Correlation of left ventricular mass determined by echocardiography with vectorcardiographic and electrocardiographic voltage measurements

Comparison of total 12-lead QRS voltage in a variety of cardiac conditions and its usefulness in predicting increased cardiac mass

Echocardiography provides a more accurate method to determine increased cardiac mass than does electrocardiography. Nevertheless, most offices of physicians do not possess echocardiographic machines, but many possess electrocardiographic machines. Many electrocardiographic criteria have been used to determine increased cardiac mass, but few of the criteria have been measured against cardiac weight determined at necropsy or after cardiac transplantation. Such was the purpose of the present study. Cardiac weight at necropsy or after transplantation was determined in 359 patients with 11 different cardiac conditions, and total 12-lead electrocardiographic QRS voltage (from the peak of the R wave to the nadir of either the Q or the S wave, whichever was deeper) was measured in each patient. Even in hearts with massively increased cardiac mass (>1,000 g), the total 12-lead QRS voltage was clearly increased (>175 mm) in only 94%, but this criterion was superior to that of previously described electrocardiographic criteria for "left ventricular hypertrophy." Hearts with excessive adipose tissue infrequently had increased total 12-lead QRS voltage despite increased cardiac weight. Likewise, patients with fatal cardiac amyloidosis had hearts of increased weight but quite low total 12-lead QRS voltage. In conclusion, 12-lead QRS voltage is useful in predicting increased cardiac mass, but that predictability is dependent in part on the cause of the increased cardiac mass.

Electrocardiographic criteria of left ventricular hypertrophy in general population

The question on whether the electrocardiographic criteria are reliable for detection of left ventricular hypertrophy (LVH) and play a role in predicting outcome is open. Answer can only proceed from population-based studies over unselected people followed up for years. In this study, 1,699 subjects from general population underwent echocardiogram and standard electrocardiogram (ECG) codified for LVH with Minnesota code and with other five methods. Other items were also recorded and used as covariables. Left ventricular mass index (LVMI) was 127.6 +/- 44.9 g m(-2) in men and 120.8 +/- 41.2 g m(-2 )in women, and correlated directly with age in both genders. Prevalence of echocardiographic LVH was 36.6% in men and 53.4% in women. LVMI correlated directly with the Sokolow-Lyon score in both genders at any age, with the Romhilt-Estes, Cornell and R(aVL) scores in all subjects but elderly men, and with the Lewis score in men and women aged < or =69 years. Sensitivity and the predictive value of electrocardiographic tests, as well as the prevalence of LVH diagnosed with electrocardiographic criteria, were always low. Specificity was high for all the tests, and in particular for the Cornell index. Only when diagnosed with echocardiogram or with the Sokolow-Lyon criterion, LVH was an independent predictor of mortality. We conclude that electrocardiographic tests cannot be used as a surrogate of echocardiogram in detecting LVH in the general population because their positive predictive value (PPV) is unacceptably low. On the contrary, they could replace echocardiography in the follow up and for prediction of outcome, when LVH has previously been correctly diagnosed with other methods.

Association Between Atherosclerotic Aortic Plaques and Left Ventricular Hypertrophy in Patients With Cerebrovascular Events

BACKGROUND AND PURPOSE

The purpose of this research was to evaluate whether an association exists between the presence of atherosclerotic plaque in the thoracic aorta and left ventricular hypertrophy (LVH) in patients with a cerebrovascular event.

METHODS

We included 116 consecutive patients (79 men; mean age, 62+/-12.4 years) with previous history of stroke or transient ischemic attack in a cross-sectional study. Transthoracic echocardiogram was performed to diagnose LVH and transesophageal echocardiogram for the detection of atheromas of the thoracic aorta. Continuous variables were analyzed by Student t or Mann-Whitney tests and categorized variables by Goodman test. From the significant association of LVH and age with atheromatous disease of the aorta, an adjustment to the multivariate logistic model was made using high blood pressure history or age as covariates. All of the statistical tests were carried out at a level of 5% significance.

RESULTS

Almost half of the patients (43.1%) presented atherosclerotic lesions in the aorta. LVH was present in 90.0% of patients with plaque and in only 30.3% of patients without plaque. Using high blood pressure as a covariate, the risk of patients with LVH presenting atherosclerotic plaque in the aorta was 18.23-fold greater than the risk for patients without LVH (95% CI, 5.68 to 58.54; P<0.0001). Adding age into the model, the risk increased to 26.36 (95% CI, 7.14 to 97.30; P<0.0001).

CONCLUSIONS

LVH detected by conventional echocardiogram is associated with high risk of atherosclerotic plaque in the aorta and would be used as a criterion for indication of transesophageal echocardiography in patients with previous stroke or transient ischemic attack LVH.

Left ventricular function and mass after orthotopic heart transplantation: a comparison of cardiovascular magnetic resonance with echocardiography

OBJECTIVE

We compared the assessment of left ventricular function and mass by M-mode echocardiography (echo) with fast breath-hold cardiovascular magnetic resonance (CMR) in patients who received orthotopic heart transplantation. We also sought to establish the reproducibility of breath-hold CMR in this patient population.

METHODS

We prospectively acquired 51 sets of echo and CMR data in 21 patients who had undergone orthotopic heart transplantation. We examined the intraobserver and interobserver reproducibility of breath-hold CMR in this group and compared it with published data. We compared the left ventricular ejection fraction (EF) and mass determined by echo with the CMR data.

RESULTS

The average time between CMR and echo was 0 +/- 7 days (mean +/- SD), the time between each set of CMR-echo data acquisition was 5.1 +/- 4.1 months. Cardiovascular magnetic resonance showed good reproducibility in this population, with intraobserver percentage variability of 2.2% +/- 2.4% for EF and 3. 2% +/- 2.7% for mass, and interobserver percentage variability of 2. 4% +/- 1.9% for EF and 2.2% +/- 1.9% for mass. The Bland-Altman limits of agreement between echo and CMR were wide for both EF (-9. 6% to 15%) and mass, irrespective of the formula used (-61.3 to 198 g for the Bennett and Evans formula, -65.4 to 196.8 g for the American Society of Echocardiography (ASE) formula, -65.3 to 181 g for the Devereux formula, and -95.2 to 64.6 g for the Teichholz formula).

CONCLUSION

Fast-acquisition CMR is reproducible in recipients of transplanted hearts. We found poor agreement with the results of echo. The choice of technique will depend on local resources as well as the clinical importance of the result. Echo remains readily available and gives rapid assessment of volumes, EF, and mass. However, the good reproducibility of CMR may make it a more suitable technique for long-term follow-up of an individual or of a study population.

