Reliability of echocardiographic and electrocardiographic parameters in assessing serial changes in left ventricular mass

Regression of electrocardiographic left ventricular hypertrophy predicts regression of echocardiographic left ventricular mass: the LIFE study

The electrocardiogram (ECG) is widely used for detection of left ventricular hypertrophy (LVH). However, whether changes in ECG LVH during antihypertensive therapy predict changes in LV mass remains unclear. Baseline and year-1 ECGs and echocardiograms were assessed in 584 hypertensive patients with ECG LVH by Sokolow-Lyon or Cornell voltage-duration product criteria at entry into the Losartan Intervention For Endpoint reduction in hypertension (LIFE) echocardiographic substudy. A >/=25% decrease in Cornell product defined regression of ECG LVH; a <25% decrease defined no significant regression; and an increase defined progression of ECG LVH. Regression of echocardiographic LVH was defined by a >/=20% reduction in LV mass. After 1 year of therapy, 155 patients (27%) had regression of ECG LVH, 286 (49%) had no significant change, and 143 (25%) had progression of ECG LVH. Compared with patients with progression of ECG LVH, patients with no significant decrease and patients with regression of ECG LVH had stepwise greater absolute decreases in LV mass (-16+/-33 vs -29+/-37 vs -32+/-41 g, P<0.001), greater percent reductions in LV mass (-5.7+/-14.6 vs -11.3+/-13.6 vs -12.3+/-15.6%, P<0.001), and were more likely to decrease LV mass by >/=20% (11.2 vs 24.8 vs 36.1%, P<0.001), even after adjusting for possible effects of baseline and change in systolic and diastolic pressures. Compared with progression of ECG LVH, regression of the Cornell product ECG LVH is associated with greater reduction in LV mass and a greater likelihood of regression of anatomic LVH.

Left ventricular geometry and function preceding neurally mediated syncope

BACKGROUND

Neurally mediated syncope has been associated with increased left ventricular (LV) fractional shortening (FS) during tilt testing, which is consistent with the hypothesis that the stimulation of LV mechanoreceptors leads to reflex hypotension and/or bradycardia. However, FS does not represent true LV contractility because of its dependence on afterload and preload.

METHODS AND RESULTS

To elucidate the role of increased contractility in the mediation of neurally mediated syncope, we compared echocardiographic measures of LV performance corrected for end-systolic stress (ESS) in 21 patients (13 women and 8 men) with unexplained syncope who had either positive (n=10) or negative (n=11) responses to a tilt-table test. Two-dimensional echocardiographic LV imaging was performed at baseline and during the initial 5 minutes of upright tilt. In the supine position, both groups had similar LV end-diastolic volume indexes, stroke volumes, FS, circumferential ESS, and afterload-independent measures of LV performance (stress-corrected midwall and FS). However, after 5 minutes of upright tilt, patients who subsequently had a positive test had a lower stroke volume, lower stress-corrected midwall shortening, and endocardial FS. The tilt-positive group also had a greater fall in ESS and FS early during upright tilt.

CONCLUSIONS

Reduced ESS, LV volume, and chamber function during initial upright tilt are associated with a subsequent positive tilt response in patients with unexplained syncope. These data suggest that if paradoxic activation of LV mechanoreceptors has a role in mediating neurally mediated syncope, it is not triggered by LV hypercontractility or increased systolic wall stress during the initial period of upright tilt.

Influence of a rapid change of left ventricular dimensions on the echocardiographic measurement of left ventricular mass by the Penn convention

OBJECTIVE

The purpose of this study was to test the robustness of the measurement of left ventricle mass (LVM), using Devereux's formula, in the presence of a rapid change in left ventricular volume induced by nitroglycerin.

DESIGN

Forty-eight healthy volunteers with excellent echocardiographic recordings were included. The intrapatient variability of LVM measurement was assessed by two consecutive echocardiograms. The intraobserver reproducibility was assessed by the rereading of 19 echocardiograms by the same observer. The effects of nitroglycerin were compared with those of a placebo in a double-blind random manner on, the left ventricular internal dimension in diastole (LVIDd), the interventricular septum thickness, the posterior wall thickness and the LVM.

RESULTS

It was shown that both the intrapatient and the intraobserver reproducibility were high. Nitroglycerin induced a significant decrease in LVIDd compared with placebo (-0.21 +/- 0.24 versus 0.01 +/- 0.21 cm, respectively, P < 0.01) and a non-significant increase in wall thickness. These variations were negatively correlated with each other (r= -0.58, P< 0.01). Despite the change of ventricular dimensions, the variation of LVM induced by nitroglycerin was not significantly different from that induced by placebo (2.0 +/- 16.0 versus 4.7 +/- 17.0 g, respectively, not significant) and close to the intrapatient variability.

CONCLUSION

This experiment failed to demonstrate any influence of a rapid variation of ventricle size on the calculation of LVM with the Penn convention and strongly supports the robustness of the method in vivo.

