The pathophysiological basis of carotid baroreceptor stimulation for the treatment of resistant hypertension.

The prevalence of resistant hypertension and existing limitations in antihypertensive drug therapy renders the interventional management of hypertension an attractive alternative. Carotid baroreceptors have been traditionally thought to be implicated only in short-term blood pressure regulation; however recent evidence suggests that the baroreceptors might play an important role even in the long-term blood pressure regulation. Electrical baroreflex stimulation appears safe and effective and might represent a useful adjunct to medical therapy in patients with resistant hypertension. This review endeavors to summarize the complex pathophysiology of blood pressure regulation, to describe the baroreflex circuit, its anatomy and physiology, to present previous data refuting a role for the baroreceptors in the long-term control of blood pressure and recent animal and human data suggesting an effective role of carotid baroreceptor activation in long-lasting blood pressure reduction. In this paper we attempt to critically evaluate existing information in this area and provide the scientific basis for carotid baroreceptor stimulation in the management of resistant hypertension.

[Prognostic value of QTc interval dispersion changes during exercise testing in hypertensive men].

INTRODUCTION: The prognostic significance of QTc dispersion changes during exercise testing (ET) in patients with left ventricular hypertrophy is not clear. OBJECTIVE: The aim was to study the dynamics of QTc interval dispersion (QTcd) in patients (pts) with left ventricular hypertrophy (LVH) during the exercise testing and its prognostic significance. METHOD: In the study we included 55 men (aged 53 years) with hypertensive left ventricular hypertrophy and a negative ET (LVH group), 20 men (aged 58 years) with a positive ET and 20 healthy men (aged 55 years). There was no statistically significant difference in the left ventricular mass index (LVMI) between LVH group and ILVH group (160.9+/-14.9 g/m2 and 152.8+/-22.7 g/m2). The first ECG was done before the ET and the second one was done during the first minute of recovery, with calculation of QTc dispersion. The patients were followed during five years for new cardiovascular events. RESULTS: During the ET, the QTcd significantly increased in LVH group (56.8+/-18.0 - 76.7+/-22.6 ms; p<0.001). A statistically significant correlation was found between the amount of ST segment depression at the end of ETand QTc dispersion at the beginning and at the end of ET (r=0.673 and r=0.698; p<0.01). The QTc dispersion was increased in 35 (63.6%) patients and decreased in 20 (36.4%) patients during the ET. Three patients (5.4%) in the first group had adverse cardiovascular events during the five-year follow-up. A multiple stepwise regression model was formed by including age, LVMI, QTc interval, QTc dispersion and change of QTc dispersion during the ET. There was no prognostic significance of QTc interval and QTc dispersion during five-year follow-up in regard to adverse cardiovascular events, but prognostic value was found for LVMI (coefficient beta=0.480; p<0.001). CONCLUSION: The increase of QTc interval dispersion is common in men with positive ET for myocardial ischemia and there is a correlation between QTc dispersion and amount of ST segment depression. The increase of QTc interval dispersion during negative ET in patients with left ventricular hypertrophy has no significant predictive value for adverse cardiovascular events, as shown in our five-year follow-up study, but it requires confirmation by investigation of larger groups of patients.

[Effect of fosinopril on progression of the asymptomatic carotid atherosclerosis and left ventricular hypertrophy in hypertensive patients].

INTRODUCTION: The cardiovascular changes (vascular structure changes, hypertrophy of the left ventricle) contribute to both the increased cardiovascular morbidity and the mortality of essential hypertension. Therefore, modern treatment strategies should not only target blood pressure (BP) reduction but also normalize cardiovascular structure and function. OBJECTIVE: Aim of the study was to determine the effect of the ACE inhibitor Fosinopril on the intima-media thickness of the common carotid artery and on the left ventricle mass after 9-month treatment of hypertensive patients. METHOD: The study included 40 patients with the arterial hypertension and the left ventricle hypertrophy verified by echocardiography. The patients were randomized on A) ACE-inhibitor--Fosinopril and B) without ACE inhibitor--atenolol, and they were followed up 9 months. The groups were not different by age, sex, and metabolic status. Color Duplex ultrasonography of the carotid arteries was performed by Acuson Sequia C236 with high-frequency linear probe of 8 MHz. The intima-media thickness of the common carotids on the left and the right was measured in diastole at 1.5 cm from the highest point of bifurcation under maximal magnification. Using the same device, the left ventricle mass and other parameters of the left ventricle were determined in M-mode and by means of 2D image. RESULTS: After 9 months, BP in both groups was reduced in similar range (group A: systolic BP from 158 to 137 mmHg, and diastolic BP from 94 to 85 mmHg, and group B: systolic BP from 164 to 137 mmHg, and diastolic BP from 87 to 84 mmHg). The thickness of the intimomedial complex in patients using Fosinopril was decreased by 0.0278 +/- 0.03 mm, while in the group of patients that did not use the ACE-inhibitor, it was increased by 0.078 +/- 0.13 mm. The left ventricle mass in patients using Fosinopril was decreased by 5 grams (312 +/- 72 g vs. 307 +/- 77 g), while in group B patients, it was increased by 15 grams (323 +/- 79 g vs. 328 +/- 58 g. Diastolic function expressed through relation E/A was improved minimally in the group A, while it worsened by 0.1 in the group B. After 9 months, serious cardiovascular events were recorded (one infarction of myocardium and one hospitalization due to the unstable angina pectoris) in two patients of the group A, while four patients of the group B had serious CV events (1 cerebrovascular stroke and 3 hospitalizations due to unstable angina pectoris). CONCLUSION: The results of our study showed that the application of Fosinopril in patients with the arterial hypertension and the left ventricle hypertrophy could efficiently block further progression of the intima-medial thickness of the common carotid artery, reduce the left ventricle mass, and improve diastolic function of the left ventricle.