Hypertension in pregnancy: hemodynamics and diurnal arterial pressure profile

OBJECTIVE

To characterize the 24-h arterial pressure (AP) profile and the left ventricular (LV) structures and functions in women with pregnancy-associated hypertension.

METHODS

Twenty nulliparous pregnant women after 20 weeks' gestation, 10 normotensive and 10 hypertensive women matched for gestational age, were hemodynamically investigated using 24-h AP monitoring and Doppler echocardiography to determine LV structures and functions, both systolic and diastolic.

RESULTS

The hypertensive women had significantly higher AP determinations throughout the 24 h, with no change in diurnal variation, i.e. nocturnal decline and early morning peaks. Their LV mass was greater and it was accompanied by a slight reduction in contractility and a significant reduction in LV relaxation. The increased AP was due to peripheral vasoconstriction, while cardiac output was preserved.

CONCLUSIONS

It appears that pregnancy-associated hypertension is caused mainly by arterial vasoconstriction and not by higher cardiac output. The hypertension increases the LV mass, which is associated with a fall in LV relaxation.

Role of left ventricular geometry in the alteration of initial QRS vectors due to concentric ventricular hypertrophy

The relation between serial magnitudes of instantaneous spatial vectors, obtained throughout ventricular depolarization, and echocardiographically estimated left ventricular (LV) mass was investigated in 64 patients with congenital aortic stenosis and in 16 patients with coarctation of the aorta. While the correlation was positive between LV mass and vector magnitudes at 50 and 60 ms after QRS onset (r = .530 and .557, P < .01), it was found to be negative with regard to the magnitude of the initial 10 and 20 ms vectors (r = -.285 and -.355, P < .01). Computer simulation of activation propagation in different models of LV enlargement has shown that the decrease of the spatial magnitude of initial vectors, as well as a marked decrease of the area of the anterior portion of the horizontal plane QRS loop and of the Q amplitude of the orthogonal z lead, are characteristic of concentric LV hypertrophy with decreased diastolic volume and were not observed with unchanged or dilated chamber size. Repeated assessment of the magnitude of initial QRS vectors may indicate changes of LV remodeling in patients with LV pressure overload.

How reliable is the electrocardiogram in detecting left ventricular hypertrophy in hypertension?

This paper assesses the sensitivity and specificity of the electrocardiogram in detecting left ventricular hypertrophy in 75 hypertensive patients. Each patient underwent a 12 lead electrocardiogram and echocardiogram. Left ventricular mass index, using echocardiogram, was calculated according to the Penn convention and left ventricular hypertrophy was assessed by standard electrocardiographic criteria. The electrocardiogram was found to be very specific but insensitive in the detection of left ventricular hypertrophy as compared with the echocardiogram. Other non-voltage dependent markers appeared to have similar reliability. We conclude that the electrocardiogram may be unreliable in the detection of left ventricular hypertrophy in hypertensive patients. Accurate assessment of left ventricular hypertrophy, in these patients should be by echocardiography.

Obesity and hypertension. Hemodynamic aspects

Elevated arterial pressure in patients with obesity-hypertension is associated with an increased cardiac output and total peripheral resistance. The elevated output is related to expanded intravascular volume that increases cardiopulmonary volume, venous return, and left ventricular preload; the elevated pressure and total peripheral resistance increase afterload. This dual ventricular overload promotes a dimorphic, concentric, and eccentric hypertrophy in response to the volume and pressure overload. Increased myocardial oxygen demand results from the elevated tension in the left ventricular wall, reflecting its increased diameter and pressure, and provides physiologic rationale for the greater potential of coronary arterial insufficiency and cardiac failure. There are greater renal blood flow and lower renal vascular resistance in patients with obesity-hypertension at any level of arterial pressure. This may be offset by an increased renal filtration fraction that may favor protein deposition and glomerulosclerosis, and predisposition of obese patients for diabetes may aggravate this problem. With weight reduction, these hemodynamic derangements may be reversed: intravascular volume contracts, cardiac output decreases, and arterial pressure falls.

Immediate and short-term cardiovascular effects of fosinopril, a new angiotensin-converting enzyme inhibitor, in patients with essential hypertension

Immediate and short-term cardiovascular effects of a new angiotensin-converting enzyme inhibitor, fosinopril, were assessed in 10 patients with mild to moderate essential hypertension. Administration of a 10 mg oral dose of fosinopril reduced mean arterial pressure (p less than 0.001) as a result of a 24% fall in total peripheral resistance (p less than 0.001). Short-term therapy (12 weeks) maintained the decrease in mean arterial pressure (p less than 0.05) by decreasing total peripheral resistance (p less than 0.01), without reflexive cardiac stimulation or expanding intravascular volume. Renal vascular resistance decreased (p less than 0.05) while renal blood flow, glomerular filtration rate and filtration fraction remained unchanged. The response pattern to mental, isometric and orthostatic stress was similarly unchanged. Left ventricular mass diminished by 11% (p less than 0.01); myocardial contractility was unaffected. Afterload was reduced (p less than 0.05), and velocity of circumferential fiber shortening and stroke volume increased (p less than 0.05). Thus, arterial pressure reduction produced by fosinopril was associated with improved systemic and renal hemodynamics and reduced left ventricular mass.

Echocardiographic assessment of infants born to diabetic mothers

Echocardiography was carried out in 31 neonates (group 1) born to diabetic mothers and 37 control infants (group 2) matched for weight and gestational age. The interventricular septum was significantly thicker in group 1 babies (mean (SD) 4.77 (1.4) mm) compared with those in group 2 (2.5 (0.7) mm); in eight it was more than 5 mm, but had regressed in six over a period of three months. There was no significant difference between the two groups in the left ventricular internal dimension, right ventricular outflow tract, or size of the left atrium or the aorta. The left ventricular mass was significantly greater in infants born to diabetic mothers. The left ventricular contractility (judged by the percentage of shortening of the internal dimension and the ejection fraction) was significantly greater in group 1. No evidence of left ventricular outflow obstruction was found on pulse Doppler echocardiography in group 1.