Measurement of left ventricular mass: methodology and expertise

The strong relation between increased left ventricular mass and cardiovascular events makes accurate measurement of left ventricular mass a high priority, especially in patients with hypertension. M-mode echocardiography is used most widely to measure left ventricular mass because of its wide availability, moderate expense, anatomic and prognostic validation and lack of radiation or claustrophobia; however, this technique is expertise-dependent and may give erroneous results in distorted ventricles. Two-dimensional and especially three-dimensional echocardiography increase the precision with which left ventricular mass is measured but they are more time-consuming and difficult to perform on a large scale. Magnetic resonance imaging provides highly accurate left ventricular mass measurements and permits tissue imaging but its use is limited by expensive, fixed facilities and claustrophobia. Cine computed X-ray tomography also measures left ventricular mass accurately and permits perfusion assessment with contrast injection but it involves radiation and the use of fixed facilities of limited availability. Understanding the strengths and limitations of available techniques can facilitate selection of the most appropriate method to measure left ventricular mass in a particular setting.

Ambulatory blood pressure and echocardiographic left ventricular dimensions in elderly hypertensive subjects

In a consecutive series of 62 hypertensive elderly subjects, the authors studied the relation of blood pressure circadian variations with echocardiographic parameters of left ventricular (LV) hypertrophy. All the subjects were submitted to an ambulatory blood pressure monitoring (ABPM) and to B- and M-mode echocardiography. In the elderly hypertensive group, LV mass index (LVMI) was more strongly related to twenty-four-hour, daytime and nighttime systolic ambulatory blood pressure (r = 0.52, r = 0.37, r = 0.51) than diastolic ambulatory blood pressures were (r = 0.32, r = 0.18, r = 0.33). Casual systolic and diastolic blood pressure (CBP) was found more weakly related to LVMI than ambulatory blood pressures were (r = 0.35, r = 0.26). Elderly hypertensive subjects were divided into two subgroups in relation to the presence (group 1) or absence (group 2) of blood pressure nocturnal decline. No differences were found between these two subgroups in regard to: casual blood pressure values, ambulatory blood pressures in the diurnal period, sex, body surface area, height, weight, and age. LVMIs were computed in all three groups and showed the following results: 89.32 +/- 19.76 in elderly normotensives, 91.21 +/- 31.32 in group 1, and 99.80 +/- 18.21 in group 2. Echocardiographic parameters of LV dimensions and LVMIs were different in group 1 and 2. An inverse correlation, statistically significant, was observed between LVMIs and the nocturnal blood pressure reduction (systolic: r = -0.36, P < 0.05; diastolic: r = -0.29, P < 0.05). These results suggest an association between a smaller LV mass and nocturnal blood pressure decline in elderly hypertensive patients.

Decreased thickening of normal myocardium with transient increased wall thickness during stress echocardiography with atrial pacing

Stress echocardiography is used increasingly in the evaluation of coronary artery disease. The echocardiographic evaluation of ischemia is based on stress-induced changes in wall motion and wall thickening of the ischemic segments. Studies have demonstrated that left ventricular volumetric changes may induce changes in wall thickness. The aim of the study was to evaluate whether significant changes in ventricular volume, wall thickness, and wall thickening occur during stress echocardiography with atrial pacing. Seven German Landrace female pigs were studied 4 weeks after the induction of a small myocardial infarction. Echocardiographic measurements were conducted in noninfarcted segments on the short-axis view at baseline and during atrial pacing at 120, 150, and 180 beats/min. End-diastolic circumferential area decreased from 12.3 +/- 2.0 cm2 at baseline to 8.9 +/- 1.9 cm2 at 180 beats/min of atrial pacing (p < 0.01). Mean wall thickness (interventricular septal plus posterior wall thickness divided by 2) increased markedly and progressively from 6.7 +/- 0.6 mm at baseline to 9.8 +/- 1.0 mm at 180 beats/min (p < 0.01). The increase in wall thickness correlated inversely with end-diastolic area (r = -0.57; p < 0.01). Percent systolic thickening decreased from 38.9 +/- 12.0 at baseline to 14.9 +/- 7.4 at 180 beats/min of atrial pacing (p < 0.01). The decrease in percent wall thickening correlated with the increase in wall thickness (r = -0.71; p < 0.01). In conclusion, this study shows that a marked increase in wall thickness (pseudohypertrophy) and decrease in percent systolic thickening are observed during rapid atrial pacing in normal myocardium and do not indicate stress-induced left ventricular dysfunction.

Psychophysiological reactivity and cardiac end-organ changes in white coat hypertension

This study aimed 1) to assess whether patients with an exaggerated blood pressure response to the doctor's presence ("white coat" effect) also display a pattern of enhanced blood pressure reactivity to mental stress and physical exercise and 2) to determine the presence of left ventricular structural and filling abnormalities in patients with white coat hypertension. We studied 56 (40 men) consecutive patients (mean [SD] age, 46.4 [9.1] years) whose clinic blood pressure was repeatedly high. Patients were classified as having white coat hypertension (n = 20) if both their mean daytime (from 7 AM to 11 PM) ambulatory systolic and diastolic blood pressures were less than 134 and 90 mm Hg, respectively. Patients were considered to have persistent hypertension (n = 36) if daytime systolic blood pressure was 134 mm Hg or more or diastolic blood pressure was 90 mm Hg or more. Eighteen subjects with clinic blood pressure lower than 140/90 mm Hg served as a normotensive control group. Blood pressure reactivity from baseline to mental arithmetic, isometric handgrip, and cycle ergometry did not display any difference among the three groups. The white coat hypertensive group had left ventricular mass index lower than the persistent hypertensive group but higher than the normotensive group. Doppler indexes of left ventricular diastolic filling displayed similar abnormalities in the white coat and persistent hypertensive groups compared with the normotensive group.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular pseudohypertrophy in cardiac tamponade: an echocardiographic study in a canine model

OBJECTIVES

This study was designed to establish whether left ventricular pseudohypertrophy in cardiac tamponade can be reproducibly induced in an experimental canine model and to investigate the mechanism of its production.

