensions of septal thickness (ST), posterior wall thickness (PWT), and LV internal dimensions (LVID) at end-diastole as:

On 2D or 3D echocardiography, LV mass theoretically can be determined by tracing epicardial borders to calculate the total ventricular volume (walls plus chamber), subtracting the volumes determined from endocardial border tracing, and then multiplying by the specific density of myocardium:

However, epicardial definition rarely is adequate for this approach. Instead, mean wall thickness is calculated from epicardial ( A ₁ ) and endocardial ( A ₂ ) cross-sectional areas in a short-axis view at the papillary muscle level. LV mass measurements often are indexed for body size (either as body surface area or height) using sex-specific normal values (see Appendix A , Table A.2 ).

Relative wall thickness is a simpler measure of ventricular geometry in patients with hypertrophy that reflects the relative thickness of the walls compared with chamber size. Relative wall thickness (RWT) is calculated from posterior wall thickness (PWT) and LV internal dimension (LVID), both at end-diastole, as:

Ventricular geometry can be classified based on relative wall thickness (normal <0.42) and LV mass as:

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  Normal geometry—Normal LV mass and normal relative wall thickness

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  Concentric hypertrophy—Increased LV mass and increased relative wall thickness

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  Eccentric hypertrophy—Increased LV mass with normal relative wall thickness

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  Concentric remodeling—Normal LV mass with increased relative wall thickness

Concentric hypertrophy is typical of ventricular pressure overload caused by aortic stenosis with a small chamber and thick walls, whereas eccentric hypertrophy is typical of chronic volume overload caused by aortic regurgitation with a dilated chamber with normal wall thickness but an increased total weight of the ventricle. Hypertensive heart disease most often results in concentric remodeling with a normal total ventricular weight but walls that are relatively thick compared with the chamber size.

Limitations and Alternate Approaches