No abstract

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: Svi or Sv2 +RV5 '-35 mm, SV +±Rv5 or RV6 > 30 mm, Sv, or SV2 + Rv5 or RV6 > 35 mm, SV2 + RV4 or Rv5 > 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 aVL > 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%: Svl, 24 mm, R aVL> 11 mm, RI + SI,, > 25 mm, RI > 13 mm, R aVL > 12 mm, RI > 15 mm, R aVL > 13 mm, and S aVR > 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.

A positive exercise electrocardiogram (ECG) has been proved to predict cardiovascular events in asymptomatic normolipidemic men. To study whether it is also predictive for hypercholesterolemic men, data from 3,806 asymptomatic hypercholesterolemic men in the Lipid Research Clinics Coronary Primary Prevention Trial were analyzed. All the men had performed a submaximal treadmill exercise test at baseline, before they were assigned to the cholestyramine or placebo treatment group. Because of missing or inconclusive data, 31 men were excluded from the analyses. A test was positive if the ST segment was displaced by greater than or equal to 1 mm (visual code) or there was greater than or equal to 10 microV-s change in the ST integral (computer code), or both. The prevalence of a positive test was 8.3%. During the 7 to 10 year (mean 7.4) follow-up period, the mortality rate from coronary heart disease was 6.7% (21 of 315) in men with a positive test and 1.3% (46 of 3,460) in men with a negative test (placebo and cholestyramine groups combined). The age-adjusted rate ratio for a positive test, compared with a negative test, was 6.7 in the placebo group and 4.8 in the cholestyramine group. With use of Cox's proportional hazards models, it was found that the risk of death from coronary heart disease associated with a positive test was 5.7 times higher in the placebo group and 4.9 times higher in the cholestyramine group after adjustment for age, smoking history, systolic blood pressure, high density lipoprotein cholesterol and low density lipoprotein cholesterol. A positive test was not significantly associated with nonfatal myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)