BACKGROUND

Past experimental and clinical studies have shown reduction of ventricular volumes resulting from cardiac tamponade. Left ventricular pseudohypertrophy, a transient thickening of myocardial walls, was recently described as a new echocardiographic sign of cardiac tamponade.

METHODS

Cardiac tamponade was induced in seven anesthetized open chest dogs with serial bolus injections of 50 ml each of 0.9% saline solution into the pericardial sac. Under hemodynamic monitoring, M-mode and two-dimensional echocardiographic measurements were performed from a right parasternal window at each stage of graded cardiac tamponade.

RESULTS

There was a progressive increase of interventricular septal and posterior wall diastolic thickness. Mean wall thickness (interventricular septal thickness + posterior wall thickness divided by 2) was 9.8 +/- 1.3 mm at baseline, 14.3 +/- 0.9 mm at peak tamponade and 9.0 +/- 1.5 mm after fluid withdrawal (p < 0.0001). Mean wall thickness correlated directly with the severity of cardiac tamponade, as estimated from the level of right arterial pressures (r = 0.75 and p < 0.0001), and with the decrease of left ventricular cavity volume (r = -0.67 and p < 0.0001). Left ventricular mass did not change significantly.

CONCLUSIONS

Left ventricular pseudohypertrophy is a constant manifestation of cardiac tamponade in a canine model. The degree of myocardial thickening correlates with the reduction of ventricular dimensions and with the severity of hemodynamic compromise, representing a constant facet of heart remodeling in cardiac tamponade.

Echocardiographic correlates of left ventricular structure among 844 mildly hypertensive men and women in the Treatment of Mild Hypertension Study (TOMHS)

BACKGROUND

Echocardiography provides a noninvasive means of assessing left ventricular (LV) structure and evidence of LV wall remodeling in hypertensive persons. The relation of demographic, biological, and other factors with LV structure can be assessed.

METHODS AND RESULTS

LV structure was assessed by M-mode echocardiograms for 511 men and 333 women with mild hypertension (average blood pressure, 140/91 mm Hg). Measurements of LV wall thicknesses and internal dimensions were made, and estimates of LV mass indexes and other derivations of structure were calculated. LV hypertrophy criteria were based on previously reported echocardiographic population studies of normal subjects. These measures were compared by age, sex, race, body mass index, systolic blood pressure, antihypertensive drug use, physical activity, alcohol intake, cigarette smoking, and urinary sodium excretion. Despite virtual absence of ECG-determined LV hypertrophy, 13% of men and 20% of women had echocardiographically determined LV hypertrophy indexed by body surface area (g/m2), and 24% of men and 45% of women had LV hypertrophy indexed by height (g/m). Black participants had slightly higher mean levels of wall thickness than nonblack participants but similar LV mass. Systolic blood pressure and urinary sodium excretion were significantly and independently associated with LV mass index and LV hypertrophy using both g/m2 and g/m. Body mass index was significantly related to LV mass index and LV hypertrophy using g/m. Smoking was significantly associated with LV mass index, i.e., using continuous measurement but not using the dichotomy for LV hypertrophy.

CONCLUSIONS

This study of a large population of men and women with mild primary hypertension, largely without ECG evidence of LV hypertrophy, showed a substantial percentage of participants with echocardiographically determined LV hypertrophy. LV mass indexes correlated positively with systolic blood pressure, body mass index, urinary sodium excretion, and smoking.

Variability between current definitions of 'normal' ambulatory blood pressure. Implications in the assessment of white coat hypertension

The assessment of white coat hypertension is complicated by the lack of generally agreed-on normal limits of ambulatory blood pressure. To assess the influence of four of these limits on the prevalence of white coat hypertension and the corresponding distribution of left ventricular hypertrophy, we performed 24-hour ambulatory blood pressure monitoring and echocardiographic studies in 346 untreated patients with essential hypertension and 47 age-matched normotensive control subjects. The upper limits of normal daytime ambulatory blood pressure were lower using standards drawn from clinically normotensive populations than using standards drawn, partly or entirely, from general populations. The prevalence of white coat hypertension differed markedly using the different standards, being 12.1%, 16.5%, 28.9%, and 53.2% (chi 2 = 346.0, p less than 0.0001). Left ventricular mass index averaged 77 g/m2 in the control group, 85 g/m2 in the two groups with white coat hypertension defined by using standards drawn from normotensive populations (both comparisons not significant versus control group), and 90 and 98 g/m2 in the two groups with white coat hypertension defined by using the other two standards (both p less than 0.01 versus control group). The prevalence of echocardiographic left ventricular hypertrophy was 0% in the control group, 2.4% and 3.5% in the two groups with white coat hypertension defined by using standards drawn from normotensive populations, and 9.0% and 14.7% in the other two groups with white coat hypertension (p less than 0.05 and p less than 0.01, respectively, versus control group).(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine vectocardiography: a comparative study relative to the validity of four tridimensional lead systems