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)

Dietary salt intake. A determinant of cardiac involvement in essential hypertension

Because a given increase in afterload does not consistently produce the same degree of left ventricular hypertrophy, we evaluated several clinical, hemodynamic, and endocrine factors that are prone to modify the adaptation of left ventricular structure in patients with mild essential hypertension (World Health Organization stages I or II). Dietary salt intake assessed by sodium excretion over 24 hours was a powerful determinant of posterior wall thickness (r = 0.64, p less than 0.001), relative wall thickness (r = 0.67, p less than 0.001), and left ventricular mass (r = 0.37, p less than 0.05). In contrast, diastolic pressure, body mass index, hematocrit, and epinephrine were found to be weaker determinants of left ventricular structure (r = 0.31-0.40, p less than 0.05). A stepwise multiple regression analysis revealed that sodium excretion was the strongest predictor for posterior wall thickness (p less than 0.02) and relative wall thickness (p less than 0.05) independent of the other examined variables. These results identify dietary salt intake as a strong determinant of cardiac structural adaptation to a persistent increase in arterial pressure. Consequently, a high salt intake might aggravate and, conversely, dietary salt restriction might prevent (or at least mitigate) the development of left ventricular hypertrophy in patients with essential hypertension.

Population implications of electrocardiographic left ventricular hypertrophy

Left ventricular (LV) hypertrophy on the electrocardiogram is an ominous harbinger of cardiovascular disease in the general population markedly increasing the risk of coronary heart disease, cardiac failure, stroke and peripheral arterial disease. This contribution to risk exceeds that of the often accompanying hypertension. Once overt coronary disease occurs, electrocardiographic LV hypertrophy also further escalates risk of cardiovascular morbidity and mortality. The risk associated with electrocardiographic LV hypertrophy is particularly great when repolarization abnormality is present. Electrocardiographic LV hypertrophy and silent electrocardiographic myocardial infarction are similar in evolution and prognosis. LV hypertrophy is an important predictor of risk of cardiac failure; the electrocardiographic manifestation of LV hypertrophy predisposes to cardiac failure more than x-ray cardiac enlargement. Electrocardiographic LV hypertrophy heralds the onset of serious cardiovascular disease and premature mortality despite lack of associated symptoms. The serious prognosis of this abnormality warrants vigorous preventive management. More prospective data are needed comparing the prognosis of echocardiographic anatomical hypertrophy with that diagnosed by electrocardiography.

Left atrial abnormalities indicating diastolic ventricular dysfunction in cardiopathy of obesity

Electrocardiograms and M-mode echocardiograms were evaluated in lean and obese patients, either normotensive or hypertensive, who were paired for mean arterial pressure, age, and sex. Electrocardiographic evidence of left atrial abnormalities (LAA) occurred more frequently (p less than 0.01) and left atrial size was greater in the obese than in the lean patients (p less than 0.01). The left atrial emptying index, an indicator of early diastolic ventricular function, was reduced in obese patients (p less than 0.01), most markedly in those with obesity-hypertension. The left atrial emptying index was reduced in obese patients with electrocardiographic LAA compared to obese patients without this electrocardiographic sign (p less than 0.02). A close correlation (r = 0.61, p less than 0.001) was obtained between the left atrial emptying index and atrial ECG abnormalities. These left atrial abnormalities in obesity and particularly in obesity-hypertension indicate diastolic ventricular dysfunction.

Biventricular cardiac hypertrophy in essential hypertension

Left ventricular hypertrophy (LVH) is the major adaptation of the heart to a prolonged increase in the left ventricular afterload in hypertension. However, the structure and function of the right ventricle have received little attention. The present study was designed to assess right ventricular structural changes in patients with established essential hypertension. To accomplish this, M-mode echocardiograms were obtained from 15 healthy normotensive subjects and 35 patients with essential hypertension-15 with normal left ventricles and 20 with clear-cut echocardiographic evidence of LVH. In comparison with the normotensive subjects, right ventricular wall thickness was increased almost twofold in the hypertensive patients with LVH (7.0 +/- 2.1 mm vs 3.7 +/- 0.8 mm; p less than 0.001); there was a significant, direct correlation between right and left ventricular wall thickness in the entire patient population (r = 0.65; p less than 0.001). Furthermore, the left atrial emptying index was significantly reduced in all patients with hypertension regardless of whether LVH was present (p less than 0.001) and suggests early diastolic functional involvement of the left ventricle in hypertension. We therefore conclude that right ventricular hypertrophy is associated with LVH in patients with hypertension, although the changes of LVH are frequently more obvious to the clinician.

Noninvasive quantification of left ventricular myocardial mass by gated proton nuclear magnetic resonance imaging

The validity of cardiac nuclear magnetic resonance imaging for determination of left ventricular myocardial mass was evaluated in nine dogs. A gated spin echo-pulsing sequence was used for in vivo imaging, obtaining 0.7 cm thick slices of the heart spaced by 1 cm. On each imaged slice, the left ventricular surface area was reproducibly determined by planimetry and was multiplied by slice spacing and specific gravity of the myocardium (1.05) to obtain slice mass. Total left ventricular mass was calculated by adding slice masses in short-axis (method I), transaxial (method II) and vertical long-axis (method III) orientations using Simpson's rule. With each method, masses of the portions of the left ventricle subject to partial volume effect either were not accounted for or alternatively were estimated from the same or an orthogonal imaging plane. Calculated left ventricular mass was compared with the actual excised left ventricular weight. With NMR imaging of in situ nonbeating hearts, best results were obtained when either method I or method II was used and partial volume effect was estimated either from the same or an orthogonal plane. With in vivo NMR imaging, best results were noted when method I was used and mass of the partial volume apex was calculated from transaxial slices: Y (in vivo NMR image) = 8.3 + 0.99X, r = 0.996, SEE = 3.14. For this method, the interobserver reliability coefficient and standard error of the measurement were 0.97 and 5.4, respectively. Compared with method I, in vivo methods II and III were associated with larger errors (SEE ranging from 13.03 to 19.03) regardless of the approach used to estimate partial volume effect. It is concluded that NMR imaging is a highly accurate noninvasive method for in vivo measurement of left ventricular mass in dogs and offers promise for accurate measurement of left ventricular mass in patients.

Use of vectorcardiography in determination of the left ventricular muscle mass

Many studies have investigated different ECG and vectorcardiographic (VCG): criteria for diagnosis of left ventricular hypertrophy (LVH). In some investigations VCG was more sensitive than ECG in this respect. This study was performed to elucidate whether it is possible also to determine the degree of LVH using VCG. Eighty cardiovascularly healthy subjects aged 15-39 were investigated with ECG, VCG (Frank system) and echocardiography. The echocardiographic left ventricular (LV) mass has been shown by others to correlate closely to the anatomical and the angiographically determined LV mass and was used as reference standard. Thirty-eight of the subjects were endurance sportsmen and had a LV mass above standard reference limits. The measured ECG variables were R-amplitude in a VL, I, V5, V6, S-amplitude in V1 and SV1 + RV5/V6 and the VCG variables were QRS spatial area and circumference and left maximal spatial vector. The sensitivity and specificity of single criteria tested were similar for ECG and VCG in the quantitative determination of LVH. The correlations between ECG-amplitudes and the magnitude of the LV mass were weak. The correlations were higher with the VCG-variables, QRS spatial circumference being superior to the others, but not good enough to permit an estimation of the LV mass in individual subjects. In conclusion, normal VCG variables were highly specific for a normal LV mass but in individuals with LVH, VCG was not useful for the estimation of the LV mass.

