On electrocardiographic-autopsy correlations in left ventricular hypertrophy. A simple postmortem index of hypertrophy proposed

Sex Differences in the Relationships Between Electrocardiographic Abnormalities and the Extent of Left Ventricular Hypertrophy by Echocardiography

BACKGROUND

Several criteria have been proposed for the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). However, their diagnostic accuracy is questionable. Furthermore, the diagnostic accuracy of abnormalities in ST-T patterns for LVH is known to be uncertain, especially in women. We examined the relationship between electrocardiographic abnormalities and the extent of LVH.

METHODS

We studied 76 men and 48 women who satisfied electrocardiographic voltage criteria for LVH (RV(5) or RV(6)> or = 2.6 mV, SV(1) + RV(5) or SV(1) + RV(6)> or = 3.5 mV). They were classified into three groups based on ST-T pattern: normal, early strain, and strain. We defined echocardiographic evidence of LVH as an LV wall thickness > or = 12 mm.

RESULTS

LVH was identified by echocardiography in 55.3% of men and in 47.9% of women. In strain and early strain groups, the prevalence of echocardiographic LVH was significantly higher in men than in women (strain group: 100 vs 75%, P < 0.05, early strain group: 81.8 vs 42.1%, P < 0.05), it did not differ significantly between men and women in normal group. In men, QRS voltage values were significantly correlated with echocardiographic indices. In group strain of men, significant good correlations were observed between QRS voltage values and echocardiographic indices. However, in women, there were no significant correlation between QRS voltage values and echocardiographic indices even in strain group.

CONCLUSIONS

The combined criteria of both QRS voltage and ST-T classification could provide a greater accuracy in diagnosing LVH compared to the criteria using QRS voltage alone in men rather than in women.

Correlation between left ventricular wall thickness and QRS voltages in Nigerians

ECG voltage criteria for left ventricular hypertrophy are based on the assumption that a thicker ventricle generates higher QRS voltages. In order to test this assertion, a study of the correlation between echocardiographically determined left ventricular wall thickness and ECG QRS voltages was carried out in 89 subjects, consisting of 35 hypertensives, 20 patients with mitral/aortic valve incompetence, and 34 controls. The results show that there was no statistically significant correlation between QRS voltages and left ventricular wall thickness. This shows that a thicker ventricle does not necessarily generate higher QRS voltages on the electrocardiogram. This may explain the already documented less than satisfactory degree of accuracy of the various ECG voltage criteria for the diagnosis of left ventricular hypertrophy.

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)

The ECG in aortic stenosis. Value of TAVF and QV6

Fifty patients with a mean age of 9.2 years (range, 1.2 to 17.5 years) had cardiac catheterization performed under standardized conditions plus a scalar ECG the previous day. Twenty different direct measurements and 25 derived measurements from the ECG were correlated with the resting peak systolic gradient across the aortic valve. Some of the best correlations were with the measured TAVF, TV6, QV6, and the sum of SV1 + RV6 with r values between .33 and .59. Another group of different patients with isolated aortic stenosis were studied with measurements of the important ECG segments. The r value of this "test" series was similar to that of the original group, so the groups were pooled. The best three-term regression equation involved TAVF, QV6, and the sum (SV1 + RV6), with r = .636. A scoring system was also devised to predict severity. If the TAVF is 0.1 mV or less or the TV6 is 0.3 mV or less or if there is no Q in V6, the gradient may be high. In our series, the ECG estimation of resting peak systolic gradient across the aortic valve in aortic stenosis was enhanced by the inclusion of TAVF and QV6 in the regression equation, as well as SV1 + RV6.

Repolarization abnormalities of left ventricular hypertrophy. Clinical, echocardiographic and hemodynamic correlates

To evaluate the clinical significance of ECG depolarization abnormalities of left ventricular hypertrophy, ECG findings were related to echocardiographic or autopsy left ventricular mass, geometry and function as well as hemodynamic overload, in a heterogeneous population of 161 patients. ST depression and asymmetric T wave inversion were present in 21/107 patients not receiving digitalis (19%) and in 33/54 (61%) receiving digitalis. In patients not receiving digitalis their prevalence increased linearly from 0% (0/31) with LV mass less than or equal to 100 grams to 100% (8/8) with LV mass over 400 grams (p less than 0.001). Patients taking digitalis manifested "strain" commonly despite a normal LV mass (4/14, 28%), but even more frequently with an LV mass over 200 grams (27/40, 68%) (p less than 0.05). In the absence of digitalis, repolarization abnormalities were also significantly associated with a reduced ejection fraction (8/17 or 47% versus 8/83 or 10%; p less than 0.001), increased LV internal diameter (9/18 or 50% versus 12/89 or 13%; p less than 0.01), and systolic blood pressure over 140 mm Hg (9/29 or 31% versus 7/61 or 11%; p less than 0.05). Increased thickness of the LV wall was not significantly associated with LV "strain" (p = 0.1). In this population, LV "strain" alone performed as well as other single or combined ECG criteria in the recognition of LVH (sensitivity 52%, specificity 95%). Thus, in the absence of digitalis, repolarization abnormalities are a highly useful ECG sign of LVH, despite numerous other factors capable of causing indistinguishable abnormalities.