For spatial vectocardiography to become applicable for cardiac investigation in cattle, it was necessary to develop a reliable standardized electrocardiographic lead system in this species. In this study, four tridimensional lead systems, initially developed in horses, were compared when applied in calves. Fifty seven electrocardiograms were collected. The between-subject variability of the magnitude and angles of the tridimensional P, QRS and T modal vectors obtained by use of each lead system was compared. Reproducibility of vectrocardiographic measurements was analyzed by comparing results obtained in 10 calves within a one day interval. The Holmes semi-orthogonal lead system, giving the lowest between-subject variability and the highest between-day reproducibility, appeared to be the most reliable lead system in order to apply vectocardiography in the bovine species.

Left ventricular filling abnormalities in asymptomatic morbid obesity

Indexes of left ventricular (LV) diastolic filling were measured by pulse Doppler echocardiography in 16 asymptomatic morbidity obese patients presenting for bariatric surgery and were compared with an age- and sex-matched lean control population. No patient had concomitant disorders known to affect diastolic function. All patients had normal systolic function. LV wall thickness and internal dimension were measured in order to calculate LV mass. Fifty percent of morbidly obese patients had LV diastolic filling abnormalities as assessed by the presence of greater than or equal to 2 abnormal variables of mitral inflow velocity. The ratio of peak early to peak late (atrial) filling velocity was significantly decreased in obese compared with control patients (1.16 +/- 0.26 vs 1.66 +/- 0.30, p less than 0.001). The peak velocity of early LV diastolic filling was significantly reduced in obese patients (75 +/- 15 vs 98 +/- 19 cm/s, p less than 0.001). The atrial contribution to stroke velocity as assessed by the time-velocity integral of late compared with total LV diastolic filling was significantly increased in obese patients (36 +/- 7 vs 27 +/- 4%, p less than 0.001). Obese patients had significantly increased LV mass (214 +/- 45 vs 138 +/- 37 g, p less than 0.001), even when corrected for body surface area (95 +/- 16 vs 76 +/- 16 g/m2, p less than 0.002). However, increased LV mass did not correlate with indexes of abnormal diastolic filling in obese patients. These data suggest that abnormalities of diastolic function occur frequently in asymptomatic morbidly obese patients and may represent a subclinical form of cardiomyopathy in the obese patient.

Risk stratification of left ventricular hypertrophy in systemic hypertension using noninvasive ambulatory blood pressure monitoring

Twenty-four-hour noninvasive ambulatory blood pressure (BP) monitoring and echocardiography were performed in 165 consecutive untreated hypertensive patients and in 92 healthy subjects. In the hypertensive group, left ventricular (LV) mass index showed closer correlations (all p less than 0.01 in the comparisons between the r coefficients) with average 24-hour ambulatory systolic (r = 0.47) and diastolic (r = 0.33) BP than with casual systolic (r = 0.35) and diastolic (r = 0.28) BP. Hypertensive patients were classified according to the difference between their observed and predicted levels of ambulatory BP (the latter assessed by regressing the observed ambulatory BP on the casual BP). When compared to those with lower than predicted ambulatory BP (less than or equal to 10 mm Hg systolic, less than or equal to 6 mm Hg diastolic), patients with higher than predicted ambulatory BP (greater than or equal to 10 mm Hg systolic and greater than or equal to 6mm Hg diastolic) had higher values of LV mass index and other indexes of LV hypertrophy (all p less than 0.01) but had similar values of casual BP. Prevalence of LV hypertrophy was 6 to 10% in the former and 35 to 39% in the latter (p less than 0.001). None of the indexes of LV structure differed between the group with low ambulatory BP and the normotensive group. It is concluded that hypertensive patients whose ambulatory BP readings are notably higher than one would predict from clinical BP readings are at highest risk of LV hypertrophy, an independent prognostic marker.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian blood pressure changes and left ventricular hypertrophy in essential hypertension