Cardiovascular effects of verapamil in patients with essential hypertension

The cardiovascular effects of intravenous verapamil and 3 months of oral administration of a slow-release form of verapamil (verapamil-SR) were studied in 10 patients with mild-to-moderate essential hypertension. Intravenous verapamil reduced arterial pressure by 15% (p less than .01) through a fall in total peripheral resistance of 29% (p less than .01); provoked a reflexive rise in heart rate (by 19%, p less than .02), cardiac output (by 74%, p less than .01), and plasma catecholamines; and shifted intravascular volume toward the cardiopulmonary circulation indicating peripheral venoconstriction. Quite in contrast to the immediate effects of the intravenous drug, oral therapy with verapamil-SR for 2 to 3 months lowered arterial pressure effectively (by 15%, p less than .01) by inducing vasodilation of 15% (p less than .02), but without causing reflex tachycardia, activation of the sympathetic-adrenergic or renin-angiotensin systems, or volume expansion. Oral therapy with verapamil-SR preserved systemic and renal blood flow and slightly reduced cardiac mass (by 6%, p less than .05) and renal vascular resistance (by 25%, p less than .05). Whereas intravenous verapamil tended to depress myocardial contractility, oral verapamil-SR did not at all affect myocardial contractility or left ventricular function. These cardiovascular effects make verapamil-SR an excellent agent for long-term antihypertensive therapy.

Measurement of left ventricular wall mass in pediatric populations

This paper reviews the techniques for obtaining technically adequate echocardiograms for epidemiologic studies. When these techniques were applied to studies of pediatric populations the following objectives were achieved: reproducible echocardiograms, observations about the relationship of echocardiographic variables to cardiovascular variables, and information about the relationship of echocardiographic and electrocardiographic variables to each other and to blood pressure. We documented the precision of M-mode left ventricular chambers and dimensions, interobserver and intraobserver variability, and the day-to-day variability of these measures. Left ventricular wall mass was significantly larger than expected for age and body size in children with persistently elevated blood pressure. The relationship between the echocardiographic and electrocardiographic variables was poor. Moreover, the electrocardiographic measures of ventricular hypertrophy did not correlate with blood pressure.

Increased left ventricular mass in a bodybuilder using anabolic steroids

As the effects of anabolic steroids on left ventricular structure and function are unknown, we carried out clinical examination, 12 lead electrocardiography and echocardiography on a 23 year old male bodybuilder using these drugs. In this subject we found values of ECG voltage criteria, left ventricular-mass, posterior wall and interventricular septal thickness which exceeded those found in normal subjects and also in other competitive, power athletes. Despite these values, however, ejection fraction remained normal. This would suggest that anabolic steroids perhaps have a direct effect on the myocardium, in addition to the effects of training, but whether this is of pathological significance is unclear.

Electrocardiographic diagnosis of chamber enlargement

The purpose of this article is to review the changing role of the electrocardiogram in the diagnosis of cardiac chamber enlargement. Electrocardiographic criteria for the diagnosis of ventricular hypertrophy and atrial enlargement are reviewed in relation to autopsy, angiographic, echocardiographic and imaging findings. The electrocardiographic theory underlying the recognition of hypertropphy or dilation incorporates a number of sound physical principles that may lead to meaningful correlations with the tissue mass, chamber diameter and intracardiac blood volume. However, there are limiting factors related to the variable orientation of the heart in the chest, variable extracardiac factors and nonspecificity of each depolarization and repolarization abnormality used in the diagnosis of hypertrophy or dilation. This explains the superiority of the new noninvasive methods, in particular echocardiography, in the diagnosis of hypertrophy. Echocardiography is superior to electrocardiography in the detection of mild hypertrophy, and is more useful in the serial follow-up of changes during progression or regression of chamber enlargement.

Severe aortic stenosis in elderly patients

Clinical and non-invasive findings were compared with catheterisation data in 91 elderly patients (mean 65 years, range 52-78) with suspected severe aortic stenosis requiring operation. Heart catheterisation showed that forty nine patients had a valve area of less than or equal to 0.6 cm2, 36 had a valve area of 0.7 - 1.0 cm2, and six an area of greater than or equal to 1.1 cm2. Coexistent aortic regurgitation was found in 85% of the cases, but severe regurgitation was found in only one patient (1%). Seventy seven per cent of patients had chest pain, 74% had dyspnoea, and 46% had exertional vertigo or syncope. Coronary angiography, which was performed in 77 patients, showed coronary artery disease in 24% of those with a history of angina pectoris and in none of those without. All patients had echodense valves; aortic valve calcification was shown by x ray in 76% and in all but one by cineradiography. The peak of the systolic murmur was delayed in 98% of the patients. Although a prolonged left ventricular ejection time was characteristic of severe aortic stenosis, a normal value did not exclude this diagnosis. Most patients (84%) had increased QRS amplitude on the electrocardiogram. Echocardiography showed an increased left ventricular wall thickness in 90% of the patients in whom it was possible to define the myocardial borders. There was an inadequate blood pressure increase in response to exercise in 82%. In about 25% of the patients the exercise test was at variance with the New York Heart Association classification. Findings suggesting severe aortic stenosis resembled those reported for younger age groups. When most findings point to severe aortic stenosis, the absence of a single symptom or non-invasive sign does not exclude severe aortic stenosis.

A prognostic comparison of asymptomatic left ventricular hypertrophy and unrecognized myocardial infarction: the Framingham Study

In 30 years of follow-up in the Framingham study, routine biennial ECG examinations revealed 315 subjects with ECG-LVH and 164 with unrecognized ECG-MI without previous cardiac explanation. Among subjects initially free of clinically evident coronary heart disease and both ECG abnormalities, the incidence of ECG-LVH was about double that of ECG-MI. Both events exhibited a male predominance and hypertensive subjects were more vulnerable to each. In subjects with asymptomatic ECG-LVH and ECG-MI, the 10-year, age-adjusted incidence of clinical coronary heart disease was greater than the rate experienced by the general Framingham sample. Rates for ECG-LVH were almost as large as those for ECG-MI. Cardiac failure and stroke also occurred more frequently among subjects with either ECG abnormality, and rates for ECG-LVH exceeded those for ECG-MI. Death from coronary heart disease, and sudden death in particular, was also increased two- to fourfold with similar risks for ECG-LVH and ECG-MI. ECG-LVH carried a significantly greater risk than ECG-MI for cardiovascular deaths in women. These findings suggest that ECG-LVH and ECG-MI are similar subclinical events with respect to predisposing characteristics and prognosis for subsequent overt cardiovascular disease including clinical manifestations of coronary heart disease.

