Influence of dietary sodium on the renin–angiotensin–aldosterone system and prevalence of left ventricular hypertrophy by EKG criteria

In a previous study of 543 patients we developed, using echocardiographic left ventricular mass as the reference standard, two new sets of criteria that improve the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). One set of criteria, which is suitable for routine clinical use, detects LVH when the sum of voltage in RaVL + SV3 (Cornell voltage) exceeds 2.8 mV in men and 2.0 mV in women. The second set of criteria, suitable for use in interpretation of the computerized electrocardiogram, uses logistic regression models based on electrocardiographic and demographic variables with independent predictive value for LVH, with separate equations for patients in sinus rhythm and atrial fibrillation. To test these criteria prospectively with use of a different reference standard, antemortem electrocardiograms were compared with left ventricular muscle mass measured at autopsy in 135 patients. Sensitivity of standard Sokolow-Lyon voltage (SLV) criteria (SV1 + RV5 or RV6 greater than 3.5 mV) for LVH was only 22%, but specificity was 100%. The Cornell voltage criteria improved sensitivity to 42%, while maintaining high specificity at 96%. Higher sensitivity (62%) was achieved by use of the new regression criteria, with a specificity of 92%. Overall test accuracy was 60% for SLV criteria, 68% for the Cornell voltage criteria, and 77% for the new regression criteria (p less than .005 vs SLV). We conclude that the Cornell voltage criteria improve the sensitivity of the electrocardiogram for detection of LVH and are easily applicable in clinical practice.(ABSTRACT TRUNCATED AT 250 WORDS)

It is uncertain whether left ventricular hypertrophy (LVH) confers an increased risk for cerebrovascular disease in apparently healthy patients with essential hypertension. A total of 2363 initially untreated hypertensive patients (mean age 51+/-12 years, 47% women) free of previous cardiovascular disease were followed up for up to 14 years (mean 5 years). At entry, all patients underwent diagnostic tests, including ECG, echocardiography, and 24-hour ambulatory blood pressure (BP) monitoring. At entry, the prevalence of LVH was 17.6% by ECG (Perugia score) and 23.7% by echocardiography (LVM >125 g/m(2)). Over the subsequent years, 105 patients experienced a first stroke or transient ischemic attack. The cerebrovascular event rate was higher among patients with LVH at entry, diagnosed by either ECG or echocardiography, than among those without hypertrophy (both P<0.01). After control for the significant influence of age, sex, diabetes, and 24-hour mean ambulatory BP, LVH by ECG conferred an increased risk for cerebrovascular events (relative risk [RR] 1.79; 95% CI 1.17 to 2.76). LVH by echocardiography also conferred a higher risk for cerebrovascular events (RR 1.64; 95% CI 1.07 to 2.68). For each increase in LV mass of 1 SD (29 g/m(2)), there was a significant independent increase in the risk for cerebrovascular events (RR 1.31; 95% CI 1.09 to 1.58). In apparently healthy patients with essential hypertension, LVH diagnosed by ECG or echocardiography confers an excess risk for stroke and transient ischemic attack independently of BP and other individual risk factors.

An increased plasma aldosterone concentration (PAC) with decreased plasma renin activity (PRA) is the abnormal endocrine finding in primary aldosteronism (PA). However, it remains unknown whether this profile is universal when blood samples are obtained in a random manner. We retrospectively evaluated the renin/aldosterone profile in 71 patients with PA due to unilateral adrenal adenoma. Blood samples were obtained randomly at an out-patient clinic and under standardized conditions during hospitalization before surgery. The frequency of PAC above 15 ng/dl, PRA below 0.5 ng angiotensin I/ml x h, and a PAC/PRA ratio greater than 35 was determined. These three variables showed a large intra- and interpatient variation. At least one measurement of PAC, PRA, and PAC/PRA ratio was in the normal range in 39%, 48%, and 31% of patients, respectively. Only 37% of patients always had the characteristic profile associated with PA. The mean values of PAC at the out-patient clinic were slightly, but significantly, lower than those in the hospital. These results clearly demonstrated that the renin/aldosterone profile in PA is not always abnormal due in part to conditions for blood sampling. We conclude that a single normal PAC, PRA, or PAC/PRA ratio does not excluded the diagnosis of PA in a hypertensive patient, but repeated measurements yields one or more abnormal parameters in the vast majority of patients. The PAC/PRA ratio is recommended to use as a screening, but other testing is required to arrive at the correct diagnosis.