Inappropriate left ventricular mass in normotensive and hypertensive patients.

T concept of “inappropriate” left ventricular (LV) mass has been used to identify observed LV mass values exceeding levels predicted by its major physiologic determinants.1 Hypertensive persons with inappropriate LV mass were more obese and exhibited a high cardiovascular risk phenotype.1 Whether inappropriate LV mass is also present and associated with similar features in normotensive subjects is unknown. Accordingly, this study compares inappropriate LV mass in normotensive persons and hypertensive patients. • • • We studied 210 clinically normal subjects (mean age 35 6 11 years) and 305 hypertensive adults (mean age 48 6 10 years). Hypertension was defined according to the Joint National Committee VI2 and by standard methods3 at $3 visits per month, or by the presence of current active antihypertensive therapy. After giving their informed consent, hypertensive patients receiving treatment (70%) discontinued therapy for at least 2 weeks before echocardiography. Normal blood pressure was defined as #130/85 mm Hg at 3 successive visits.4 Exclusion criteria were ischemic heart disease (medical history, clinical examination, standard electrocardiography, and/or presence of wall motion abnormality by 2-dimensional echocardiography), diabetes mellitus (by history and fasting blood glucose $126 mg/dl), valvular heart disease (by clinical examination and Doppler echocardiography), secondary hypertension, dilated or hypertrophic cardiomyopathy, left bundle branch block, thyroid disease, treatment with oral contraceptives, or participation in professional physical training programs. Two-dimensionally guided M-mode echocardiograms were recorded by expert sonographers using commercially available equipment (ESAOTE Biomedica, Florence, Italy) with 2.5to 3.5-MHz annulararray transducers. Echocardiograms were read according to the American Society of Echocardiography recommendations.4,5 An anatomically validated formula was used to calculate LV mass6 using reliable measurements.7 Relative wall thickness was calculated as posterior wall thickness/LV end-diastolic radius. LV end-diastolic and end-systolic volumes were calculated using Teichholz’ cube formula,8 and used to derive stroke volume. LV mass was indexed for body height (m) to account for obesity. LV hypertrophy was defined as LV mass index $51 g/m, a prognostically validated partition value.9 LV diastolic dimension was normalized for the first power of body height.10 LV shortening at endocardial and midwall levels, circumferential end-systolic stress, and stress-corrected midwall shortening were computed by standard methods.11 Myocardial dysfunction was defined by stresscorrected midwall fractional shortening ,89.2% (the fifth percentile of the reference normal distribution).12 Observed LV mass in each subject was divided for the value predicted by an equation including gender, height and stroke work (systolic blood pressure 3 stroke volume 3 0.0144),1,13 and expressed as a percentage (percent-predicted LV mass). The equation was developed in a separate reference population of 393 normal-weight, normotensive adults, aged 18 to 85 years13 (90% confidence interval 73% to 128%). In the present study, percent predicted LV mass .128% was defined as “inappropriate LV mass,” and values between 73% and 128% were defined as “appropriate” LV mass. Subjects with low percent-predicted LV mass (#73%) were excluded (3 normotensive and 2 hypertensive subjects). Data were analyzed using commercially available statistical packages. Variables are presented as mean 6 SD. Comparison among categorical variables was performed by chi-square statistics with Monte Carlo correction for the exact p value. Student’s or Welch’s t test was used for crude comparisons. Analysis of covariance was used to adjust for age and body mass index (BMI). Pearson’s correlation, partial correlation, and multiple regression analyses were used to evaluate correlates of the percent-predicted LV mass. Logistic regression analysis was used to evaluate independent correlates of inappropriate LV mass. A 2-tailed a #0.05 was used to reject the null hypothesis. Hypertensive subjects were older, more frequently men, and had higher BMI, but similar body height and higher absolute and indexed LV mass than normotensives. (Table 1) Stroke volume was higher in hypertensives independent of age and BMI. Inappropriate LV mass was seen more often among hypertensives than normotensives, a difference that disappeared after adjusting for age and BMI. Normotensive persons (Table 2) with inappropriate LV mass tended to be older and had higher BMI. The From Inter-University Center for Study and Research on Obesity, Department of Clinical and Experimental Medicine, “Federico II” University Hospital, School of Medicine, Naples, Italy; and Division of Cardiology, The New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York. This report was supported in part by grant MURST 1998, Ministry of University and Research, Rome, Italy. Dr. de Simone’s address is: Dipartimento di Medicina Clinica e Sperimentale, Policlinico dell’Universita Federico II, via S. Pansini 5, 80131 Naples, Italy. E-mail: simogi@unina.it. Manuscript received June 14, 2000; revised manuscript received and accepted August 14, 2000.