Immediate and short-term hemodynamic effects of diltiazem in patients with hypertension

The immediate effects of intravenous diltiazem effects and short-term (4 weeks) of the oral drug on systemic and regional hemodynamics, cardiac structure, and humoral responses were evaluated by previously reported methods in nine patients with mild-to-moderate essential hypertension and in one patient with primary aldosteronism. Diltiazem was first administered in three intravenous doses of 0.06, 0.06, and 0.12 mg/kg, respectively; patients were then treated for 4 weeks with daily doses ranging from 240 to 360 mg (average 300 mg). Intravenous diltiazem immediately reduced mean arterial pressure (from 115 +/- 3 to 96 +/- 3 mm Hg; p less than .01) through a fall in total peripheral resistance index (from 37 +/- 3 to 23 +/- 2 U/m2; p less than .01) that was associated with an increase in heart rate (from 66 +/- 2 to 77 +/- 3 beats/min; p less than .01) and cardiac index (from 3.3 +/- 0.3 to 4.3 +/- 0.4 liters/min/m2; p less than .01). These changes were not associated with changes in plasma levels of catecholamines or aldosterone or in plasma renin activity. After 4 weeks the significant decrease in mean arterial pressure persisted (104 +/- 3 mm Hg; p less than .01) and there were still no changes in the humoral substances or plasma volume. Renal blood flow index increased (from 368 +/- 52 to 462 +/- 57 ml/min/m2; p less than .01) and renal vascular resistance index decreased (from 0.37 +/- 0.06 to 0.26 +/- 0.04 U/m2; p less than .01), while splanchnic hemodynamics did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiographic estimate of peak systolic pressure gradient in children with aortic stenosis

In children with congenital aortic stenosis a modified mapping system was created to explore the electrocardiographic potentials on the chest surface from the left sternal edge (direct anterior), left axillary line (direct lateral) and midchest (45 degrees anterior to the lateral lead) in the third through the seventh intercostal spaces. Potentials were normalized according to chest size based on elliptical and cylindrical models of the chest with the heart at the center. The unadjusted and adjusted potentials were correlated with the peak systolic gradients across the left ventricular outflow tract and equations to predict the gradients were derived by stepwise multiple regression analysis. The best equation was: Gradient = -15.0 +(3.845 X MCT 4) +(0.474 X CD X LSS 3) + (0.138 X CD X MCS 3) where MCT 4 = T wave amplitude in the lead in the fourth interspace in the midclavicular line CD = AP chest diameter in cm LSS 3 = S wave amplitude in the lead in the third interspace at the left sternal border MCS 3 = S wave amplitude in the lead in the third interspace in the midclavicular line (R = 0.84, SEE = 24.3) There are areas on the chest surface that are unexplored by standard electrocardiography. The electrocardiographic potentials from these areas, when normalized for chest size, yield better estimates of transaortic gradients than previous estimates from the routine electrocardiogram.

Mechanisms of altered myocardial contractility during hemodialysis: importance of changes in the ionized calcium to plasma potassium ratio

Hemodialysis is associated with alterations in myocardial contractility, but duration and precise determinants responsible for these changes are unknown. We investigated the effect of several variables, established to influence left ventricular (LV) contractility, which normally changed during dialysis: the plasma concentrations of ionized calcium, potassium, bicarbonate, and magnesium and the removal of uremic toxins. The influence of three different isovolemic bicarbonate-dialysis procedures in 16 patients with normal (group 1) and hypertrophied myocardium (group 2) was assessed by echocardiography prior to and up to 44 h following each dialysis. During the first procedure, ionized calcium and potassium concentration decreased, but LV performance remained unchanged in both groups. The second procedure with increased ionized calcium and decreased potassium concentration resulted in an improvement of mean circumferential fiber shortening (VCF from 1.15 to 1.56 circ/s (P less than 0.001) in group 1 and from 1.05 to 1.16 circ/s (P less than 0.05) in group 2. The positive inotropic effect declined gradually up to 12 h (group 1) and 2.5 h (group 2) respectively. In the third procedure when ionized calcium was increased and potassium concentration remained unchanged contractility did not improve. Removal of uremic toxins, decrease in magnesium, and increase in bicarbonate concentrations were comparable during each procedure. These results suggest that the ionized calcium to potassium ratio is the important determinant of dialysis-related augmentation in LV contractility. In LV hypertrophy the expected contractile response is diminished indicating a depressed inotropic state.

Electrocardiographic observations in clinically isolated, pure, chronic, severe aortic regurgitation: analysis of 30 necropsy patients aged 19 to 65 years

Certain electrocardiographic findings are described in 30 necropsy patients with clinically isolated pure, chronic, severe aortic regurgitation. They were 19 to 65 years old (mean 45). The hearts of the 22 men ranged in weight from 430 to 1,110 g (mean 717) and of the 8 women, from 375 to 950 g (mean 638). Four had grossly visible left ventricular (LV) scars. All but 1 patient was in sinus rhythm. The PR interval was greater than 0.20 second in 8 patients (28%) and the QRS duration was greater than or equal to 0.12 second in 6 patients (20%). Only 5 patients (17%) had 1 or more ventricular premature complexes recorded on the resting electrocardiogram analyzed. The mean QRS amplitude for each of the 12 leads averaged 23 mm. The highest mean QRS voltage occurred in leads V2 and V3 (each 38 mm), and the lowest in lead aVR (11 mm). The mean QRS voltage in V5 was higher than in V6 (33 vs 28 mm) and in 22 patients (73%) the QRS voltage in V5 was higher than in V6. The sum of the S wave in V1 plus the larger of the R wave in V5 or V6 (Sokolow-Lyon index) averaged 51 mm and in only 22 patients (73%) was it greater than 35 mm. The Romhilt-Estes voltage criteria for LV hypertrophy was fulfilled even less frequently, despite the severe degrees of LV hypertrophy in the patients studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertension and sudden death. Increased ventricular ectopic activity in left ventricular hypertrophy

The present study was designed to detect and quantify cardiac arrhythmias in hypertensive patients with left ventricular hypertrophy. Continuous ambulatory electrocardiographic tracings and arterial pressure were recorded for 24 hours in 14 normotensive subjects, 10 patients with established essential hypertension without left ventricular hypertrophy, and 16 hypertensive patients with left ventricular hypertrophy by electrocardiographic criteria. Urinary excretion of norepinephrine was simultaneously measured over four successive four-hour and one eight-hour period. Patients with left ventricular hypertrophy had significantly more ventricular (but not atrial) premature contractions than those without left ventricular hypertrophy or than normotensive subjects. Five patients with left ventricular hypertrophy had episodes of more than 30 premature ventricular contractions per minute. Higher-grade ventricular ectopic activity such as coupled premature ventricular contractions was seen in two, and multifocal premature ventricular contractions were seen in three in the group with left ventricular hypertrophy. No difference in urinary catecholamine excretion rates among the three groups was seen. Left ventricular hypertrophy has been shown to be an independent risk factor for sudden death and acute myocardial infarction. Electrocardiographic monitoring of patients with left ventricular hypertrophy allows identification of those who have the highest risk and, therefore, require the most aggressive therapeutic intervention.