The effects of circadian blood pressure (BP) changes on the echocardiographic parameters of left ventricular (LV) hypertrophy were investigated in 235 consecutive subjects (137 unselected untreated patients with essential hypertension and 98 healthy normotensive subjects) who underwent 24-hour noninvasive ambulatory blood pressure monitoring (ABPM) and cross-sectional and M-mode echocardiography. In the hypertensive group, LV mass index correlated with nighttime (8:00 PM to 6:00 AM) systolic (r = 0.51) and diastolic (r = 0.35) blood pressure more closely than with daytime (6:00 AM to 8:00 PM) systolic (r = 0.38) and diastolic (r = 0.20) BP, or with casual systolic (r = 0.33) and diastolic (r = 0.27) BP. Hypertensive patients were divided into two groups by presence (group 1) and absence (group 2) of a reduction of both systolic and diastolic BP during the night by an average of more than 10% of the daytime pressure. Casual BP, ambulatory daytime systolic and diastolic BP, sex, body surface area, duration of hypertension, prevalence of diabetes, quantity of sleep during monitoring, funduscopic changes, and serum creatinine did not differ between the two groups. LV mass index, after adjustment for the age, the sex, the height, and the daytime BP differences between the two groups (analysis of covariance) was 82.4 g/m2 in the normotensive patient group, 83.5 g/m2 in hypertensive patients of group 1 and 98.3 g/m2 in hypertensive patients of group 2 (normotensive patients vs. group 1, p = NS; group 1 vs. group 2, p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Initial assessment of the patient with hypertension

The initial assessment of a patient with hypertension can easily be done in a primary-care setting. The goals of the examination are to determine whether the patient is truly hypertensive and, if so, the severity of the hypertension, the degree of target-organ involvement, the presence of curable causes of hypertension, the patient's overall cardiovascular risk profile, and the patient's understanding and willingness to adopt necessary life-style changes and comply with treatment.

Prediction of left ventricular ejection fraction using a unique method of chest x-ray and ECG analysis: a noninvasive index of cardiac performance based on the concept of heart volume and mass interrelationship

A reasonably accurate, simple, inexpensive, noninvasive method of determining ejection fraction (EF) is necessary to evaluate left ventricular function in epidemiologic studies and individual patients. Using the concepts of left ventricular mass reflected by precordial R wave summation (M) and left ventricular volume (V) estimated by chest roentgenography in 114 patients with myocardial disease undergoing left ventriculography, EF was predicted with the formula: EF = 63.74 - (2.16.V) + (0.34.M); R2 = 0.69; standard error of the estimate (SEE) = 11. Because angiographic inferior wall motion (IWM) abnormalities significantly affected the results, but inferior Q waves were usually only present in patients having one infarct, a noninvasive technique to predict the presence of inferior wall motion abnormality (IMA) in patients having multiple infarcts was developed and based on the relationship of precordial R wave summation (M) and roentgenographic heart volumenometry (V). By combining V, M, and IMA (which predicted IWM) to determine EF, multiple linear regression analysis showed that EF = 67.30 - (1.56.V) + (0.23.M) - (14.18 IMA) (R2 = 0.77; SEE = 9). Prospective validation of the formula was then done in 139 consecutive individuals, with R2 = 0.49 and SEE = 9. This study demonstrates that routinely performed, simple, inexpensive clinical tests provide data that can be combined by multiple regression analysis to predict resting EF in patients with heart disease affecting the left ventricle. This unique method may allow inexpensive ventricular function screening in large population studies and in addition might provide an independent index of myocardial performance for clinical use, since it reflects the amount of contractile mass per unit of left ventricular volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of blood pressure changes on development and regression of electrocardiographic left ventricular hypertrophy: a 26 year longitudinal study

At the Radiation Effects Research Foundation, medical examinations have been conducted biennially since 1958 on a fixed population of approximately 20,000 individuals. Blood pressure measurements and electrocardiographic (ECG) recordings are available for 6,569 individuals who were monitored for at least 11 of the 13 2 year intervals between 1958 and 1984. Data from 601 individuals who had satisfied the Foundation's ECG diagnostic criteria of left ventricular hypertrophy ("Kagan-Yano code") on at least one occasion were reviewed. Both the development and the regression of ECG left ventricular hypertrophy were ascertained in 61 subjects (17 men and 44 women). During the course of development of ECG left ventricular hypertrophy, hypertension (including borderline cases) was noted in 83.3% of the subjects. The most common pattern of ECG left ventricular hypertrophy development was high voltage, followed by ST-T changes. In about half of these cases, the condition of hypertrophy regression was associated with lowering of blood pressure, marked by the disappearance of high voltage ECG readings.

Comparison between the effects of urapidil and methyldopa on left ventricular hypertrophy and haemodynamics in humans

In a randomised double-blind study the effects on left ventricular mass (LV mass) and cardiac haemodynamics of urapidil, an antihypertensive agent with a vascular postsynaptic alpha 1-blocking action and a central antihypertensive effect, were compared with those of methyldopa in 29 patients with essential hypertension. During a 3-month period, urapidil was initially given at 120 mg/day and increased to 180 mg/day if a satisfactory antihypertensive response was not achieved. Methyldopa was started at 100 mg/day and increased to 1500 mg/day if an adequate blood pressure response was not achieved. Echocardiographic measurements were obtained at baseline and after 12 weeks' active treatment. The frequency rates of responders (DBP less than 95 mm Hg) on urapidil and methyldopa were 54% and 62%, respectively, after 12 weeks. In the group as a whole there was a nonsignificant tendency for decreased LV mass on both active drugs. However, the haemodynamic changes were difficult to interpret because of baseline differences between the 2 treatment groups.