Eelectrocardiographic correlates of ultrasonically increased septal, left ventricular posterior wall and left ventricular internal dimensions

The electrocardiograms (ECG) of 64 subjects who exhibited an echocardiographically demonstrable increase in thickness of the interventricular septum and left ventricular posterior wall (Group 1, 22 patients), isolated left ventricular internal dimension (Group 2,26 patients), combined wall thickness and chamber diameter (Group 3, 2 patients), and septal thickness, (Group 4, asymmetric septal hypertrophy, 14 patients) were reviewed in order to determine sensitivity of ECG criteria for the diagnosis of left ventricular hypertrophy (LVH) proposed in 1949 by Sokolow and Lyon (13), in 1968 by Romhilt and Estes (14), and in 1973 the New York Heart Association (15). Relative sensitivity of the three methods was as follows: Total group, NYHA (77%) greater than Sokolow and Lyon (67%) greater than Romhilt and Estes (58%); Group 1, NYHA (91%) greater than Sokolow and Lyon (73%) greater than Romhilt and Estes (54%); Group 2, NYHA and Sokolow and Lyon (65%) greater than Romhilt and Estes (61%); Group 4, NYHA (79%) greater than Sokolow and Lyon (64%) greater than Romhilt and Estes (57%). We conclude that 1)ECG criteria of the NYHA for the diagnosis of LVH correlate best with an increase of ultrasonically determined septal, left ventricular posterior wall or left ventricular internal dimensions when compared with voltage criteria of Sokolow and Lyon and the point score system of Romhilt and Estes; and 2) isolated increase of left ventricular internal dimension, in the absence of thickened septum or posterior left ventricular wall, frequently results in ECG criteria compatible with the diagnosis of LVH.

Theoretical considerations on the electrocardiogram of ventricular hypertrophy

The electrical effect of ventricular hypertrophy is evaluated with an idealized model. Perfectly symmetrical hypertrophy is expected to enlarge the QRS complex with a certain proportion of the amplitude and duration. If the conduction velocity is unaltered, the QRS area will be increased proportionally to the myocardial mass. 2) Based on the preservation of the ventricular gradient, the secondary T change is expressed as a function of the QRS and G vectors. A theoretically interesting parameter, G/QRS ratio, is defined as a measure of the "ventricular gradient density," which is important for the over-all recovery pattern. This ratio is decreased in ventricular hypertrophy and is closely related to the QRS-T angle. 3) From the viewpoint of the theory, clinical cases with left ventricular hypertrophy are examined. The theory describes the cases with uncompicated hypertension fairly well, although variations from case to case are not small. Underlying assumptions and causes of deviations in actual cases are discussed.

A study of the human heart as a multiple dipole electrical source. II. Diagnosis and quantitation of left ventricular hypertrophy

Using the method previously described, the time-varying strengths of 12 dipoles (representing the depolarization of the ventricles) were calculated from body surface potential measurements. Dipole activities (DA) were obtained for each dipole by time integration of its strength.

Seventy-two patients with angiographically determined left ventricular muscle weight (LVMW) were studied. Fifty-two of 53 patients with increased LVMW had increased DA in the left ventricle and septum (LVSDA). Thus, diagnostic sensitivity was 98%. Sixteen of 19 patients with normal LVMW had normal LVSDA (specificity, 84%). The correlation between LVSDA and LVMW was r 2 =86%, and the standard error of the LVMW estimate ( see ) was±49 g. A subgroup with pure left ventricular hypertrophy (LVH) consisting of 27 patients over 25 years of age with isolated aortic valve disease was studied separately. The correlation between LVSDA and LVMW was r 2 =92% and see was ±31 g. After correcting for the uncertainty in the angiographic LVMW measurements, the see for the complete group was reduced to ±37 g.

The diagnosis and quantitation of LVH with this method was considerably better than with conventional electrocardiography or vectorcardiography.

A critical appraisal of the electrocardiographic criteria for the diagnosis of left ventricular hypertrophy

Thirty-three different electrocardiographic criteria for left ventricular hypertrophy have been evaluated in 360 autopsied hearts utilizing a chamber dissection technic. One hundred and sixty hearts had left ventricular hypertrophy, and 200 hearts did not (146 of these were normal, and 54 had right ventricular hypertrophy).

The following five electrocardiographic criteria had a sensitivity of 56% but 10.5% to 14.5% false positives: S v1 or S v2 +R v5 ≥35 mm, S v1 +R v5 or R v6 >30 mm, S v1 , or S v2 + R v5 or R v6 >35 mm, S v2 +R v4 or R v5 >35 mm, R+S>40 mm. A point-score system employing a combination of criteria had a sensitivity of 54%, but lowered the false positives to 3%. The best limb-lead criterion was R aV L >7.5 which had a sensitivity of 22.5% with only 3.5% false positives. The following criteria had no false positives, but the highest sensitivity was 19%: S v1 ≥24 mm, R aV L >11 mm, R I +S III >25 mm, R I >13 mm, R aV L >12 mm, R I >15 mm, R aV L >13 mm, and S aV R >14 mm. Overall the precordial lead criteria were considerably more sensitive but less specific than the limb lead criteria. Since only six of the 200 hearts without left ventricular hypertrophy were in persons less than 30 years of age, this is not the major explanation for the high incidence of false positives in the more sensitive voltage criteria. The problems of using voltage criteria alone and the need for new criteria and approaches to the electrocardiographic diagnosis of left ventricular hypertrophy are discussed.