Relation of regional echo amplitude to left ventricular function and the electrocardiogram in left ventricular hypertrophy

In order to determine the relation between three manifestations of left ventricular hypertrophy--ST-T wave changes on the electrocardiogram, diastolic disturbances, and increased myocardial echo intensity--M mode and cross sectional echocardiograms were recorded in 12 normal subjects, 15 athletes, 16 patients with hypertrophic cardiomyopathy, and 42 patients with secondary left ventricular hypertrophy due to aortic stenosis (20), severe essential hypertension (8), coarctation (7), or subaortic stenosis (7). M mode echocardiograms were digitised and cross sectional echocardiograms were analysed for regional echo intensity. In patients with hypertrophy regional echo amplitude was significantly increased in mid and basal septum and posterior left ventricular wall. Patients with increased echo amplitude in any region showed a higher incidence of ST-T wave abnormalities than those without and of diastolic abnormalities--including prolongation of isovolumic relaxation time, delay in mitral valve opening with respect to minimum cavity dimension, and a reduction in peak rate of posterior wall thinning and dimension increase. There was a significant rank order correlation between median pixel count and these diastolic abnormalities. No significant differences were demonstrable in these relations between the diagnostic groups. By contrast, electrocardiographic findings, diastolic function, and pixel count were uniformly normal in athletes, although the increase in left ventricular mass was similar to that in the patients. Thus an increase in left ventricular mass alone is not responsible for repolarisation or wall motion abnormalities occurring in pathological left ventricular hypertrophy. These latter changes are, however, strongly associated with the change in myocardial properties detected as an increase in echo intensity and may be due to increased interstitial fibrosis.

Improvement in depressed cardiac function in hypertensive patients during pindolol treatment

To assess changes in left ventricular function during antihypertensive treatment using pindolol, a beta-adrenocepter blocking drug with potent intrinsic sympathomimetic activity, serial echocardiographic measurements were obtained in 70 hypertensive patients before and during 15 weeks of treatment with pindolol. For analysis, the patients were separated into three groups on the basis of their baseline left ventricular fractional shortening (Group I, 35 patients with normal fractional shortening of 28 percent or more; Group II, 16 patients with abnormal fractional shortening of 21 to 27 percent; and Group III, 19 patients with markedly abnormal fractional shortening of 20 percent or less). More than half of the patients in Group I and Group II had decreases in mean blood pressure of 10 percent or more in response to pindolol, but only one fourth of Group III patients had similar responses (p less than 0.05). Patients with normal pretreatment fractional shortening had a mild decrease in fractional shortening during pindolol treatment, whereas patients with either abnormal or markedly abnormal fractional shortening had an increase in fractional shortening. This increase in fractional shortening suggests the possibility that the partial agonist or intrinsic sympathomimetic activity of pindolol may play a role in preserving left ventricular function in patients with borderline or impaired function.

Enalapril improves systemic and renal hemodynamics and allows regression of left ventricular mass in essential hypertension

Enalapril, a new angiotensin-converting enzyme inhibitor, is an effective antihypertensive agent for both renovascular and essential hypertension. It is structurally different from captopril in that it does not possess a sulfhydryl group. The systemic and renal hemodynamic, biochemical and cardiac adaptive changes induced by enalapril were studied in 8 patients with essential hypertension before and after 12 weeks of therapy. Mean arterial pressure decreased from 110 to 90 mm Hg (p less than 0.01), and this was mediated through a decrease in total peripheral resistance from 42 +/- 3 to 32 +/- 3 U (p less than 0.01). Cardiac index and heart rate did not change. Renal plasma flow was increased in 6 of 8 patients and renal vascular resistance decreased from 123 +/- 6 to 91 +/- 7 U (p less than 0.001). Left ventricular mass index decreased from a mean of 166 +/- 29 to 117 +/- 8 g/m2 (p less than 0.05) without impaired myocardial contractility. Thus, enalapril lowers arterial pressure by reducing total peripheral resistance without reflexive cardiac effects. It also has favorable hemodynamic effects on the kidney. This is the first report of regression of LV mass with this agent in man.

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.

Essential hypertension in the elderly: haemodynamics, intravascular volume, plasma renin activity, and circulating catecholamine levels

In an attempt to dissociate the cardiovascular adaptations to high blood pressure from those of ageing, 30 patients with established essential hypertension aged over 65 years were matched for mean arterial pressure, race, sex, height, and weight with 30 patients younger than 42 years. Cardiac output, heart rate, stroke volume, intravascular volume, renal blood flow, and plasma renin activity were significantly lower in the elderly, whereas total peripheral (and renal vascular) resistance, left ventricular posterior wall and septal thicknesses, and left ventricular mass were higher. Intravascular volume correlated inversely with total peripheral resistance in both groups and in all patients. Pathophysiological findings of essential hypertension in the elderly are characterised by a hypertrophied heart of the concentric type with a low cardiac output resulting from a smaller stroke volume and a slower heart rate. Renal blood flow is disproportionally reduced and total peripheral and renal vascular resistance elevated.