Reproducibility of echocardiographic left ventricular measurements

Serial echocardiograms with acceptable reproducibility of measurements may be produced by careful performance and interpretation of the studies. The following recommendations have been shown to enhance reproducibility. Strict adherence to quality control is necessary to generate echocardiograms of the highest technical quality. Sonographers should be aware of the definition of a technically adequate study--including correct beam or plane angulation and continuous visualization of interfaces--and seek this ideal in every study. Participation by the sonographer in performance of measurements enhances recognition of the requirements for accurate quantitative echocardiography. Regular machine calibration is a prerequisite to accurate quantitative echocardiography. Considerable effort must be made to standardize the position of each acoustic window and angulation from which the patient is imaged--with deviation from these norms being recorded for future reference. If at all possible, measurements should be taken at end expiration. If that is not possible, measurement of several consecutive beats will limit the impact of respiratory variation. A uniform convention of measurement should be adopted. The best candidates for M-mode measurements are the American Society of Echocardiography recommendations for general measurement and the Penn convention for calculation of M-mode left ventricular mass. Further data is needed to determine which approaches to two-dimensional measurements best combine accuracy and reproducibility. Interpretation of echocardiograms may be made most reproducible by measuring pertinent parameters from multiple beats and using the mean as the result and by having at least two readers interpret each echocardiogram, possibly with two separate readings by each reader.

Standardization in the measurement of left ventricular wall mass. M-mode echocardiography

A wide variety of approaches to M-mode echocardiographic methods for estimation of left ventricular mass have been proposed and employed in hypertensive heart disease. The cube function geometry, which assumes an ellipsoid of revolution with a length twice the minor axis, appears to be optimal provided left ventricular shape is relatively normal. The Penn measurement technique for wall thickness and diameter is best validated, but American Society of Echocardiography measurements can be used with appropriate regression correction. Changes in instrumentation may warrant reexamination of measurement techniques as well as the relative value of M-mode and two-dimensional echocardiographic techniques for estimation of left ventricular mass.

Performance of primary and derived M-mode echocardiographic measurements for detection of left ventricular hypertrophy in necropsied subjects and in patients with systemic hypertension, mitral regurgitation and dilated cardiomyopathy

To determine which M-mode echocardiographic (echo) measurement best detects left ventricular (LV) hypertrophy, the sensitivity and specificity of upper normal limits of echo LV anatomic measurements (previously shown to have 97% specificity in living normal subjects) were tested in 60 necropsied patients with anatomic hypertrophy and in 28 necropsied patients with normal left ventricles. The prevalence of hypertrophy by each echo criterion was determined in 165 living patients with systemic hypertension, mitral regurgitation or dilated cardiomyopathy. The best separation between patients with normal vs increased necropsy LV mass was obtained using sex-specific echo LV mass index criteria (overall accuracy = 73 of 88 patients, 83%). Lower overall accuracies for separation of patients with and without hypertrophy were observed for echo cross-sectional area (59 of 88 patients, 67%; p less than 0.05 vs LV mass index) and indexes of LV wall thickness (39 to 51%, p less than 0.001). Among 113 living patients with moderate or severe hypertension, mitral regurgitation or dilated cardiomyopathy, LV mass index was increased in 73%, cross-sectional area index in 58% (p less than 0.02 vs LV mass index), and posterior wall thickness, septal thickness and relative wall thickness in only 11 to 32% (all p less than 0.001 vs LV mass index). Thus, an M-mode echo LV mass index of more than 134 g/m2 in men and more than 110 g/m2 in women detects concentric and eccentric LV hypertrophy accurately by comparison with necropsy and clinical reference standards; cross-sectional area is slightly less useful; and other M-mode echo criteria of LV hypertrophy perform too poorly to be clinically applicable.

Echocardiographic assessment of left ventricular hypertrophy: comparison to necropsy findings

To determine the accuracy of echocardiographic left ventricular (LV) dimension and mass measurements for detection and quantification of LV hypertrophy, results of blindly read antemortem echocardiograms were compared with LV mass measurements made at necropsy in 55 patients. LV mass was calculated using M-mode LV measurements by Penn and American Society of Echocardiography (ASE) conventions and cube function and volume correction formulas in 52 patients. Penn-cube LV mass correlated closely with necropsy LV mass (r = 0.92, p less than 0.001) and overestimated it by only 6%; sensitivity in 18 patients with LV hypertrophy (necropsy LV mass more than 215 g) was 100% (18 of 18 patients) and specificity was 86% (29 of 34 patients). ASE-cube LV mass correlated similarly to necropsy LV mass (r = 0.90, p less than 0.001), but systematically overestimated it (by a mean of 25%); the overestimation could be corrected by the equation: LV mass = 0.80 (ASE-cube LV mass) + 0.6 g. Use of ASE measurements in the volume correction formula systematically underestimated necropsy LV mass (by a mean of 30%). In a subset of 9 patients, 3 of whom had technically inadequate M-mode echocardiograms, 2-dimensional echocardiographic (echo) LV mass by 2 methods was also significantly related to necropsy LV mass (r = 0.68, p less than 0.05 and r = 0.82, p less than 0.01). Among other indexes of LV anatomy, only measurement of myocardial cross-sectional area was acceptably accurate for quantitation of LV mass (r = 0.80, p less than 0.001) or diagnosis of LV hypertrophy (sensitivity = 72%, specificity = 94%).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of weight reduction on left ventricular mass. A randomized controlled trial in young, overweight hypertensive patients

