PubMed · 1570962
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V F Rempusheski. 1992. Using reliability and validity in clinical practice.. https://doi.org/10.1016/s0897-1897(05)80087-4
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BACKGROUND: It is uncertain whether left ventricular hypertrophy (LVH) confers an increased risk for cerebrovascular disease in apparently healthy patients with essential hypertension. METHODS AND RESULTS: 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). CONCLUSIONS: 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.
BACKGROUND: Early diastolic intraventricular pressure gradients (IVPGs) have been proposed to relate to left ventricular (LV) elastic recoil and early ventricular "suction." Animal studies have demonstrated relationships between IVPGs and systolic and diastolic indices during acute ischemia. However, data on the effects of improvements in LV function in humans and the relationship to IVPGs are lacking. METHODS AND RESULTS: Eight patients undergoing CABG and/or infarct exclusion surgery had a triple-sensor high-fidelity catheter placed across the mitral valve intraoperatively for simultaneous recording of left atrial (LA), basal LV, and apical LV pressures. Hemodynamic data obtained before bypass were compared with those with similar LA pressures and heart rates obtained after bypass. From each LV waveform, the time constant of LV relaxation (tau), +dP/dt(max), and -dP/dt(max) were determined. Transesophageal echocardiography was used to determined end-diastolic (EDV) and end-systolic (ESV) volumes and ejection fractions (EF). At similar LA pressures and heart rates, IVPG increased after bypass (before bypass 1.64+/-0.79 mm Hg; after bypass 2.67+/-1.25 mm Hg; P<0.01). Significant improvements were observed in ESV, as well as in apical and basal +dP/dt(max), -dP/dt(max), and tau (each P<0.05). Overall, IVPGs correlated inversely with both ESV (IVPG=-0.027[ESV]+3.46, r=-0.64) and EDV (IVPG=-0.027[EDV]+4.30, r=-0.70). Improvements in IVPGs correlated with improvements in apical tau (Deltatau =5.93[DeltaIVPG]+4.76, r=0.91) and basal tau (Deltatau =2.41[DeltaIVPG]+5.13, r=-0.67). Relative changes in IVPGs correlated with changes in ESV (DeltaESV=-0.97[%DeltaIVPG]+23.34, r=-0.79), EDV (DeltaEDV=-1.16[%DeltaIVPG]+34.92, r=-0.84), and EF (DeltaEF=0.38[%DeltaIVPG]-8.39, r=0.85). CONCLUSIONS: Improvements in LV function also increase IVPGs. These changes in IVPGs, suggestive of increases in LV suction and elastic recoil, correlate directly with improvements in LV relaxation and ESV.
The kidney, by regulating the volume of fluid in the body, plays a key role in regulating blood pressure (BP). The kidney uses primarily sodium and, to a lesser extent, urea to maintain the appropriate volume of fluid. Genetic variation in proteins that determine sodium reabsorption and excretion is known to significantly influence BP. However, the influence of genetic variation in urea transporters on BP has not been examined. We determined therefore whether nucleotide variation in the kidney-specific human urea transporter, HUT2, is associated with variation in BP. After determining the genomic structure of the coding sequence, seven single nucleotide polymorphisms (SNPs) were identified. Two of the SNPs result in Val/Ile and Ala/Thr amino acid substitutions at positions 227 and 357 in the HUT2 open reading frame, respectively. Another SNP is silent and four others are in introns or the 3' untranslated region. Over 1000 hypertensive and low-normotensive individuals of Chinese origin were typed for five of these SNPs using a high-throughput genotyping method. The Ile227 and Ala357 alleles were associated with low diastolic BP in men but not women, with odds ratios 2.1 [95% confidence interval (CI) 1.5-2.7, P < 0.001] and 1.5 (95% CI 1.2-1.8, P < 0.001), respectively. There was a similar trend for systolic BP, and odds ratios for the Ile227 and Ala357 alleles were 1.7 (95% CI 1.2-2.3, P = 0.002) and 1.3 (95% CI 1.1-1.6, P = 0.007), respectively, in men.