Prevalence and natural history of electrocardiographic left ventricular hypertrophy

Left ventricular hypertrophy, particularly on the electrocardiogram, is an ominous, not an incidental accompaniment of hypertension and cardiovascular disease. The prevalence of electrocardiographic left ventricular hypertrophy increases with age with a slight male predominance, and one in 10 persons aged 30 to 62 can expect to have it within 12 years. At any age, cardiac enlargement on roentgenograms is twice as prevalent as electrocardiographic left ventricular hypertrophy, and in only 16 percent of those with x-ray evidence of cardiac enlargement does electrocardiographic left ventricular hypertrophy subsequently develop. Hypertension predisposes and at systolic pressures exceeding 180 mm Hg evidence of electrocardiographic left ventricular hypertrophy develops in 50 percent, with no closer relation to diastolic, than to systolic pressure. In addition to drastic curtailment of life expectancy, electrocardiographic left ventricular hypertrophy is a harbinger of serious cardiovascular disease. Definite electrocardiographic left ventricular hypertrophy is associated with an eightfold increase in cardiovascular mortality and a sixfold increase in coronary mortality. Electrocardiographic left ventricular hypertrophy with repolarization criteria more than doubles the risk of hypertension alone and carries a greater risk of cardiovascular morbidity and mortality than cardiac enlargement. It identifies hypertensive patients with a compromised coronary circulation and myocardial damage. Risk of stroke, cardiac failure, and every clinical manifestation of coronary heart disease is substantially increased. In those with electrocardiographic left ventricular hypertrophy risk of cardiac failure is three times that in those with hypertension alone. Electrocardiographic left ventricular hypertrophy based solely on voltage criteria reflects chiefly the severity and duration of associated hypertension, carrying only half the cardiovascular risk of electrocardiographic left ventricular hypertrophy with repolarization abnormality. The precise pathologic and anatomic meaning of electrocardiographic left ventricular hypertrophy is unclear in view of the modest correlations with anatomic, x-ray, ventriculographic, and electrocardiographic measures of cardiac hypertrophy. The electrocardiographic aberrations are as much a product of myocardial damage as hypertrophy, and their appearance must be regarded as a grave prognostic sign in the course of cardiovascular disease.

A quantitative relationship of electrocardiographic criteria of left ventricular hypertrophy with echocardiographic left ventricular mass: a multivariate approach

The purpose of this study was to evaluate the sensitivity of various electrocardiographic (EKG) criteria of left ventricular hypertrophy (LVH) in relation to echocardiographic left ventricular mass (LVME) and to assess the relative strength of various EKG variables used in the diagnosis of LVH by multivariate analysis. An attempt was also made to determine if a new combination of precordial and T-wave voltage could improve the sensitivity of EKG. In 89 patients, M-mode echocardiograms and standard EKGs were studied. Correlation of Romhilt-Estes point-score system with LVME was r = 0.621, sensitivity and specificity was 57 and 81%, respectively. Other voltage criteria had lower sensitivity. Various combinations of precordial and T-wave voltage were not superior. The quantitative relationship of individual EKG variable, QRS duration, S V1-3, R V4-6, strain T wave, left atrial abnormality, intrinsicoid deflection and axis, with LVM was, r = 0.661, 0.595, 0.429, 0.42, 0.347, and 0.225, respectively. By multivariate analysis, QRS duration, S V1-3, T-wave and R V4-6 voltage had F-value (relative strength) of 27.95, 27.15, 22.02, and 4.03, respectively, other variables were statistically insignificant. In conclusion, the most important EKG variables predictive of LVH are QRS duration, S V1-3, strain T-wave and lateral voltage in decreasing value. Rescoring these variables in accordance to their correlation to LVM may improve EKG sensitivity for the diagnosis of LVH.

Racial differences in cardiac adaptation to essential hypertension determined by echocardiographic indexes

Epidemiologic data point to racial differences in cardiac adaptation to hypertension. In this study, echocardiography and measurement of systemic hemodynamics were performed in 30 black and 30 white patients with untreated essential hypertension. Each black patient was matched with a white patient for age, sex and mean arterial pressure. Wall thickness measurements were similar, but left ventricular mass index was significantly increased in blacks (probability [p] less than 0.05). There was a nonsignificant increase in the number of black patients with posterior wall thickness greater than 1.1 cm. Only in black patients was posterior wall thickness related to systolic (r = 0.45; p = 0.008) and diastolic (r = 0.44; p = 0.0042) pressure and to total peripheral resistance (r = 0.32; p less than 0.046). Thus, although ventricular wall thickness changes are similar in black and white patients, qualitative differences exist in the cardiac adaptive process to systemic hypertension.

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.

The evaluation of left and right ventricular hypertrophy in combined ventricular overload by electrocardiography: relationship with the echocardiographic data

The electrocardiographic and echocardiographic (M-mode) data were analyzed in 29 patients affected by mitral or combined mitral and aortic valve disease and with hemodynamically documented biventricular overload. No electrocardiographic parameter significantly correlated with the left ventricular internal dimension at end diastole (LVIDd), the left posterior wall (LVPW) thickness and the left ventricular mass (LV mass). A significant correlation was observed between the R/S ratio in V1 and V2, the rV1 and either the end-diastolic right ventricular internal dimension (RVIDs) or the pulmonary artery systolic pressure (PASP). The R/S ratio greater than or equal to 1 in V1 was the most sensitive among the conventional electrocardiographic criteria of right ventricular enlargement. Three groups of patients were selected on the basis of RVIDd and LV mass: Group A included nine patients with right ventricular dilatation and normal LV mass; Group B included ten patients without right ventricular dilatation and with increased LV mass; Group C included ten patients without right ventricular dilatation and with normal LV mass. The R/S ratio in V1 was significantly greater in patients in group A than in those in groups B or C. No electrocardiographic parameter was found to be significantly different between groups B and C. When only LV mass was considered (independently from RVId and PASP), no electrocardiographic parameter differentiated patients with LV mass greater than 203 g from those with LV mass less than 203 g. We conclude that in patients with biventricular overload secondary to acquired valvular disease: 1) the electrocardiographic diagnosis of left ventricular enlargement is unreliable; and 2) the R/S ratio in V1 is the most sensitive parameter to predict right ventricular enlargement or severe pulmonary hypertension.

Electrocardiographic measures of left ventricular hypertrophy in children across the distribution of blood pressure: the Muscatine study

We sought to test the effectiveness of the ECG as a measure of increased left ventricular wall mass in children with high blood pressure. One hundred eighty-one children, ages 9-18 years, were selected from the lowest, middle and highest quintile of systolic blood pressure from the Muscatine Study, based upon two biennial school screenings. After correction for age, sex, height, weight and skinfold thickness, children with the highest blood pressure had increased echocardiographic left ventricular wall mass (p less than 0.02). Voltage measurements of maximum R and S waves in the standard and precordial leads were measured by computer. We correlated blood pressure and echocardiographic measurements of the interventricular septum, left ventricular posterior wall and left ventricular wall mass to electrocardiographic combinations used to predict left ventricular hypertrophy in both children and adults. The electrocardiographic correlations ranged from -0.01 to + 0.17. Poor correlations were found between electrocardiographic measures and blood pressure, left ventricular wall thickness or left ventricular wall mass. Skinfold thickness and weight had negative correlations, suggesting a damping effect upon measured voltage. We conclude that the echocardiogram is a more sensitive measurement of increased left ventricular mass than the ECG in children with elevated blood pressure.