We compared the effects of weight reduction, metoprolol, and placebo on M-mode echocardiographic measurements of the thickness and mass of the left ventricular wall in a 21-week, randomized controlled trial that enrolled 41 young, overweight patients with hypertension. At the end of the follow-up period, the patients in the weight-reduction group had lost an average of 8.3 kg, and their blood pressure had decreased by an average of 14/13 mm Hg, as compared with 12/8 mm Hg in the metoprolol group and 9/4 mm Hg in the placebo group. In the weight-reduction group, interventricular septal and posterior-wall thickness decreased by 14 percent and 11 percent, respectively, and left ventricular mass decreased by 20 percent (16 percent when adjusted for body-surface area). Decreases in interventricular septal and posterior-wall thickness and in left ventricular mass in the weight-reduction group were significantly greater than those in the placebo group. The changes in thickness of the interventricular septum and the left ventricular mass in the weight-reduction group were also greater than those in the metoprolol group. Changes in weight, independent of changes in blood pressure, were directly associated with changes in left ventricular mass. We conclude that weight reduction decreases left ventricular mass in overweight hypertensive patients and that control of obesity is important not only for the treatment of hypertension but also for the prevention of left ventricular hypertrophy.

Electrocardiographic detection of left ventricular hypertrophy: development and prospective validation of improved criteria

To develop improved electrocardiographic criteria of left ventricular hypertrophy, individual electrocardiographic voltage measurements were compared with echocardiographic left ventricular mass in a "learning series" of 414 subjects. The strongest independent relations with left ventricular mass were exhibited by the S wave in lead V3, the R wave in lead a VL and the T wave in lead V1 (each p less than 0.001), and by age and sex. Better electrocardiographic detection of left ventricular hypertrophy was achieved by new criteria that stratified QRS voltage and repolarization findings in sex and age subsets. For men, at all ages, left ventricular hypertrophy is suggested by QRS voltage alone when the R wave in lead aVL and the S wave in lead V3 total more than 35 mm. When this voltage exceeds 22 mm, left ventricular hypertrophy is suggested in men under age 40 years when the T wave in lead V1 is positive (greater than or equal to 0 mm), and in men 40 years or older when the T wave in lead V1 is at least 2 mm. For women, at all ages, left ventricular hypertrophy is suggested when the R wave in lead a VL and the S wave in lead V3 total more than 25 mm. When this voltage exceeds 12 mm, left ventricular hypertrophy is suggested in women under 40 when the T wave in lead V1 is positive (greater than or equal to 0 mm), and in women over 40 when the T wave in lead V1 is 2 mm or greater.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of echocardiographic and autopsy measurements of cardiac dimensions in the horse

This study was initiated to determine the accuracy of M-mode echocardiography in measuring left ventricular dimensions and estimating heart weights in horses. Left ventricular free wall and interventricular septal thickness and left ventricular external and internal diameters were measured and heart weights estimated from the echocardiograms of 47 horses. Autopsy measurements of the same parameters were then recorded. Statistical comparison of the data demonstrated: (1) Systolic measurements of wall thickness more closely resembled the heart in death than the diastolic measurements; (2) good correlations existed between parameters measured echocardiographically and at autopsy, especially wall thicknesses and left ventricular external diameter (maximum r = 0.82); (3) heart weight was readily predicted from echocardiographic wall thickness regressions (maximum R-squared = 68 per cent). M-mode echocardiography demonstrated the potential for direct and accurate measurements of cardiac mass and some ventricular dimensions in the horse. The data suggested that intense rigor and exsanguination may render the autopsied heart unsatisfactory for comparative measurements when assessing techniques such as echocardiography.

Standardization of M-mode echocardiographic left ventricular anatomic measurements

To improve standardization of echocardiographic left ventricular anatomic measurements, echographic left ventricular dimensions and mass were related to body size indexes, sex, age and blood pressure. Independent normal populations comprised 92 hospital-based subjects (64 women, 28 men) and 133 subjects from a population sample (55 women, 78 men). All measurements of chamber size, wall thickness and mass differed between men and women in both series (p less than 0.01 to p less than 0.001). Left ventricular mass was related most closely to body surface area among measurements of body size (r = 0.37, p less than 0.01 to r = 0.57, p less than 0.001) in all four groups. Indexation by body surface area eliminated sex differences in wall thicknesses and internal dimension, but a significant sex difference in left ventricular mass index persisted (89 +/- 21 g/m2 in men versus 69 + 19 g/m2 in women in the entire series, p less than 0.0001). The 97th percentile of left ventricular mass index was identical in both groups of men (136 and 132 g/m2) and women (112 and 109 g/m2). A highly significant difference in lean body mass, estimated from 24 hour urine creatine excretion, was observed between men and women (58 +/- 15 versus 40 +/- 13 kg, p less than 0.001) and no sex difference existed in left ventricular mass indexed by lean body mass (3.4 +/- 1.3 versus 3.5 +/- 1.5 g/kg). Weak correlations were observed between left ventricular mass/lean body mass and systolic or diastolic blood pressure (r = 0.25, p less than 0.05 and r = 0.28, p less than 0.01, respectively) but not age (18 to 72 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Development and regression of left ventricular hypertrophy