Electrocardiographic observations in severe aortic valve stenosis: correlative necropsy study to clinical, hemodynamic,, and ECG variables demonstrating relation of 12-lead QRS amplitude to peak systolic transaortic pressure gradient

Most ECG studies in patients with aortic valve stenosis (AS) have involved living patients in whom the status of the left ventricular (LV) myocardium, epicardial coronary arteries, and mitral valve was not precisely known. We examined the 12-lead ECG recorded within 2 months of death in 50 patients aged 16 to 65 years (mean 48) with peak systolic pressure gradients (PSPG) across the aortic valve ranging from 52 to 180 mm Hg (mean 98) and anatomically normal mitral valves. Excluding four patients with complete left bundle branch block (LBBB), 44 (96%) of the other 46 patients had the usual voltage criteria for LV hypertrophy (LVH). Measurement of the total 12-lead QRS amplitude, which ranged from 144 to 417 mm (10 mm = 1 mV), (mean 257) proved useful for it correlated directly with PSPG across the aortic valve and, when the four LBBB patients were excluded, with the peak LV systolic pressure. The total 12-lead QRS amplitude (mm) was similar in most patients to the LV systolic pressure (mm Hg). Thus, subtraction of the indirect systemic arterial systolic pressure (mm Hg) from the total 12-lead QRS amplitude (mm) provides a reasonable noninvasive prediction of the PSPG across the aortic valve in patients with moderate to severe AS. Additionally, the mean of the total 12-lead QRS amplitude was significantly (p less than 0.05) greater in the 11 younger (less than or equal to 40 years) than in the 39 older patients (278 mm vs 257 mm), in the 14 women than in the 36 men (277 mm vs 240 mm), in the 22 patients with heavier (greater than 600 gm) hearts (274 mm vs 244 mm), in the 34 patients without compared to the 16 with significant coronary arterial narrowing (270 mm vs 238 mm), and in the 22 patients without compared to the 24 with ECG myocardial damage patterns (269 mm vs 236 mm).

Alterations in the electrocardiogram of spontaneously hypertensive rats by chronic antihypertensive therapy with captopril

To determine whether the electrocardiogram (ECG) could detect a reduction in ventricular mass with chronic antihypertensive therapy, ECGs were obtained in two year old female normotensive (NR) and spontaneously hypertensive rats (SHR) following nine months of treatment with captopril or water. The ECG of untreated SHR was considerably different than that of age- and sex-matched NR. The notable differences were the increased voltage, left axis deviation, a delay in the intrinsicoid deflection, and the increased frequency of left atrial abnormalities. Chronic captopril therapy produced a substantial reduction in left ventricular mass in the SHR (NR, 0.63 +/- 0.01; SHR, 1.08 +/- 0.03; captopril SHR, 0.80 +/- 0.04 g). The ECG reflected this regression of left ventricular hypertrophy since the voltage and axis of the treated SHR were no longer different than those of NR. Thus, the ECG may be effective in evaluating the regression of cardiac hypertrophy in response to chronic therapy in experimental hypertension.

Echocardiographic assessment of the left ventricle in juvenile hypertension

We studied with M-mode echocardiography the morphology and function of the left ventricle in a group of 36 juvenile hypertensives with borderline hypertension, whose cuff arm pressure exceeded 150/90 mmHg in at least three separate sessions. The results were compared with those of 23 age-matched normotensives with no evidence of any cardiovascular disease. Left ventricular hypertrophy (i.e. septum and/or posterior wall thicknesses in diastole greater than or equal to 12 mm) was present in 13 subjects of the hypertensive group (36%). Significant increase of interventricular septal thickness together with higher septum/posterior wall ratio and a higher incidence of asymmetric septal hypertrophy were the most characteristic findings in juvenile hypertensives. Of the functional parameters the only observed difference between the two groups was an elevated peak velocity of left ventricular contraction in hypertensives which tended to correlate inversely with the values of septum/posterior wall ratio. Additional comparison of electrocardiographic and echocardiographic detection of left ventricular hypertrophy in young hypertensives revealed a lower sensitivity but a satisfactory specificity of electrocardiography (31 and 87% respectively). The results indicate that besides an elevated systemic arterial pressure, other factors such as increased sympathetic or humoral activity may play a role in the incipient stage of essential hypertension and that isolated septal hypertrophy seems to be an early sign of cardiac involvement.

New aspects on training bradycardia

Rats were trained by treadmill running after chemical sympathectomy with 6-hydroxy-dopamine or during chronic beta receptor blockade. Contrary to untreated trained animals, sympathectomized rats did not get a reduction of the intrinsic heart rate after training despite an increased heart weight. In contrast, no cardiac hypertrophy occurred after training during beta adrenergic blockade but the heart rate during exercise was reduced in these animals. It is concluded that the training-induced bradycardia contains a lowering of the intrinsic heart rate and that this is not dependent on the stimulation of cardiac beta receptors or the magnitude of heart rate increase during exercise. The results also indicate that there is not a causal relationship between the training-induced bradycardia and cardiac hypertrophy. The latter conclusion is supported by an echocardiographic study in humans where no correlation was found between IHR and cardiac dimensions.

Amyloid cardiomyopathy: characterization by a distinctive voltage/mass relation

Fourteen patients with biopsy-proved systemic amyloidosis underwent noninvasive cardiac testing to assess the presence and severity of cardiac amyloidosis. There was a clear tendency for electrocardiographic voltage to be low (sum of S wave in lead V1 plus R wave in lead V5 or V6 [SV1 + RV5 or V6] = 14.6 +/- 4.8 mm; normal range 15 to 35) and echocardiographic muscle cross-sectional area to be increased (11.4 +/- 2.7 cm2/m2; normal range 6 to 10). When the electrocardiographic or the echocardiographic data were examined individually, and especially when they were compared and contrasted with similar measurements from patients with pericardial disease (n = 8) or aortic valve disease (n = 24), it was apparent that the electrocardiogram and the echocardiogram had limited specificity in the diagnosis of amyloidosis. However, when the analysis combined these two techniques, a distinctive pattern emerged. There was an inverse correlation between voltage and muscle cross-sectional area (r = -0.79) in patients with amyloidosis; moreover, marked derangement of the voltage/cross-sectional area relation was associated with clinical symptoms and mortality. In addition, patients with amyloidosis and cardiac symptoms had abnormal left ventricular chamber radius to wall thickness ratios, consistent with infiltration of the myocardium as the primary abnormality in cardiac amyloidosis.