Left ventricular hypertrophy is an important adaptive response to chronic pressure or volume overload of the left ventricle. The different types and the pathophysiologic mechanisms of the development of left ventricular hypertrophy in various disease states are reviewed. Detection of left ventricular hypertrophy may be accomplished by electrocardiography and cardiac angiography. Echocardiography, however, is the most accurate noninvasive method to detect the presence and estimate the severity of increased left ventricular mass. The clinical significance of left ventricular hypertrophy and its prognostic implications in several cardiac diseases associated with hypertrophy are discussed. The critical transition stage from adaptive, compensatory and reversible left ventricular hypertrophy to "pathologic" hypertrophy with impaired left ventricular contractility and irreversible myocardial damage is yet unknown. Recent data are presented that provide evidence of regression of left ventricular hypertrophy after medical treatment of patients with hypertension and after aortic valve replacement in patients with aortic valve disease. The clinical importance of regression of hypertrophy and its effects on long-term prognosis remain to be determined.

Electrocardiographic changes after physical training in patients with myocardial infarction

Electrocardiographic voltage measurements were performed in 24 men with an inferior myocardial infarction before and after 14 +/- 0.5 weeks of physical training. Oxygen uptake at peak exercise increased 42% and heart rate at rest was significantly decreased after training. Increases were found in the magnitude of the R waves in leads II, aVF and V4 to V6; of the S wave in leads V1 and V3; of the T waves in V5 and V6; and of the Sokolow index of QRS voltage. Also, the magnitude of the mean electrical vector in the frontal plane was significantly higher after training. These data were compared with those derived from two electrocardiographic tracings, separated by an average of 19 +/- 1.5 weeks, of 20 other patients with an inferior myocardial infarction who were comparable in age, weight, risk factor and delay between infarction and first examination, but who were not trained. When the electrocardiographic changes between the two observations were compared for the two groups, the trained patients show significant increases in the magnitude of the R wave in the left precordial leads, and leads II and aVF and the Sokolow voltage criterion; in the magnitude of the T wave in leads V5 and V6; and in the magnitude of the mean electrical vector in the frontal plane. It is concluded that physical training in patients with myocardial infarction can alter cardiac structure, as evaluated by voltage measurements on the electrocardiogram.

Canine left ventricular mass estimation by two-dimensional echocardiography

This study was designed to develop a two-dimensional echocardiographic method of measuring the mass of the left ventricle. The general formula for an ellipse was used to derive an algorithm that described the shell volume of concentric truncated ellipsoids. In 10 canine left ventricular two-dimensional echocardiograms, this algorithm accurately predicted postmortem left ventricular mass (r = .98, SEE +/- 6 g) and was independent of cardiac cycle phase (systole vs diastole, r = .92).

Echocardiographic changes after successful renal transplantation in young nondiabetic patients

Eighteen young nondiabetic patients with chronic renal failure were studied by M-mode echocardiography before and three to 67 weeks after a successful renal transplant. Left ventricular mass (LVM), cardiac output (CO), and stroke work, which were increased before the operation, decreased afterward, in some cases to normal values. Both regression of the LVM and normalization of CO were detected as early as three weeks postoperatively and probably resulted from changes in the end-diastolic volume, mean systemic blood pressure, and hematocrit as a consequence of normal renal function. Because all the patients had normal left ventricular function and only moderate dilatation of the left ventricle, it is not known whether these striking beneficial changes after SRT also will occur in patients with significant dilatation or dysfunction of the left ventricle.

Effects of exercise training on left ventricular mass in patients with ischemic heart disease

To determine whether exercise training results in increased left ventricular mass in patients with ischemic heart disease, we obtained echocardiograms in 14 coronary patients before and after an average of seven months (range 3 to 14 months) of supervised arm and leg exercise. Each echocardiogram was interpreted jointly by two blinded observers, using three different measurement conventions and a semiautomated method of analysis to minimize errors of interpretation. Exercise training led to subjective improvement in all 14 patients, and to an objective increase in functional capacity in 13 of 14 patients, as evidenced by an increase in maximal oxygen consumption estimated from symptom-limited treadmill exercise testing (8.8 +/- 2.7 (SD) and 10.7 +/- 2.5 METS before and after training, respectively, p less than 0.01). However, this functional improvement was not accompanied by any significant change in left ventricular end-diastolic diameter, or posterior wall or interventricular septal thickness. Likewise, left ventricular cross-sectional area (CSA), an index of left ventricular mass which corrects for altered ventricular volume and theoretically reflects directional changes in mass despite nonuniform wall thickness, did not change significantly after training by any measurement convention (CSA = 18.0 +/- 6.5 and 17.6 +/- 6.5 cm2 before and after training, respectively, by American Society of Echocardiography measurements). These data strongly suggest that improved functional capacity after exercise training in patients with ischemic heart disease is not due to exercise-induced left ventricular hypertrophy.